Hindawi Publishing CorporationInternational Journal of Carbohydrate ChemistryVolume 2013 Article ID 463907 15 pageshttpdxdoiorg1011552013463907

Research ArticleCertain Rheological Aspects of Functionalized Guar Gum

Meenu Kapoor1 Dhriti Khandal1 Ruchi Gupta1 Pinklesh Arora1 Geetha Seshadri1

Saroj Aggarwal1 and Rakesh Kumar Khandal2

1 Shriram Institute of Technology Gautum Buddh Technical University IET Campus Sitapur Road Lucknow 226 021 India2 Gautum Buddh Technical University IET Campus Sitapur Road Lucknow 226 021 India

Correspondence should be addressed to Rakesh Kumar Khandal drrkkhandalgmailcom

Received 16 January 2013 Accepted 6 March 2013

Academic Editor R J Linhardt

Copyright copy 2013 Meenu Kapoor et alThis is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Guar gum and its derivatives are highly important industrial hydrocolloids as they find applications in various industrial sectorsGuar is a polymer of high molecular weight and its aqueous solutions exhibit unique rheological properties which has led toits wide acceptance by the industry In certain industrial applications low molecular weight guar and its derivatives are neededand conventionally chemical depolymerisation of guar is carried out for this purpose Radiation processing is a novel and greentechnology for carrying out depolymerization and can be an ideal substitute for chemical depolymerisation technique In order tostudy the effect of radiation on guar derivatives three types of derivatives have been taken in the present study carboxymethylhydroxyethyl and methyl guar The effect of 1ndash50KGy radiation dose on the rheological behavior of these derivatives has beenstudied and the results have been described in the present paper The effect on storage and loss modulus with respect to frequencyand effect on viscosity with respect to shear rate have been discussed in detail

1 Introduction

Guar gum is a polygalactomannan found in the endospermof the seeds of the plant Cyamopsis tetragonolobus It is ahydrophilic heteropolysaccharide of mannose and galactosemonomer units where the mannose forms the main linearchain of the polymer and the galactose forms the pendantbranches The mannose units are linked together by 120573-14 glycosidic bonds and the galactose units are linked tomannose through 120572-16 glycosidic bonds [1] The mannoseto galactose ratio of guar gum has been reported to beapproximately 2 1 Thus every second mannose unit bearsa branch of galactose unit

Guar gum is a high molecular weight polysaccharide(generallymore than 2million gmol) that can form extensiveintermolecular H-bonding resulting in high solvation andthereby increased viscosity [2] These attributes of guar gumfind it varied applications in the industry [3ndash11] Guar gumfunctions as a thickener emulsion stabilizer gelling agentfilm former or texture modifier

Despite the unique rheological behavior there are certainlimitations of guar gumwhich need to be overcome to ensure

its effective use The excessive hydrophilicity of guar gumalong with the high molecular mass prevents complete orhomogeneous solvation or hydration of the polymer Theresulting two-phase aqueous solution has certain regionsshowing increased viscosity and other regions showing thesolid phase of undissolved guar gum The other drawback ofguar gum is the low thermal and shear stability as observedin other natural polysaccharides which reduces the durabilityand imposes temperature and heat conditions for its effectiveperformance

In order to overcome the disadvantages of guar gum itsmodification is carried out mainly by the functionalizationof the hydroxyl groups present on guar backbone Variousfunctionalities can be introduced on guar by carrying outetherification of guar with different reagents as shown inTable 1

Another aspect of guar gum is its high molecular weightwhich may not be always desirable In several industrialapplications low molecular weight guar is used which isconventionally produced by degradation of native guar byfollowing chemical route A novel method for degradation ofguar can be radiation processing technology A comparison

2 International Journal of Carbohydrate Chemistry

Table 1 Etherification reactions of guar

S no Reaction Reagent1 Carboxymethylation Monochloroacetic acid2 Cationization Quaternary ammonium salts3 Methylation Methyl chloride4 Hydroxyethylpropylation Ethylenepropylene oxide

of the methodology followed for the degradation of guar byconventional route and by radiation processing is given inFigure 1

The most important property of guar gum is its uniquerheology which makes it an invaluable industrial productThe rheological behavior of guar has been a subject forstudy for scientists world over Venkataiah and Mahadevan[12] investigated the aqueous solutions of guar gum as wellas its nonionic hydroxypropyl and anionic carboxymethylderivatives for their flow properties in the range of lowto moderately high shear rates and observed the transitionfrom Newtonian fluid to pseudoplastic fluid Wientjes et al[13] studied the linear viscoelastic behavior of guar gumsolutions as a function of frequency temperature polymerconcentration and molecular weight and revealed the impor-tance of different relaxation mechanisms Aubry and Moan[14] focused on the rheological effect of hydrophobicallymodified hydroxypropyl guar gumanddemonstrated that thelinear andnonlinear rheological behaviors of such associatingsystems were dependent on the nature concentration anddistribution along the chain of hydrophobic junctions Zhanget al [15] have studied the semidilute solutions of hydrox-ypropyl guar gum (HPGG) with respect to their viscositychanges under variousHPGG concentrations added salts andtemperatures could be well described by the Cross viscositymodel

In the present paper the effect of irradiation on guar andits carboxymethyl hydroxypropyl and methyl derivativeshas been studied in respect to the change in the rheologicalbehavior

2 Materials and Methods

Themethodology followed for studying the effect of radiationprocessing on guar and its derivatives involved the followingsteps

21 Guar Gum and Derivatives The sample of guar gum wasprocured from a local supplier The carboxymethyl hydrox-ypropyl and methyl derivatives of DSMS 01 and 02were synthesized by well-established techniques as publishedpreviously [16 17]

22 Irradiation of Samples Guar gum and its derivatives(hydroxypropyl carboxymethyl and methyl of DS 01 and02) were sealed in plastic bottles which were packed in acardboard boxThe box was then irradiated at different doses(1 25 5 10 20 and 50KGy) at the Co-60 gamma irradiationfacility available within the institute All specimens were

Chemical

Low molecular weight guar

Low molecular weight guar

Radiation processing

Guar powdersplit Guar powdersplit

Slurrysoaking

Depolymerising agent

Temperature

Washing

Drying

Grinding

Sieving

Irradiation at desired dose

Figure 1 Comparison of the processing steps involved in depoly-merisation of guar by Chemical Synthesis Route

finely grounded to pass 200 120583m sieves before subjecting themto irradiation The irradiation was carried out on 200 g batchsize in case of all the specimens at each dose

23 Preparation of Solutions The moisture content of everysample was determined by heating the sample in an aircirculating oven till constant weight Aqueous solutions of 1were prepared after applying the moisture correction factorThe desired amount of sample was weighed and dissolved inrequired amount of water using either an overheadmotorizedstirrer or a magnetic stirrer Three hours of stirring wasgiven to each sample before allowing it to stand overnightat ambient conditions The following day the solution wasconsidered ready for the rheological evaluation

24 Rheological Evaluation The rheology study of 1 aque-ous solutions of guar gum and its hydroxypropyl (MS =01 and 02) carboxymethyl (DS = 01 and 02) and methylderivatives (DS = 01 and 02) was carried out on theRheometer (MARSThermo Fisher) at 25∘C temperatureThelinear viscoelastic range was determined from the amplitudesweep by varying the shear stress at a constant frequency of1Hz Next the frequency sweep was carried out at a shearstress (or amplitude value) lying in the linear viscoelasticregion The effect of shear rate on the viscosity of sampleswas also determined by studying the change in viscosity withvarying shear rate from 1 to 30 rpm

3 Results and Discussion

Guar gum and its derivatives of carboxymethyl hydrox-ypropyl and methyl derivatives with 01 and 02DSMS werestudied by rheology before and after gamma irradiation tounderstand the effect of radiation on the viscosity of thesample The effect of ionizing radiation on polysaccharides is

International Journal of Carbohydrate Chemistry 3

Table 2 Crossover frequencies of guar and its various derivatives

Radiation dose (KGy) Crossover frequency (Hz)CMG (DS = 01) CMG (DS = 02) HEG (MS = 01) HEG (MS = 02) MG (DS = 01) MG (DS = 02)

0 Nil 0299 0161 0134 Nil 01671 2101 6539 2717 05298 Nil 051425 6755 894 6776 4234 4443 49955 1691 2223 1840 986 1224 105810 1053 9191 1460 1269 1218 153920 3857 3275 2717 8335 6755 695950 178 1282 1588 1862 Nil 2591

known to cause degradationwith a consequent loss in the vis-cosity The derivatives of polysaccharides like carboxymethylderivative of cellulose are however known to result information of gel when their aqueous solutions are subjectedto an appropriate radiation dose The competition betweenradiation-induced chain scission and chain crosslinkinginfluences the resulting viscosity or formation of gel by thepolysaccharide after irradiation Thus polysaccharides canbe modified using ionizing radiation provided there is apossibility of reducing chain scission andor favoring chaincrosslinking during irradiation

The following sections discuss the rheology studies foreach sample separately

31 Study on Change in Storage Modulus and Loss ModulusThe plot obtained from the frequency sweep study gives theeffect of change in frequency on the storage (elastic 1198661015840)and the loss (viscous 11986610158401015840) moduli The effect of radiationon the storage modulus and loss modulus was studied andthe change in crossover frequencies of irradiated sampleshas been given in Table 2 The effect of radiation on therheological behavior of each of the derivatives has beendescribed separately

311 Carboxymethyl Guar The carboxymethyl guar (CMG)samples were irradiated and their viscoelastic behavior wasstudied as described in the previous section The change instorage (elastic 1198661015840) and the loss (viscous 11986610158401015840) moduli wasstudied over a range of frequency 1 to 30Hz and the resultsobtained have been shown in Figures 2 and 3 Followinginferences can be drawn from the data presented in Figures 2and 3 and Table 2

(i) As evident from the Figures 2 and 3 in case ofCMG of DS 01 there is no crossover of the 1198661015840 and11986610158401015840 whereas in case of CMG of DS 02 crossoverfrequency is 029Hz This shows that the elasticnature predominates throughout in case of CMGof DS 01 whereas elasticity dominates only afterfrequency of 029Hz in case of CMG of DS 02

(ii) As shown in Table 2 the crossover frequency in-creases as the radiation dose increases up to 5KGyand the value is higher in case of CMGofDS 02 thanCMG of DS 01 This shows that the elastic nature

is more dominating for CMG of DS 01 than CMGof DS 02 The explanation for this can be found inthe fact that initially the chains in guar gum form H-bonding linkages in themselves leading to solid-likebehavior But as the carboxymethyl (-CH

2COONa)

substitution is carried out on the guar chain thedistance between the chains increases leading toopening up of the chains as the H-bonding linkagesget decreased Thus solid-like behavior or elasticitydecreases on increasing the substitution

(iii) This can also be explained by saying that duringfrequency sweep study the chains get pushed towardseach other and form aggregates The carboxymethylgroup being an ionic group will cause repulsionamongst the chains due to repulsion between like-charged moieties Thus a greater frequency will beneeded to push the chains together in case of a samplehaving higher ionic substituents that is CMG ofDS = 02 to form aggregates leading to solid-like orelastic behavior

(iv) Beyond 5KGy radiation dose the crossover fre-quency is very close for both CMGs because themolecular chain breaks on irradiation leading toformation of small oligomeric chains of similar sizein both CMGs of DS of 01 and 02 Thus the effectof frequency is felt equally by both these samples

(v) The values of 1198661015840 and 11986610158401015840 are seen to decrease withthe increase in radiation dose which indicates chainscissioning

Another aspect is the effect of radiation on the car-boxymethyl guar As seen from Table 2 the crossover fre-quency increases with the increase in radiation dose up to5KGy and then it starts to decrease Irradiation leads tobreaking up of the chain leading to reduction in molecularweight Up to 5KGy radiation dose chain scissioning istaking place leading to decrease in molecular weight and lessinteraction of the smaller chains formed As the interactionbetween the chains decreases viscous behavior predominatesor in other words elasticity or the solid-like behavior getsdecreased Now beyond 5KGy radiation dose it is observedthat the crossover frequency gets decreased which maysignify formation of aggregates between the chains leading tomore solid-like behavior at lower frequencies

4 International Journal of Carbohydrate Chemistry

102

101

01 10 100 1000

119891 (Hz)

119866998400119866998400998400

(Pa)

(a) CMG DS = 01 0 KGy

102

101

100

01 10 100 1000

119891 (Hz)

119866998400119866998400998400

(Pa)

(b) CMG DS = 01 1 KGy

01 10 100 1000

102

101

100

119891 (Hz)

119866998400119866998400998400

(Pa)

(c) CMG DS = 01 25 KGy

01 10 100 1000

102

101

100

10minus1

119891 (Hz)119866998400119866998400998400

(Pa)

(d) CMG DS = 01 5 KGy

01 10 100 1000

102

101

100

10minus1

10minus2

119891 (Hz)

119866998400119866998400998400

(Pa)

(e) CMG DS = 01 10 KGy

01 10 100 1000

101

100

10minus1

10minus2

10minus3

10minus4

119891 (Hz)

119866998400119866998400998400

(Pa)

(f) CMG DS = 01 20 KGy

101

100

10minus1

10minus2

10minus3

10minus4

01 10 100 1000

119891 (Hz)

119866998400998400 = 119891 (119891)

119866998400 = 119891 (119891)

119866998400119866998400998400

(Pa)

(g) CMG DS = 01 50 KGy

Figure 2 Effect of radiation processing on the viscoelastic behavior of carboxymethylated guar (CMG) of degree of substitution (DS) = 01(a) unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy(g) irradiated at 50KGy

International Journal of Carbohydrate Chemistry 5

102

101

100

01 10 100 1000

119891 (Hz)

119866998400119866998400998400

(Pa)

(a) CMG DS = 02 0 KGy

102

101

100

10minus1

01 10 100 1000

119891 (Hz)

119866998400119866998400998400

(Pa)

(b) CMG DS = 02 1 KGy

01 10 100 1000

102

101

100

10minus1

119891 (Hz)

119866998400119866998400998400

(Pa)

(c) CMG DS = 02 25 KGy

01 10 100 1000

101

100

10minus1

119891 (Hz)

119866998400119866998400998400

(Pa)

(d) CMG DS = 02 5 KGy

102

101

100

10minus2

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) CMG DS = 02 10 KGy

101

100

10minus1

10minus2

10minus3

10minus4

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) CMG DS = 02 20 KGy

01 10 100 1000

101

102

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (119891)119866998400 = 119891 (119891)

(g) CMG DS = 02 50 KGy

Figure 3 Effect of radiation processing on the viscoelastic behavior of carboxymethylated guar (CMG) of degree of substitution (DS) = 02(a) unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy(g) irradiated at 50KGy

312 Hydroxyethyl Guar The hydroxyethyl guar (HEG)samples were irradiated and their viscoelastic behavior wasstudied as described in the previous section The change instorage (elastic 1198661015840) and the loss (viscous 11986610158401015840) moduli wasstudied over a range of frequency 1 to 30Hz and the results

obtained have been shown in Figures 4 and 5 On the basis ofthe results obtained the following observations were made

(i) As evident from Figures 4 and 5 in case of HEGof MS 02 the crossover frequency of the 1198661015840 and

6 International Journal of Carbohydrate Chemistry

102

101

01 10 100

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) HEGMS = 01 0 KGy

01 10 100

102

101

100

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) HEGMS = 01 1 KGy

102

101

100

10minus1

01 10 100

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) HEGMS = 01 25 KGy

01 10 100

101

100

10minus1

10minus2

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) HEGMS = 01 5 KGy

01 10 100

102

101

100

10minus1

10minus2

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) HEGMS = 01 10 KGy

01 10 100

102

101

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) HEGMS = 01 20 KGy

01 10 100

101

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (119891)119866998400 = 119891 (119891)

(g) HEGMS = 01 50 KGy

Figure 4 Effect of radiation processing on the viscoelastic behavior of hydroxyethylated guar (HEG) of molar substitution (MS) = 01 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

International Journal of Carbohydrate Chemistry 7

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) HEGMS = 02 0 KGy

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) HEGMS = 02 1 KGy

102

101

100

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) HEGMS = 02 25 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) HEGMS = 02 5 KGy

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) HEGMS = 02 10 KGy

01 10 100 1000

101

100

10minus1

10minus2

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) HEGMS = 02 20 KGy

01 10 100 1000

101

102

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (119891)119866998400 = 119891 (119891)

(g) HEGMS = 02 50 KGy

Figure 5 Effect of radiation processing on viscoelastic properties of hydroxyethyl guar (HEG) havingmolar substitution 02 (a) unirradiated(b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g) irradiated at50KGy

8 International Journal of Carbohydrate Chemistry

11986610158401015840 is lesser than that of HEG of MS 01 till 20 KGyradiation dose This means that elastic nature pre-dominates in case of HEG of MS 02 which may bedue to the presence of greater number of ndash(CH

2ndashO)nndash

H groups leading to increase in H-bonding and thusmore solid-like behavior

(ii) On comparing the crossover frequencies of HEG ofMS 01 after irradiation it can be seen from thedata that crossover frequency increases till 5 KGydoseand then it decreases whereas in case of HEG ofMS 02 the crossover frequency increases till 10 KGydose and then it decreases This can be explainedon the basis of interactions taking place between themacromolecular chains in these two HEGs In case ofHEG of MS 01 intermolecular interactions are lessas compared to HEG of MS 02 and thus less elasticnature

(iii) Also in case of HEG of MS 02 as the substitu-tion increases the coiling of macromolecular chaindecreases due to steric hindrance thereby causingmore intramolecular interactions than intermolec-ular interactions Less coiling of the chain causesmore exposure to irradiation and thus greater chainscissioning and more viscous response of the macro-molecule

(iv) As the radiation dose increases there is more chainscissioning leading to formation of oligomeric chainsThese chains form intermolecular hydrogen bondinglinkages leading to elastic behavior at lower frequen-cies

(v) The 1198661015840 and 11986610158401015840 values decrease on increasing theradiation dose which signifies chain scissioning

313 Methyl Guar The methyl guar (MG) samples wereirradiated and their viscoelastic behavior was studied asdescribed in the previous section The change in storage(elastic 1198661015840) and the loss (viscous 11986610158401015840) moduli was studiedover a range of frequency 1 to 30Hz and the results obtainedhave been shown in Figures 6 and 7

The following observations were made from the resultsIn case of MG of DS 01 no crossover of 1198661015840 and11986610158401015840 curves is seen in unirradiated and irradiated sampleat 1 KGy dose This shows that the elasticity predominatesMethyl group is hydrophobic in nature and its substitutionreduces the number of hydroxyl groups on guar moleculeand opens up the guar chains This leads to more number ofintermolecular interactions than intramolecular interactionsand thus increases elasticity

(i) On increasing the radiation dose up to 10KGy theelastic component decreasesThis can be attributed tothe fact that chain scissioning takes place and now theH-bonding interactions take place between smallerchains which reduces the elasticity and viscousbehavior predominates Due to this the crossoverfrequency increases till 10 KGy dose

(ii) Beyond 10KGy dose there is increase in the elasticcomponent which may be because of interactions in

the smaller chains because of hydrophobic methylgroup

32 Study on Effect of Irradiation on Shear Rate The effectof radiation on the change in viscosity with increase in shearrate (1 to 30s) was studied and has been shown in Figures 8to 13 To analyze this data the minimum viscosity (viscosityobtained at shear rate value of 30s) obtained for each of thesamples was plotted against the radiation dose (Figure 14)and the shear rate at which shear rate versus viscosity curvereaches a plateau was plotted with respect to the increase inradiation dose (Figure 15) for all the samples (CMGHEGandMG)

33 Radiation Dose versus Viscosity As evident fromFigure 14 the minimum viscosity attained by the 1 solutionof various derivatives both before and after irradiation showsa decreasing trend with respect to increase in the radiationdose The decrease is less pronounced in the case of sampleshaving higher substitution which shows that sampleswith greater substitution level exhibit higher resistance todepolymerisation

34 Radiation Dose versus Shear Rate Figure 15 shows theeffect of increasing the radiation dose on shear rate neededto achieve nearly constant viscosity with respect to changein shear rate As the radiation dose is increased the shearrate value at which nearly constant viscosity is achieveddecreases and at the same time the behavior of the three typesof derivatives is quite different for each type

In case of CMG the shear rate required to achieve nearlyconstant viscosity decreases with the increase in radiationdose This means that as the radiation dose is increasing theshear stability of carboxymethyl guar is increasing In otherwords the oligomeric chains of carboxymethyl guar formedon its irradiation exhibit better shear stability When we lookat the results obtained in case of hydroxyethyl guar then itbecomes evident that nearly constant viscosity in this case isachieved at higher shear rate values although a decreasingtrend in shear rate values is observed in this case also Incase of methyl guar also on increasing the radiation dosethe shear rate required to achieve nearly constant viscositydecreases In case of methyl guar of DS 01 the shear ratevalue was found to be nearly constant from 25 to 50KGyradiation dose

4 Conclusion

The depolymerisation of polymers and polymeric materialsby radiation processing is a dry technique Further forachieving the desired results one does not have to use anyof the additives In other words by radiation processing onecan depolymerize guar powder as such without making itssolution in water and without incorporation of additives

Radiation processing of materials such as polymersfood products precious stones medical goods has beenwidely adopted industrially since it is a continuous operationwhich is highly precise energy saving and reproducible

International Journal of Carbohydrate Chemistry 9

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) MG DS = 01 0 KGy

01 10 100 1000

102

101

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) MG DS = 01 1 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) MG DS = 01 25 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) MG DS = 01 5 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) MG DS = 01 10 KGy

102

101

100

10minus2

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) MG DS = 01 20 KGy

102

101

100

10minus2

10minus3

01 10 100 1000

119866998400998400 = 119891 (f)119866998400 = 119891 (f)

119866998400119866998400998400

(Pa)

119891 (Hz)

10minus1

(g) MG DS = 01 50 KGy

Figure 6 Effect of radiation processing on the viscoelastic behavior of methylated guar (MG) of degree of substitution (DS) = 01 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

10 International Journal of Carbohydrate Chemistry

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) MG DS = 02 0 KGy

01 10 100 1000

102

103

101

100

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) MG DS = 02 1 KGy

01 10 100 1000

102

101

100

10minus1

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) MG DS = 02 25 KGy

01 10 100 1000

102

101

100

10minus1

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) MG DS = 02 5 KGy

102

101

100

10minus1

10minus2

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) MG DS = 02 10 KGy

102

101

100

10minus1

10minus2

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) MG DS = 02 20 KGy

102

101

100

10minus1

10minus2

10minus3

10minus4

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (f)119866998400 = 119891 (f)

(g) MG DS = 02 50 KGy

Figure 7 Effect of radiation processing on the viscoelastic behavior of methylated guar (MG) of degree of substitution (DS) = 02 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

International Journal of Carbohydrate Chemistry 11

20000

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

0

25 5 75 10 125 15 175 20 225 25 275 30

Visc

osity

(cps

)

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 8 Effect of radiation processing on the shear stability ofcarboxymethylated guar (CMG) of degree of substitution (DS) =01 unirradiated and irradiated

3500

3000

2500

2000

1500

1000

500

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 9 Effect of radiation processing on the shear stability ofcarboxymethylated guar (CMG) of degree of substitution (DS) =02 unirradiated and irradiated

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 10 Effect of radiation processing on the shear stability ofhydroxyethylated guar (HEG) of molar substitution (MS) = 01unirradiated and irradiated

25000

20000

15000

10000

5000

0

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Visc

osity

(cps

)

Figure 11 Effect of radiation processing on the shear stability ofhydroxyethylated guar (HEG) of molar substitution (MS) = 02unirradiated and irradiated

25000

20000

15000

10000

5000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 12 Effect of radiation processing on the shear stabilityof methylated guar (MG) of degree of substitution (DS) = 01unirradiated and irradiated

16000

14000

12000

10000

8000

6000

4000

2000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 13 Effect of radiation processing on the shear stabilityof methylated guar (MG) of degree of substitution (DS) = 02unirradiated and irradiated

12 International Journal of Carbohydrate Chemistry

2000

1800

1600

1400

1200

1000

800

600

400

200

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(a) CMG DS = 01

700

600

500

400

300

200

100

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(b) CMG DS = 02

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(c) HEG MS = 01

2000

1500

1000

500

0

0

20 40 60

Visc

osity

(cps

)

Radiation dose (KGy)

(d) HEG MS = 02

0 20 40 60

Radiation dose (KGy)

2500

2000

1500

1000

500

0

Visc

osity

(cps

)

(e) MG DS = 01

2000

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(f) MG DS = 02

Figure 14 The plot of minimum viscosity (at shear rate 30s) attained by the sample while subjecting it to shear from 1 to 30s for (a) CMGDS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02 with respect to radiation dose

International Journal of Carbohydrate Chemistry 13

30

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(a) CMG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(b) CMG DS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(c) HEG MS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(d) HEG MS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(e) MG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)

0

20 40 60

(f) MG DS = 02

Figure 15The plot of shear rate value versus radiation doseThe shear rate value was taken from the study carried out by increasing the shearrate and monitoring change in viscosity The point at which the curve between shear rate and viscosity reaches plateau was taken for plottingradiation dose versus shear rate for samples (a) CMG DS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02with respect to radiation dose

The depolymerisation of synthetic polymers by radiationprocessing for recycling of monomers has been known forquite some timeThepresent paper is an attempt to initiate theuse of this technology for radiation processing of modifiednatural polymers The gamma irradiation facility used for

the current studies is an industrial plant and it has been inoperation for about 20 years now where large volumes ofindustrial products are irradiated every day

From the results presented here it is evident that thedepolymerisation of guar is achieved with the radiation dose

14 International Journal of Carbohydrate Chemistry

of 1 KGy and above as seen from the observation of viscosityof 1 of guar derivatives getting reduced from as high a levelas 10000 cps (for unirradiated guar derivative) to as low alevel as 1 cps at 25∘C (for guar derivatives irradiated at 20ndash50KGy)

Inspite of this knowledge which can be easily usedfor scaling up of the process to commercial level doubtsare raised about the scalability of the process Whetherthe process can be used for bulk material is the commonapprehension in the minds of the processors of guar Whilethe present study would help clear many of the doubtsregarding the suitability of radiation processing technologybut the data about the scalability of the process would actuallyeliminate all sorts of doubts

Eventhough the results presented in this paper pertain tothe batch size of 200 g for each guar derivative at each dosethe same was found valid even for the bigger batch size (intons) The results of large batches were the same as obtainedfor the small batches Here it must be mentioned that thedose optimization for the purpose would be necessary for thepurpose of studying the scalability

From the present study the following can be concluded

(i) Radiation processing of guar derivatives leads to theirchain scissioning

(ii) Radiation processing leads to reduction in viscosity ofaqueous solutions of guar derivatives

(iii) Irradiation technique can be a good tool for tailormaking the guar derivatives of desired rheologicalproperties

(iv) The minimum viscosity attained by the 1 solutionof various derivatives shows a decreasing trend withrespect to increase in the radiation dose

(v) In case of carboxymethyl guar the crossover fre-quency increases as the radiation dose increases upto 5KGy and the value is higher in case of CMG ofDS 02 than in that of CMG of DS 01 This showsthat the elastic nature is more dominating for CMGof DS 01 than for CMG of DS 02

(vi) In case of hydroxyethyl guar ofMS 02 the crossoverfrequency of the 1198661015840 and 11986610158401015840 is lesser than that of HEGof MS 01 till 20 KGy radiation dose This meansthat elastic nature predominates in case of HEG ofMS 02 which may be due to the presence of greaternumber of ndash(CH

2ndashO)nndashH groups leading to increase

in H-bonding and thus more solid-like behavior(vii) In case of methyl guar on increasing the radiation

dose up to 10KGy the elastic component decreasesThis can be attributed to the fact that chain scissioningtakes place and now the H-bonding interactions takeplace between smaller chains which reduces theelasticity and viscous behavior predominates Dueto this the crossover frequency increases till 10 KGydose

(viii) As the radiation dose is increased the shear ratevalue at which nearly constant viscosity is achieveddecreases

Acknowledgment

The authors express sincere gratitude to the management ofShriram Institute for Industrial Research Delhi India for thekind support

References

[1] L Wang and L M Zhang ldquoViscoelastic characterization ofa new guar gum derivative containing anionic carboxymethyland cationic 2-hydroxy-3-(trimethylammonio)propyl substit-uentsrdquo Industrial Crops and Products vol 29 no 2-3 pp 524ndash529 2009

[2] C Sandolo PMatricardi F Alhaique and T Coviello ldquoEffect oftemperature and cross-linking density on rheology of chemicalcross-linked guar gum at the gel pointrdquo Food Hydrocolloids vol23 no 1 pp 210ndash220 2009

[3] H N Englyst V Anderson and J H Cummings ldquoStarch andnon-starch polysaccharides in some cereal foodsrdquo Journal of theScience of Food and Agriculture vol 34 no 12 pp 1434ndash14401983

[4] R L Feddersen and S N Thorp Industrial Gums AcaedemicPress San Diego Calif USA 1993

[5] D D Roberts J S Elmore K R Langley and J BakkerldquoEffects of sucrose guar gum and carboxymethylcelluloseon the release of volatile flavor compounds under dynamicconditionsrdquo Journal of Agricultural and Food Chemistry vol 44no 5 pp 1321ndash1326 1996

[6] D R Picout S B Ross-Murphy K Jumel and S E HardingldquoPressure cell assisted solution characterization of polysaccha-rides 2 Locust bean gum and tara gumrdquo Biomacromoleculesvol 3 no 4 pp 761ndash767 2002

[7] R S Blackburn ldquoNatural polysaccharides and their interactionswith dyemolecules applications in effluent treatmentrdquoEnviron-mental Science and Technology vol 38 no 18 pp 4905ndash49092004

[8] M Urdiaın A Domenech-Sanchez S Albertı V J Benedıand J A Rossello ldquoNew method of DNA isolation from twofood additives suitable for authentication in polymerase chainreaction assaysrdquo Journal of Agricultural and FoodChemistry vol53 no 9 pp 3345ndash3347 2005

[9] R P Singh S Pal andDMal ldquoA high performance flocculatingagent and viscosifiers based on cationic guar gumrdquoMacromolec-ular Symposia vol 242 pp 227ndash234 2006

[10] S P Zhao DMa and LM Zhang ldquoNew semi-interpenetratingnetwork hydrogels synthesis characterization and propertiesrdquoMacromolecular Bioscience vol 6 no 6 pp 445ndash451 2006

[11] J Z Yi and L M Zhang ldquoBiodegradable blend films basedon two polysaccharide derivatives and their use as Ibuprofen-releasing matricesrdquo Journal of Applied Polymer Science vol 103no 6 pp 3553ndash3559 2007

[12] S Venkataiah and E G Mahadevan ldquoRheological propertiesof hydroxypropyl and sodium carboxymethyl substituted guargums in aqueous solutionrdquo Journal of Applied Polymer Sciencevol 27 no 5 pp 1533ndash1548 1982

[13] R H W Wientjes M H G Duits R J J Jongschaap andJ Mellema ldquoLinear rheology of guar gum solutionsrdquo Macro-molecules vol 33 no 26 pp 9594ndash9605 2000

[14] T Aubry and M Moan ldquoRheological behavior of a hydropho-bically associating water soluble polymerrdquo Journal of Rheologyvol 38 no 6 pp 1681ndash1692 1994

International Journal of Carbohydrate Chemistry 15

[15] L M Zhang T Kong and P S Hui ldquoSemi-dilute solutions ofhydroxypropyl guar gum viscosity behaviour and thixotropicpropertiesrdquo Journal of the Science of Food and Agriculture vol87 no 4 pp 684ndash688 2007

[16] N N G Swamy T S Dharmarajan and K L K ParanjothildquoDerivatization of guar to various hydroxy alkyl derivatives andtheir characterizationrdquo Indian Drugs vol 43 no 9 pp 756ndash7592006

[17] H Gong M Liu J Chen F Han C Gao and B ZhangldquoSynthesis and characterization of carboxymethyl guar gumandrheological properties of its solutionsrdquo Carbohydrate Polymersvol 88 no 3 pp 1015ndash1022 2012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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CatalystsJournal of

2 International Journal of Carbohydrate Chemistry

Table 1 Etherification reactions of guar

S no Reaction Reagent1 Carboxymethylation Monochloroacetic acid2 Cationization Quaternary ammonium salts3 Methylation Methyl chloride4 Hydroxyethylpropylation Ethylenepropylene oxide

of the methodology followed for the degradation of guar byconventional route and by radiation processing is given inFigure 1

The most important property of guar gum is its uniquerheology which makes it an invaluable industrial productThe rheological behavior of guar has been a subject forstudy for scientists world over Venkataiah and Mahadevan[12] investigated the aqueous solutions of guar gum as wellas its nonionic hydroxypropyl and anionic carboxymethylderivatives for their flow properties in the range of lowto moderately high shear rates and observed the transitionfrom Newtonian fluid to pseudoplastic fluid Wientjes et al[13] studied the linear viscoelastic behavior of guar gumsolutions as a function of frequency temperature polymerconcentration and molecular weight and revealed the impor-tance of different relaxation mechanisms Aubry and Moan[14] focused on the rheological effect of hydrophobicallymodified hydroxypropyl guar gumanddemonstrated that thelinear andnonlinear rheological behaviors of such associatingsystems were dependent on the nature concentration anddistribution along the chain of hydrophobic junctions Zhanget al [15] have studied the semidilute solutions of hydrox-ypropyl guar gum (HPGG) with respect to their viscositychanges under variousHPGG concentrations added salts andtemperatures could be well described by the Cross viscositymodel

In the present paper the effect of irradiation on guar andits carboxymethyl hydroxypropyl and methyl derivativeshas been studied in respect to the change in the rheologicalbehavior

2 Materials and Methods

Themethodology followed for studying the effect of radiationprocessing on guar and its derivatives involved the followingsteps

21 Guar Gum and Derivatives The sample of guar gum wasprocured from a local supplier The carboxymethyl hydrox-ypropyl and methyl derivatives of DSMS 01 and 02were synthesized by well-established techniques as publishedpreviously [16 17]

22 Irradiation of Samples Guar gum and its derivatives(hydroxypropyl carboxymethyl and methyl of DS 01 and02) were sealed in plastic bottles which were packed in acardboard boxThe box was then irradiated at different doses(1 25 5 10 20 and 50KGy) at the Co-60 gamma irradiationfacility available within the institute All specimens were

Chemical

Low molecular weight guar

Low molecular weight guar

Radiation processing

Guar powdersplit Guar powdersplit

Slurrysoaking

Depolymerising agent

Temperature

Washing

Drying

Grinding

Sieving

Irradiation at desired dose

Figure 1 Comparison of the processing steps involved in depoly-merisation of guar by Chemical Synthesis Route

finely grounded to pass 200 120583m sieves before subjecting themto irradiation The irradiation was carried out on 200 g batchsize in case of all the specimens at each dose

23 Preparation of Solutions The moisture content of everysample was determined by heating the sample in an aircirculating oven till constant weight Aqueous solutions of 1were prepared after applying the moisture correction factorThe desired amount of sample was weighed and dissolved inrequired amount of water using either an overheadmotorizedstirrer or a magnetic stirrer Three hours of stirring wasgiven to each sample before allowing it to stand overnightat ambient conditions The following day the solution wasconsidered ready for the rheological evaluation

24 Rheological Evaluation The rheology study of 1 aque-ous solutions of guar gum and its hydroxypropyl (MS =01 and 02) carboxymethyl (DS = 01 and 02) and methylderivatives (DS = 01 and 02) was carried out on theRheometer (MARSThermo Fisher) at 25∘C temperatureThelinear viscoelastic range was determined from the amplitudesweep by varying the shear stress at a constant frequency of1Hz Next the frequency sweep was carried out at a shearstress (or amplitude value) lying in the linear viscoelasticregion The effect of shear rate on the viscosity of sampleswas also determined by studying the change in viscosity withvarying shear rate from 1 to 30 rpm

3 Results and Discussion

Guar gum and its derivatives of carboxymethyl hydrox-ypropyl and methyl derivatives with 01 and 02DSMS werestudied by rheology before and after gamma irradiation tounderstand the effect of radiation on the viscosity of thesample The effect of ionizing radiation on polysaccharides is

International Journal of Carbohydrate Chemistry 3

Table 2 Crossover frequencies of guar and its various derivatives

Radiation dose (KGy) Crossover frequency (Hz)CMG (DS = 01) CMG (DS = 02) HEG (MS = 01) HEG (MS = 02) MG (DS = 01) MG (DS = 02)

0 Nil 0299 0161 0134 Nil 01671 2101 6539 2717 05298 Nil 051425 6755 894 6776 4234 4443 49955 1691 2223 1840 986 1224 105810 1053 9191 1460 1269 1218 153920 3857 3275 2717 8335 6755 695950 178 1282 1588 1862 Nil 2591

known to cause degradationwith a consequent loss in the vis-cosity The derivatives of polysaccharides like carboxymethylderivative of cellulose are however known to result information of gel when their aqueous solutions are subjectedto an appropriate radiation dose The competition betweenradiation-induced chain scission and chain crosslinkinginfluences the resulting viscosity or formation of gel by thepolysaccharide after irradiation Thus polysaccharides canbe modified using ionizing radiation provided there is apossibility of reducing chain scission andor favoring chaincrosslinking during irradiation

The following sections discuss the rheology studies foreach sample separately

31 Study on Change in Storage Modulus and Loss ModulusThe plot obtained from the frequency sweep study gives theeffect of change in frequency on the storage (elastic 1198661015840)and the loss (viscous 11986610158401015840) moduli The effect of radiationon the storage modulus and loss modulus was studied andthe change in crossover frequencies of irradiated sampleshas been given in Table 2 The effect of radiation on therheological behavior of each of the derivatives has beendescribed separately

311 Carboxymethyl Guar The carboxymethyl guar (CMG)samples were irradiated and their viscoelastic behavior wasstudied as described in the previous section The change instorage (elastic 1198661015840) and the loss (viscous 11986610158401015840) moduli wasstudied over a range of frequency 1 to 30Hz and the resultsobtained have been shown in Figures 2 and 3 Followinginferences can be drawn from the data presented in Figures 2and 3 and Table 2

(i) As evident from the Figures 2 and 3 in case ofCMG of DS 01 there is no crossover of the 1198661015840 and11986610158401015840 whereas in case of CMG of DS 02 crossoverfrequency is 029Hz This shows that the elasticnature predominates throughout in case of CMGof DS 01 whereas elasticity dominates only afterfrequency of 029Hz in case of CMG of DS 02

(ii) As shown in Table 2 the crossover frequency in-creases as the radiation dose increases up to 5KGyand the value is higher in case of CMGofDS 02 thanCMG of DS 01 This shows that the elastic nature

is more dominating for CMG of DS 01 than CMGof DS 02 The explanation for this can be found inthe fact that initially the chains in guar gum form H-bonding linkages in themselves leading to solid-likebehavior But as the carboxymethyl (-CH

2COONa)

substitution is carried out on the guar chain thedistance between the chains increases leading toopening up of the chains as the H-bonding linkagesget decreased Thus solid-like behavior or elasticitydecreases on increasing the substitution

(iii) This can also be explained by saying that duringfrequency sweep study the chains get pushed towardseach other and form aggregates The carboxymethylgroup being an ionic group will cause repulsionamongst the chains due to repulsion between like-charged moieties Thus a greater frequency will beneeded to push the chains together in case of a samplehaving higher ionic substituents that is CMG ofDS = 02 to form aggregates leading to solid-like orelastic behavior

(iv) Beyond 5KGy radiation dose the crossover fre-quency is very close for both CMGs because themolecular chain breaks on irradiation leading toformation of small oligomeric chains of similar sizein both CMGs of DS of 01 and 02 Thus the effectof frequency is felt equally by both these samples

(v) The values of 1198661015840 and 11986610158401015840 are seen to decrease withthe increase in radiation dose which indicates chainscissioning

Another aspect is the effect of radiation on the car-boxymethyl guar As seen from Table 2 the crossover fre-quency increases with the increase in radiation dose up to5KGy and then it starts to decrease Irradiation leads tobreaking up of the chain leading to reduction in molecularweight Up to 5KGy radiation dose chain scissioning istaking place leading to decrease in molecular weight and lessinteraction of the smaller chains formed As the interactionbetween the chains decreases viscous behavior predominatesor in other words elasticity or the solid-like behavior getsdecreased Now beyond 5KGy radiation dose it is observedthat the crossover frequency gets decreased which maysignify formation of aggregates between the chains leading tomore solid-like behavior at lower frequencies

4 International Journal of Carbohydrate Chemistry

102

101

01 10 100 1000

119891 (Hz)

119866998400119866998400998400

(Pa)

(a) CMG DS = 01 0 KGy

102

101

100

01 10 100 1000

119891 (Hz)

119866998400119866998400998400

(Pa)

(b) CMG DS = 01 1 KGy

01 10 100 1000

102

101

100

119891 (Hz)

119866998400119866998400998400

(Pa)

(c) CMG DS = 01 25 KGy

01 10 100 1000

102

101

100

10minus1

119891 (Hz)119866998400119866998400998400

(Pa)

(d) CMG DS = 01 5 KGy

01 10 100 1000

102

101

100

10minus1

10minus2

119891 (Hz)

119866998400119866998400998400

(Pa)

(e) CMG DS = 01 10 KGy

01 10 100 1000

101

100

10minus1

10minus2

10minus3

10minus4

119891 (Hz)

119866998400119866998400998400

(Pa)

(f) CMG DS = 01 20 KGy

101

100

10minus1

10minus2

10minus3

10minus4

01 10 100 1000

119891 (Hz)

119866998400998400 = 119891 (119891)

119866998400 = 119891 (119891)

119866998400119866998400998400

(Pa)

(g) CMG DS = 01 50 KGy

Figure 2 Effect of radiation processing on the viscoelastic behavior of carboxymethylated guar (CMG) of degree of substitution (DS) = 01(a) unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy(g) irradiated at 50KGy

International Journal of Carbohydrate Chemistry 5

102

101

100

01 10 100 1000

119891 (Hz)

119866998400119866998400998400

(Pa)

(a) CMG DS = 02 0 KGy

102

101

100

10minus1

01 10 100 1000

119891 (Hz)

119866998400119866998400998400

(Pa)

(b) CMG DS = 02 1 KGy

01 10 100 1000

102

101

100

10minus1

119891 (Hz)

119866998400119866998400998400

(Pa)

(c) CMG DS = 02 25 KGy

01 10 100 1000

101

100

10minus1

119891 (Hz)

119866998400119866998400998400

(Pa)

(d) CMG DS = 02 5 KGy

102

101

100

10minus2

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) CMG DS = 02 10 KGy

101

100

10minus1

10minus2

10minus3

10minus4

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) CMG DS = 02 20 KGy

01 10 100 1000

101

102

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (119891)119866998400 = 119891 (119891)

(g) CMG DS = 02 50 KGy

Figure 3 Effect of radiation processing on the viscoelastic behavior of carboxymethylated guar (CMG) of degree of substitution (DS) = 02(a) unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy(g) irradiated at 50KGy

312 Hydroxyethyl Guar The hydroxyethyl guar (HEG)samples were irradiated and their viscoelastic behavior wasstudied as described in the previous section The change instorage (elastic 1198661015840) and the loss (viscous 11986610158401015840) moduli wasstudied over a range of frequency 1 to 30Hz and the results

obtained have been shown in Figures 4 and 5 On the basis ofthe results obtained the following observations were made

(i) As evident from Figures 4 and 5 in case of HEGof MS 02 the crossover frequency of the 1198661015840 and

6 International Journal of Carbohydrate Chemistry

102

101

01 10 100

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) HEGMS = 01 0 KGy

01 10 100

102

101

100

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) HEGMS = 01 1 KGy

102

101

100

10minus1

01 10 100

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) HEGMS = 01 25 KGy

01 10 100

101

100

10minus1

10minus2

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) HEGMS = 01 5 KGy

01 10 100

102

101

100

10minus1

10minus2

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) HEGMS = 01 10 KGy

01 10 100

102

101

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) HEGMS = 01 20 KGy

01 10 100

101

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (119891)119866998400 = 119891 (119891)

(g) HEGMS = 01 50 KGy

Figure 4 Effect of radiation processing on the viscoelastic behavior of hydroxyethylated guar (HEG) of molar substitution (MS) = 01 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

International Journal of Carbohydrate Chemistry 7

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) HEGMS = 02 0 KGy

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) HEGMS = 02 1 KGy

102

101

100

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) HEGMS = 02 25 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) HEGMS = 02 5 KGy

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) HEGMS = 02 10 KGy

01 10 100 1000

101

100

10minus1

10minus2

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) HEGMS = 02 20 KGy

01 10 100 1000

101

102

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (119891)119866998400 = 119891 (119891)

(g) HEGMS = 02 50 KGy

Figure 5 Effect of radiation processing on viscoelastic properties of hydroxyethyl guar (HEG) havingmolar substitution 02 (a) unirradiated(b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g) irradiated at50KGy

8 International Journal of Carbohydrate Chemistry

11986610158401015840 is lesser than that of HEG of MS 01 till 20 KGyradiation dose This means that elastic nature pre-dominates in case of HEG of MS 02 which may bedue to the presence of greater number of ndash(CH

2ndashO)nndash

H groups leading to increase in H-bonding and thusmore solid-like behavior

(ii) On comparing the crossover frequencies of HEG ofMS 01 after irradiation it can be seen from thedata that crossover frequency increases till 5 KGydoseand then it decreases whereas in case of HEG ofMS 02 the crossover frequency increases till 10 KGydose and then it decreases This can be explainedon the basis of interactions taking place between themacromolecular chains in these two HEGs In case ofHEG of MS 01 intermolecular interactions are lessas compared to HEG of MS 02 and thus less elasticnature

(iii) Also in case of HEG of MS 02 as the substitu-tion increases the coiling of macromolecular chaindecreases due to steric hindrance thereby causingmore intramolecular interactions than intermolec-ular interactions Less coiling of the chain causesmore exposure to irradiation and thus greater chainscissioning and more viscous response of the macro-molecule

(iv) As the radiation dose increases there is more chainscissioning leading to formation of oligomeric chainsThese chains form intermolecular hydrogen bondinglinkages leading to elastic behavior at lower frequen-cies

(v) The 1198661015840 and 11986610158401015840 values decrease on increasing theradiation dose which signifies chain scissioning

313 Methyl Guar The methyl guar (MG) samples wereirradiated and their viscoelastic behavior was studied asdescribed in the previous section The change in storage(elastic 1198661015840) and the loss (viscous 11986610158401015840) moduli was studiedover a range of frequency 1 to 30Hz and the results obtainedhave been shown in Figures 6 and 7

The following observations were made from the resultsIn case of MG of DS 01 no crossover of 1198661015840 and11986610158401015840 curves is seen in unirradiated and irradiated sampleat 1 KGy dose This shows that the elasticity predominatesMethyl group is hydrophobic in nature and its substitutionreduces the number of hydroxyl groups on guar moleculeand opens up the guar chains This leads to more number ofintermolecular interactions than intramolecular interactionsand thus increases elasticity

(i) On increasing the radiation dose up to 10KGy theelastic component decreasesThis can be attributed tothe fact that chain scissioning takes place and now theH-bonding interactions take place between smallerchains which reduces the elasticity and viscousbehavior predominates Due to this the crossoverfrequency increases till 10 KGy dose

(ii) Beyond 10KGy dose there is increase in the elasticcomponent which may be because of interactions in

the smaller chains because of hydrophobic methylgroup

32 Study on Effect of Irradiation on Shear Rate The effectof radiation on the change in viscosity with increase in shearrate (1 to 30s) was studied and has been shown in Figures 8to 13 To analyze this data the minimum viscosity (viscosityobtained at shear rate value of 30s) obtained for each of thesamples was plotted against the radiation dose (Figure 14)and the shear rate at which shear rate versus viscosity curvereaches a plateau was plotted with respect to the increase inradiation dose (Figure 15) for all the samples (CMGHEGandMG)

33 Radiation Dose versus Viscosity As evident fromFigure 14 the minimum viscosity attained by the 1 solutionof various derivatives both before and after irradiation showsa decreasing trend with respect to increase in the radiationdose The decrease is less pronounced in the case of sampleshaving higher substitution which shows that sampleswith greater substitution level exhibit higher resistance todepolymerisation

34 Radiation Dose versus Shear Rate Figure 15 shows theeffect of increasing the radiation dose on shear rate neededto achieve nearly constant viscosity with respect to changein shear rate As the radiation dose is increased the shearrate value at which nearly constant viscosity is achieveddecreases and at the same time the behavior of the three typesof derivatives is quite different for each type

In case of CMG the shear rate required to achieve nearlyconstant viscosity decreases with the increase in radiationdose This means that as the radiation dose is increasing theshear stability of carboxymethyl guar is increasing In otherwords the oligomeric chains of carboxymethyl guar formedon its irradiation exhibit better shear stability When we lookat the results obtained in case of hydroxyethyl guar then itbecomes evident that nearly constant viscosity in this case isachieved at higher shear rate values although a decreasingtrend in shear rate values is observed in this case also Incase of methyl guar also on increasing the radiation dosethe shear rate required to achieve nearly constant viscositydecreases In case of methyl guar of DS 01 the shear ratevalue was found to be nearly constant from 25 to 50KGyradiation dose

4 Conclusion

The depolymerisation of polymers and polymeric materialsby radiation processing is a dry technique Further forachieving the desired results one does not have to use anyof the additives In other words by radiation processing onecan depolymerize guar powder as such without making itssolution in water and without incorporation of additives

Radiation processing of materials such as polymersfood products precious stones medical goods has beenwidely adopted industrially since it is a continuous operationwhich is highly precise energy saving and reproducible

International Journal of Carbohydrate Chemistry 9

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) MG DS = 01 0 KGy

01 10 100 1000

102

101

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) MG DS = 01 1 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) MG DS = 01 25 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) MG DS = 01 5 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) MG DS = 01 10 KGy

102

101

100

10minus2

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) MG DS = 01 20 KGy

102

101

100

10minus2

10minus3

01 10 100 1000

119866998400998400 = 119891 (f)119866998400 = 119891 (f)

119866998400119866998400998400

(Pa)

119891 (Hz)

10minus1

(g) MG DS = 01 50 KGy

Figure 6 Effect of radiation processing on the viscoelastic behavior of methylated guar (MG) of degree of substitution (DS) = 01 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

10 International Journal of Carbohydrate Chemistry

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) MG DS = 02 0 KGy

01 10 100 1000

102

103

101

100

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) MG DS = 02 1 KGy

01 10 100 1000

102

101

100

10minus1

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) MG DS = 02 25 KGy

01 10 100 1000

102

101

100

10minus1

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) MG DS = 02 5 KGy

102

101

100

10minus1

10minus2

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) MG DS = 02 10 KGy

102

101

100

10minus1

10minus2

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) MG DS = 02 20 KGy

102

101

100

10minus1

10minus2

10minus3

10minus4

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (f)119866998400 = 119891 (f)

(g) MG DS = 02 50 KGy

Figure 7 Effect of radiation processing on the viscoelastic behavior of methylated guar (MG) of degree of substitution (DS) = 02 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

International Journal of Carbohydrate Chemistry 11

20000

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

0

25 5 75 10 125 15 175 20 225 25 275 30

Visc

osity

(cps

)

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 8 Effect of radiation processing on the shear stability ofcarboxymethylated guar (CMG) of degree of substitution (DS) =01 unirradiated and irradiated

3500

3000

2500

2000

1500

1000

500

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 9 Effect of radiation processing on the shear stability ofcarboxymethylated guar (CMG) of degree of substitution (DS) =02 unirradiated and irradiated

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 10 Effect of radiation processing on the shear stability ofhydroxyethylated guar (HEG) of molar substitution (MS) = 01unirradiated and irradiated

25000

20000

15000

10000

5000

0

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Visc

osity

(cps

)

Figure 11 Effect of radiation processing on the shear stability ofhydroxyethylated guar (HEG) of molar substitution (MS) = 02unirradiated and irradiated

25000

20000

15000

10000

5000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 12 Effect of radiation processing on the shear stabilityof methylated guar (MG) of degree of substitution (DS) = 01unirradiated and irradiated

16000

14000

12000

10000

8000

6000

4000

2000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 13 Effect of radiation processing on the shear stabilityof methylated guar (MG) of degree of substitution (DS) = 02unirradiated and irradiated

12 International Journal of Carbohydrate Chemistry

2000

1800

1600

1400

1200

1000

800

600

400

200

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(a) CMG DS = 01

700

600

500

400

300

200

100

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(b) CMG DS = 02

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(c) HEG MS = 01

2000

1500

1000

500

0

0

20 40 60

Visc

osity

(cps

)

Radiation dose (KGy)

(d) HEG MS = 02

0 20 40 60

Radiation dose (KGy)

2500

2000

1500

1000

500

0

Visc

osity

(cps

)

(e) MG DS = 01

2000

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(f) MG DS = 02

Figure 14 The plot of minimum viscosity (at shear rate 30s) attained by the sample while subjecting it to shear from 1 to 30s for (a) CMGDS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02 with respect to radiation dose

International Journal of Carbohydrate Chemistry 13

30

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(a) CMG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(b) CMG DS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(c) HEG MS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(d) HEG MS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(e) MG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)

0

20 40 60

(f) MG DS = 02

Figure 15The plot of shear rate value versus radiation doseThe shear rate value was taken from the study carried out by increasing the shearrate and monitoring change in viscosity The point at which the curve between shear rate and viscosity reaches plateau was taken for plottingradiation dose versus shear rate for samples (a) CMG DS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02with respect to radiation dose

The depolymerisation of synthetic polymers by radiationprocessing for recycling of monomers has been known forquite some timeThepresent paper is an attempt to initiate theuse of this technology for radiation processing of modifiednatural polymers The gamma irradiation facility used for

the current studies is an industrial plant and it has been inoperation for about 20 years now where large volumes ofindustrial products are irradiated every day

From the results presented here it is evident that thedepolymerisation of guar is achieved with the radiation dose

14 International Journal of Carbohydrate Chemistry

of 1 KGy and above as seen from the observation of viscosityof 1 of guar derivatives getting reduced from as high a levelas 10000 cps (for unirradiated guar derivative) to as low alevel as 1 cps at 25∘C (for guar derivatives irradiated at 20ndash50KGy)

Inspite of this knowledge which can be easily usedfor scaling up of the process to commercial level doubtsare raised about the scalability of the process Whetherthe process can be used for bulk material is the commonapprehension in the minds of the processors of guar Whilethe present study would help clear many of the doubtsregarding the suitability of radiation processing technologybut the data about the scalability of the process would actuallyeliminate all sorts of doubts

Eventhough the results presented in this paper pertain tothe batch size of 200 g for each guar derivative at each dosethe same was found valid even for the bigger batch size (intons) The results of large batches were the same as obtainedfor the small batches Here it must be mentioned that thedose optimization for the purpose would be necessary for thepurpose of studying the scalability

From the present study the following can be concluded

(i) Radiation processing of guar derivatives leads to theirchain scissioning

(ii) Radiation processing leads to reduction in viscosity ofaqueous solutions of guar derivatives

(iii) Irradiation technique can be a good tool for tailormaking the guar derivatives of desired rheologicalproperties

(iv) The minimum viscosity attained by the 1 solutionof various derivatives shows a decreasing trend withrespect to increase in the radiation dose

(v) In case of carboxymethyl guar the crossover fre-quency increases as the radiation dose increases upto 5KGy and the value is higher in case of CMG ofDS 02 than in that of CMG of DS 01 This showsthat the elastic nature is more dominating for CMGof DS 01 than for CMG of DS 02

(vi) In case of hydroxyethyl guar ofMS 02 the crossoverfrequency of the 1198661015840 and 11986610158401015840 is lesser than that of HEGof MS 01 till 20 KGy radiation dose This meansthat elastic nature predominates in case of HEG ofMS 02 which may be due to the presence of greaternumber of ndash(CH

2ndashO)nndashH groups leading to increase

in H-bonding and thus more solid-like behavior(vii) In case of methyl guar on increasing the radiation

dose up to 10KGy the elastic component decreasesThis can be attributed to the fact that chain scissioningtakes place and now the H-bonding interactions takeplace between smaller chains which reduces theelasticity and viscous behavior predominates Dueto this the crossover frequency increases till 10 KGydose

(viii) As the radiation dose is increased the shear ratevalue at which nearly constant viscosity is achieveddecreases

Acknowledgment

The authors express sincere gratitude to the management ofShriram Institute for Industrial Research Delhi India for thekind support

References

[1] L Wang and L M Zhang ldquoViscoelastic characterization ofa new guar gum derivative containing anionic carboxymethyland cationic 2-hydroxy-3-(trimethylammonio)propyl substit-uentsrdquo Industrial Crops and Products vol 29 no 2-3 pp 524ndash529 2009

[2] C Sandolo PMatricardi F Alhaique and T Coviello ldquoEffect oftemperature and cross-linking density on rheology of chemicalcross-linked guar gum at the gel pointrdquo Food Hydrocolloids vol23 no 1 pp 210ndash220 2009

[3] H N Englyst V Anderson and J H Cummings ldquoStarch andnon-starch polysaccharides in some cereal foodsrdquo Journal of theScience of Food and Agriculture vol 34 no 12 pp 1434ndash14401983

[4] R L Feddersen and S N Thorp Industrial Gums AcaedemicPress San Diego Calif USA 1993

[5] D D Roberts J S Elmore K R Langley and J BakkerldquoEffects of sucrose guar gum and carboxymethylcelluloseon the release of volatile flavor compounds under dynamicconditionsrdquo Journal of Agricultural and Food Chemistry vol 44no 5 pp 1321ndash1326 1996

[6] D R Picout S B Ross-Murphy K Jumel and S E HardingldquoPressure cell assisted solution characterization of polysaccha-rides 2 Locust bean gum and tara gumrdquo Biomacromoleculesvol 3 no 4 pp 761ndash767 2002

[7] R S Blackburn ldquoNatural polysaccharides and their interactionswith dyemolecules applications in effluent treatmentrdquoEnviron-mental Science and Technology vol 38 no 18 pp 4905ndash49092004

[8] M Urdiaın A Domenech-Sanchez S Albertı V J Benedıand J A Rossello ldquoNew method of DNA isolation from twofood additives suitable for authentication in polymerase chainreaction assaysrdquo Journal of Agricultural and FoodChemistry vol53 no 9 pp 3345ndash3347 2005

[9] R P Singh S Pal andDMal ldquoA high performance flocculatingagent and viscosifiers based on cationic guar gumrdquoMacromolec-ular Symposia vol 242 pp 227ndash234 2006

[10] S P Zhao DMa and LM Zhang ldquoNew semi-interpenetratingnetwork hydrogels synthesis characterization and propertiesrdquoMacromolecular Bioscience vol 6 no 6 pp 445ndash451 2006

[11] J Z Yi and L M Zhang ldquoBiodegradable blend films basedon two polysaccharide derivatives and their use as Ibuprofen-releasing matricesrdquo Journal of Applied Polymer Science vol 103no 6 pp 3553ndash3559 2007

[12] S Venkataiah and E G Mahadevan ldquoRheological propertiesof hydroxypropyl and sodium carboxymethyl substituted guargums in aqueous solutionrdquo Journal of Applied Polymer Sciencevol 27 no 5 pp 1533ndash1548 1982

[13] R H W Wientjes M H G Duits R J J Jongschaap andJ Mellema ldquoLinear rheology of guar gum solutionsrdquo Macro-molecules vol 33 no 26 pp 9594ndash9605 2000

[14] T Aubry and M Moan ldquoRheological behavior of a hydropho-bically associating water soluble polymerrdquo Journal of Rheologyvol 38 no 6 pp 1681ndash1692 1994

International Journal of Carbohydrate Chemistry 15

[15] L M Zhang T Kong and P S Hui ldquoSemi-dilute solutions ofhydroxypropyl guar gum viscosity behaviour and thixotropicpropertiesrdquo Journal of the Science of Food and Agriculture vol87 no 4 pp 684ndash688 2007

[16] N N G Swamy T S Dharmarajan and K L K ParanjothildquoDerivatization of guar to various hydroxy alkyl derivatives andtheir characterizationrdquo Indian Drugs vol 43 no 9 pp 756ndash7592006

[17] H Gong M Liu J Chen F Han C Gao and B ZhangldquoSynthesis and characterization of carboxymethyl guar gumandrheological properties of its solutionsrdquo Carbohydrate Polymersvol 88 no 3 pp 1015ndash1022 2012

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International Journal of Carbohydrate Chemistry 3

Table 2 Crossover frequencies of guar and its various derivatives

Radiation dose (KGy) Crossover frequency (Hz)CMG (DS = 01) CMG (DS = 02) HEG (MS = 01) HEG (MS = 02) MG (DS = 01) MG (DS = 02)

0 Nil 0299 0161 0134 Nil 01671 2101 6539 2717 05298 Nil 051425 6755 894 6776 4234 4443 49955 1691 2223 1840 986 1224 105810 1053 9191 1460 1269 1218 153920 3857 3275 2717 8335 6755 695950 178 1282 1588 1862 Nil 2591

known to cause degradationwith a consequent loss in the vis-cosity The derivatives of polysaccharides like carboxymethylderivative of cellulose are however known to result information of gel when their aqueous solutions are subjectedto an appropriate radiation dose The competition betweenradiation-induced chain scission and chain crosslinkinginfluences the resulting viscosity or formation of gel by thepolysaccharide after irradiation Thus polysaccharides canbe modified using ionizing radiation provided there is apossibility of reducing chain scission andor favoring chaincrosslinking during irradiation

The following sections discuss the rheology studies foreach sample separately

31 Study on Change in Storage Modulus and Loss ModulusThe plot obtained from the frequency sweep study gives theeffect of change in frequency on the storage (elastic 1198661015840)and the loss (viscous 11986610158401015840) moduli The effect of radiationon the storage modulus and loss modulus was studied andthe change in crossover frequencies of irradiated sampleshas been given in Table 2 The effect of radiation on therheological behavior of each of the derivatives has beendescribed separately

311 Carboxymethyl Guar The carboxymethyl guar (CMG)samples were irradiated and their viscoelastic behavior wasstudied as described in the previous section The change instorage (elastic 1198661015840) and the loss (viscous 11986610158401015840) moduli wasstudied over a range of frequency 1 to 30Hz and the resultsobtained have been shown in Figures 2 and 3 Followinginferences can be drawn from the data presented in Figures 2and 3 and Table 2

(i) As evident from the Figures 2 and 3 in case ofCMG of DS 01 there is no crossover of the 1198661015840 and11986610158401015840 whereas in case of CMG of DS 02 crossoverfrequency is 029Hz This shows that the elasticnature predominates throughout in case of CMGof DS 01 whereas elasticity dominates only afterfrequency of 029Hz in case of CMG of DS 02

(ii) As shown in Table 2 the crossover frequency in-creases as the radiation dose increases up to 5KGyand the value is higher in case of CMGofDS 02 thanCMG of DS 01 This shows that the elastic nature

is more dominating for CMG of DS 01 than CMGof DS 02 The explanation for this can be found inthe fact that initially the chains in guar gum form H-bonding linkages in themselves leading to solid-likebehavior But as the carboxymethyl (-CH

2COONa)

substitution is carried out on the guar chain thedistance between the chains increases leading toopening up of the chains as the H-bonding linkagesget decreased Thus solid-like behavior or elasticitydecreases on increasing the substitution

(iii) This can also be explained by saying that duringfrequency sweep study the chains get pushed towardseach other and form aggregates The carboxymethylgroup being an ionic group will cause repulsionamongst the chains due to repulsion between like-charged moieties Thus a greater frequency will beneeded to push the chains together in case of a samplehaving higher ionic substituents that is CMG ofDS = 02 to form aggregates leading to solid-like orelastic behavior

(iv) Beyond 5KGy radiation dose the crossover fre-quency is very close for both CMGs because themolecular chain breaks on irradiation leading toformation of small oligomeric chains of similar sizein both CMGs of DS of 01 and 02 Thus the effectof frequency is felt equally by both these samples

(v) The values of 1198661015840 and 11986610158401015840 are seen to decrease withthe increase in radiation dose which indicates chainscissioning

Another aspect is the effect of radiation on the car-boxymethyl guar As seen from Table 2 the crossover fre-quency increases with the increase in radiation dose up to5KGy and then it starts to decrease Irradiation leads tobreaking up of the chain leading to reduction in molecularweight Up to 5KGy radiation dose chain scissioning istaking place leading to decrease in molecular weight and lessinteraction of the smaller chains formed As the interactionbetween the chains decreases viscous behavior predominatesor in other words elasticity or the solid-like behavior getsdecreased Now beyond 5KGy radiation dose it is observedthat the crossover frequency gets decreased which maysignify formation of aggregates between the chains leading tomore solid-like behavior at lower frequencies

4 International Journal of Carbohydrate Chemistry

102

101

01 10 100 1000

119891 (Hz)

119866998400119866998400998400

(Pa)

(a) CMG DS = 01 0 KGy

102

101

100

01 10 100 1000

119891 (Hz)

119866998400119866998400998400

(Pa)

(b) CMG DS = 01 1 KGy

01 10 100 1000

102

101

100

119891 (Hz)

119866998400119866998400998400

(Pa)

(c) CMG DS = 01 25 KGy

01 10 100 1000

102

101

100

10minus1

119891 (Hz)119866998400119866998400998400

(Pa)

(d) CMG DS = 01 5 KGy

01 10 100 1000

102

101

100

10minus1

10minus2

119891 (Hz)

119866998400119866998400998400

(Pa)

(e) CMG DS = 01 10 KGy

01 10 100 1000

101

100

10minus1

10minus2

10minus3

10minus4

119891 (Hz)

119866998400119866998400998400

(Pa)

(f) CMG DS = 01 20 KGy

101

100

10minus1

10minus2

10minus3

10minus4

01 10 100 1000

119891 (Hz)

119866998400998400 = 119891 (119891)

119866998400 = 119891 (119891)

119866998400119866998400998400

(Pa)

(g) CMG DS = 01 50 KGy

Figure 2 Effect of radiation processing on the viscoelastic behavior of carboxymethylated guar (CMG) of degree of substitution (DS) = 01(a) unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy(g) irradiated at 50KGy

International Journal of Carbohydrate Chemistry 5

102

101

100

01 10 100 1000

119891 (Hz)

119866998400119866998400998400

(Pa)

(a) CMG DS = 02 0 KGy

102

101

100

10minus1

01 10 100 1000

119891 (Hz)

119866998400119866998400998400

(Pa)

(b) CMG DS = 02 1 KGy

01 10 100 1000

102

101

100

10minus1

119891 (Hz)

119866998400119866998400998400

(Pa)

(c) CMG DS = 02 25 KGy

01 10 100 1000

101

100

10minus1

119891 (Hz)

119866998400119866998400998400

(Pa)

(d) CMG DS = 02 5 KGy

102

101

100

10minus2

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) CMG DS = 02 10 KGy

101

100

10minus1

10minus2

10minus3

10minus4

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) CMG DS = 02 20 KGy

01 10 100 1000

101

102

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (119891)119866998400 = 119891 (119891)

(g) CMG DS = 02 50 KGy

Figure 3 Effect of radiation processing on the viscoelastic behavior of carboxymethylated guar (CMG) of degree of substitution (DS) = 02(a) unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy(g) irradiated at 50KGy

312 Hydroxyethyl Guar The hydroxyethyl guar (HEG)samples were irradiated and their viscoelastic behavior wasstudied as described in the previous section The change instorage (elastic 1198661015840) and the loss (viscous 11986610158401015840) moduli wasstudied over a range of frequency 1 to 30Hz and the results

obtained have been shown in Figures 4 and 5 On the basis ofthe results obtained the following observations were made

(i) As evident from Figures 4 and 5 in case of HEGof MS 02 the crossover frequency of the 1198661015840 and

6 International Journal of Carbohydrate Chemistry

102

101

01 10 100

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) HEGMS = 01 0 KGy

01 10 100

102

101

100

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) HEGMS = 01 1 KGy

102

101

100

10minus1

01 10 100

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) HEGMS = 01 25 KGy

01 10 100

101

100

10minus1

10minus2

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) HEGMS = 01 5 KGy

01 10 100

102

101

100

10minus1

10minus2

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) HEGMS = 01 10 KGy

01 10 100

102

101

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) HEGMS = 01 20 KGy

01 10 100

101

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (119891)119866998400 = 119891 (119891)

(g) HEGMS = 01 50 KGy

Figure 4 Effect of radiation processing on the viscoelastic behavior of hydroxyethylated guar (HEG) of molar substitution (MS) = 01 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

International Journal of Carbohydrate Chemistry 7

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) HEGMS = 02 0 KGy

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) HEGMS = 02 1 KGy

102

101

100

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) HEGMS = 02 25 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) HEGMS = 02 5 KGy

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) HEGMS = 02 10 KGy

01 10 100 1000

101

100

10minus1

10minus2

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) HEGMS = 02 20 KGy

01 10 100 1000

101

102

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (119891)119866998400 = 119891 (119891)

(g) HEGMS = 02 50 KGy

Figure 5 Effect of radiation processing on viscoelastic properties of hydroxyethyl guar (HEG) havingmolar substitution 02 (a) unirradiated(b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g) irradiated at50KGy

8 International Journal of Carbohydrate Chemistry

11986610158401015840 is lesser than that of HEG of MS 01 till 20 KGyradiation dose This means that elastic nature pre-dominates in case of HEG of MS 02 which may bedue to the presence of greater number of ndash(CH

2ndashO)nndash

H groups leading to increase in H-bonding and thusmore solid-like behavior

(ii) On comparing the crossover frequencies of HEG ofMS 01 after irradiation it can be seen from thedata that crossover frequency increases till 5 KGydoseand then it decreases whereas in case of HEG ofMS 02 the crossover frequency increases till 10 KGydose and then it decreases This can be explainedon the basis of interactions taking place between themacromolecular chains in these two HEGs In case ofHEG of MS 01 intermolecular interactions are lessas compared to HEG of MS 02 and thus less elasticnature

(iii) Also in case of HEG of MS 02 as the substitu-tion increases the coiling of macromolecular chaindecreases due to steric hindrance thereby causingmore intramolecular interactions than intermolec-ular interactions Less coiling of the chain causesmore exposure to irradiation and thus greater chainscissioning and more viscous response of the macro-molecule

(iv) As the radiation dose increases there is more chainscissioning leading to formation of oligomeric chainsThese chains form intermolecular hydrogen bondinglinkages leading to elastic behavior at lower frequen-cies

(v) The 1198661015840 and 11986610158401015840 values decrease on increasing theradiation dose which signifies chain scissioning

313 Methyl Guar The methyl guar (MG) samples wereirradiated and their viscoelastic behavior was studied asdescribed in the previous section The change in storage(elastic 1198661015840) and the loss (viscous 11986610158401015840) moduli was studiedover a range of frequency 1 to 30Hz and the results obtainedhave been shown in Figures 6 and 7

The following observations were made from the resultsIn case of MG of DS 01 no crossover of 1198661015840 and11986610158401015840 curves is seen in unirradiated and irradiated sampleat 1 KGy dose This shows that the elasticity predominatesMethyl group is hydrophobic in nature and its substitutionreduces the number of hydroxyl groups on guar moleculeand opens up the guar chains This leads to more number ofintermolecular interactions than intramolecular interactionsand thus increases elasticity

(i) On increasing the radiation dose up to 10KGy theelastic component decreasesThis can be attributed tothe fact that chain scissioning takes place and now theH-bonding interactions take place between smallerchains which reduces the elasticity and viscousbehavior predominates Due to this the crossoverfrequency increases till 10 KGy dose

(ii) Beyond 10KGy dose there is increase in the elasticcomponent which may be because of interactions in

the smaller chains because of hydrophobic methylgroup

32 Study on Effect of Irradiation on Shear Rate The effectof radiation on the change in viscosity with increase in shearrate (1 to 30s) was studied and has been shown in Figures 8to 13 To analyze this data the minimum viscosity (viscosityobtained at shear rate value of 30s) obtained for each of thesamples was plotted against the radiation dose (Figure 14)and the shear rate at which shear rate versus viscosity curvereaches a plateau was plotted with respect to the increase inradiation dose (Figure 15) for all the samples (CMGHEGandMG)

33 Radiation Dose versus Viscosity As evident fromFigure 14 the minimum viscosity attained by the 1 solutionof various derivatives both before and after irradiation showsa decreasing trend with respect to increase in the radiationdose The decrease is less pronounced in the case of sampleshaving higher substitution which shows that sampleswith greater substitution level exhibit higher resistance todepolymerisation

34 Radiation Dose versus Shear Rate Figure 15 shows theeffect of increasing the radiation dose on shear rate neededto achieve nearly constant viscosity with respect to changein shear rate As the radiation dose is increased the shearrate value at which nearly constant viscosity is achieveddecreases and at the same time the behavior of the three typesof derivatives is quite different for each type

In case of CMG the shear rate required to achieve nearlyconstant viscosity decreases with the increase in radiationdose This means that as the radiation dose is increasing theshear stability of carboxymethyl guar is increasing In otherwords the oligomeric chains of carboxymethyl guar formedon its irradiation exhibit better shear stability When we lookat the results obtained in case of hydroxyethyl guar then itbecomes evident that nearly constant viscosity in this case isachieved at higher shear rate values although a decreasingtrend in shear rate values is observed in this case also Incase of methyl guar also on increasing the radiation dosethe shear rate required to achieve nearly constant viscositydecreases In case of methyl guar of DS 01 the shear ratevalue was found to be nearly constant from 25 to 50KGyradiation dose

4 Conclusion

The depolymerisation of polymers and polymeric materialsby radiation processing is a dry technique Further forachieving the desired results one does not have to use anyof the additives In other words by radiation processing onecan depolymerize guar powder as such without making itssolution in water and without incorporation of additives

Radiation processing of materials such as polymersfood products precious stones medical goods has beenwidely adopted industrially since it is a continuous operationwhich is highly precise energy saving and reproducible

International Journal of Carbohydrate Chemistry 9

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) MG DS = 01 0 KGy

01 10 100 1000

102

101

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) MG DS = 01 1 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) MG DS = 01 25 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) MG DS = 01 5 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) MG DS = 01 10 KGy

102

101

100

10minus2

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) MG DS = 01 20 KGy

102

101

100

10minus2

10minus3

01 10 100 1000

119866998400998400 = 119891 (f)119866998400 = 119891 (f)

119866998400119866998400998400

(Pa)

119891 (Hz)

10minus1

(g) MG DS = 01 50 KGy

Figure 6 Effect of radiation processing on the viscoelastic behavior of methylated guar (MG) of degree of substitution (DS) = 01 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

10 International Journal of Carbohydrate Chemistry

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) MG DS = 02 0 KGy

01 10 100 1000

102

103

101

100

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) MG DS = 02 1 KGy

01 10 100 1000

102

101

100

10minus1

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) MG DS = 02 25 KGy

01 10 100 1000

102

101

100

10minus1

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) MG DS = 02 5 KGy

102

101

100

10minus1

10minus2

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) MG DS = 02 10 KGy

102

101

100

10minus1

10minus2

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) MG DS = 02 20 KGy

102

101

100

10minus1

10minus2

10minus3

10minus4

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (f)119866998400 = 119891 (f)

(g) MG DS = 02 50 KGy

Figure 7 Effect of radiation processing on the viscoelastic behavior of methylated guar (MG) of degree of substitution (DS) = 02 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

International Journal of Carbohydrate Chemistry 11

20000

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

0

25 5 75 10 125 15 175 20 225 25 275 30

Visc

osity

(cps

)

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 8 Effect of radiation processing on the shear stability ofcarboxymethylated guar (CMG) of degree of substitution (DS) =01 unirradiated and irradiated

3500

3000

2500

2000

1500

1000

500

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 9 Effect of radiation processing on the shear stability ofcarboxymethylated guar (CMG) of degree of substitution (DS) =02 unirradiated and irradiated

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 10 Effect of radiation processing on the shear stability ofhydroxyethylated guar (HEG) of molar substitution (MS) = 01unirradiated and irradiated

25000

20000

15000

10000

5000

0

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Visc

osity

(cps

)

Figure 11 Effect of radiation processing on the shear stability ofhydroxyethylated guar (HEG) of molar substitution (MS) = 02unirradiated and irradiated

25000

20000

15000

10000

5000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 12 Effect of radiation processing on the shear stabilityof methylated guar (MG) of degree of substitution (DS) = 01unirradiated and irradiated

16000

14000

12000

10000

8000

6000

4000

2000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 13 Effect of radiation processing on the shear stabilityof methylated guar (MG) of degree of substitution (DS) = 02unirradiated and irradiated

12 International Journal of Carbohydrate Chemistry

2000

1800

1600

1400

1200

1000

800

600

400

200

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(a) CMG DS = 01

700

600

500

400

300

200

100

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(b) CMG DS = 02

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(c) HEG MS = 01

2000

1500

1000

500

0

0

20 40 60

Visc

osity

(cps

)

Radiation dose (KGy)

(d) HEG MS = 02

0 20 40 60

Radiation dose (KGy)

2500

2000

1500

1000

500

0

Visc

osity

(cps

)

(e) MG DS = 01

2000

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(f) MG DS = 02

Figure 14 The plot of minimum viscosity (at shear rate 30s) attained by the sample while subjecting it to shear from 1 to 30s for (a) CMGDS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02 with respect to radiation dose

International Journal of Carbohydrate Chemistry 13

30

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(a) CMG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(b) CMG DS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(c) HEG MS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(d) HEG MS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(e) MG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)

0

20 40 60

(f) MG DS = 02

Figure 15The plot of shear rate value versus radiation doseThe shear rate value was taken from the study carried out by increasing the shearrate and monitoring change in viscosity The point at which the curve between shear rate and viscosity reaches plateau was taken for plottingradiation dose versus shear rate for samples (a) CMG DS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02with respect to radiation dose

The depolymerisation of synthetic polymers by radiationprocessing for recycling of monomers has been known forquite some timeThepresent paper is an attempt to initiate theuse of this technology for radiation processing of modifiednatural polymers The gamma irradiation facility used for

the current studies is an industrial plant and it has been inoperation for about 20 years now where large volumes ofindustrial products are irradiated every day

From the results presented here it is evident that thedepolymerisation of guar is achieved with the radiation dose

14 International Journal of Carbohydrate Chemistry

of 1 KGy and above as seen from the observation of viscosityof 1 of guar derivatives getting reduced from as high a levelas 10000 cps (for unirradiated guar derivative) to as low alevel as 1 cps at 25∘C (for guar derivatives irradiated at 20ndash50KGy)

Inspite of this knowledge which can be easily usedfor scaling up of the process to commercial level doubtsare raised about the scalability of the process Whetherthe process can be used for bulk material is the commonapprehension in the minds of the processors of guar Whilethe present study would help clear many of the doubtsregarding the suitability of radiation processing technologybut the data about the scalability of the process would actuallyeliminate all sorts of doubts

Eventhough the results presented in this paper pertain tothe batch size of 200 g for each guar derivative at each dosethe same was found valid even for the bigger batch size (intons) The results of large batches were the same as obtainedfor the small batches Here it must be mentioned that thedose optimization for the purpose would be necessary for thepurpose of studying the scalability

From the present study the following can be concluded

(i) Radiation processing of guar derivatives leads to theirchain scissioning

(ii) Radiation processing leads to reduction in viscosity ofaqueous solutions of guar derivatives

(iii) Irradiation technique can be a good tool for tailormaking the guar derivatives of desired rheologicalproperties

(iv) The minimum viscosity attained by the 1 solutionof various derivatives shows a decreasing trend withrespect to increase in the radiation dose

(v) In case of carboxymethyl guar the crossover fre-quency increases as the radiation dose increases upto 5KGy and the value is higher in case of CMG ofDS 02 than in that of CMG of DS 01 This showsthat the elastic nature is more dominating for CMGof DS 01 than for CMG of DS 02

(vi) In case of hydroxyethyl guar ofMS 02 the crossoverfrequency of the 1198661015840 and 11986610158401015840 is lesser than that of HEGof MS 01 till 20 KGy radiation dose This meansthat elastic nature predominates in case of HEG ofMS 02 which may be due to the presence of greaternumber of ndash(CH

2ndashO)nndashH groups leading to increase

in H-bonding and thus more solid-like behavior(vii) In case of methyl guar on increasing the radiation

dose up to 10KGy the elastic component decreasesThis can be attributed to the fact that chain scissioningtakes place and now the H-bonding interactions takeplace between smaller chains which reduces theelasticity and viscous behavior predominates Dueto this the crossover frequency increases till 10 KGydose

(viii) As the radiation dose is increased the shear ratevalue at which nearly constant viscosity is achieveddecreases

Acknowledgment

The authors express sincere gratitude to the management ofShriram Institute for Industrial Research Delhi India for thekind support

References

[1] L Wang and L M Zhang ldquoViscoelastic characterization ofa new guar gum derivative containing anionic carboxymethyland cationic 2-hydroxy-3-(trimethylammonio)propyl substit-uentsrdquo Industrial Crops and Products vol 29 no 2-3 pp 524ndash529 2009

[2] C Sandolo PMatricardi F Alhaique and T Coviello ldquoEffect oftemperature and cross-linking density on rheology of chemicalcross-linked guar gum at the gel pointrdquo Food Hydrocolloids vol23 no 1 pp 210ndash220 2009

[3] H N Englyst V Anderson and J H Cummings ldquoStarch andnon-starch polysaccharides in some cereal foodsrdquo Journal of theScience of Food and Agriculture vol 34 no 12 pp 1434ndash14401983

[4] R L Feddersen and S N Thorp Industrial Gums AcaedemicPress San Diego Calif USA 1993

[5] D D Roberts J S Elmore K R Langley and J BakkerldquoEffects of sucrose guar gum and carboxymethylcelluloseon the release of volatile flavor compounds under dynamicconditionsrdquo Journal of Agricultural and Food Chemistry vol 44no 5 pp 1321ndash1326 1996

[6] D R Picout S B Ross-Murphy K Jumel and S E HardingldquoPressure cell assisted solution characterization of polysaccha-rides 2 Locust bean gum and tara gumrdquo Biomacromoleculesvol 3 no 4 pp 761ndash767 2002

[7] R S Blackburn ldquoNatural polysaccharides and their interactionswith dyemolecules applications in effluent treatmentrdquoEnviron-mental Science and Technology vol 38 no 18 pp 4905ndash49092004

[8] M Urdiaın A Domenech-Sanchez S Albertı V J Benedıand J A Rossello ldquoNew method of DNA isolation from twofood additives suitable for authentication in polymerase chainreaction assaysrdquo Journal of Agricultural and FoodChemistry vol53 no 9 pp 3345ndash3347 2005

[9] R P Singh S Pal andDMal ldquoA high performance flocculatingagent and viscosifiers based on cationic guar gumrdquoMacromolec-ular Symposia vol 242 pp 227ndash234 2006

[10] S P Zhao DMa and LM Zhang ldquoNew semi-interpenetratingnetwork hydrogels synthesis characterization and propertiesrdquoMacromolecular Bioscience vol 6 no 6 pp 445ndash451 2006

[11] J Z Yi and L M Zhang ldquoBiodegradable blend films basedon two polysaccharide derivatives and their use as Ibuprofen-releasing matricesrdquo Journal of Applied Polymer Science vol 103no 6 pp 3553ndash3559 2007

[12] S Venkataiah and E G Mahadevan ldquoRheological propertiesof hydroxypropyl and sodium carboxymethyl substituted guargums in aqueous solutionrdquo Journal of Applied Polymer Sciencevol 27 no 5 pp 1533ndash1548 1982

[13] R H W Wientjes M H G Duits R J J Jongschaap andJ Mellema ldquoLinear rheology of guar gum solutionsrdquo Macro-molecules vol 33 no 26 pp 9594ndash9605 2000

[14] T Aubry and M Moan ldquoRheological behavior of a hydropho-bically associating water soluble polymerrdquo Journal of Rheologyvol 38 no 6 pp 1681ndash1692 1994

International Journal of Carbohydrate Chemistry 15

[15] L M Zhang T Kong and P S Hui ldquoSemi-dilute solutions ofhydroxypropyl guar gum viscosity behaviour and thixotropicpropertiesrdquo Journal of the Science of Food and Agriculture vol87 no 4 pp 684ndash688 2007

[16] N N G Swamy T S Dharmarajan and K L K ParanjothildquoDerivatization of guar to various hydroxy alkyl derivatives andtheir characterizationrdquo Indian Drugs vol 43 no 9 pp 756ndash7592006

[17] H Gong M Liu J Chen F Han C Gao and B ZhangldquoSynthesis and characterization of carboxymethyl guar gumandrheological properties of its solutionsrdquo Carbohydrate Polymersvol 88 no 3 pp 1015ndash1022 2012

Submit your manuscripts athttpwwwhindawicom

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CatalystsJournal of

4 International Journal of Carbohydrate Chemistry

102

101

01 10 100 1000

119891 (Hz)

119866998400119866998400998400

(Pa)

(a) CMG DS = 01 0 KGy

102

101

100

01 10 100 1000

119891 (Hz)

119866998400119866998400998400

(Pa)

(b) CMG DS = 01 1 KGy

01 10 100 1000

102

101

100

119891 (Hz)

119866998400119866998400998400

(Pa)

(c) CMG DS = 01 25 KGy

01 10 100 1000

102

101

100

10minus1

119891 (Hz)119866998400119866998400998400

(Pa)

(d) CMG DS = 01 5 KGy

01 10 100 1000

102

101

100

10minus1

10minus2

119891 (Hz)

119866998400119866998400998400

(Pa)

(e) CMG DS = 01 10 KGy

01 10 100 1000

101

100

10minus1

10minus2

10minus3

10minus4

119891 (Hz)

119866998400119866998400998400

(Pa)

(f) CMG DS = 01 20 KGy

101

100

10minus1

10minus2

10minus3

10minus4

01 10 100 1000

119891 (Hz)

119866998400998400 = 119891 (119891)

119866998400 = 119891 (119891)

119866998400119866998400998400

(Pa)

(g) CMG DS = 01 50 KGy

Figure 2 Effect of radiation processing on the viscoelastic behavior of carboxymethylated guar (CMG) of degree of substitution (DS) = 01(a) unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy(g) irradiated at 50KGy

International Journal of Carbohydrate Chemistry 5

102

101

100

01 10 100 1000

119891 (Hz)

119866998400119866998400998400

(Pa)

(a) CMG DS = 02 0 KGy

102

101

100

10minus1

01 10 100 1000

119891 (Hz)

119866998400119866998400998400

(Pa)

(b) CMG DS = 02 1 KGy

01 10 100 1000

102

101

100

10minus1

119891 (Hz)

119866998400119866998400998400

(Pa)

(c) CMG DS = 02 25 KGy

01 10 100 1000

101

100

10minus1

119891 (Hz)

119866998400119866998400998400

(Pa)

(d) CMG DS = 02 5 KGy

102

101

100

10minus2

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) CMG DS = 02 10 KGy

101

100

10minus1

10minus2

10minus3

10minus4

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) CMG DS = 02 20 KGy

01 10 100 1000

101

102

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (119891)119866998400 = 119891 (119891)

(g) CMG DS = 02 50 KGy

Figure 3 Effect of radiation processing on the viscoelastic behavior of carboxymethylated guar (CMG) of degree of substitution (DS) = 02(a) unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy(g) irradiated at 50KGy

312 Hydroxyethyl Guar The hydroxyethyl guar (HEG)samples were irradiated and their viscoelastic behavior wasstudied as described in the previous section The change instorage (elastic 1198661015840) and the loss (viscous 11986610158401015840) moduli wasstudied over a range of frequency 1 to 30Hz and the results

obtained have been shown in Figures 4 and 5 On the basis ofthe results obtained the following observations were made

(i) As evident from Figures 4 and 5 in case of HEGof MS 02 the crossover frequency of the 1198661015840 and

6 International Journal of Carbohydrate Chemistry

102

101

01 10 100

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) HEGMS = 01 0 KGy

01 10 100

102

101

100

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) HEGMS = 01 1 KGy

102

101

100

10minus1

01 10 100

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) HEGMS = 01 25 KGy

01 10 100

101

100

10minus1

10minus2

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) HEGMS = 01 5 KGy

01 10 100

102

101

100

10minus1

10minus2

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) HEGMS = 01 10 KGy

01 10 100

102

101

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) HEGMS = 01 20 KGy

01 10 100

101

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (119891)119866998400 = 119891 (119891)

(g) HEGMS = 01 50 KGy

Figure 4 Effect of radiation processing on the viscoelastic behavior of hydroxyethylated guar (HEG) of molar substitution (MS) = 01 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

International Journal of Carbohydrate Chemistry 7

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) HEGMS = 02 0 KGy

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) HEGMS = 02 1 KGy

102

101

100

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) HEGMS = 02 25 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) HEGMS = 02 5 KGy

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) HEGMS = 02 10 KGy

01 10 100 1000

101

100

10minus1

10minus2

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) HEGMS = 02 20 KGy

01 10 100 1000

101

102

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (119891)119866998400 = 119891 (119891)

(g) HEGMS = 02 50 KGy

Figure 5 Effect of radiation processing on viscoelastic properties of hydroxyethyl guar (HEG) havingmolar substitution 02 (a) unirradiated(b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g) irradiated at50KGy

8 International Journal of Carbohydrate Chemistry

11986610158401015840 is lesser than that of HEG of MS 01 till 20 KGyradiation dose This means that elastic nature pre-dominates in case of HEG of MS 02 which may bedue to the presence of greater number of ndash(CH

2ndashO)nndash

H groups leading to increase in H-bonding and thusmore solid-like behavior

(ii) On comparing the crossover frequencies of HEG ofMS 01 after irradiation it can be seen from thedata that crossover frequency increases till 5 KGydoseand then it decreases whereas in case of HEG ofMS 02 the crossover frequency increases till 10 KGydose and then it decreases This can be explainedon the basis of interactions taking place between themacromolecular chains in these two HEGs In case ofHEG of MS 01 intermolecular interactions are lessas compared to HEG of MS 02 and thus less elasticnature

(iii) Also in case of HEG of MS 02 as the substitu-tion increases the coiling of macromolecular chaindecreases due to steric hindrance thereby causingmore intramolecular interactions than intermolec-ular interactions Less coiling of the chain causesmore exposure to irradiation and thus greater chainscissioning and more viscous response of the macro-molecule

(iv) As the radiation dose increases there is more chainscissioning leading to formation of oligomeric chainsThese chains form intermolecular hydrogen bondinglinkages leading to elastic behavior at lower frequen-cies

(v) The 1198661015840 and 11986610158401015840 values decrease on increasing theradiation dose which signifies chain scissioning

313 Methyl Guar The methyl guar (MG) samples wereirradiated and their viscoelastic behavior was studied asdescribed in the previous section The change in storage(elastic 1198661015840) and the loss (viscous 11986610158401015840) moduli was studiedover a range of frequency 1 to 30Hz and the results obtainedhave been shown in Figures 6 and 7

The following observations were made from the resultsIn case of MG of DS 01 no crossover of 1198661015840 and11986610158401015840 curves is seen in unirradiated and irradiated sampleat 1 KGy dose This shows that the elasticity predominatesMethyl group is hydrophobic in nature and its substitutionreduces the number of hydroxyl groups on guar moleculeand opens up the guar chains This leads to more number ofintermolecular interactions than intramolecular interactionsand thus increases elasticity

(i) On increasing the radiation dose up to 10KGy theelastic component decreasesThis can be attributed tothe fact that chain scissioning takes place and now theH-bonding interactions take place between smallerchains which reduces the elasticity and viscousbehavior predominates Due to this the crossoverfrequency increases till 10 KGy dose

(ii) Beyond 10KGy dose there is increase in the elasticcomponent which may be because of interactions in

the smaller chains because of hydrophobic methylgroup

32 Study on Effect of Irradiation on Shear Rate The effectof radiation on the change in viscosity with increase in shearrate (1 to 30s) was studied and has been shown in Figures 8to 13 To analyze this data the minimum viscosity (viscosityobtained at shear rate value of 30s) obtained for each of thesamples was plotted against the radiation dose (Figure 14)and the shear rate at which shear rate versus viscosity curvereaches a plateau was plotted with respect to the increase inradiation dose (Figure 15) for all the samples (CMGHEGandMG)

33 Radiation Dose versus Viscosity As evident fromFigure 14 the minimum viscosity attained by the 1 solutionof various derivatives both before and after irradiation showsa decreasing trend with respect to increase in the radiationdose The decrease is less pronounced in the case of sampleshaving higher substitution which shows that sampleswith greater substitution level exhibit higher resistance todepolymerisation

34 Radiation Dose versus Shear Rate Figure 15 shows theeffect of increasing the radiation dose on shear rate neededto achieve nearly constant viscosity with respect to changein shear rate As the radiation dose is increased the shearrate value at which nearly constant viscosity is achieveddecreases and at the same time the behavior of the three typesof derivatives is quite different for each type

In case of CMG the shear rate required to achieve nearlyconstant viscosity decreases with the increase in radiationdose This means that as the radiation dose is increasing theshear stability of carboxymethyl guar is increasing In otherwords the oligomeric chains of carboxymethyl guar formedon its irradiation exhibit better shear stability When we lookat the results obtained in case of hydroxyethyl guar then itbecomes evident that nearly constant viscosity in this case isachieved at higher shear rate values although a decreasingtrend in shear rate values is observed in this case also Incase of methyl guar also on increasing the radiation dosethe shear rate required to achieve nearly constant viscositydecreases In case of methyl guar of DS 01 the shear ratevalue was found to be nearly constant from 25 to 50KGyradiation dose

4 Conclusion

The depolymerisation of polymers and polymeric materialsby radiation processing is a dry technique Further forachieving the desired results one does not have to use anyof the additives In other words by radiation processing onecan depolymerize guar powder as such without making itssolution in water and without incorporation of additives

Radiation processing of materials such as polymersfood products precious stones medical goods has beenwidely adopted industrially since it is a continuous operationwhich is highly precise energy saving and reproducible

International Journal of Carbohydrate Chemistry 9

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) MG DS = 01 0 KGy

01 10 100 1000

102

101

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) MG DS = 01 1 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) MG DS = 01 25 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) MG DS = 01 5 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) MG DS = 01 10 KGy

102

101

100

10minus2

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) MG DS = 01 20 KGy

102

101

100

10minus2

10minus3

01 10 100 1000

119866998400998400 = 119891 (f)119866998400 = 119891 (f)

119866998400119866998400998400

(Pa)

119891 (Hz)

10minus1

(g) MG DS = 01 50 KGy

Figure 6 Effect of radiation processing on the viscoelastic behavior of methylated guar (MG) of degree of substitution (DS) = 01 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

10 International Journal of Carbohydrate Chemistry

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) MG DS = 02 0 KGy

01 10 100 1000

102

103

101

100

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) MG DS = 02 1 KGy

01 10 100 1000

102

101

100

10minus1

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) MG DS = 02 25 KGy

01 10 100 1000

102

101

100

10minus1

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) MG DS = 02 5 KGy

102

101

100

10minus1

10minus2

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) MG DS = 02 10 KGy

102

101

100

10minus1

10minus2

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) MG DS = 02 20 KGy

102

101

100

10minus1

10minus2

10minus3

10minus4

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (f)119866998400 = 119891 (f)

(g) MG DS = 02 50 KGy

Figure 7 Effect of radiation processing on the viscoelastic behavior of methylated guar (MG) of degree of substitution (DS) = 02 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

International Journal of Carbohydrate Chemistry 11

20000

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

0

25 5 75 10 125 15 175 20 225 25 275 30

Visc

osity

(cps

)

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 8 Effect of radiation processing on the shear stability ofcarboxymethylated guar (CMG) of degree of substitution (DS) =01 unirradiated and irradiated

3500

3000

2500

2000

1500

1000

500

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 9 Effect of radiation processing on the shear stability ofcarboxymethylated guar (CMG) of degree of substitution (DS) =02 unirradiated and irradiated

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 10 Effect of radiation processing on the shear stability ofhydroxyethylated guar (HEG) of molar substitution (MS) = 01unirradiated and irradiated

25000

20000

15000

10000

5000

0

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Visc

osity

(cps

)

Figure 11 Effect of radiation processing on the shear stability ofhydroxyethylated guar (HEG) of molar substitution (MS) = 02unirradiated and irradiated

25000

20000

15000

10000

5000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 12 Effect of radiation processing on the shear stabilityof methylated guar (MG) of degree of substitution (DS) = 01unirradiated and irradiated

16000

14000

12000

10000

8000

6000

4000

2000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 13 Effect of radiation processing on the shear stabilityof methylated guar (MG) of degree of substitution (DS) = 02unirradiated and irradiated

12 International Journal of Carbohydrate Chemistry

2000

1800

1600

1400

1200

1000

800

600

400

200

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(a) CMG DS = 01

700

600

500

400

300

200

100

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(b) CMG DS = 02

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(c) HEG MS = 01

2000

1500

1000

500

0

0

20 40 60

Visc

osity

(cps

)

Radiation dose (KGy)

(d) HEG MS = 02

0 20 40 60

Radiation dose (KGy)

2500

2000

1500

1000

500

0

Visc

osity

(cps

)

(e) MG DS = 01

2000

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(f) MG DS = 02

Figure 14 The plot of minimum viscosity (at shear rate 30s) attained by the sample while subjecting it to shear from 1 to 30s for (a) CMGDS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02 with respect to radiation dose

International Journal of Carbohydrate Chemistry 13

30

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(a) CMG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(b) CMG DS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(c) HEG MS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(d) HEG MS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(e) MG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)

0

20 40 60

(f) MG DS = 02

Figure 15The plot of shear rate value versus radiation doseThe shear rate value was taken from the study carried out by increasing the shearrate and monitoring change in viscosity The point at which the curve between shear rate and viscosity reaches plateau was taken for plottingradiation dose versus shear rate for samples (a) CMG DS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02with respect to radiation dose

The depolymerisation of synthetic polymers by radiationprocessing for recycling of monomers has been known forquite some timeThepresent paper is an attempt to initiate theuse of this technology for radiation processing of modifiednatural polymers The gamma irradiation facility used for

the current studies is an industrial plant and it has been inoperation for about 20 years now where large volumes ofindustrial products are irradiated every day

From the results presented here it is evident that thedepolymerisation of guar is achieved with the radiation dose

14 International Journal of Carbohydrate Chemistry

of 1 KGy and above as seen from the observation of viscosityof 1 of guar derivatives getting reduced from as high a levelas 10000 cps (for unirradiated guar derivative) to as low alevel as 1 cps at 25∘C (for guar derivatives irradiated at 20ndash50KGy)

Inspite of this knowledge which can be easily usedfor scaling up of the process to commercial level doubtsare raised about the scalability of the process Whetherthe process can be used for bulk material is the commonapprehension in the minds of the processors of guar Whilethe present study would help clear many of the doubtsregarding the suitability of radiation processing technologybut the data about the scalability of the process would actuallyeliminate all sorts of doubts

Eventhough the results presented in this paper pertain tothe batch size of 200 g for each guar derivative at each dosethe same was found valid even for the bigger batch size (intons) The results of large batches were the same as obtainedfor the small batches Here it must be mentioned that thedose optimization for the purpose would be necessary for thepurpose of studying the scalability

From the present study the following can be concluded

(i) Radiation processing of guar derivatives leads to theirchain scissioning

(ii) Radiation processing leads to reduction in viscosity ofaqueous solutions of guar derivatives

(iii) Irradiation technique can be a good tool for tailormaking the guar derivatives of desired rheologicalproperties

(iv) The minimum viscosity attained by the 1 solutionof various derivatives shows a decreasing trend withrespect to increase in the radiation dose

(v) In case of carboxymethyl guar the crossover fre-quency increases as the radiation dose increases upto 5KGy and the value is higher in case of CMG ofDS 02 than in that of CMG of DS 01 This showsthat the elastic nature is more dominating for CMGof DS 01 than for CMG of DS 02

(vi) In case of hydroxyethyl guar ofMS 02 the crossoverfrequency of the 1198661015840 and 11986610158401015840 is lesser than that of HEGof MS 01 till 20 KGy radiation dose This meansthat elastic nature predominates in case of HEG ofMS 02 which may be due to the presence of greaternumber of ndash(CH

2ndashO)nndashH groups leading to increase

in H-bonding and thus more solid-like behavior(vii) In case of methyl guar on increasing the radiation

dose up to 10KGy the elastic component decreasesThis can be attributed to the fact that chain scissioningtakes place and now the H-bonding interactions takeplace between smaller chains which reduces theelasticity and viscous behavior predominates Dueto this the crossover frequency increases till 10 KGydose

(viii) As the radiation dose is increased the shear ratevalue at which nearly constant viscosity is achieveddecreases

Acknowledgment

The authors express sincere gratitude to the management ofShriram Institute for Industrial Research Delhi India for thekind support

References

[1] L Wang and L M Zhang ldquoViscoelastic characterization ofa new guar gum derivative containing anionic carboxymethyland cationic 2-hydroxy-3-(trimethylammonio)propyl substit-uentsrdquo Industrial Crops and Products vol 29 no 2-3 pp 524ndash529 2009

[2] C Sandolo PMatricardi F Alhaique and T Coviello ldquoEffect oftemperature and cross-linking density on rheology of chemicalcross-linked guar gum at the gel pointrdquo Food Hydrocolloids vol23 no 1 pp 210ndash220 2009

[3] H N Englyst V Anderson and J H Cummings ldquoStarch andnon-starch polysaccharides in some cereal foodsrdquo Journal of theScience of Food and Agriculture vol 34 no 12 pp 1434ndash14401983

[4] R L Feddersen and S N Thorp Industrial Gums AcaedemicPress San Diego Calif USA 1993

[5] D D Roberts J S Elmore K R Langley and J BakkerldquoEffects of sucrose guar gum and carboxymethylcelluloseon the release of volatile flavor compounds under dynamicconditionsrdquo Journal of Agricultural and Food Chemistry vol 44no 5 pp 1321ndash1326 1996

[6] D R Picout S B Ross-Murphy K Jumel and S E HardingldquoPressure cell assisted solution characterization of polysaccha-rides 2 Locust bean gum and tara gumrdquo Biomacromoleculesvol 3 no 4 pp 761ndash767 2002

[7] R S Blackburn ldquoNatural polysaccharides and their interactionswith dyemolecules applications in effluent treatmentrdquoEnviron-mental Science and Technology vol 38 no 18 pp 4905ndash49092004

[8] M Urdiaın A Domenech-Sanchez S Albertı V J Benedıand J A Rossello ldquoNew method of DNA isolation from twofood additives suitable for authentication in polymerase chainreaction assaysrdquo Journal of Agricultural and FoodChemistry vol53 no 9 pp 3345ndash3347 2005

[9] R P Singh S Pal andDMal ldquoA high performance flocculatingagent and viscosifiers based on cationic guar gumrdquoMacromolec-ular Symposia vol 242 pp 227ndash234 2006

[10] S P Zhao DMa and LM Zhang ldquoNew semi-interpenetratingnetwork hydrogels synthesis characterization and propertiesrdquoMacromolecular Bioscience vol 6 no 6 pp 445ndash451 2006

[11] J Z Yi and L M Zhang ldquoBiodegradable blend films basedon two polysaccharide derivatives and their use as Ibuprofen-releasing matricesrdquo Journal of Applied Polymer Science vol 103no 6 pp 3553ndash3559 2007

[12] S Venkataiah and E G Mahadevan ldquoRheological propertiesof hydroxypropyl and sodium carboxymethyl substituted guargums in aqueous solutionrdquo Journal of Applied Polymer Sciencevol 27 no 5 pp 1533ndash1548 1982

[13] R H W Wientjes M H G Duits R J J Jongschaap andJ Mellema ldquoLinear rheology of guar gum solutionsrdquo Macro-molecules vol 33 no 26 pp 9594ndash9605 2000

[14] T Aubry and M Moan ldquoRheological behavior of a hydropho-bically associating water soluble polymerrdquo Journal of Rheologyvol 38 no 6 pp 1681ndash1692 1994

International Journal of Carbohydrate Chemistry 15

[15] L M Zhang T Kong and P S Hui ldquoSemi-dilute solutions ofhydroxypropyl guar gum viscosity behaviour and thixotropicpropertiesrdquo Journal of the Science of Food and Agriculture vol87 no 4 pp 684ndash688 2007

[16] N N G Swamy T S Dharmarajan and K L K ParanjothildquoDerivatization of guar to various hydroxy alkyl derivatives andtheir characterizationrdquo Indian Drugs vol 43 no 9 pp 756ndash7592006

[17] H Gong M Liu J Chen F Han C Gao and B ZhangldquoSynthesis and characterization of carboxymethyl guar gumandrheological properties of its solutionsrdquo Carbohydrate Polymersvol 88 no 3 pp 1015ndash1022 2012

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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CatalystsJournal of

International Journal of Carbohydrate Chemistry 5

102

101

100

01 10 100 1000

119891 (Hz)

119866998400119866998400998400

(Pa)

(a) CMG DS = 02 0 KGy

102

101

100

10minus1

01 10 100 1000

119891 (Hz)

119866998400119866998400998400

(Pa)

(b) CMG DS = 02 1 KGy

01 10 100 1000

102

101

100

10minus1

119891 (Hz)

119866998400119866998400998400

(Pa)

(c) CMG DS = 02 25 KGy

01 10 100 1000

101

100

10minus1

119891 (Hz)

119866998400119866998400998400

(Pa)

(d) CMG DS = 02 5 KGy

102

101

100

10minus2

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) CMG DS = 02 10 KGy

101

100

10minus1

10minus2

10minus3

10minus4

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) CMG DS = 02 20 KGy

01 10 100 1000

101

102

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (119891)119866998400 = 119891 (119891)

(g) CMG DS = 02 50 KGy

Figure 3 Effect of radiation processing on the viscoelastic behavior of carboxymethylated guar (CMG) of degree of substitution (DS) = 02(a) unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy(g) irradiated at 50KGy

312 Hydroxyethyl Guar The hydroxyethyl guar (HEG)samples were irradiated and their viscoelastic behavior wasstudied as described in the previous section The change instorage (elastic 1198661015840) and the loss (viscous 11986610158401015840) moduli wasstudied over a range of frequency 1 to 30Hz and the results

obtained have been shown in Figures 4 and 5 On the basis ofthe results obtained the following observations were made

(i) As evident from Figures 4 and 5 in case of HEGof MS 02 the crossover frequency of the 1198661015840 and

6 International Journal of Carbohydrate Chemistry

102

101

01 10 100

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) HEGMS = 01 0 KGy

01 10 100

102

101

100

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) HEGMS = 01 1 KGy

102

101

100

10minus1

01 10 100

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) HEGMS = 01 25 KGy

01 10 100

101

100

10minus1

10minus2

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) HEGMS = 01 5 KGy

01 10 100

102

101

100

10minus1

10minus2

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) HEGMS = 01 10 KGy

01 10 100

102

101

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) HEGMS = 01 20 KGy

01 10 100

101

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (119891)119866998400 = 119891 (119891)

(g) HEGMS = 01 50 KGy

Figure 4 Effect of radiation processing on the viscoelastic behavior of hydroxyethylated guar (HEG) of molar substitution (MS) = 01 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

International Journal of Carbohydrate Chemistry 7

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) HEGMS = 02 0 KGy

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) HEGMS = 02 1 KGy

102

101

100

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) HEGMS = 02 25 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) HEGMS = 02 5 KGy

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) HEGMS = 02 10 KGy

01 10 100 1000

101

100

10minus1

10minus2

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) HEGMS = 02 20 KGy

01 10 100 1000

101

102

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (119891)119866998400 = 119891 (119891)

(g) HEGMS = 02 50 KGy

Figure 5 Effect of radiation processing on viscoelastic properties of hydroxyethyl guar (HEG) havingmolar substitution 02 (a) unirradiated(b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g) irradiated at50KGy

8 International Journal of Carbohydrate Chemistry

11986610158401015840 is lesser than that of HEG of MS 01 till 20 KGyradiation dose This means that elastic nature pre-dominates in case of HEG of MS 02 which may bedue to the presence of greater number of ndash(CH

2ndashO)nndash

H groups leading to increase in H-bonding and thusmore solid-like behavior

(ii) On comparing the crossover frequencies of HEG ofMS 01 after irradiation it can be seen from thedata that crossover frequency increases till 5 KGydoseand then it decreases whereas in case of HEG ofMS 02 the crossover frequency increases till 10 KGydose and then it decreases This can be explainedon the basis of interactions taking place between themacromolecular chains in these two HEGs In case ofHEG of MS 01 intermolecular interactions are lessas compared to HEG of MS 02 and thus less elasticnature

(iii) Also in case of HEG of MS 02 as the substitu-tion increases the coiling of macromolecular chaindecreases due to steric hindrance thereby causingmore intramolecular interactions than intermolec-ular interactions Less coiling of the chain causesmore exposure to irradiation and thus greater chainscissioning and more viscous response of the macro-molecule

(iv) As the radiation dose increases there is more chainscissioning leading to formation of oligomeric chainsThese chains form intermolecular hydrogen bondinglinkages leading to elastic behavior at lower frequen-cies

(v) The 1198661015840 and 11986610158401015840 values decrease on increasing theradiation dose which signifies chain scissioning

313 Methyl Guar The methyl guar (MG) samples wereirradiated and their viscoelastic behavior was studied asdescribed in the previous section The change in storage(elastic 1198661015840) and the loss (viscous 11986610158401015840) moduli was studiedover a range of frequency 1 to 30Hz and the results obtainedhave been shown in Figures 6 and 7

The following observations were made from the resultsIn case of MG of DS 01 no crossover of 1198661015840 and11986610158401015840 curves is seen in unirradiated and irradiated sampleat 1 KGy dose This shows that the elasticity predominatesMethyl group is hydrophobic in nature and its substitutionreduces the number of hydroxyl groups on guar moleculeand opens up the guar chains This leads to more number ofintermolecular interactions than intramolecular interactionsand thus increases elasticity

(i) On increasing the radiation dose up to 10KGy theelastic component decreasesThis can be attributed tothe fact that chain scissioning takes place and now theH-bonding interactions take place between smallerchains which reduces the elasticity and viscousbehavior predominates Due to this the crossoverfrequency increases till 10 KGy dose

(ii) Beyond 10KGy dose there is increase in the elasticcomponent which may be because of interactions in

the smaller chains because of hydrophobic methylgroup

32 Study on Effect of Irradiation on Shear Rate The effectof radiation on the change in viscosity with increase in shearrate (1 to 30s) was studied and has been shown in Figures 8to 13 To analyze this data the minimum viscosity (viscosityobtained at shear rate value of 30s) obtained for each of thesamples was plotted against the radiation dose (Figure 14)and the shear rate at which shear rate versus viscosity curvereaches a plateau was plotted with respect to the increase inradiation dose (Figure 15) for all the samples (CMGHEGandMG)

33 Radiation Dose versus Viscosity As evident fromFigure 14 the minimum viscosity attained by the 1 solutionof various derivatives both before and after irradiation showsa decreasing trend with respect to increase in the radiationdose The decrease is less pronounced in the case of sampleshaving higher substitution which shows that sampleswith greater substitution level exhibit higher resistance todepolymerisation

34 Radiation Dose versus Shear Rate Figure 15 shows theeffect of increasing the radiation dose on shear rate neededto achieve nearly constant viscosity with respect to changein shear rate As the radiation dose is increased the shearrate value at which nearly constant viscosity is achieveddecreases and at the same time the behavior of the three typesof derivatives is quite different for each type

In case of CMG the shear rate required to achieve nearlyconstant viscosity decreases with the increase in radiationdose This means that as the radiation dose is increasing theshear stability of carboxymethyl guar is increasing In otherwords the oligomeric chains of carboxymethyl guar formedon its irradiation exhibit better shear stability When we lookat the results obtained in case of hydroxyethyl guar then itbecomes evident that nearly constant viscosity in this case isachieved at higher shear rate values although a decreasingtrend in shear rate values is observed in this case also Incase of methyl guar also on increasing the radiation dosethe shear rate required to achieve nearly constant viscositydecreases In case of methyl guar of DS 01 the shear ratevalue was found to be nearly constant from 25 to 50KGyradiation dose

4 Conclusion

The depolymerisation of polymers and polymeric materialsby radiation processing is a dry technique Further forachieving the desired results one does not have to use anyof the additives In other words by radiation processing onecan depolymerize guar powder as such without making itssolution in water and without incorporation of additives

Radiation processing of materials such as polymersfood products precious stones medical goods has beenwidely adopted industrially since it is a continuous operationwhich is highly precise energy saving and reproducible

International Journal of Carbohydrate Chemistry 9

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) MG DS = 01 0 KGy

01 10 100 1000

102

101

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) MG DS = 01 1 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) MG DS = 01 25 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) MG DS = 01 5 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) MG DS = 01 10 KGy

102

101

100

10minus2

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) MG DS = 01 20 KGy

102

101

100

10minus2

10minus3

01 10 100 1000

119866998400998400 = 119891 (f)119866998400 = 119891 (f)

119866998400119866998400998400

(Pa)

119891 (Hz)

10minus1

(g) MG DS = 01 50 KGy

Figure 6 Effect of radiation processing on the viscoelastic behavior of methylated guar (MG) of degree of substitution (DS) = 01 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

10 International Journal of Carbohydrate Chemistry

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) MG DS = 02 0 KGy

01 10 100 1000

102

103

101

100

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) MG DS = 02 1 KGy

01 10 100 1000

102

101

100

10minus1

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) MG DS = 02 25 KGy

01 10 100 1000

102

101

100

10minus1

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) MG DS = 02 5 KGy

102

101

100

10minus1

10minus2

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) MG DS = 02 10 KGy

102

101

100

10minus1

10minus2

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) MG DS = 02 20 KGy

102

101

100

10minus1

10minus2

10minus3

10minus4

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (f)119866998400 = 119891 (f)

(g) MG DS = 02 50 KGy

Figure 7 Effect of radiation processing on the viscoelastic behavior of methylated guar (MG) of degree of substitution (DS) = 02 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

International Journal of Carbohydrate Chemistry 11

20000

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

0

25 5 75 10 125 15 175 20 225 25 275 30

Visc

osity

(cps

)

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 8 Effect of radiation processing on the shear stability ofcarboxymethylated guar (CMG) of degree of substitution (DS) =01 unirradiated and irradiated

3500

3000

2500

2000

1500

1000

500

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 9 Effect of radiation processing on the shear stability ofcarboxymethylated guar (CMG) of degree of substitution (DS) =02 unirradiated and irradiated

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 10 Effect of radiation processing on the shear stability ofhydroxyethylated guar (HEG) of molar substitution (MS) = 01unirradiated and irradiated

25000

20000

15000

10000

5000

0

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Visc

osity

(cps

)

Figure 11 Effect of radiation processing on the shear stability ofhydroxyethylated guar (HEG) of molar substitution (MS) = 02unirradiated and irradiated

25000

20000

15000

10000

5000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 12 Effect of radiation processing on the shear stabilityof methylated guar (MG) of degree of substitution (DS) = 01unirradiated and irradiated

16000

14000

12000

10000

8000

6000

4000

2000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 13 Effect of radiation processing on the shear stabilityof methylated guar (MG) of degree of substitution (DS) = 02unirradiated and irradiated

12 International Journal of Carbohydrate Chemistry

2000

1800

1600

1400

1200

1000

800

600

400

200

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(a) CMG DS = 01

700

600

500

400

300

200

100

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(b) CMG DS = 02

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(c) HEG MS = 01

2000

1500

1000

500

0

0

20 40 60

Visc

osity

(cps

)

Radiation dose (KGy)

(d) HEG MS = 02

0 20 40 60

Radiation dose (KGy)

2500

2000

1500

1000

500

0

Visc

osity

(cps

)

(e) MG DS = 01

2000

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(f) MG DS = 02

Figure 14 The plot of minimum viscosity (at shear rate 30s) attained by the sample while subjecting it to shear from 1 to 30s for (a) CMGDS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02 with respect to radiation dose

International Journal of Carbohydrate Chemistry 13

30

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(a) CMG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(b) CMG DS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(c) HEG MS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(d) HEG MS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(e) MG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)

0

20 40 60

(f) MG DS = 02

Figure 15The plot of shear rate value versus radiation doseThe shear rate value was taken from the study carried out by increasing the shearrate and monitoring change in viscosity The point at which the curve between shear rate and viscosity reaches plateau was taken for plottingradiation dose versus shear rate for samples (a) CMG DS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02with respect to radiation dose

The depolymerisation of synthetic polymers by radiationprocessing for recycling of monomers has been known forquite some timeThepresent paper is an attempt to initiate theuse of this technology for radiation processing of modifiednatural polymers The gamma irradiation facility used for

the current studies is an industrial plant and it has been inoperation for about 20 years now where large volumes ofindustrial products are irradiated every day

From the results presented here it is evident that thedepolymerisation of guar is achieved with the radiation dose

14 International Journal of Carbohydrate Chemistry

of 1 KGy and above as seen from the observation of viscosityof 1 of guar derivatives getting reduced from as high a levelas 10000 cps (for unirradiated guar derivative) to as low alevel as 1 cps at 25∘C (for guar derivatives irradiated at 20ndash50KGy)

Inspite of this knowledge which can be easily usedfor scaling up of the process to commercial level doubtsare raised about the scalability of the process Whetherthe process can be used for bulk material is the commonapprehension in the minds of the processors of guar Whilethe present study would help clear many of the doubtsregarding the suitability of radiation processing technologybut the data about the scalability of the process would actuallyeliminate all sorts of doubts

Eventhough the results presented in this paper pertain tothe batch size of 200 g for each guar derivative at each dosethe same was found valid even for the bigger batch size (intons) The results of large batches were the same as obtainedfor the small batches Here it must be mentioned that thedose optimization for the purpose would be necessary for thepurpose of studying the scalability

From the present study the following can be concluded

(i) Radiation processing of guar derivatives leads to theirchain scissioning

(ii) Radiation processing leads to reduction in viscosity ofaqueous solutions of guar derivatives

(iii) Irradiation technique can be a good tool for tailormaking the guar derivatives of desired rheologicalproperties

(iv) The minimum viscosity attained by the 1 solutionof various derivatives shows a decreasing trend withrespect to increase in the radiation dose

(v) In case of carboxymethyl guar the crossover fre-quency increases as the radiation dose increases upto 5KGy and the value is higher in case of CMG ofDS 02 than in that of CMG of DS 01 This showsthat the elastic nature is more dominating for CMGof DS 01 than for CMG of DS 02

(vi) In case of hydroxyethyl guar ofMS 02 the crossoverfrequency of the 1198661015840 and 11986610158401015840 is lesser than that of HEGof MS 01 till 20 KGy radiation dose This meansthat elastic nature predominates in case of HEG ofMS 02 which may be due to the presence of greaternumber of ndash(CH

2ndashO)nndashH groups leading to increase

in H-bonding and thus more solid-like behavior(vii) In case of methyl guar on increasing the radiation

dose up to 10KGy the elastic component decreasesThis can be attributed to the fact that chain scissioningtakes place and now the H-bonding interactions takeplace between smaller chains which reduces theelasticity and viscous behavior predominates Dueto this the crossover frequency increases till 10 KGydose

(viii) As the radiation dose is increased the shear ratevalue at which nearly constant viscosity is achieveddecreases

Acknowledgment

The authors express sincere gratitude to the management ofShriram Institute for Industrial Research Delhi India for thekind support

References

[1] L Wang and L M Zhang ldquoViscoelastic characterization ofa new guar gum derivative containing anionic carboxymethyland cationic 2-hydroxy-3-(trimethylammonio)propyl substit-uentsrdquo Industrial Crops and Products vol 29 no 2-3 pp 524ndash529 2009

[2] C Sandolo PMatricardi F Alhaique and T Coviello ldquoEffect oftemperature and cross-linking density on rheology of chemicalcross-linked guar gum at the gel pointrdquo Food Hydrocolloids vol23 no 1 pp 210ndash220 2009

[3] H N Englyst V Anderson and J H Cummings ldquoStarch andnon-starch polysaccharides in some cereal foodsrdquo Journal of theScience of Food and Agriculture vol 34 no 12 pp 1434ndash14401983

[4] R L Feddersen and S N Thorp Industrial Gums AcaedemicPress San Diego Calif USA 1993

[5] D D Roberts J S Elmore K R Langley and J BakkerldquoEffects of sucrose guar gum and carboxymethylcelluloseon the release of volatile flavor compounds under dynamicconditionsrdquo Journal of Agricultural and Food Chemistry vol 44no 5 pp 1321ndash1326 1996

[6] D R Picout S B Ross-Murphy K Jumel and S E HardingldquoPressure cell assisted solution characterization of polysaccha-rides 2 Locust bean gum and tara gumrdquo Biomacromoleculesvol 3 no 4 pp 761ndash767 2002

[7] R S Blackburn ldquoNatural polysaccharides and their interactionswith dyemolecules applications in effluent treatmentrdquoEnviron-mental Science and Technology vol 38 no 18 pp 4905ndash49092004

[8] M Urdiaın A Domenech-Sanchez S Albertı V J Benedıand J A Rossello ldquoNew method of DNA isolation from twofood additives suitable for authentication in polymerase chainreaction assaysrdquo Journal of Agricultural and FoodChemistry vol53 no 9 pp 3345ndash3347 2005

[9] R P Singh S Pal andDMal ldquoA high performance flocculatingagent and viscosifiers based on cationic guar gumrdquoMacromolec-ular Symposia vol 242 pp 227ndash234 2006

[10] S P Zhao DMa and LM Zhang ldquoNew semi-interpenetratingnetwork hydrogels synthesis characterization and propertiesrdquoMacromolecular Bioscience vol 6 no 6 pp 445ndash451 2006

[11] J Z Yi and L M Zhang ldquoBiodegradable blend films basedon two polysaccharide derivatives and their use as Ibuprofen-releasing matricesrdquo Journal of Applied Polymer Science vol 103no 6 pp 3553ndash3559 2007

[12] S Venkataiah and E G Mahadevan ldquoRheological propertiesof hydroxypropyl and sodium carboxymethyl substituted guargums in aqueous solutionrdquo Journal of Applied Polymer Sciencevol 27 no 5 pp 1533ndash1548 1982

[13] R H W Wientjes M H G Duits R J J Jongschaap andJ Mellema ldquoLinear rheology of guar gum solutionsrdquo Macro-molecules vol 33 no 26 pp 9594ndash9605 2000

[14] T Aubry and M Moan ldquoRheological behavior of a hydropho-bically associating water soluble polymerrdquo Journal of Rheologyvol 38 no 6 pp 1681ndash1692 1994

International Journal of Carbohydrate Chemistry 15

[15] L M Zhang T Kong and P S Hui ldquoSemi-dilute solutions ofhydroxypropyl guar gum viscosity behaviour and thixotropicpropertiesrdquo Journal of the Science of Food and Agriculture vol87 no 4 pp 684ndash688 2007

[16] N N G Swamy T S Dharmarajan and K L K ParanjothildquoDerivatization of guar to various hydroxy alkyl derivatives andtheir characterizationrdquo Indian Drugs vol 43 no 9 pp 756ndash7592006

[17] H Gong M Liu J Chen F Han C Gao and B ZhangldquoSynthesis and characterization of carboxymethyl guar gumandrheological properties of its solutionsrdquo Carbohydrate Polymersvol 88 no 3 pp 1015ndash1022 2012

Submit your manuscripts athttpwwwhindawicom

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CatalystsJournal of

6 International Journal of Carbohydrate Chemistry

102

101

01 10 100

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) HEGMS = 01 0 KGy

01 10 100

102

101

100

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) HEGMS = 01 1 KGy

102

101

100

10minus1

01 10 100

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) HEGMS = 01 25 KGy

01 10 100

101

100

10minus1

10minus2

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) HEGMS = 01 5 KGy

01 10 100

102

101

100

10minus1

10minus2

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) HEGMS = 01 10 KGy

01 10 100

102

101

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) HEGMS = 01 20 KGy

01 10 100

101

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (119891)119866998400 = 119891 (119891)

(g) HEGMS = 01 50 KGy

Figure 4 Effect of radiation processing on the viscoelastic behavior of hydroxyethylated guar (HEG) of molar substitution (MS) = 01 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

International Journal of Carbohydrate Chemistry 7

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) HEGMS = 02 0 KGy

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) HEGMS = 02 1 KGy

102

101

100

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) HEGMS = 02 25 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) HEGMS = 02 5 KGy

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) HEGMS = 02 10 KGy

01 10 100 1000

101

100

10minus1

10minus2

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) HEGMS = 02 20 KGy

01 10 100 1000

101

102

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (119891)119866998400 = 119891 (119891)

(g) HEGMS = 02 50 KGy

Figure 5 Effect of radiation processing on viscoelastic properties of hydroxyethyl guar (HEG) havingmolar substitution 02 (a) unirradiated(b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g) irradiated at50KGy

8 International Journal of Carbohydrate Chemistry

11986610158401015840 is lesser than that of HEG of MS 01 till 20 KGyradiation dose This means that elastic nature pre-dominates in case of HEG of MS 02 which may bedue to the presence of greater number of ndash(CH

2ndashO)nndash

H groups leading to increase in H-bonding and thusmore solid-like behavior

(ii) On comparing the crossover frequencies of HEG ofMS 01 after irradiation it can be seen from thedata that crossover frequency increases till 5 KGydoseand then it decreases whereas in case of HEG ofMS 02 the crossover frequency increases till 10 KGydose and then it decreases This can be explainedon the basis of interactions taking place between themacromolecular chains in these two HEGs In case ofHEG of MS 01 intermolecular interactions are lessas compared to HEG of MS 02 and thus less elasticnature

(iii) Also in case of HEG of MS 02 as the substitu-tion increases the coiling of macromolecular chaindecreases due to steric hindrance thereby causingmore intramolecular interactions than intermolec-ular interactions Less coiling of the chain causesmore exposure to irradiation and thus greater chainscissioning and more viscous response of the macro-molecule

(iv) As the radiation dose increases there is more chainscissioning leading to formation of oligomeric chainsThese chains form intermolecular hydrogen bondinglinkages leading to elastic behavior at lower frequen-cies

(v) The 1198661015840 and 11986610158401015840 values decrease on increasing theradiation dose which signifies chain scissioning

313 Methyl Guar The methyl guar (MG) samples wereirradiated and their viscoelastic behavior was studied asdescribed in the previous section The change in storage(elastic 1198661015840) and the loss (viscous 11986610158401015840) moduli was studiedover a range of frequency 1 to 30Hz and the results obtainedhave been shown in Figures 6 and 7

The following observations were made from the resultsIn case of MG of DS 01 no crossover of 1198661015840 and11986610158401015840 curves is seen in unirradiated and irradiated sampleat 1 KGy dose This shows that the elasticity predominatesMethyl group is hydrophobic in nature and its substitutionreduces the number of hydroxyl groups on guar moleculeand opens up the guar chains This leads to more number ofintermolecular interactions than intramolecular interactionsand thus increases elasticity

(i) On increasing the radiation dose up to 10KGy theelastic component decreasesThis can be attributed tothe fact that chain scissioning takes place and now theH-bonding interactions take place between smallerchains which reduces the elasticity and viscousbehavior predominates Due to this the crossoverfrequency increases till 10 KGy dose

(ii) Beyond 10KGy dose there is increase in the elasticcomponent which may be because of interactions in

the smaller chains because of hydrophobic methylgroup

32 Study on Effect of Irradiation on Shear Rate The effectof radiation on the change in viscosity with increase in shearrate (1 to 30s) was studied and has been shown in Figures 8to 13 To analyze this data the minimum viscosity (viscosityobtained at shear rate value of 30s) obtained for each of thesamples was plotted against the radiation dose (Figure 14)and the shear rate at which shear rate versus viscosity curvereaches a plateau was plotted with respect to the increase inradiation dose (Figure 15) for all the samples (CMGHEGandMG)

33 Radiation Dose versus Viscosity As evident fromFigure 14 the minimum viscosity attained by the 1 solutionof various derivatives both before and after irradiation showsa decreasing trend with respect to increase in the radiationdose The decrease is less pronounced in the case of sampleshaving higher substitution which shows that sampleswith greater substitution level exhibit higher resistance todepolymerisation

34 Radiation Dose versus Shear Rate Figure 15 shows theeffect of increasing the radiation dose on shear rate neededto achieve nearly constant viscosity with respect to changein shear rate As the radiation dose is increased the shearrate value at which nearly constant viscosity is achieveddecreases and at the same time the behavior of the three typesof derivatives is quite different for each type

In case of CMG the shear rate required to achieve nearlyconstant viscosity decreases with the increase in radiationdose This means that as the radiation dose is increasing theshear stability of carboxymethyl guar is increasing In otherwords the oligomeric chains of carboxymethyl guar formedon its irradiation exhibit better shear stability When we lookat the results obtained in case of hydroxyethyl guar then itbecomes evident that nearly constant viscosity in this case isachieved at higher shear rate values although a decreasingtrend in shear rate values is observed in this case also Incase of methyl guar also on increasing the radiation dosethe shear rate required to achieve nearly constant viscositydecreases In case of methyl guar of DS 01 the shear ratevalue was found to be nearly constant from 25 to 50KGyradiation dose

4 Conclusion

The depolymerisation of polymers and polymeric materialsby radiation processing is a dry technique Further forachieving the desired results one does not have to use anyof the additives In other words by radiation processing onecan depolymerize guar powder as such without making itssolution in water and without incorporation of additives

Radiation processing of materials such as polymersfood products precious stones medical goods has beenwidely adopted industrially since it is a continuous operationwhich is highly precise energy saving and reproducible

International Journal of Carbohydrate Chemistry 9

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) MG DS = 01 0 KGy

01 10 100 1000

102

101

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) MG DS = 01 1 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) MG DS = 01 25 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) MG DS = 01 5 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) MG DS = 01 10 KGy

102

101

100

10minus2

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) MG DS = 01 20 KGy

102

101

100

10minus2

10minus3

01 10 100 1000

119866998400998400 = 119891 (f)119866998400 = 119891 (f)

119866998400119866998400998400

(Pa)

119891 (Hz)

10minus1

(g) MG DS = 01 50 KGy

Figure 6 Effect of radiation processing on the viscoelastic behavior of methylated guar (MG) of degree of substitution (DS) = 01 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

10 International Journal of Carbohydrate Chemistry

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) MG DS = 02 0 KGy

01 10 100 1000

102

103

101

100

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) MG DS = 02 1 KGy

01 10 100 1000

102

101

100

10minus1

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) MG DS = 02 25 KGy

01 10 100 1000

102

101

100

10minus1

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) MG DS = 02 5 KGy

102

101

100

10minus1

10minus2

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) MG DS = 02 10 KGy

102

101

100

10minus1

10minus2

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) MG DS = 02 20 KGy

102

101

100

10minus1

10minus2

10minus3

10minus4

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (f)119866998400 = 119891 (f)

(g) MG DS = 02 50 KGy

Figure 7 Effect of radiation processing on the viscoelastic behavior of methylated guar (MG) of degree of substitution (DS) = 02 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

International Journal of Carbohydrate Chemistry 11

20000

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

0

25 5 75 10 125 15 175 20 225 25 275 30

Visc

osity

(cps

)

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 8 Effect of radiation processing on the shear stability ofcarboxymethylated guar (CMG) of degree of substitution (DS) =01 unirradiated and irradiated

3500

3000

2500

2000

1500

1000

500

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 9 Effect of radiation processing on the shear stability ofcarboxymethylated guar (CMG) of degree of substitution (DS) =02 unirradiated and irradiated

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 10 Effect of radiation processing on the shear stability ofhydroxyethylated guar (HEG) of molar substitution (MS) = 01unirradiated and irradiated

25000

20000

15000

10000

5000

0

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Visc

osity

(cps

)

Figure 11 Effect of radiation processing on the shear stability ofhydroxyethylated guar (HEG) of molar substitution (MS) = 02unirradiated and irradiated

25000

20000

15000

10000

5000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 12 Effect of radiation processing on the shear stabilityof methylated guar (MG) of degree of substitution (DS) = 01unirradiated and irradiated

16000

14000

12000

10000

8000

6000

4000

2000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 13 Effect of radiation processing on the shear stabilityof methylated guar (MG) of degree of substitution (DS) = 02unirradiated and irradiated

12 International Journal of Carbohydrate Chemistry

2000

1800

1600

1400

1200

1000

800

600

400

200

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(a) CMG DS = 01

700

600

500

400

300

200

100

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(b) CMG DS = 02

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(c) HEG MS = 01

2000

1500

1000

500

0

0

20 40 60

Visc

osity

(cps

)

Radiation dose (KGy)

(d) HEG MS = 02

0 20 40 60

Radiation dose (KGy)

2500

2000

1500

1000

500

0

Visc

osity

(cps

)

(e) MG DS = 01

2000

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(f) MG DS = 02

Figure 14 The plot of minimum viscosity (at shear rate 30s) attained by the sample while subjecting it to shear from 1 to 30s for (a) CMGDS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02 with respect to radiation dose

International Journal of Carbohydrate Chemistry 13

30

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(a) CMG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(b) CMG DS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(c) HEG MS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(d) HEG MS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(e) MG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)

0

20 40 60

(f) MG DS = 02

Figure 15The plot of shear rate value versus radiation doseThe shear rate value was taken from the study carried out by increasing the shearrate and monitoring change in viscosity The point at which the curve between shear rate and viscosity reaches plateau was taken for plottingradiation dose versus shear rate for samples (a) CMG DS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02with respect to radiation dose

The depolymerisation of synthetic polymers by radiationprocessing for recycling of monomers has been known forquite some timeThepresent paper is an attempt to initiate theuse of this technology for radiation processing of modifiednatural polymers The gamma irradiation facility used for

the current studies is an industrial plant and it has been inoperation for about 20 years now where large volumes ofindustrial products are irradiated every day

From the results presented here it is evident that thedepolymerisation of guar is achieved with the radiation dose

14 International Journal of Carbohydrate Chemistry

of 1 KGy and above as seen from the observation of viscosityof 1 of guar derivatives getting reduced from as high a levelas 10000 cps (for unirradiated guar derivative) to as low alevel as 1 cps at 25∘C (for guar derivatives irradiated at 20ndash50KGy)

Inspite of this knowledge which can be easily usedfor scaling up of the process to commercial level doubtsare raised about the scalability of the process Whetherthe process can be used for bulk material is the commonapprehension in the minds of the processors of guar Whilethe present study would help clear many of the doubtsregarding the suitability of radiation processing technologybut the data about the scalability of the process would actuallyeliminate all sorts of doubts

Eventhough the results presented in this paper pertain tothe batch size of 200 g for each guar derivative at each dosethe same was found valid even for the bigger batch size (intons) The results of large batches were the same as obtainedfor the small batches Here it must be mentioned that thedose optimization for the purpose would be necessary for thepurpose of studying the scalability

From the present study the following can be concluded

(i) Radiation processing of guar derivatives leads to theirchain scissioning

(ii) Radiation processing leads to reduction in viscosity ofaqueous solutions of guar derivatives

(iii) Irradiation technique can be a good tool for tailormaking the guar derivatives of desired rheologicalproperties

(iv) The minimum viscosity attained by the 1 solutionof various derivatives shows a decreasing trend withrespect to increase in the radiation dose

(v) In case of carboxymethyl guar the crossover fre-quency increases as the radiation dose increases upto 5KGy and the value is higher in case of CMG ofDS 02 than in that of CMG of DS 01 This showsthat the elastic nature is more dominating for CMGof DS 01 than for CMG of DS 02

(vi) In case of hydroxyethyl guar ofMS 02 the crossoverfrequency of the 1198661015840 and 11986610158401015840 is lesser than that of HEGof MS 01 till 20 KGy radiation dose This meansthat elastic nature predominates in case of HEG ofMS 02 which may be due to the presence of greaternumber of ndash(CH

2ndashO)nndashH groups leading to increase

in H-bonding and thus more solid-like behavior(vii) In case of methyl guar on increasing the radiation

dose up to 10KGy the elastic component decreasesThis can be attributed to the fact that chain scissioningtakes place and now the H-bonding interactions takeplace between smaller chains which reduces theelasticity and viscous behavior predominates Dueto this the crossover frequency increases till 10 KGydose

(viii) As the radiation dose is increased the shear ratevalue at which nearly constant viscosity is achieveddecreases

Acknowledgment

The authors express sincere gratitude to the management ofShriram Institute for Industrial Research Delhi India for thekind support

References

[1] L Wang and L M Zhang ldquoViscoelastic characterization ofa new guar gum derivative containing anionic carboxymethyland cationic 2-hydroxy-3-(trimethylammonio)propyl substit-uentsrdquo Industrial Crops and Products vol 29 no 2-3 pp 524ndash529 2009

[2] C Sandolo PMatricardi F Alhaique and T Coviello ldquoEffect oftemperature and cross-linking density on rheology of chemicalcross-linked guar gum at the gel pointrdquo Food Hydrocolloids vol23 no 1 pp 210ndash220 2009

[3] H N Englyst V Anderson and J H Cummings ldquoStarch andnon-starch polysaccharides in some cereal foodsrdquo Journal of theScience of Food and Agriculture vol 34 no 12 pp 1434ndash14401983

[4] R L Feddersen and S N Thorp Industrial Gums AcaedemicPress San Diego Calif USA 1993

[5] D D Roberts J S Elmore K R Langley and J BakkerldquoEffects of sucrose guar gum and carboxymethylcelluloseon the release of volatile flavor compounds under dynamicconditionsrdquo Journal of Agricultural and Food Chemistry vol 44no 5 pp 1321ndash1326 1996

[6] D R Picout S B Ross-Murphy K Jumel and S E HardingldquoPressure cell assisted solution characterization of polysaccha-rides 2 Locust bean gum and tara gumrdquo Biomacromoleculesvol 3 no 4 pp 761ndash767 2002

[7] R S Blackburn ldquoNatural polysaccharides and their interactionswith dyemolecules applications in effluent treatmentrdquoEnviron-mental Science and Technology vol 38 no 18 pp 4905ndash49092004

[8] M Urdiaın A Domenech-Sanchez S Albertı V J Benedıand J A Rossello ldquoNew method of DNA isolation from twofood additives suitable for authentication in polymerase chainreaction assaysrdquo Journal of Agricultural and FoodChemistry vol53 no 9 pp 3345ndash3347 2005

[9] R P Singh S Pal andDMal ldquoA high performance flocculatingagent and viscosifiers based on cationic guar gumrdquoMacromolec-ular Symposia vol 242 pp 227ndash234 2006

[10] S P Zhao DMa and LM Zhang ldquoNew semi-interpenetratingnetwork hydrogels synthesis characterization and propertiesrdquoMacromolecular Bioscience vol 6 no 6 pp 445ndash451 2006

[11] J Z Yi and L M Zhang ldquoBiodegradable blend films basedon two polysaccharide derivatives and their use as Ibuprofen-releasing matricesrdquo Journal of Applied Polymer Science vol 103no 6 pp 3553ndash3559 2007

[12] S Venkataiah and E G Mahadevan ldquoRheological propertiesof hydroxypropyl and sodium carboxymethyl substituted guargums in aqueous solutionrdquo Journal of Applied Polymer Sciencevol 27 no 5 pp 1533ndash1548 1982

[13] R H W Wientjes M H G Duits R J J Jongschaap andJ Mellema ldquoLinear rheology of guar gum solutionsrdquo Macro-molecules vol 33 no 26 pp 9594ndash9605 2000

[14] T Aubry and M Moan ldquoRheological behavior of a hydropho-bically associating water soluble polymerrdquo Journal of Rheologyvol 38 no 6 pp 1681ndash1692 1994

International Journal of Carbohydrate Chemistry 15

[15] L M Zhang T Kong and P S Hui ldquoSemi-dilute solutions ofhydroxypropyl guar gum viscosity behaviour and thixotropicpropertiesrdquo Journal of the Science of Food and Agriculture vol87 no 4 pp 684ndash688 2007

[16] N N G Swamy T S Dharmarajan and K L K ParanjothildquoDerivatization of guar to various hydroxy alkyl derivatives andtheir characterizationrdquo Indian Drugs vol 43 no 9 pp 756ndash7592006

[17] H Gong M Liu J Chen F Han C Gao and B ZhangldquoSynthesis and characterization of carboxymethyl guar gumandrheological properties of its solutionsrdquo Carbohydrate Polymersvol 88 no 3 pp 1015ndash1022 2012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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CatalystsJournal of

International Journal of Carbohydrate Chemistry 7

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) HEGMS = 02 0 KGy

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) HEGMS = 02 1 KGy

102

101

100

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) HEGMS = 02 25 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) HEGMS = 02 5 KGy

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) HEGMS = 02 10 KGy

01 10 100 1000

101

100

10minus1

10minus2

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) HEGMS = 02 20 KGy

01 10 100 1000

101

102

100

10minus1

10minus2

10minus3

10minus4

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (119891)119866998400 = 119891 (119891)

(g) HEGMS = 02 50 KGy

Figure 5 Effect of radiation processing on viscoelastic properties of hydroxyethyl guar (HEG) havingmolar substitution 02 (a) unirradiated(b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g) irradiated at50KGy

8 International Journal of Carbohydrate Chemistry

11986610158401015840 is lesser than that of HEG of MS 01 till 20 KGyradiation dose This means that elastic nature pre-dominates in case of HEG of MS 02 which may bedue to the presence of greater number of ndash(CH

2ndashO)nndash

H groups leading to increase in H-bonding and thusmore solid-like behavior

(ii) On comparing the crossover frequencies of HEG ofMS 01 after irradiation it can be seen from thedata that crossover frequency increases till 5 KGydoseand then it decreases whereas in case of HEG ofMS 02 the crossover frequency increases till 10 KGydose and then it decreases This can be explainedon the basis of interactions taking place between themacromolecular chains in these two HEGs In case ofHEG of MS 01 intermolecular interactions are lessas compared to HEG of MS 02 and thus less elasticnature

(iii) Also in case of HEG of MS 02 as the substitu-tion increases the coiling of macromolecular chaindecreases due to steric hindrance thereby causingmore intramolecular interactions than intermolec-ular interactions Less coiling of the chain causesmore exposure to irradiation and thus greater chainscissioning and more viscous response of the macro-molecule

(iv) As the radiation dose increases there is more chainscissioning leading to formation of oligomeric chainsThese chains form intermolecular hydrogen bondinglinkages leading to elastic behavior at lower frequen-cies

(v) The 1198661015840 and 11986610158401015840 values decrease on increasing theradiation dose which signifies chain scissioning

313 Methyl Guar The methyl guar (MG) samples wereirradiated and their viscoelastic behavior was studied asdescribed in the previous section The change in storage(elastic 1198661015840) and the loss (viscous 11986610158401015840) moduli was studiedover a range of frequency 1 to 30Hz and the results obtainedhave been shown in Figures 6 and 7

The following observations were made from the resultsIn case of MG of DS 01 no crossover of 1198661015840 and11986610158401015840 curves is seen in unirradiated and irradiated sampleat 1 KGy dose This shows that the elasticity predominatesMethyl group is hydrophobic in nature and its substitutionreduces the number of hydroxyl groups on guar moleculeand opens up the guar chains This leads to more number ofintermolecular interactions than intramolecular interactionsand thus increases elasticity

(i) On increasing the radiation dose up to 10KGy theelastic component decreasesThis can be attributed tothe fact that chain scissioning takes place and now theH-bonding interactions take place between smallerchains which reduces the elasticity and viscousbehavior predominates Due to this the crossoverfrequency increases till 10 KGy dose

(ii) Beyond 10KGy dose there is increase in the elasticcomponent which may be because of interactions in

the smaller chains because of hydrophobic methylgroup

32 Study on Effect of Irradiation on Shear Rate The effectof radiation on the change in viscosity with increase in shearrate (1 to 30s) was studied and has been shown in Figures 8to 13 To analyze this data the minimum viscosity (viscosityobtained at shear rate value of 30s) obtained for each of thesamples was plotted against the radiation dose (Figure 14)and the shear rate at which shear rate versus viscosity curvereaches a plateau was plotted with respect to the increase inradiation dose (Figure 15) for all the samples (CMGHEGandMG)

33 Radiation Dose versus Viscosity As evident fromFigure 14 the minimum viscosity attained by the 1 solutionof various derivatives both before and after irradiation showsa decreasing trend with respect to increase in the radiationdose The decrease is less pronounced in the case of sampleshaving higher substitution which shows that sampleswith greater substitution level exhibit higher resistance todepolymerisation

34 Radiation Dose versus Shear Rate Figure 15 shows theeffect of increasing the radiation dose on shear rate neededto achieve nearly constant viscosity with respect to changein shear rate As the radiation dose is increased the shearrate value at which nearly constant viscosity is achieveddecreases and at the same time the behavior of the three typesof derivatives is quite different for each type

In case of CMG the shear rate required to achieve nearlyconstant viscosity decreases with the increase in radiationdose This means that as the radiation dose is increasing theshear stability of carboxymethyl guar is increasing In otherwords the oligomeric chains of carboxymethyl guar formedon its irradiation exhibit better shear stability When we lookat the results obtained in case of hydroxyethyl guar then itbecomes evident that nearly constant viscosity in this case isachieved at higher shear rate values although a decreasingtrend in shear rate values is observed in this case also Incase of methyl guar also on increasing the radiation dosethe shear rate required to achieve nearly constant viscositydecreases In case of methyl guar of DS 01 the shear ratevalue was found to be nearly constant from 25 to 50KGyradiation dose

4 Conclusion

The depolymerisation of polymers and polymeric materialsby radiation processing is a dry technique Further forachieving the desired results one does not have to use anyof the additives In other words by radiation processing onecan depolymerize guar powder as such without making itssolution in water and without incorporation of additives

Radiation processing of materials such as polymersfood products precious stones medical goods has beenwidely adopted industrially since it is a continuous operationwhich is highly precise energy saving and reproducible

International Journal of Carbohydrate Chemistry 9

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) MG DS = 01 0 KGy

01 10 100 1000

102

101

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) MG DS = 01 1 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) MG DS = 01 25 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) MG DS = 01 5 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) MG DS = 01 10 KGy

102

101

100

10minus2

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) MG DS = 01 20 KGy

102

101

100

10minus2

10minus3

01 10 100 1000

119866998400998400 = 119891 (f)119866998400 = 119891 (f)

119866998400119866998400998400

(Pa)

119891 (Hz)

10minus1

(g) MG DS = 01 50 KGy

Figure 6 Effect of radiation processing on the viscoelastic behavior of methylated guar (MG) of degree of substitution (DS) = 01 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

10 International Journal of Carbohydrate Chemistry

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) MG DS = 02 0 KGy

01 10 100 1000

102

103

101

100

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) MG DS = 02 1 KGy

01 10 100 1000

102

101

100

10minus1

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) MG DS = 02 25 KGy

01 10 100 1000

102

101

100

10minus1

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) MG DS = 02 5 KGy

102

101

100

10minus1

10minus2

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) MG DS = 02 10 KGy

102

101

100

10minus1

10minus2

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) MG DS = 02 20 KGy

102

101

100

10minus1

10minus2

10minus3

10minus4

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (f)119866998400 = 119891 (f)

(g) MG DS = 02 50 KGy

Figure 7 Effect of radiation processing on the viscoelastic behavior of methylated guar (MG) of degree of substitution (DS) = 02 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

International Journal of Carbohydrate Chemistry 11

20000

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

0

25 5 75 10 125 15 175 20 225 25 275 30

Visc

osity

(cps

)

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 8 Effect of radiation processing on the shear stability ofcarboxymethylated guar (CMG) of degree of substitution (DS) =01 unirradiated and irradiated

3500

3000

2500

2000

1500

1000

500

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 9 Effect of radiation processing on the shear stability ofcarboxymethylated guar (CMG) of degree of substitution (DS) =02 unirradiated and irradiated

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 10 Effect of radiation processing on the shear stability ofhydroxyethylated guar (HEG) of molar substitution (MS) = 01unirradiated and irradiated

25000

20000

15000

10000

5000

0

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Visc

osity

(cps

)

Figure 11 Effect of radiation processing on the shear stability ofhydroxyethylated guar (HEG) of molar substitution (MS) = 02unirradiated and irradiated

25000

20000

15000

10000

5000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 12 Effect of radiation processing on the shear stabilityof methylated guar (MG) of degree of substitution (DS) = 01unirradiated and irradiated

16000

14000

12000

10000

8000

6000

4000

2000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 13 Effect of radiation processing on the shear stabilityof methylated guar (MG) of degree of substitution (DS) = 02unirradiated and irradiated

12 International Journal of Carbohydrate Chemistry

2000

1800

1600

1400

1200

1000

800

600

400

200

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(a) CMG DS = 01

700

600

500

400

300

200

100

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(b) CMG DS = 02

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(c) HEG MS = 01

2000

1500

1000

500

0

0

20 40 60

Visc

osity

(cps

)

Radiation dose (KGy)

(d) HEG MS = 02

0 20 40 60

Radiation dose (KGy)

2500

2000

1500

1000

500

0

Visc

osity

(cps

)

(e) MG DS = 01

2000

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(f) MG DS = 02

Figure 14 The plot of minimum viscosity (at shear rate 30s) attained by the sample while subjecting it to shear from 1 to 30s for (a) CMGDS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02 with respect to radiation dose

International Journal of Carbohydrate Chemistry 13

30

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(a) CMG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(b) CMG DS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(c) HEG MS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(d) HEG MS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(e) MG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)

0

20 40 60

(f) MG DS = 02

Figure 15The plot of shear rate value versus radiation doseThe shear rate value was taken from the study carried out by increasing the shearrate and monitoring change in viscosity The point at which the curve between shear rate and viscosity reaches plateau was taken for plottingradiation dose versus shear rate for samples (a) CMG DS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02with respect to radiation dose

The depolymerisation of synthetic polymers by radiationprocessing for recycling of monomers has been known forquite some timeThepresent paper is an attempt to initiate theuse of this technology for radiation processing of modifiednatural polymers The gamma irradiation facility used for

the current studies is an industrial plant and it has been inoperation for about 20 years now where large volumes ofindustrial products are irradiated every day

From the results presented here it is evident that thedepolymerisation of guar is achieved with the radiation dose

14 International Journal of Carbohydrate Chemistry

of 1 KGy and above as seen from the observation of viscosityof 1 of guar derivatives getting reduced from as high a levelas 10000 cps (for unirradiated guar derivative) to as low alevel as 1 cps at 25∘C (for guar derivatives irradiated at 20ndash50KGy)

Inspite of this knowledge which can be easily usedfor scaling up of the process to commercial level doubtsare raised about the scalability of the process Whetherthe process can be used for bulk material is the commonapprehension in the minds of the processors of guar Whilethe present study would help clear many of the doubtsregarding the suitability of radiation processing technologybut the data about the scalability of the process would actuallyeliminate all sorts of doubts

Eventhough the results presented in this paper pertain tothe batch size of 200 g for each guar derivative at each dosethe same was found valid even for the bigger batch size (intons) The results of large batches were the same as obtainedfor the small batches Here it must be mentioned that thedose optimization for the purpose would be necessary for thepurpose of studying the scalability

From the present study the following can be concluded

(i) Radiation processing of guar derivatives leads to theirchain scissioning

(ii) Radiation processing leads to reduction in viscosity ofaqueous solutions of guar derivatives

(iii) Irradiation technique can be a good tool for tailormaking the guar derivatives of desired rheologicalproperties

(iv) The minimum viscosity attained by the 1 solutionof various derivatives shows a decreasing trend withrespect to increase in the radiation dose

(v) In case of carboxymethyl guar the crossover fre-quency increases as the radiation dose increases upto 5KGy and the value is higher in case of CMG ofDS 02 than in that of CMG of DS 01 This showsthat the elastic nature is more dominating for CMGof DS 01 than for CMG of DS 02

(vi) In case of hydroxyethyl guar ofMS 02 the crossoverfrequency of the 1198661015840 and 11986610158401015840 is lesser than that of HEGof MS 01 till 20 KGy radiation dose This meansthat elastic nature predominates in case of HEG ofMS 02 which may be due to the presence of greaternumber of ndash(CH

2ndashO)nndashH groups leading to increase

in H-bonding and thus more solid-like behavior(vii) In case of methyl guar on increasing the radiation

dose up to 10KGy the elastic component decreasesThis can be attributed to the fact that chain scissioningtakes place and now the H-bonding interactions takeplace between smaller chains which reduces theelasticity and viscous behavior predominates Dueto this the crossover frequency increases till 10 KGydose

(viii) As the radiation dose is increased the shear ratevalue at which nearly constant viscosity is achieveddecreases

Acknowledgment

The authors express sincere gratitude to the management ofShriram Institute for Industrial Research Delhi India for thekind support

References

[1] L Wang and L M Zhang ldquoViscoelastic characterization ofa new guar gum derivative containing anionic carboxymethyland cationic 2-hydroxy-3-(trimethylammonio)propyl substit-uentsrdquo Industrial Crops and Products vol 29 no 2-3 pp 524ndash529 2009

[2] C Sandolo PMatricardi F Alhaique and T Coviello ldquoEffect oftemperature and cross-linking density on rheology of chemicalcross-linked guar gum at the gel pointrdquo Food Hydrocolloids vol23 no 1 pp 210ndash220 2009

[3] H N Englyst V Anderson and J H Cummings ldquoStarch andnon-starch polysaccharides in some cereal foodsrdquo Journal of theScience of Food and Agriculture vol 34 no 12 pp 1434ndash14401983

[4] R L Feddersen and S N Thorp Industrial Gums AcaedemicPress San Diego Calif USA 1993

[5] D D Roberts J S Elmore K R Langley and J BakkerldquoEffects of sucrose guar gum and carboxymethylcelluloseon the release of volatile flavor compounds under dynamicconditionsrdquo Journal of Agricultural and Food Chemistry vol 44no 5 pp 1321ndash1326 1996

[6] D R Picout S B Ross-Murphy K Jumel and S E HardingldquoPressure cell assisted solution characterization of polysaccha-rides 2 Locust bean gum and tara gumrdquo Biomacromoleculesvol 3 no 4 pp 761ndash767 2002

[7] R S Blackburn ldquoNatural polysaccharides and their interactionswith dyemolecules applications in effluent treatmentrdquoEnviron-mental Science and Technology vol 38 no 18 pp 4905ndash49092004

[8] M Urdiaın A Domenech-Sanchez S Albertı V J Benedıand J A Rossello ldquoNew method of DNA isolation from twofood additives suitable for authentication in polymerase chainreaction assaysrdquo Journal of Agricultural and FoodChemistry vol53 no 9 pp 3345ndash3347 2005

[9] R P Singh S Pal andDMal ldquoA high performance flocculatingagent and viscosifiers based on cationic guar gumrdquoMacromolec-ular Symposia vol 242 pp 227ndash234 2006

[10] S P Zhao DMa and LM Zhang ldquoNew semi-interpenetratingnetwork hydrogels synthesis characterization and propertiesrdquoMacromolecular Bioscience vol 6 no 6 pp 445ndash451 2006

[11] J Z Yi and L M Zhang ldquoBiodegradable blend films basedon two polysaccharide derivatives and their use as Ibuprofen-releasing matricesrdquo Journal of Applied Polymer Science vol 103no 6 pp 3553ndash3559 2007

[12] S Venkataiah and E G Mahadevan ldquoRheological propertiesof hydroxypropyl and sodium carboxymethyl substituted guargums in aqueous solutionrdquo Journal of Applied Polymer Sciencevol 27 no 5 pp 1533ndash1548 1982

[13] R H W Wientjes M H G Duits R J J Jongschaap andJ Mellema ldquoLinear rheology of guar gum solutionsrdquo Macro-molecules vol 33 no 26 pp 9594ndash9605 2000

[14] T Aubry and M Moan ldquoRheological behavior of a hydropho-bically associating water soluble polymerrdquo Journal of Rheologyvol 38 no 6 pp 1681ndash1692 1994

International Journal of Carbohydrate Chemistry 15

[15] L M Zhang T Kong and P S Hui ldquoSemi-dilute solutions ofhydroxypropyl guar gum viscosity behaviour and thixotropicpropertiesrdquo Journal of the Science of Food and Agriculture vol87 no 4 pp 684ndash688 2007

[16] N N G Swamy T S Dharmarajan and K L K ParanjothildquoDerivatization of guar to various hydroxy alkyl derivatives andtheir characterizationrdquo Indian Drugs vol 43 no 9 pp 756ndash7592006

[17] H Gong M Liu J Chen F Han C Gao and B ZhangldquoSynthesis and characterization of carboxymethyl guar gumandrheological properties of its solutionsrdquo Carbohydrate Polymersvol 88 no 3 pp 1015ndash1022 2012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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CatalystsJournal of

8 International Journal of Carbohydrate Chemistry

11986610158401015840 is lesser than that of HEG of MS 01 till 20 KGyradiation dose This means that elastic nature pre-dominates in case of HEG of MS 02 which may bedue to the presence of greater number of ndash(CH

2ndashO)nndash

H groups leading to increase in H-bonding and thusmore solid-like behavior

(ii) On comparing the crossover frequencies of HEG ofMS 01 after irradiation it can be seen from thedata that crossover frequency increases till 5 KGydoseand then it decreases whereas in case of HEG ofMS 02 the crossover frequency increases till 10 KGydose and then it decreases This can be explainedon the basis of interactions taking place between themacromolecular chains in these two HEGs In case ofHEG of MS 01 intermolecular interactions are lessas compared to HEG of MS 02 and thus less elasticnature

(iii) Also in case of HEG of MS 02 as the substitu-tion increases the coiling of macromolecular chaindecreases due to steric hindrance thereby causingmore intramolecular interactions than intermolec-ular interactions Less coiling of the chain causesmore exposure to irradiation and thus greater chainscissioning and more viscous response of the macro-molecule

(iv) As the radiation dose increases there is more chainscissioning leading to formation of oligomeric chainsThese chains form intermolecular hydrogen bondinglinkages leading to elastic behavior at lower frequen-cies

(v) The 1198661015840 and 11986610158401015840 values decrease on increasing theradiation dose which signifies chain scissioning

313 Methyl Guar The methyl guar (MG) samples wereirradiated and their viscoelastic behavior was studied asdescribed in the previous section The change in storage(elastic 1198661015840) and the loss (viscous 11986610158401015840) moduli was studiedover a range of frequency 1 to 30Hz and the results obtainedhave been shown in Figures 6 and 7

The following observations were made from the resultsIn case of MG of DS 01 no crossover of 1198661015840 and11986610158401015840 curves is seen in unirradiated and irradiated sampleat 1 KGy dose This shows that the elasticity predominatesMethyl group is hydrophobic in nature and its substitutionreduces the number of hydroxyl groups on guar moleculeand opens up the guar chains This leads to more number ofintermolecular interactions than intramolecular interactionsand thus increases elasticity

(i) On increasing the radiation dose up to 10KGy theelastic component decreasesThis can be attributed tothe fact that chain scissioning takes place and now theH-bonding interactions take place between smallerchains which reduces the elasticity and viscousbehavior predominates Due to this the crossoverfrequency increases till 10 KGy dose

(ii) Beyond 10KGy dose there is increase in the elasticcomponent which may be because of interactions in

the smaller chains because of hydrophobic methylgroup

32 Study on Effect of Irradiation on Shear Rate The effectof radiation on the change in viscosity with increase in shearrate (1 to 30s) was studied and has been shown in Figures 8to 13 To analyze this data the minimum viscosity (viscosityobtained at shear rate value of 30s) obtained for each of thesamples was plotted against the radiation dose (Figure 14)and the shear rate at which shear rate versus viscosity curvereaches a plateau was plotted with respect to the increase inradiation dose (Figure 15) for all the samples (CMGHEGandMG)

33 Radiation Dose versus Viscosity As evident fromFigure 14 the minimum viscosity attained by the 1 solutionof various derivatives both before and after irradiation showsa decreasing trend with respect to increase in the radiationdose The decrease is less pronounced in the case of sampleshaving higher substitution which shows that sampleswith greater substitution level exhibit higher resistance todepolymerisation

34 Radiation Dose versus Shear Rate Figure 15 shows theeffect of increasing the radiation dose on shear rate neededto achieve nearly constant viscosity with respect to changein shear rate As the radiation dose is increased the shearrate value at which nearly constant viscosity is achieveddecreases and at the same time the behavior of the three typesof derivatives is quite different for each type

In case of CMG the shear rate required to achieve nearlyconstant viscosity decreases with the increase in radiationdose This means that as the radiation dose is increasing theshear stability of carboxymethyl guar is increasing In otherwords the oligomeric chains of carboxymethyl guar formedon its irradiation exhibit better shear stability When we lookat the results obtained in case of hydroxyethyl guar then itbecomes evident that nearly constant viscosity in this case isachieved at higher shear rate values although a decreasingtrend in shear rate values is observed in this case also Incase of methyl guar also on increasing the radiation dosethe shear rate required to achieve nearly constant viscositydecreases In case of methyl guar of DS 01 the shear ratevalue was found to be nearly constant from 25 to 50KGyradiation dose

4 Conclusion

The depolymerisation of polymers and polymeric materialsby radiation processing is a dry technique Further forachieving the desired results one does not have to use anyof the additives In other words by radiation processing onecan depolymerize guar powder as such without making itssolution in water and without incorporation of additives

Radiation processing of materials such as polymersfood products precious stones medical goods has beenwidely adopted industrially since it is a continuous operationwhich is highly precise energy saving and reproducible

International Journal of Carbohydrate Chemistry 9

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) MG DS = 01 0 KGy

01 10 100 1000

102

101

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) MG DS = 01 1 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) MG DS = 01 25 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) MG DS = 01 5 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) MG DS = 01 10 KGy

102

101

100

10minus2

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) MG DS = 01 20 KGy

102

101

100

10minus2

10minus3

01 10 100 1000

119866998400998400 = 119891 (f)119866998400 = 119891 (f)

119866998400119866998400998400

(Pa)

119891 (Hz)

10minus1

(g) MG DS = 01 50 KGy

Figure 6 Effect of radiation processing on the viscoelastic behavior of methylated guar (MG) of degree of substitution (DS) = 01 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

10 International Journal of Carbohydrate Chemistry

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) MG DS = 02 0 KGy

01 10 100 1000

102

103

101

100

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) MG DS = 02 1 KGy

01 10 100 1000

102

101

100

10minus1

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) MG DS = 02 25 KGy

01 10 100 1000

102

101

100

10minus1

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) MG DS = 02 5 KGy

102

101

100

10minus1

10minus2

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) MG DS = 02 10 KGy

102

101

100

10minus1

10minus2

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) MG DS = 02 20 KGy

102

101

100

10minus1

10minus2

10minus3

10minus4

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (f)119866998400 = 119891 (f)

(g) MG DS = 02 50 KGy

Figure 7 Effect of radiation processing on the viscoelastic behavior of methylated guar (MG) of degree of substitution (DS) = 02 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

International Journal of Carbohydrate Chemistry 11

20000

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

0

25 5 75 10 125 15 175 20 225 25 275 30

Visc

osity

(cps

)

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 8 Effect of radiation processing on the shear stability ofcarboxymethylated guar (CMG) of degree of substitution (DS) =01 unirradiated and irradiated

3500

3000

2500

2000

1500

1000

500

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 9 Effect of radiation processing on the shear stability ofcarboxymethylated guar (CMG) of degree of substitution (DS) =02 unirradiated and irradiated

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 10 Effect of radiation processing on the shear stability ofhydroxyethylated guar (HEG) of molar substitution (MS) = 01unirradiated and irradiated

25000

20000

15000

10000

5000

0

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Visc

osity

(cps

)

Figure 11 Effect of radiation processing on the shear stability ofhydroxyethylated guar (HEG) of molar substitution (MS) = 02unirradiated and irradiated

25000

20000

15000

10000

5000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 12 Effect of radiation processing on the shear stabilityof methylated guar (MG) of degree of substitution (DS) = 01unirradiated and irradiated

16000

14000

12000

10000

8000

6000

4000

2000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 13 Effect of radiation processing on the shear stabilityof methylated guar (MG) of degree of substitution (DS) = 02unirradiated and irradiated

12 International Journal of Carbohydrate Chemistry

2000

1800

1600

1400

1200

1000

800

600

400

200

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(a) CMG DS = 01

700

600

500

400

300

200

100

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(b) CMG DS = 02

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(c) HEG MS = 01

2000

1500

1000

500

0

0

20 40 60

Visc

osity

(cps

)

Radiation dose (KGy)

(d) HEG MS = 02

0 20 40 60

Radiation dose (KGy)

2500

2000

1500

1000

500

0

Visc

osity

(cps

)

(e) MG DS = 01

2000

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(f) MG DS = 02

Figure 14 The plot of minimum viscosity (at shear rate 30s) attained by the sample while subjecting it to shear from 1 to 30s for (a) CMGDS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02 with respect to radiation dose

International Journal of Carbohydrate Chemistry 13

30

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(a) CMG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(b) CMG DS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(c) HEG MS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(d) HEG MS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(e) MG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)

0

20 40 60

(f) MG DS = 02

Figure 15The plot of shear rate value versus radiation doseThe shear rate value was taken from the study carried out by increasing the shearrate and monitoring change in viscosity The point at which the curve between shear rate and viscosity reaches plateau was taken for plottingradiation dose versus shear rate for samples (a) CMG DS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02with respect to radiation dose

The depolymerisation of synthetic polymers by radiationprocessing for recycling of monomers has been known forquite some timeThepresent paper is an attempt to initiate theuse of this technology for radiation processing of modifiednatural polymers The gamma irradiation facility used for

the current studies is an industrial plant and it has been inoperation for about 20 years now where large volumes ofindustrial products are irradiated every day

From the results presented here it is evident that thedepolymerisation of guar is achieved with the radiation dose

14 International Journal of Carbohydrate Chemistry

of 1 KGy and above as seen from the observation of viscosityof 1 of guar derivatives getting reduced from as high a levelas 10000 cps (for unirradiated guar derivative) to as low alevel as 1 cps at 25∘C (for guar derivatives irradiated at 20ndash50KGy)

Inspite of this knowledge which can be easily usedfor scaling up of the process to commercial level doubtsare raised about the scalability of the process Whetherthe process can be used for bulk material is the commonapprehension in the minds of the processors of guar Whilethe present study would help clear many of the doubtsregarding the suitability of radiation processing technologybut the data about the scalability of the process would actuallyeliminate all sorts of doubts

Eventhough the results presented in this paper pertain tothe batch size of 200 g for each guar derivative at each dosethe same was found valid even for the bigger batch size (intons) The results of large batches were the same as obtainedfor the small batches Here it must be mentioned that thedose optimization for the purpose would be necessary for thepurpose of studying the scalability

From the present study the following can be concluded

(i) Radiation processing of guar derivatives leads to theirchain scissioning

(ii) Radiation processing leads to reduction in viscosity ofaqueous solutions of guar derivatives

(iii) Irradiation technique can be a good tool for tailormaking the guar derivatives of desired rheologicalproperties

(iv) The minimum viscosity attained by the 1 solutionof various derivatives shows a decreasing trend withrespect to increase in the radiation dose

(v) In case of carboxymethyl guar the crossover fre-quency increases as the radiation dose increases upto 5KGy and the value is higher in case of CMG ofDS 02 than in that of CMG of DS 01 This showsthat the elastic nature is more dominating for CMGof DS 01 than for CMG of DS 02

(vi) In case of hydroxyethyl guar ofMS 02 the crossoverfrequency of the 1198661015840 and 11986610158401015840 is lesser than that of HEGof MS 01 till 20 KGy radiation dose This meansthat elastic nature predominates in case of HEG ofMS 02 which may be due to the presence of greaternumber of ndash(CH

2ndashO)nndashH groups leading to increase

in H-bonding and thus more solid-like behavior(vii) In case of methyl guar on increasing the radiation

dose up to 10KGy the elastic component decreasesThis can be attributed to the fact that chain scissioningtakes place and now the H-bonding interactions takeplace between smaller chains which reduces theelasticity and viscous behavior predominates Dueto this the crossover frequency increases till 10 KGydose

(viii) As the radiation dose is increased the shear ratevalue at which nearly constant viscosity is achieveddecreases

Acknowledgment

The authors express sincere gratitude to the management ofShriram Institute for Industrial Research Delhi India for thekind support

References

[1] L Wang and L M Zhang ldquoViscoelastic characterization ofa new guar gum derivative containing anionic carboxymethyland cationic 2-hydroxy-3-(trimethylammonio)propyl substit-uentsrdquo Industrial Crops and Products vol 29 no 2-3 pp 524ndash529 2009

[2] C Sandolo PMatricardi F Alhaique and T Coviello ldquoEffect oftemperature and cross-linking density on rheology of chemicalcross-linked guar gum at the gel pointrdquo Food Hydrocolloids vol23 no 1 pp 210ndash220 2009

[3] H N Englyst V Anderson and J H Cummings ldquoStarch andnon-starch polysaccharides in some cereal foodsrdquo Journal of theScience of Food and Agriculture vol 34 no 12 pp 1434ndash14401983

[4] R L Feddersen and S N Thorp Industrial Gums AcaedemicPress San Diego Calif USA 1993

[5] D D Roberts J S Elmore K R Langley and J BakkerldquoEffects of sucrose guar gum and carboxymethylcelluloseon the release of volatile flavor compounds under dynamicconditionsrdquo Journal of Agricultural and Food Chemistry vol 44no 5 pp 1321ndash1326 1996

[6] D R Picout S B Ross-Murphy K Jumel and S E HardingldquoPressure cell assisted solution characterization of polysaccha-rides 2 Locust bean gum and tara gumrdquo Biomacromoleculesvol 3 no 4 pp 761ndash767 2002

[7] R S Blackburn ldquoNatural polysaccharides and their interactionswith dyemolecules applications in effluent treatmentrdquoEnviron-mental Science and Technology vol 38 no 18 pp 4905ndash49092004

[8] M Urdiaın A Domenech-Sanchez S Albertı V J Benedıand J A Rossello ldquoNew method of DNA isolation from twofood additives suitable for authentication in polymerase chainreaction assaysrdquo Journal of Agricultural and FoodChemistry vol53 no 9 pp 3345ndash3347 2005

[9] R P Singh S Pal andDMal ldquoA high performance flocculatingagent and viscosifiers based on cationic guar gumrdquoMacromolec-ular Symposia vol 242 pp 227ndash234 2006

[10] S P Zhao DMa and LM Zhang ldquoNew semi-interpenetratingnetwork hydrogels synthesis characterization and propertiesrdquoMacromolecular Bioscience vol 6 no 6 pp 445ndash451 2006

[11] J Z Yi and L M Zhang ldquoBiodegradable blend films basedon two polysaccharide derivatives and their use as Ibuprofen-releasing matricesrdquo Journal of Applied Polymer Science vol 103no 6 pp 3553ndash3559 2007

[12] S Venkataiah and E G Mahadevan ldquoRheological propertiesof hydroxypropyl and sodium carboxymethyl substituted guargums in aqueous solutionrdquo Journal of Applied Polymer Sciencevol 27 no 5 pp 1533ndash1548 1982

[13] R H W Wientjes M H G Duits R J J Jongschaap andJ Mellema ldquoLinear rheology of guar gum solutionsrdquo Macro-molecules vol 33 no 26 pp 9594ndash9605 2000

[14] T Aubry and M Moan ldquoRheological behavior of a hydropho-bically associating water soluble polymerrdquo Journal of Rheologyvol 38 no 6 pp 1681ndash1692 1994

International Journal of Carbohydrate Chemistry 15

[15] L M Zhang T Kong and P S Hui ldquoSemi-dilute solutions ofhydroxypropyl guar gum viscosity behaviour and thixotropicpropertiesrdquo Journal of the Science of Food and Agriculture vol87 no 4 pp 684ndash688 2007

[16] N N G Swamy T S Dharmarajan and K L K ParanjothildquoDerivatization of guar to various hydroxy alkyl derivatives andtheir characterizationrdquo Indian Drugs vol 43 no 9 pp 756ndash7592006

[17] H Gong M Liu J Chen F Han C Gao and B ZhangldquoSynthesis and characterization of carboxymethyl guar gumandrheological properties of its solutionsrdquo Carbohydrate Polymersvol 88 no 3 pp 1015ndash1022 2012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

International Journal of Carbohydrate Chemistry 9

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) MG DS = 01 0 KGy

01 10 100 1000

102

101

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) MG DS = 01 1 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) MG DS = 01 25 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) MG DS = 01 5 KGy

102

101

100

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) MG DS = 01 10 KGy

102

101

100

10minus2

10minus1

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) MG DS = 01 20 KGy

102

101

100

10minus2

10minus3

01 10 100 1000

119866998400998400 = 119891 (f)119866998400 = 119891 (f)

119866998400119866998400998400

(Pa)

119891 (Hz)

10minus1

(g) MG DS = 01 50 KGy

Figure 6 Effect of radiation processing on the viscoelastic behavior of methylated guar (MG) of degree of substitution (DS) = 01 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

10 International Journal of Carbohydrate Chemistry

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) MG DS = 02 0 KGy

01 10 100 1000

102

103

101

100

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) MG DS = 02 1 KGy

01 10 100 1000

102

101

100

10minus1

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) MG DS = 02 25 KGy

01 10 100 1000

102

101

100

10minus1

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) MG DS = 02 5 KGy

102

101

100

10minus1

10minus2

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) MG DS = 02 10 KGy

102

101

100

10minus1

10minus2

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) MG DS = 02 20 KGy

102

101

100

10minus1

10minus2

10minus3

10minus4

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (f)119866998400 = 119891 (f)

(g) MG DS = 02 50 KGy

Figure 7 Effect of radiation processing on the viscoelastic behavior of methylated guar (MG) of degree of substitution (DS) = 02 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

International Journal of Carbohydrate Chemistry 11

20000

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

0

25 5 75 10 125 15 175 20 225 25 275 30

Visc

osity

(cps

)

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 8 Effect of radiation processing on the shear stability ofcarboxymethylated guar (CMG) of degree of substitution (DS) =01 unirradiated and irradiated

3500

3000

2500

2000

1500

1000

500

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 9 Effect of radiation processing on the shear stability ofcarboxymethylated guar (CMG) of degree of substitution (DS) =02 unirradiated and irradiated

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 10 Effect of radiation processing on the shear stability ofhydroxyethylated guar (HEG) of molar substitution (MS) = 01unirradiated and irradiated

25000

20000

15000

10000

5000

0

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Visc

osity

(cps

)

Figure 11 Effect of radiation processing on the shear stability ofhydroxyethylated guar (HEG) of molar substitution (MS) = 02unirradiated and irradiated

25000

20000

15000

10000

5000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 12 Effect of radiation processing on the shear stabilityof methylated guar (MG) of degree of substitution (DS) = 01unirradiated and irradiated

16000

14000

12000

10000

8000

6000

4000

2000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 13 Effect of radiation processing on the shear stabilityof methylated guar (MG) of degree of substitution (DS) = 02unirradiated and irradiated

12 International Journal of Carbohydrate Chemistry

2000

1800

1600

1400

1200

1000

800

600

400

200

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(a) CMG DS = 01

700

600

500

400

300

200

100

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(b) CMG DS = 02

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(c) HEG MS = 01

2000

1500

1000

500

0

0

20 40 60

Visc

osity

(cps

)

Radiation dose (KGy)

(d) HEG MS = 02

0 20 40 60

Radiation dose (KGy)

2500

2000

1500

1000

500

0

Visc

osity

(cps

)

(e) MG DS = 01

2000

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(f) MG DS = 02

Figure 14 The plot of minimum viscosity (at shear rate 30s) attained by the sample while subjecting it to shear from 1 to 30s for (a) CMGDS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02 with respect to radiation dose

International Journal of Carbohydrate Chemistry 13

30

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(a) CMG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(b) CMG DS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(c) HEG MS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(d) HEG MS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(e) MG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)

0

20 40 60

(f) MG DS = 02

Figure 15The plot of shear rate value versus radiation doseThe shear rate value was taken from the study carried out by increasing the shearrate and monitoring change in viscosity The point at which the curve between shear rate and viscosity reaches plateau was taken for plottingradiation dose versus shear rate for samples (a) CMG DS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02with respect to radiation dose

The depolymerisation of synthetic polymers by radiationprocessing for recycling of monomers has been known forquite some timeThepresent paper is an attempt to initiate theuse of this technology for radiation processing of modifiednatural polymers The gamma irradiation facility used for

the current studies is an industrial plant and it has been inoperation for about 20 years now where large volumes ofindustrial products are irradiated every day

From the results presented here it is evident that thedepolymerisation of guar is achieved with the radiation dose

14 International Journal of Carbohydrate Chemistry

of 1 KGy and above as seen from the observation of viscosityof 1 of guar derivatives getting reduced from as high a levelas 10000 cps (for unirradiated guar derivative) to as low alevel as 1 cps at 25∘C (for guar derivatives irradiated at 20ndash50KGy)

Inspite of this knowledge which can be easily usedfor scaling up of the process to commercial level doubtsare raised about the scalability of the process Whetherthe process can be used for bulk material is the commonapprehension in the minds of the processors of guar Whilethe present study would help clear many of the doubtsregarding the suitability of radiation processing technologybut the data about the scalability of the process would actuallyeliminate all sorts of doubts

Eventhough the results presented in this paper pertain tothe batch size of 200 g for each guar derivative at each dosethe same was found valid even for the bigger batch size (intons) The results of large batches were the same as obtainedfor the small batches Here it must be mentioned that thedose optimization for the purpose would be necessary for thepurpose of studying the scalability

From the present study the following can be concluded

(i) Radiation processing of guar derivatives leads to theirchain scissioning

(ii) Radiation processing leads to reduction in viscosity ofaqueous solutions of guar derivatives

(iii) Irradiation technique can be a good tool for tailormaking the guar derivatives of desired rheologicalproperties

(iv) The minimum viscosity attained by the 1 solutionof various derivatives shows a decreasing trend withrespect to increase in the radiation dose

(v) In case of carboxymethyl guar the crossover fre-quency increases as the radiation dose increases upto 5KGy and the value is higher in case of CMG ofDS 02 than in that of CMG of DS 01 This showsthat the elastic nature is more dominating for CMGof DS 01 than for CMG of DS 02

(vi) In case of hydroxyethyl guar ofMS 02 the crossoverfrequency of the 1198661015840 and 11986610158401015840 is lesser than that of HEGof MS 01 till 20 KGy radiation dose This meansthat elastic nature predominates in case of HEG ofMS 02 which may be due to the presence of greaternumber of ndash(CH

2ndashO)nndashH groups leading to increase

in H-bonding and thus more solid-like behavior(vii) In case of methyl guar on increasing the radiation

dose up to 10KGy the elastic component decreasesThis can be attributed to the fact that chain scissioningtakes place and now the H-bonding interactions takeplace between smaller chains which reduces theelasticity and viscous behavior predominates Dueto this the crossover frequency increases till 10 KGydose

(viii) As the radiation dose is increased the shear ratevalue at which nearly constant viscosity is achieveddecreases

Acknowledgment

The authors express sincere gratitude to the management ofShriram Institute for Industrial Research Delhi India for thekind support

References

[1] L Wang and L M Zhang ldquoViscoelastic characterization ofa new guar gum derivative containing anionic carboxymethyland cationic 2-hydroxy-3-(trimethylammonio)propyl substit-uentsrdquo Industrial Crops and Products vol 29 no 2-3 pp 524ndash529 2009

[2] C Sandolo PMatricardi F Alhaique and T Coviello ldquoEffect oftemperature and cross-linking density on rheology of chemicalcross-linked guar gum at the gel pointrdquo Food Hydrocolloids vol23 no 1 pp 210ndash220 2009

[3] H N Englyst V Anderson and J H Cummings ldquoStarch andnon-starch polysaccharides in some cereal foodsrdquo Journal of theScience of Food and Agriculture vol 34 no 12 pp 1434ndash14401983

[4] R L Feddersen and S N Thorp Industrial Gums AcaedemicPress San Diego Calif USA 1993

[5] D D Roberts J S Elmore K R Langley and J BakkerldquoEffects of sucrose guar gum and carboxymethylcelluloseon the release of volatile flavor compounds under dynamicconditionsrdquo Journal of Agricultural and Food Chemistry vol 44no 5 pp 1321ndash1326 1996

[6] D R Picout S B Ross-Murphy K Jumel and S E HardingldquoPressure cell assisted solution characterization of polysaccha-rides 2 Locust bean gum and tara gumrdquo Biomacromoleculesvol 3 no 4 pp 761ndash767 2002

[7] R S Blackburn ldquoNatural polysaccharides and their interactionswith dyemolecules applications in effluent treatmentrdquoEnviron-mental Science and Technology vol 38 no 18 pp 4905ndash49092004

[8] M Urdiaın A Domenech-Sanchez S Albertı V J Benedıand J A Rossello ldquoNew method of DNA isolation from twofood additives suitable for authentication in polymerase chainreaction assaysrdquo Journal of Agricultural and FoodChemistry vol53 no 9 pp 3345ndash3347 2005

[9] R P Singh S Pal andDMal ldquoA high performance flocculatingagent and viscosifiers based on cationic guar gumrdquoMacromolec-ular Symposia vol 242 pp 227ndash234 2006

[10] S P Zhao DMa and LM Zhang ldquoNew semi-interpenetratingnetwork hydrogels synthesis characterization and propertiesrdquoMacromolecular Bioscience vol 6 no 6 pp 445ndash451 2006

[11] J Z Yi and L M Zhang ldquoBiodegradable blend films basedon two polysaccharide derivatives and their use as Ibuprofen-releasing matricesrdquo Journal of Applied Polymer Science vol 103no 6 pp 3553ndash3559 2007

[12] S Venkataiah and E G Mahadevan ldquoRheological propertiesof hydroxypropyl and sodium carboxymethyl substituted guargums in aqueous solutionrdquo Journal of Applied Polymer Sciencevol 27 no 5 pp 1533ndash1548 1982

[13] R H W Wientjes M H G Duits R J J Jongschaap andJ Mellema ldquoLinear rheology of guar gum solutionsrdquo Macro-molecules vol 33 no 26 pp 9594ndash9605 2000

[14] T Aubry and M Moan ldquoRheological behavior of a hydropho-bically associating water soluble polymerrdquo Journal of Rheologyvol 38 no 6 pp 1681ndash1692 1994

International Journal of Carbohydrate Chemistry 15

[15] L M Zhang T Kong and P S Hui ldquoSemi-dilute solutions ofhydroxypropyl guar gum viscosity behaviour and thixotropicpropertiesrdquo Journal of the Science of Food and Agriculture vol87 no 4 pp 684ndash688 2007

[16] N N G Swamy T S Dharmarajan and K L K ParanjothildquoDerivatization of guar to various hydroxy alkyl derivatives andtheir characterizationrdquo Indian Drugs vol 43 no 9 pp 756ndash7592006

[17] H Gong M Liu J Chen F Han C Gao and B ZhangldquoSynthesis and characterization of carboxymethyl guar gumandrheological properties of its solutionsrdquo Carbohydrate Polymersvol 88 no 3 pp 1015ndash1022 2012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

10 International Journal of Carbohydrate Chemistry

102

101

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(a) MG DS = 02 0 KGy

01 10 100 1000

102

103

101

100

119866998400119866998400998400

(Pa)

119891 (Hz)

(b) MG DS = 02 1 KGy

01 10 100 1000

102

101

100

10minus1

119866998400119866998400998400

(Pa)

119891 (Hz)

(c) MG DS = 02 25 KGy

01 10 100 1000

102

101

100

10minus1

119866998400119866998400998400

(Pa)

119891 (Hz)

(d) MG DS = 02 5 KGy

102

101

100

10minus1

10minus2

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(e) MG DS = 02 10 KGy

102

101

100

10minus1

10minus2

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

(f) MG DS = 02 20 KGy

102

101

100

10minus1

10minus2

10minus3

10minus4

01 10 100 1000

119866998400119866998400998400

(Pa)

119891 (Hz)

119866998400998400 = 119891 (f)119866998400 = 119891 (f)

(g) MG DS = 02 50 KGy

Figure 7 Effect of radiation processing on the viscoelastic behavior of methylated guar (MG) of degree of substitution (DS) = 02 (a)unirradiated (b) irradiated at 1 KGy (c) irradiated at 25 KGy (d) irradiated at 5 KGy (e) irradiated at 10 KGy (f) irradiated at 20KGy (g)irradiated at 50KGy

International Journal of Carbohydrate Chemistry 11

20000

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

0

25 5 75 10 125 15 175 20 225 25 275 30

Visc

osity

(cps

)

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 8 Effect of radiation processing on the shear stability ofcarboxymethylated guar (CMG) of degree of substitution (DS) =01 unirradiated and irradiated

3500

3000

2500

2000

1500

1000

500

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 9 Effect of radiation processing on the shear stability ofcarboxymethylated guar (CMG) of degree of substitution (DS) =02 unirradiated and irradiated

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 10 Effect of radiation processing on the shear stability ofhydroxyethylated guar (HEG) of molar substitution (MS) = 01unirradiated and irradiated

25000

20000

15000

10000

5000

0

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Visc

osity

(cps

)

Figure 11 Effect of radiation processing on the shear stability ofhydroxyethylated guar (HEG) of molar substitution (MS) = 02unirradiated and irradiated

25000

20000

15000

10000

5000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 12 Effect of radiation processing on the shear stabilityof methylated guar (MG) of degree of substitution (DS) = 01unirradiated and irradiated

16000

14000

12000

10000

8000

6000

4000

2000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 13 Effect of radiation processing on the shear stabilityof methylated guar (MG) of degree of substitution (DS) = 02unirradiated and irradiated

12 International Journal of Carbohydrate Chemistry

2000

1800

1600

1400

1200

1000

800

600

400

200

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(a) CMG DS = 01

700

600

500

400

300

200

100

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(b) CMG DS = 02

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(c) HEG MS = 01

2000

1500

1000

500

0

0

20 40 60

Visc

osity

(cps

)

Radiation dose (KGy)

(d) HEG MS = 02

0 20 40 60

Radiation dose (KGy)

2500

2000

1500

1000

500

0

Visc

osity

(cps

)

(e) MG DS = 01

2000

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(f) MG DS = 02

Figure 14 The plot of minimum viscosity (at shear rate 30s) attained by the sample while subjecting it to shear from 1 to 30s for (a) CMGDS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02 with respect to radiation dose

International Journal of Carbohydrate Chemistry 13

30

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(a) CMG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(b) CMG DS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(c) HEG MS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(d) HEG MS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(e) MG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)

0

20 40 60

(f) MG DS = 02

Figure 15The plot of shear rate value versus radiation doseThe shear rate value was taken from the study carried out by increasing the shearrate and monitoring change in viscosity The point at which the curve between shear rate and viscosity reaches plateau was taken for plottingradiation dose versus shear rate for samples (a) CMG DS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02with respect to radiation dose

The depolymerisation of synthetic polymers by radiationprocessing for recycling of monomers has been known forquite some timeThepresent paper is an attempt to initiate theuse of this technology for radiation processing of modifiednatural polymers The gamma irradiation facility used for

the current studies is an industrial plant and it has been inoperation for about 20 years now where large volumes ofindustrial products are irradiated every day

From the results presented here it is evident that thedepolymerisation of guar is achieved with the radiation dose

14 International Journal of Carbohydrate Chemistry

of 1 KGy and above as seen from the observation of viscosityof 1 of guar derivatives getting reduced from as high a levelas 10000 cps (for unirradiated guar derivative) to as low alevel as 1 cps at 25∘C (for guar derivatives irradiated at 20ndash50KGy)

Inspite of this knowledge which can be easily usedfor scaling up of the process to commercial level doubtsare raised about the scalability of the process Whetherthe process can be used for bulk material is the commonapprehension in the minds of the processors of guar Whilethe present study would help clear many of the doubtsregarding the suitability of radiation processing technologybut the data about the scalability of the process would actuallyeliminate all sorts of doubts

Eventhough the results presented in this paper pertain tothe batch size of 200 g for each guar derivative at each dosethe same was found valid even for the bigger batch size (intons) The results of large batches were the same as obtainedfor the small batches Here it must be mentioned that thedose optimization for the purpose would be necessary for thepurpose of studying the scalability

From the present study the following can be concluded

(i) Radiation processing of guar derivatives leads to theirchain scissioning

(ii) Radiation processing leads to reduction in viscosity ofaqueous solutions of guar derivatives

(iii) Irradiation technique can be a good tool for tailormaking the guar derivatives of desired rheologicalproperties

(iv) The minimum viscosity attained by the 1 solutionof various derivatives shows a decreasing trend withrespect to increase in the radiation dose

(v) In case of carboxymethyl guar the crossover fre-quency increases as the radiation dose increases upto 5KGy and the value is higher in case of CMG ofDS 02 than in that of CMG of DS 01 This showsthat the elastic nature is more dominating for CMGof DS 01 than for CMG of DS 02

(vi) In case of hydroxyethyl guar ofMS 02 the crossoverfrequency of the 1198661015840 and 11986610158401015840 is lesser than that of HEGof MS 01 till 20 KGy radiation dose This meansthat elastic nature predominates in case of HEG ofMS 02 which may be due to the presence of greaternumber of ndash(CH

2ndashO)nndashH groups leading to increase

in H-bonding and thus more solid-like behavior(vii) In case of methyl guar on increasing the radiation

dose up to 10KGy the elastic component decreasesThis can be attributed to the fact that chain scissioningtakes place and now the H-bonding interactions takeplace between smaller chains which reduces theelasticity and viscous behavior predominates Dueto this the crossover frequency increases till 10 KGydose

(viii) As the radiation dose is increased the shear ratevalue at which nearly constant viscosity is achieveddecreases

Acknowledgment

The authors express sincere gratitude to the management ofShriram Institute for Industrial Research Delhi India for thekind support

References

[1] L Wang and L M Zhang ldquoViscoelastic characterization ofa new guar gum derivative containing anionic carboxymethyland cationic 2-hydroxy-3-(trimethylammonio)propyl substit-uentsrdquo Industrial Crops and Products vol 29 no 2-3 pp 524ndash529 2009

[2] C Sandolo PMatricardi F Alhaique and T Coviello ldquoEffect oftemperature and cross-linking density on rheology of chemicalcross-linked guar gum at the gel pointrdquo Food Hydrocolloids vol23 no 1 pp 210ndash220 2009

[3] H N Englyst V Anderson and J H Cummings ldquoStarch andnon-starch polysaccharides in some cereal foodsrdquo Journal of theScience of Food and Agriculture vol 34 no 12 pp 1434ndash14401983

[4] R L Feddersen and S N Thorp Industrial Gums AcaedemicPress San Diego Calif USA 1993

[5] D D Roberts J S Elmore K R Langley and J BakkerldquoEffects of sucrose guar gum and carboxymethylcelluloseon the release of volatile flavor compounds under dynamicconditionsrdquo Journal of Agricultural and Food Chemistry vol 44no 5 pp 1321ndash1326 1996

[6] D R Picout S B Ross-Murphy K Jumel and S E HardingldquoPressure cell assisted solution characterization of polysaccha-rides 2 Locust bean gum and tara gumrdquo Biomacromoleculesvol 3 no 4 pp 761ndash767 2002

[7] R S Blackburn ldquoNatural polysaccharides and their interactionswith dyemolecules applications in effluent treatmentrdquoEnviron-mental Science and Technology vol 38 no 18 pp 4905ndash49092004

[8] M Urdiaın A Domenech-Sanchez S Albertı V J Benedıand J A Rossello ldquoNew method of DNA isolation from twofood additives suitable for authentication in polymerase chainreaction assaysrdquo Journal of Agricultural and FoodChemistry vol53 no 9 pp 3345ndash3347 2005

[9] R P Singh S Pal andDMal ldquoA high performance flocculatingagent and viscosifiers based on cationic guar gumrdquoMacromolec-ular Symposia vol 242 pp 227ndash234 2006

[10] S P Zhao DMa and LM Zhang ldquoNew semi-interpenetratingnetwork hydrogels synthesis characterization and propertiesrdquoMacromolecular Bioscience vol 6 no 6 pp 445ndash451 2006

[11] J Z Yi and L M Zhang ldquoBiodegradable blend films basedon two polysaccharide derivatives and their use as Ibuprofen-releasing matricesrdquo Journal of Applied Polymer Science vol 103no 6 pp 3553ndash3559 2007

[12] S Venkataiah and E G Mahadevan ldquoRheological propertiesof hydroxypropyl and sodium carboxymethyl substituted guargums in aqueous solutionrdquo Journal of Applied Polymer Sciencevol 27 no 5 pp 1533ndash1548 1982

[13] R H W Wientjes M H G Duits R J J Jongschaap andJ Mellema ldquoLinear rheology of guar gum solutionsrdquo Macro-molecules vol 33 no 26 pp 9594ndash9605 2000

[14] T Aubry and M Moan ldquoRheological behavior of a hydropho-bically associating water soluble polymerrdquo Journal of Rheologyvol 38 no 6 pp 1681ndash1692 1994

International Journal of Carbohydrate Chemistry 15

[15] L M Zhang T Kong and P S Hui ldquoSemi-dilute solutions ofhydroxypropyl guar gum viscosity behaviour and thixotropicpropertiesrdquo Journal of the Science of Food and Agriculture vol87 no 4 pp 684ndash688 2007

[16] N N G Swamy T S Dharmarajan and K L K ParanjothildquoDerivatization of guar to various hydroxy alkyl derivatives andtheir characterizationrdquo Indian Drugs vol 43 no 9 pp 756ndash7592006

[17] H Gong M Liu J Chen F Han C Gao and B ZhangldquoSynthesis and characterization of carboxymethyl guar gumandrheological properties of its solutionsrdquo Carbohydrate Polymersvol 88 no 3 pp 1015ndash1022 2012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

International Journal of Carbohydrate Chemistry 11

20000

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

0

25 5 75 10 125 15 175 20 225 25 275 30

Visc

osity

(cps

)

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 8 Effect of radiation processing on the shear stability ofcarboxymethylated guar (CMG) of degree of substitution (DS) =01 unirradiated and irradiated

3500

3000

2500

2000

1500

1000

500

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 9 Effect of radiation processing on the shear stability ofcarboxymethylated guar (CMG) of degree of substitution (DS) =02 unirradiated and irradiated

18000

16000

14000

12000

10000

8000

6000

4000

2000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 10 Effect of radiation processing on the shear stability ofhydroxyethylated guar (HEG) of molar substitution (MS) = 01unirradiated and irradiated

25000

20000

15000

10000

5000

0

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Visc

osity

(cps

)

Figure 11 Effect of radiation processing on the shear stability ofhydroxyethylated guar (HEG) of molar substitution (MS) = 02unirradiated and irradiated

25000

20000

15000

10000

5000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 12 Effect of radiation processing on the shear stabilityof methylated guar (MG) of degree of substitution (DS) = 01unirradiated and irradiated

16000

14000

12000

10000

8000

6000

4000

2000

0

Visc

osity

(cps

)

0 25 5 75 10 125 15 175 20 225 25 275 30

Shear rate (sminus1)

0 KGy5 KGy50 KGy

1 KGy10 KGy25 KGy

20 KGy

Figure 13 Effect of radiation processing on the shear stabilityof methylated guar (MG) of degree of substitution (DS) = 02unirradiated and irradiated

12 International Journal of Carbohydrate Chemistry

2000

1800

1600

1400

1200

1000

800

600

400

200

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(a) CMG DS = 01

700

600

500

400

300

200

100

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(b) CMG DS = 02

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(c) HEG MS = 01

2000

1500

1000

500

0

0

20 40 60

Visc

osity

(cps

)

Radiation dose (KGy)

(d) HEG MS = 02

0 20 40 60

Radiation dose (KGy)

2500

2000

1500

1000

500

0

Visc

osity

(cps

)

(e) MG DS = 01

2000

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(f) MG DS = 02

Figure 14 The plot of minimum viscosity (at shear rate 30s) attained by the sample while subjecting it to shear from 1 to 30s for (a) CMGDS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02 with respect to radiation dose

International Journal of Carbohydrate Chemistry 13

30

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(a) CMG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(b) CMG DS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(c) HEG MS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(d) HEG MS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(e) MG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)

0

20 40 60

(f) MG DS = 02

Figure 15The plot of shear rate value versus radiation doseThe shear rate value was taken from the study carried out by increasing the shearrate and monitoring change in viscosity The point at which the curve between shear rate and viscosity reaches plateau was taken for plottingradiation dose versus shear rate for samples (a) CMG DS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02with respect to radiation dose

The depolymerisation of synthetic polymers by radiationprocessing for recycling of monomers has been known forquite some timeThepresent paper is an attempt to initiate theuse of this technology for radiation processing of modifiednatural polymers The gamma irradiation facility used for

the current studies is an industrial plant and it has been inoperation for about 20 years now where large volumes ofindustrial products are irradiated every day

From the results presented here it is evident that thedepolymerisation of guar is achieved with the radiation dose

14 International Journal of Carbohydrate Chemistry

of 1 KGy and above as seen from the observation of viscosityof 1 of guar derivatives getting reduced from as high a levelas 10000 cps (for unirradiated guar derivative) to as low alevel as 1 cps at 25∘C (for guar derivatives irradiated at 20ndash50KGy)

Inspite of this knowledge which can be easily usedfor scaling up of the process to commercial level doubtsare raised about the scalability of the process Whetherthe process can be used for bulk material is the commonapprehension in the minds of the processors of guar Whilethe present study would help clear many of the doubtsregarding the suitability of radiation processing technologybut the data about the scalability of the process would actuallyeliminate all sorts of doubts

Eventhough the results presented in this paper pertain tothe batch size of 200 g for each guar derivative at each dosethe same was found valid even for the bigger batch size (intons) The results of large batches were the same as obtainedfor the small batches Here it must be mentioned that thedose optimization for the purpose would be necessary for thepurpose of studying the scalability

From the present study the following can be concluded

(i) Radiation processing of guar derivatives leads to theirchain scissioning

(ii) Radiation processing leads to reduction in viscosity ofaqueous solutions of guar derivatives

(iii) Irradiation technique can be a good tool for tailormaking the guar derivatives of desired rheologicalproperties

(iv) The minimum viscosity attained by the 1 solutionof various derivatives shows a decreasing trend withrespect to increase in the radiation dose

(v) In case of carboxymethyl guar the crossover fre-quency increases as the radiation dose increases upto 5KGy and the value is higher in case of CMG ofDS 02 than in that of CMG of DS 01 This showsthat the elastic nature is more dominating for CMGof DS 01 than for CMG of DS 02

(vi) In case of hydroxyethyl guar ofMS 02 the crossoverfrequency of the 1198661015840 and 11986610158401015840 is lesser than that of HEGof MS 01 till 20 KGy radiation dose This meansthat elastic nature predominates in case of HEG ofMS 02 which may be due to the presence of greaternumber of ndash(CH

2ndashO)nndashH groups leading to increase

in H-bonding and thus more solid-like behavior(vii) In case of methyl guar on increasing the radiation

dose up to 10KGy the elastic component decreasesThis can be attributed to the fact that chain scissioningtakes place and now the H-bonding interactions takeplace between smaller chains which reduces theelasticity and viscous behavior predominates Dueto this the crossover frequency increases till 10 KGydose

(viii) As the radiation dose is increased the shear ratevalue at which nearly constant viscosity is achieveddecreases

Acknowledgment

The authors express sincere gratitude to the management ofShriram Institute for Industrial Research Delhi India for thekind support

References

[1] L Wang and L M Zhang ldquoViscoelastic characterization ofa new guar gum derivative containing anionic carboxymethyland cationic 2-hydroxy-3-(trimethylammonio)propyl substit-uentsrdquo Industrial Crops and Products vol 29 no 2-3 pp 524ndash529 2009

[2] C Sandolo PMatricardi F Alhaique and T Coviello ldquoEffect oftemperature and cross-linking density on rheology of chemicalcross-linked guar gum at the gel pointrdquo Food Hydrocolloids vol23 no 1 pp 210ndash220 2009

[3] H N Englyst V Anderson and J H Cummings ldquoStarch andnon-starch polysaccharides in some cereal foodsrdquo Journal of theScience of Food and Agriculture vol 34 no 12 pp 1434ndash14401983

[4] R L Feddersen and S N Thorp Industrial Gums AcaedemicPress San Diego Calif USA 1993

[5] D D Roberts J S Elmore K R Langley and J BakkerldquoEffects of sucrose guar gum and carboxymethylcelluloseon the release of volatile flavor compounds under dynamicconditionsrdquo Journal of Agricultural and Food Chemistry vol 44no 5 pp 1321ndash1326 1996

[6] D R Picout S B Ross-Murphy K Jumel and S E HardingldquoPressure cell assisted solution characterization of polysaccha-rides 2 Locust bean gum and tara gumrdquo Biomacromoleculesvol 3 no 4 pp 761ndash767 2002

[7] R S Blackburn ldquoNatural polysaccharides and their interactionswith dyemolecules applications in effluent treatmentrdquoEnviron-mental Science and Technology vol 38 no 18 pp 4905ndash49092004

[8] M Urdiaın A Domenech-Sanchez S Albertı V J Benedıand J A Rossello ldquoNew method of DNA isolation from twofood additives suitable for authentication in polymerase chainreaction assaysrdquo Journal of Agricultural and FoodChemistry vol53 no 9 pp 3345ndash3347 2005

[9] R P Singh S Pal andDMal ldquoA high performance flocculatingagent and viscosifiers based on cationic guar gumrdquoMacromolec-ular Symposia vol 242 pp 227ndash234 2006

[10] S P Zhao DMa and LM Zhang ldquoNew semi-interpenetratingnetwork hydrogels synthesis characterization and propertiesrdquoMacromolecular Bioscience vol 6 no 6 pp 445ndash451 2006

[11] J Z Yi and L M Zhang ldquoBiodegradable blend films basedon two polysaccharide derivatives and their use as Ibuprofen-releasing matricesrdquo Journal of Applied Polymer Science vol 103no 6 pp 3553ndash3559 2007

[12] S Venkataiah and E G Mahadevan ldquoRheological propertiesof hydroxypropyl and sodium carboxymethyl substituted guargums in aqueous solutionrdquo Journal of Applied Polymer Sciencevol 27 no 5 pp 1533ndash1548 1982

[13] R H W Wientjes M H G Duits R J J Jongschaap andJ Mellema ldquoLinear rheology of guar gum solutionsrdquo Macro-molecules vol 33 no 26 pp 9594ndash9605 2000

[14] T Aubry and M Moan ldquoRheological behavior of a hydropho-bically associating water soluble polymerrdquo Journal of Rheologyvol 38 no 6 pp 1681ndash1692 1994

International Journal of Carbohydrate Chemistry 15

[15] L M Zhang T Kong and P S Hui ldquoSemi-dilute solutions ofhydroxypropyl guar gum viscosity behaviour and thixotropicpropertiesrdquo Journal of the Science of Food and Agriculture vol87 no 4 pp 684ndash688 2007

[16] N N G Swamy T S Dharmarajan and K L K ParanjothildquoDerivatization of guar to various hydroxy alkyl derivatives andtheir characterizationrdquo Indian Drugs vol 43 no 9 pp 756ndash7592006

[17] H Gong M Liu J Chen F Han C Gao and B ZhangldquoSynthesis and characterization of carboxymethyl guar gumandrheological properties of its solutionsrdquo Carbohydrate Polymersvol 88 no 3 pp 1015ndash1022 2012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

12 International Journal of Carbohydrate Chemistry

2000

1800

1600

1400

1200

1000

800

600

400

200

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(a) CMG DS = 01

700

600

500

400

300

200

100

0

Visc

osity

(cps

)

0 20 40 60

Radiation dose (KGy)

(b) CMG DS = 02

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(c) HEG MS = 01

2000

1500

1000

500

0

0

20 40 60

Visc

osity

(cps

)

Radiation dose (KGy)

(d) HEG MS = 02

0 20 40 60

Radiation dose (KGy)

2500

2000

1500

1000

500

0

Visc

osity

(cps

)

(e) MG DS = 01

2000

1800

1600

1400

1200

1000

800

600

400

200

0

0 20 40 60

Radiation dose (KGy)

Visc

osity

(cps

)

(f) MG DS = 02

Figure 14 The plot of minimum viscosity (at shear rate 30s) attained by the sample while subjecting it to shear from 1 to 30s for (a) CMGDS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02 with respect to radiation dose

International Journal of Carbohydrate Chemistry 13

30

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(a) CMG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(b) CMG DS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(c) HEG MS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(d) HEG MS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(e) MG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)

0

20 40 60

(f) MG DS = 02

Figure 15The plot of shear rate value versus radiation doseThe shear rate value was taken from the study carried out by increasing the shearrate and monitoring change in viscosity The point at which the curve between shear rate and viscosity reaches plateau was taken for plottingradiation dose versus shear rate for samples (a) CMG DS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02with respect to radiation dose

The depolymerisation of synthetic polymers by radiationprocessing for recycling of monomers has been known forquite some timeThepresent paper is an attempt to initiate theuse of this technology for radiation processing of modifiednatural polymers The gamma irradiation facility used for

the current studies is an industrial plant and it has been inoperation for about 20 years now where large volumes ofindustrial products are irradiated every day

From the results presented here it is evident that thedepolymerisation of guar is achieved with the radiation dose

14 International Journal of Carbohydrate Chemistry

of 1 KGy and above as seen from the observation of viscosityof 1 of guar derivatives getting reduced from as high a levelas 10000 cps (for unirradiated guar derivative) to as low alevel as 1 cps at 25∘C (for guar derivatives irradiated at 20ndash50KGy)

Inspite of this knowledge which can be easily usedfor scaling up of the process to commercial level doubtsare raised about the scalability of the process Whetherthe process can be used for bulk material is the commonapprehension in the minds of the processors of guar Whilethe present study would help clear many of the doubtsregarding the suitability of radiation processing technologybut the data about the scalability of the process would actuallyeliminate all sorts of doubts

Eventhough the results presented in this paper pertain tothe batch size of 200 g for each guar derivative at each dosethe same was found valid even for the bigger batch size (intons) The results of large batches were the same as obtainedfor the small batches Here it must be mentioned that thedose optimization for the purpose would be necessary for thepurpose of studying the scalability

From the present study the following can be concluded

(i) Radiation processing of guar derivatives leads to theirchain scissioning

(ii) Radiation processing leads to reduction in viscosity ofaqueous solutions of guar derivatives

(iii) Irradiation technique can be a good tool for tailormaking the guar derivatives of desired rheologicalproperties

(iv) The minimum viscosity attained by the 1 solutionof various derivatives shows a decreasing trend withrespect to increase in the radiation dose

(v) In case of carboxymethyl guar the crossover fre-quency increases as the radiation dose increases upto 5KGy and the value is higher in case of CMG ofDS 02 than in that of CMG of DS 01 This showsthat the elastic nature is more dominating for CMGof DS 01 than for CMG of DS 02

(vi) In case of hydroxyethyl guar ofMS 02 the crossoverfrequency of the 1198661015840 and 11986610158401015840 is lesser than that of HEGof MS 01 till 20 KGy radiation dose This meansthat elastic nature predominates in case of HEG ofMS 02 which may be due to the presence of greaternumber of ndash(CH

2ndashO)nndashH groups leading to increase

in H-bonding and thus more solid-like behavior(vii) In case of methyl guar on increasing the radiation

dose up to 10KGy the elastic component decreasesThis can be attributed to the fact that chain scissioningtakes place and now the H-bonding interactions takeplace between smaller chains which reduces theelasticity and viscous behavior predominates Dueto this the crossover frequency increases till 10 KGydose

(viii) As the radiation dose is increased the shear ratevalue at which nearly constant viscosity is achieveddecreases

Acknowledgment

The authors express sincere gratitude to the management ofShriram Institute for Industrial Research Delhi India for thekind support

References

[1] L Wang and L M Zhang ldquoViscoelastic characterization ofa new guar gum derivative containing anionic carboxymethyland cationic 2-hydroxy-3-(trimethylammonio)propyl substit-uentsrdquo Industrial Crops and Products vol 29 no 2-3 pp 524ndash529 2009

[2] C Sandolo PMatricardi F Alhaique and T Coviello ldquoEffect oftemperature and cross-linking density on rheology of chemicalcross-linked guar gum at the gel pointrdquo Food Hydrocolloids vol23 no 1 pp 210ndash220 2009

[3] H N Englyst V Anderson and J H Cummings ldquoStarch andnon-starch polysaccharides in some cereal foodsrdquo Journal of theScience of Food and Agriculture vol 34 no 12 pp 1434ndash14401983

[4] R L Feddersen and S N Thorp Industrial Gums AcaedemicPress San Diego Calif USA 1993

[5] D D Roberts J S Elmore K R Langley and J BakkerldquoEffects of sucrose guar gum and carboxymethylcelluloseon the release of volatile flavor compounds under dynamicconditionsrdquo Journal of Agricultural and Food Chemistry vol 44no 5 pp 1321ndash1326 1996

[6] D R Picout S B Ross-Murphy K Jumel and S E HardingldquoPressure cell assisted solution characterization of polysaccha-rides 2 Locust bean gum and tara gumrdquo Biomacromoleculesvol 3 no 4 pp 761ndash767 2002

[7] R S Blackburn ldquoNatural polysaccharides and their interactionswith dyemolecules applications in effluent treatmentrdquoEnviron-mental Science and Technology vol 38 no 18 pp 4905ndash49092004

[8] M Urdiaın A Domenech-Sanchez S Albertı V J Benedıand J A Rossello ldquoNew method of DNA isolation from twofood additives suitable for authentication in polymerase chainreaction assaysrdquo Journal of Agricultural and FoodChemistry vol53 no 9 pp 3345ndash3347 2005

[9] R P Singh S Pal andDMal ldquoA high performance flocculatingagent and viscosifiers based on cationic guar gumrdquoMacromolec-ular Symposia vol 242 pp 227ndash234 2006

[10] S P Zhao DMa and LM Zhang ldquoNew semi-interpenetratingnetwork hydrogels synthesis characterization and propertiesrdquoMacromolecular Bioscience vol 6 no 6 pp 445ndash451 2006

[11] J Z Yi and L M Zhang ldquoBiodegradable blend films basedon two polysaccharide derivatives and their use as Ibuprofen-releasing matricesrdquo Journal of Applied Polymer Science vol 103no 6 pp 3553ndash3559 2007

[12] S Venkataiah and E G Mahadevan ldquoRheological propertiesof hydroxypropyl and sodium carboxymethyl substituted guargums in aqueous solutionrdquo Journal of Applied Polymer Sciencevol 27 no 5 pp 1533ndash1548 1982

[13] R H W Wientjes M H G Duits R J J Jongschaap andJ Mellema ldquoLinear rheology of guar gum solutionsrdquo Macro-molecules vol 33 no 26 pp 9594ndash9605 2000

[14] T Aubry and M Moan ldquoRheological behavior of a hydropho-bically associating water soluble polymerrdquo Journal of Rheologyvol 38 no 6 pp 1681ndash1692 1994

International Journal of Carbohydrate Chemistry 15

[15] L M Zhang T Kong and P S Hui ldquoSemi-dilute solutions ofhydroxypropyl guar gum viscosity behaviour and thixotropicpropertiesrdquo Journal of the Science of Food and Agriculture vol87 no 4 pp 684ndash688 2007

[16] N N G Swamy T S Dharmarajan and K L K ParanjothildquoDerivatization of guar to various hydroxy alkyl derivatives andtheir characterizationrdquo Indian Drugs vol 43 no 9 pp 756ndash7592006

[17] H Gong M Liu J Chen F Han C Gao and B ZhangldquoSynthesis and characterization of carboxymethyl guar gumandrheological properties of its solutionsrdquo Carbohydrate Polymersvol 88 no 3 pp 1015ndash1022 2012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

International Journal of Carbohydrate Chemistry 13

30

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(a) CMG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(b) CMG DS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(c) HEG MS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(d) HEG MS = 02

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)0 20 40 60

(e) MG DS = 01

25

20

15

10

5

0

Shea

r rat

e (s)

Radiation dose (KGy)

0

20 40 60

(f) MG DS = 02

Figure 15The plot of shear rate value versus radiation doseThe shear rate value was taken from the study carried out by increasing the shearrate and monitoring change in viscosity The point at which the curve between shear rate and viscosity reaches plateau was taken for plottingradiation dose versus shear rate for samples (a) CMG DS = 01 and (b) 02 (c) HEGMS = 01 and (d) 02 and (e) MG DS = 01 and (f) 02with respect to radiation dose

The depolymerisation of synthetic polymers by radiationprocessing for recycling of monomers has been known forquite some timeThepresent paper is an attempt to initiate theuse of this technology for radiation processing of modifiednatural polymers The gamma irradiation facility used for

the current studies is an industrial plant and it has been inoperation for about 20 years now where large volumes ofindustrial products are irradiated every day

From the results presented here it is evident that thedepolymerisation of guar is achieved with the radiation dose

14 International Journal of Carbohydrate Chemistry

of 1 KGy and above as seen from the observation of viscosityof 1 of guar derivatives getting reduced from as high a levelas 10000 cps (for unirradiated guar derivative) to as low alevel as 1 cps at 25∘C (for guar derivatives irradiated at 20ndash50KGy)

Inspite of this knowledge which can be easily usedfor scaling up of the process to commercial level doubtsare raised about the scalability of the process Whetherthe process can be used for bulk material is the commonapprehension in the minds of the processors of guar Whilethe present study would help clear many of the doubtsregarding the suitability of radiation processing technologybut the data about the scalability of the process would actuallyeliminate all sorts of doubts

Eventhough the results presented in this paper pertain tothe batch size of 200 g for each guar derivative at each dosethe same was found valid even for the bigger batch size (intons) The results of large batches were the same as obtainedfor the small batches Here it must be mentioned that thedose optimization for the purpose would be necessary for thepurpose of studying the scalability

From the present study the following can be concluded

(i) Radiation processing of guar derivatives leads to theirchain scissioning

(ii) Radiation processing leads to reduction in viscosity ofaqueous solutions of guar derivatives

(iii) Irradiation technique can be a good tool for tailormaking the guar derivatives of desired rheologicalproperties

(iv) The minimum viscosity attained by the 1 solutionof various derivatives shows a decreasing trend withrespect to increase in the radiation dose

(v) In case of carboxymethyl guar the crossover fre-quency increases as the radiation dose increases upto 5KGy and the value is higher in case of CMG ofDS 02 than in that of CMG of DS 01 This showsthat the elastic nature is more dominating for CMGof DS 01 than for CMG of DS 02

(vi) In case of hydroxyethyl guar ofMS 02 the crossoverfrequency of the 1198661015840 and 11986610158401015840 is lesser than that of HEGof MS 01 till 20 KGy radiation dose This meansthat elastic nature predominates in case of HEG ofMS 02 which may be due to the presence of greaternumber of ndash(CH

2ndashO)nndashH groups leading to increase

in H-bonding and thus more solid-like behavior(vii) In case of methyl guar on increasing the radiation

dose up to 10KGy the elastic component decreasesThis can be attributed to the fact that chain scissioningtakes place and now the H-bonding interactions takeplace between smaller chains which reduces theelasticity and viscous behavior predominates Dueto this the crossover frequency increases till 10 KGydose

(viii) As the radiation dose is increased the shear ratevalue at which nearly constant viscosity is achieveddecreases

Acknowledgment

The authors express sincere gratitude to the management ofShriram Institute for Industrial Research Delhi India for thekind support

References

[1] L Wang and L M Zhang ldquoViscoelastic characterization ofa new guar gum derivative containing anionic carboxymethyland cationic 2-hydroxy-3-(trimethylammonio)propyl substit-uentsrdquo Industrial Crops and Products vol 29 no 2-3 pp 524ndash529 2009

[2] C Sandolo PMatricardi F Alhaique and T Coviello ldquoEffect oftemperature and cross-linking density on rheology of chemicalcross-linked guar gum at the gel pointrdquo Food Hydrocolloids vol23 no 1 pp 210ndash220 2009

[3] H N Englyst V Anderson and J H Cummings ldquoStarch andnon-starch polysaccharides in some cereal foodsrdquo Journal of theScience of Food and Agriculture vol 34 no 12 pp 1434ndash14401983

[4] R L Feddersen and S N Thorp Industrial Gums AcaedemicPress San Diego Calif USA 1993

[5] D D Roberts J S Elmore K R Langley and J BakkerldquoEffects of sucrose guar gum and carboxymethylcelluloseon the release of volatile flavor compounds under dynamicconditionsrdquo Journal of Agricultural and Food Chemistry vol 44no 5 pp 1321ndash1326 1996

[6] D R Picout S B Ross-Murphy K Jumel and S E HardingldquoPressure cell assisted solution characterization of polysaccha-rides 2 Locust bean gum and tara gumrdquo Biomacromoleculesvol 3 no 4 pp 761ndash767 2002

[7] R S Blackburn ldquoNatural polysaccharides and their interactionswith dyemolecules applications in effluent treatmentrdquoEnviron-mental Science and Technology vol 38 no 18 pp 4905ndash49092004

[8] M Urdiaın A Domenech-Sanchez S Albertı V J Benedıand J A Rossello ldquoNew method of DNA isolation from twofood additives suitable for authentication in polymerase chainreaction assaysrdquo Journal of Agricultural and FoodChemistry vol53 no 9 pp 3345ndash3347 2005

[9] R P Singh S Pal andDMal ldquoA high performance flocculatingagent and viscosifiers based on cationic guar gumrdquoMacromolec-ular Symposia vol 242 pp 227ndash234 2006

[10] S P Zhao DMa and LM Zhang ldquoNew semi-interpenetratingnetwork hydrogels synthesis characterization and propertiesrdquoMacromolecular Bioscience vol 6 no 6 pp 445ndash451 2006

[11] J Z Yi and L M Zhang ldquoBiodegradable blend films basedon two polysaccharide derivatives and their use as Ibuprofen-releasing matricesrdquo Journal of Applied Polymer Science vol 103no 6 pp 3553ndash3559 2007

[12] S Venkataiah and E G Mahadevan ldquoRheological propertiesof hydroxypropyl and sodium carboxymethyl substituted guargums in aqueous solutionrdquo Journal of Applied Polymer Sciencevol 27 no 5 pp 1533ndash1548 1982

[13] R H W Wientjes M H G Duits R J J Jongschaap andJ Mellema ldquoLinear rheology of guar gum solutionsrdquo Macro-molecules vol 33 no 26 pp 9594ndash9605 2000

[14] T Aubry and M Moan ldquoRheological behavior of a hydropho-bically associating water soluble polymerrdquo Journal of Rheologyvol 38 no 6 pp 1681ndash1692 1994

International Journal of Carbohydrate Chemistry 15

[15] L M Zhang T Kong and P S Hui ldquoSemi-dilute solutions ofhydroxypropyl guar gum viscosity behaviour and thixotropicpropertiesrdquo Journal of the Science of Food and Agriculture vol87 no 4 pp 684ndash688 2007

[16] N N G Swamy T S Dharmarajan and K L K ParanjothildquoDerivatization of guar to various hydroxy alkyl derivatives andtheir characterizationrdquo Indian Drugs vol 43 no 9 pp 756ndash7592006

[17] H Gong M Liu J Chen F Han C Gao and B ZhangldquoSynthesis and characterization of carboxymethyl guar gumandrheological properties of its solutionsrdquo Carbohydrate Polymersvol 88 no 3 pp 1015ndash1022 2012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

14 International Journal of Carbohydrate Chemistry

of 1 KGy and above as seen from the observation of viscosityof 1 of guar derivatives getting reduced from as high a levelas 10000 cps (for unirradiated guar derivative) to as low alevel as 1 cps at 25∘C (for guar derivatives irradiated at 20ndash50KGy)

Inspite of this knowledge which can be easily usedfor scaling up of the process to commercial level doubtsare raised about the scalability of the process Whetherthe process can be used for bulk material is the commonapprehension in the minds of the processors of guar Whilethe present study would help clear many of the doubtsregarding the suitability of radiation processing technologybut the data about the scalability of the process would actuallyeliminate all sorts of doubts

Eventhough the results presented in this paper pertain tothe batch size of 200 g for each guar derivative at each dosethe same was found valid even for the bigger batch size (intons) The results of large batches were the same as obtainedfor the small batches Here it must be mentioned that thedose optimization for the purpose would be necessary for thepurpose of studying the scalability

From the present study the following can be concluded

(i) Radiation processing of guar derivatives leads to theirchain scissioning

(ii) Radiation processing leads to reduction in viscosity ofaqueous solutions of guar derivatives

(iii) Irradiation technique can be a good tool for tailormaking the guar derivatives of desired rheologicalproperties

(iv) The minimum viscosity attained by the 1 solutionof various derivatives shows a decreasing trend withrespect to increase in the radiation dose

(v) In case of carboxymethyl guar the crossover fre-quency increases as the radiation dose increases upto 5KGy and the value is higher in case of CMG ofDS 02 than in that of CMG of DS 01 This showsthat the elastic nature is more dominating for CMGof DS 01 than for CMG of DS 02

(vi) In case of hydroxyethyl guar ofMS 02 the crossoverfrequency of the 1198661015840 and 11986610158401015840 is lesser than that of HEGof MS 01 till 20 KGy radiation dose This meansthat elastic nature predominates in case of HEG ofMS 02 which may be due to the presence of greaternumber of ndash(CH

2ndashO)nndashH groups leading to increase

in H-bonding and thus more solid-like behavior(vii) In case of methyl guar on increasing the radiation

dose up to 10KGy the elastic component decreasesThis can be attributed to the fact that chain scissioningtakes place and now the H-bonding interactions takeplace between smaller chains which reduces theelasticity and viscous behavior predominates Dueto this the crossover frequency increases till 10 KGydose

(viii) As the radiation dose is increased the shear ratevalue at which nearly constant viscosity is achieveddecreases

Acknowledgment

The authors express sincere gratitude to the management ofShriram Institute for Industrial Research Delhi India for thekind support

References

[1] L Wang and L M Zhang ldquoViscoelastic characterization ofa new guar gum derivative containing anionic carboxymethyland cationic 2-hydroxy-3-(trimethylammonio)propyl substit-uentsrdquo Industrial Crops and Products vol 29 no 2-3 pp 524ndash529 2009

[2] C Sandolo PMatricardi F Alhaique and T Coviello ldquoEffect oftemperature and cross-linking density on rheology of chemicalcross-linked guar gum at the gel pointrdquo Food Hydrocolloids vol23 no 1 pp 210ndash220 2009

[3] H N Englyst V Anderson and J H Cummings ldquoStarch andnon-starch polysaccharides in some cereal foodsrdquo Journal of theScience of Food and Agriculture vol 34 no 12 pp 1434ndash14401983

[4] R L Feddersen and S N Thorp Industrial Gums AcaedemicPress San Diego Calif USA 1993

[5] D D Roberts J S Elmore K R Langley and J BakkerldquoEffects of sucrose guar gum and carboxymethylcelluloseon the release of volatile flavor compounds under dynamicconditionsrdquo Journal of Agricultural and Food Chemistry vol 44no 5 pp 1321ndash1326 1996

[6] D R Picout S B Ross-Murphy K Jumel and S E HardingldquoPressure cell assisted solution characterization of polysaccha-rides 2 Locust bean gum and tara gumrdquo Biomacromoleculesvol 3 no 4 pp 761ndash767 2002

[7] R S Blackburn ldquoNatural polysaccharides and their interactionswith dyemolecules applications in effluent treatmentrdquoEnviron-mental Science and Technology vol 38 no 18 pp 4905ndash49092004

[8] M Urdiaın A Domenech-Sanchez S Albertı V J Benedıand J A Rossello ldquoNew method of DNA isolation from twofood additives suitable for authentication in polymerase chainreaction assaysrdquo Journal of Agricultural and FoodChemistry vol53 no 9 pp 3345ndash3347 2005

[9] R P Singh S Pal andDMal ldquoA high performance flocculatingagent and viscosifiers based on cationic guar gumrdquoMacromolec-ular Symposia vol 242 pp 227ndash234 2006

[10] S P Zhao DMa and LM Zhang ldquoNew semi-interpenetratingnetwork hydrogels synthesis characterization and propertiesrdquoMacromolecular Bioscience vol 6 no 6 pp 445ndash451 2006

[11] J Z Yi and L M Zhang ldquoBiodegradable blend films basedon two polysaccharide derivatives and their use as Ibuprofen-releasing matricesrdquo Journal of Applied Polymer Science vol 103no 6 pp 3553ndash3559 2007

[12] S Venkataiah and E G Mahadevan ldquoRheological propertiesof hydroxypropyl and sodium carboxymethyl substituted guargums in aqueous solutionrdquo Journal of Applied Polymer Sciencevol 27 no 5 pp 1533ndash1548 1982

[13] R H W Wientjes M H G Duits R J J Jongschaap andJ Mellema ldquoLinear rheology of guar gum solutionsrdquo Macro-molecules vol 33 no 26 pp 9594ndash9605 2000

[14] T Aubry and M Moan ldquoRheological behavior of a hydropho-bically associating water soluble polymerrdquo Journal of Rheologyvol 38 no 6 pp 1681ndash1692 1994

International Journal of Carbohydrate Chemistry 15

[15] L M Zhang T Kong and P S Hui ldquoSemi-dilute solutions ofhydroxypropyl guar gum viscosity behaviour and thixotropicpropertiesrdquo Journal of the Science of Food and Agriculture vol87 no 4 pp 684ndash688 2007

[16] N N G Swamy T S Dharmarajan and K L K ParanjothildquoDerivatization of guar to various hydroxy alkyl derivatives andtheir characterizationrdquo Indian Drugs vol 43 no 9 pp 756ndash7592006

[17] H Gong M Liu J Chen F Han C Gao and B ZhangldquoSynthesis and characterization of carboxymethyl guar gumandrheological properties of its solutionsrdquo Carbohydrate Polymersvol 88 no 3 pp 1015ndash1022 2012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

International Journal of Carbohydrate Chemistry 15

[15] L M Zhang T Kong and P S Hui ldquoSemi-dilute solutions ofhydroxypropyl guar gum viscosity behaviour and thixotropicpropertiesrdquo Journal of the Science of Food and Agriculture vol87 no 4 pp 684ndash688 2007

[16] N N G Swamy T S Dharmarajan and K L K ParanjothildquoDerivatization of guar to various hydroxy alkyl derivatives andtheir characterizationrdquo Indian Drugs vol 43 no 9 pp 756ndash7592006

[17] H Gong M Liu J Chen F Han C Gao and B ZhangldquoSynthesis and characterization of carboxymethyl guar gumandrheological properties of its solutionsrdquo Carbohydrate Polymersvol 88 no 3 pp 1015ndash1022 2012

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of