polymeric coatings based on ldpe and taurit - … no4_p395-402_oct … · thylamine,...

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Chemical Industry & Chemical Engineering Quarterly Available on line at Association of the Chemical Engineers of Serbia AChE www.ache.org.rs/CICEQ Chem. Ind. Chem. Eng. Q. 25 (4) 395402 (2019) CI&CEQ 395 KAZIM S. NADIROV MANAP K. ZHANTASOV AIZHAN A. YESSENTAYEVA GULMIRA ZH. BIMBETOVA SAULE A. SAKIBAYEVA AINUR S. SADYRBAYEVA RAZIA A. ISSAYEVA ZHADRA A. SHINGISBAYEVA ARSLANBEK K. ORYNBASAROV KHAMIT A. SARSENBAYEV M. Auezov South Kazakhstan State University, Shymkent, Kazakhstan SCIENTIFIC PAPER UDC 621.643:620.197.6:678 POLYMERIC COATINGS BASED ON LDPE AND TAURIT - PREPARATION, STRUCTURE AND MECHANICAL PROPERTIES Article Highlights The preparation method and performance behaviour of polymer composite systems are described The composites have been prepared via extrusion blending The results indicate that the obtained composites can be used as pipeline coatings Abstract The article describes a preparation method and performance behaviour of polymer composite systems with a matrix of LDPE and a reinforcing agent of taurit. Taurit (a species of shungite) is an inexpensive, well-available and envi- ronmentally friendly mineral, compatible with many polymers. The composites have been prepared via extrusion blending and their mechanical and protect- ive properties have been studied. Performance of taurit-containing materials has been compared with properties of composites with other commonly used fillers (carbon black, talc, aluminium oxide, asbestos fibres, etc.) and taurit was proven to be the most efficient reinforcement in this series. The results indicate that the obtained composites can be used as coatings for pipelines to protect them from corrosion and mechanical damage. Keywords: polymer composite systems, protection coating, taurit-con- taining materials, pipelines. In the contemporary world, almost all oil, natural gas and some petrochemical products are trans- ported through pipelines. Damages of pipelines can cause substantial risks both for the environment, inhabitants and the economy of the region, within the territory where the pipelines are laid down. Since metal pipes are located in the ground and sea beds and make contact with an aggressive exter- nal environment (underground waters, salts, acids, microorganisms, etc.), they need protective coatings. In addition, due to the fact that pipes are widely used in the oil and gas industry, their contact with corrosive technological fluids, which are used in the course of prospecting and production of the productive format- ions is not excluded as well, while these technological Correspondence: M.K. Zhantasov, M. Auezov South Kazakhstan State University, Shymkent (160019, Shymkent, Karasu, 58 – 17), Republic of Kazakhstan. E-mail: [email protected] Paper received: 25 January, 2019 Paper revised: 27 March, 2019 Paper accepted: 7 May, 2019 https://doi.org/10.2298/CICEQ190125017N fluids are based on acids and other caustic agents [1,2]. Moreover, signs of these technological fluids can be found within the hydrocarbons, which are ext- racted from the productive formation [3]. Therefore, coatings of tubes and tanks are exp- ected to display the following properties [4,5]: - Resistance to water and moisture. Percolation of water under the coating can accelerate the rate of corrosion of the underlying steel tube and can also lead to detachment of the cover from the steel surface; - Resistance to mechanical damage. When pipes are installed underground, pressure on their surface increases manyfold. Furthermore, small sharp-edged stones and other particles which are also present in the soil can make scratches and cracks on the sur- face of tubes. Coatings are supposed to protect the tube surface from this kind of damage. - High thermal stability. Temperature-induced expansion and contraction of the polymer layer can cause its separation from the tube, therefore pro- tective covers have to be resistant to temperature changes;

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Page 1: POLYMERIC COATINGS BASED ON LDPE AND TAURIT - … No4_p395-402_Oct … · thylamine, 2,6-di-tert-butyl-4-methylphenol, 6-ethoxy- -2,2,4-trimethyl-1,2-dihydroquinoline and gossypol

Chemical Industry & Chemical Engineering Quarterly

Available on line at Association of the Chemical Engineers of Serbia AChE www.ache.org.rs/CICEQ

Chem. Ind. Chem. Eng. Q. 25 (4) 395−402 (2019) CI&CEQ

395

KAZIM S. NADIROV

MANAP K. ZHANTASOV AIZHAN A. YESSENTAYEVA

GULMIRA ZH. BIMBETOVA SAULE A. SAKIBAYEVA

AINUR S. SADYRBAYEVA RAZIA A. ISSAYEVA

ZHADRA A. SHINGISBAYEVA ARSLANBEK K.

ORYNBASAROV KHAMIT A. SARSENBAYEV

M. Auezov South Kazakhstan State University, Shymkent,

Kazakhstan

SCIENTIFIC PAPER

UDC 621.643:620.197.6:678

POLYMERIC COATINGS BASED ON LDPE AND TAURIT - PREPARATION, STRUCTURE AND MECHANICAL PROPERTIES

Article Highlights • The preparation method and performance behaviour of polymer composite systems are

described • The composites have been prepared via extrusion blending • The results indicate that the obtained composites can be used as pipeline coatings Abstract

The article describes a preparation method and performance behaviour of polymer composite systems with a matrix of LDPE and a reinforcing agent of taurit. Taurit (a species of shungite) is an inexpensive, well-available and envi-ronmentally friendly mineral, compatible with many polymers. The composites have been prepared via extrusion blending and their mechanical and protect-ive properties have been studied. Performance of taurit-containing materials has been compared with properties of composites with other commonly used fillers (carbon black, talc, aluminium oxide, asbestos fibres, etc.) and taurit was proven to be the most efficient reinforcement in this series. The results indicate that the obtained composites can be used as coatings for pipelines to protect them from corrosion and mechanical damage.

Keywords: polymer composite systems, protection coating, taurit-con-taining materials, pipelines.

In the contemporary world, almost all oil, natural gas and some petrochemical products are trans-ported through pipelines. Damages of pipelines can cause substantial risks both for the environment, inhabitants and the economy of the region, within the territory where the pipelines are laid down.

Since metal pipes are located in the ground and sea beds and make contact with an aggressive exter-nal environment (underground waters, salts, acids, microorganisms, etc.), they need protective coatings. In addition, due to the fact that pipes are widely used in the oil and gas industry, their contact with corrosive technological fluids, which are used in the course of prospecting and production of the productive format-ions is not excluded as well, while these technological

Correspondence: M.K. Zhantasov, M. Auezov South Kazakhstan State University, Shymkent (160019, Shymkent, Karasu, 58 – 17), Republic of Kazakhstan. E-mail: [email protected] Paper received: 25 January, 2019 Paper revised: 27 March, 2019 Paper accepted: 7 May, 2019

https://doi.org/10.2298/CICEQ190125017N

fluids are based on acids and other caustic agents [1,2]. Moreover, signs of these technological fluids can be found within the hydrocarbons, which are ext-racted from the productive formation [3].

Therefore, coatings of tubes and tanks are exp-ected to display the following properties [4,5]:

- Resistance to water and moisture. Percolation of water under the coating can accelerate the rate of corrosion of the underlying steel tube and can also lead to detachment of the cover from the steel surface;

- Resistance to mechanical damage. When pipes are installed underground, pressure on their surface increases manyfold. Furthermore, small sharp-edged stones and other particles which are also present in the soil can make scratches and cracks on the sur-face of tubes. Coatings are supposed to protect the tube surface from this kind of damage.

- High thermal stability. Temperature-induced expansion and contraction of the polymer layer can cause its separation from the tube, therefore pro-tective covers have to be resistant to temperature changes;

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- All the components of the coatings must be insoluble in water, oil and oil derivatives. Clay, silica gel, charcoal and some other compounds have good absorbent properties. It is important that during con-tact with soil, elements of the coatings should not be absorbed.

- High electrical resistance is necessary for pipes with cathodic protection.

- Pipes buried in soil cannot be replaced after a short period of time, therefore, the operational life of tube covers should exceed 20 years.

Different types of coatings have been used for protection of the external surface of oil and gas trans-mission pipelines against corrosion, chemical penet-ration and mechanical damage. Coal tar enamel is the oldest coating used in this field. The main disad-vantages of this material are brittleness, insufficient adhesion to the metal surface and low mechanical strength. Later, coatings from different synthetic poly-mers have been developed [6-10]. Polyurethane pro-ved to be the most efficient coating with excellent erosion-corrosion behaviour, high mechanical pro-perties and heat resistance [6]. Due to the high cost of this material, it is mainly used in special cases, such as places with high temperature. On the other hand, polyethylene (PE) is much cheaper than polyure-thane. The major problem with this polymer is the lack of adhesion between PE and steel surface, therefore, an additional adhesive layer is required. The most commonly used coating systems contain two or three layers, an upper protective layer made from polyethyl-ene and an adhesive sublayer based on epoxy resin or ethylene vinyl acetate [9-10]. One of the ways to increase the service life of pipelines is improving the properties of the materials from which coatings are prepared while maintaining, or even reducing, their cost. In this regard, it is desirable to use cheap and well-available components and fillers in the develop-ment of coatings. In recent years, very interesting and promising investigations of the highly energetic modi-fications of polyethylene coatings were performed [11,12], however, it is necessary to perform further investigations in order to estimate the possibility of widespread introduction of the results of these inves-tigations into the wide-ranging practice. Therefore, we will concentrate our attention on the modification of polymer coatings with the help of additions of mineral fillers and wastes of cotton production, due to the fact that such coating will be extremely inexpensive.

Nowadays, there exists a big variety of reinfor-cements for polymer matrices. Most frequently used fillers are carbon black, talc, graphite, chalk, silicon oxide (white carbon), aluminium oxide, etc. [13,14]. In

this study, the main filler was shungite mineral of two types - taurit shale and taurit carbonate (Koksu dep-osit in Kazakhstan in the Almaty region). Interest in the use of shungite is caused by the following factors [15]:

- It contains as major ingredients non-crys-talline carbon and silicon dioxide. These components are similar in chemical nature to the widely used reinforcements carbon black and white carbon (silicon dioxide).

- Shungite is compatible with many polar and non-polar polymers due to the presence of hydrophilic and hydrophobic components and to the metastable structure of shungite carbon. Surface properties of shungite and its structure can be easily altered by chemical modification.

- Shungite species are widespread and occur shallow. The explored resources of this mineral are estimated at hundreds of million tons [16,17].

Structural features and physical and chemical properties of shungite minerals are described in detail [18].

The matrix polymer for preparation of the com-posites was low-density polyethylene (LDPE) – an inexpensive and well-available polymer.

The main objective of the present study is the development of composites based on LDPE and taurit with good mechanical and protective properties. The resulting composite materials have then been charac-terized with respect to their morphology, mechanical behaviour, thermal stability, corrosion resistance, and other characteristics, and the optimum content of the mineral in the composite has been found. Properties of taurit-containing materials have been compared with properties of composites with other commonly used fillers.

MATERIALS AND METHODS

For preparation of the composites we used two types of shungite from the Koksu field (Kazakhstan); these minerals belong to the second species of shun-gite with carbon content less than 20%. Physical and chemical properties of shungite depend primarily on the ratio of carbon and mineral components and their structure. Composition and main characteristics of the fillers are given in Table 1. In addition to these con-stituents, taurit may contain the elements Zn, Ni, Y, Cr, Co, etc.; their total content is less than 1%.

Before blending with a polymer, the minerals were ground using a jaw crusher, a ball mill and a ceramic attritor. After the third stage, the powder was obtained with a density of 1.17-1.20 g/cm3 and a par-

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ticle size of 10-90 μm. According to electron micro-scopy analysis, taurit particles have a wide size distri-bution and a predominantly spherical shape.

Table 1. Composition of minerals (%) used as fillers in the study

Component Taurit shale Taurit carbonate

Carbon 1.0-16.0 4.5-18.0

Mineral constituents

SiO2 50.0-75.0 29.0-42.0

Al2O3 5.0-13.0 5.0-9.0

Fe2O3 3.0-4.0 2.0-5.0

K2O 1.0-2.0 1.5-3.0

CaO 0.2-6.0 20.0-32.0

Na2O 0.2-0.5 0.2-0.7

MgO 0.71 2.32

TiO2 0.2-0.5 0.2-0.5

Mn 0.1 0.08

Ba 0.06 0.08

Zr 0.05 0.05

Sr 0.04 0.05

V 0.015 0.015

B 0.01 0.02

As a matrix, we used a polymer compound PE-1 which consists of LDPE and 10% technical gossypol. Technical gossypol is another component of the pre-pared composite, this is gossypol resin, 2,2-di-3- -methyl-5-isopropyl-1,6,7-trihydroxy-8-naphthaldehyde [19-22]. These substances are waste pieces of pro-duction of cottonseed oil. Our previous studies showed that it effectively inhibits radical reactions and oxidation of polyolefins and therefore can be applied as a stabilizer for polymers. The resin content was 0.5% of weight of LDPE.

The following compounds were used as the sta-biliser for the polymer composition: phenyl-β-naph-thylamine, 2,6-di-tert-butyl-4-methylphenol, 6-ethoxy- -2,2,4-trimethyl-1,2-dihydroquinoline and gossypol.

The chloroform solution of the gossypol resin was used in order to measure the infrared spectrum. This solution has been prepared in accordance with the following procedure: from the very beginning, it is necessary to add 60 mL of chloroform to the flask, which contains the initial sample of the technical gos-sypol. Then it is necessary to shake the flask in order to mix the substances and close the flask with the help of the tight stopper/plug in order to prevent ext-rusion of this plug under the action of the internal pressure. Then it is necessary to install the flask into the mechanical shaker and shake it with sufficient energy in order to ensure that the sample will be washed from the walls of the flask during not fewer

than 15 flushing operations. The plug has to be opened and washed with the help of chloroform that is to be added from the previously washed and dosed bottle, which is equipped with a thin tip. The extracted mixture is then filtered in vacuum with the help of the previously prepared filter, thus obtaining the filtrate in the volume of 100 mL. The flask was installed under the hood, then rinsed with the chloroform that is to be dosed with the help of the washing bottle and flushing liquids are poured through the filter. The filter was washed with several small portions of chloroform, then diluted with chloroform (volume up to 100 mL) and mixed thoroughly. Instead of shaking and stirring these samples can be treated with ethyl alcohol and aniline in two beakers (volume of each beaker: 50 mL) and then they can be moved into the vessel, which contains 60 mL of chloroform, which was mixed and filtered in the course of 3 ablutions. Two mL of the filtrate were poured into the volumetric flask (vol-ume of the flask: 25 mL), diluted with chloroform up to the full volume and mixed thoroughly. In the course of these operations, the intensity of colour was observed with the help of a spectrophotometer or photoelectric colorimeter, while using chloroform as the reference solution. Portion of the gossypol in the course of dilut-ion up to the achievement of the required volume (25 mL) in order to ensure reading of the infrared spectra can be scalable on the basis of the standard curve or it can be calculated in accordance with the value, which was calculated as the ratio of the optical den-sity and concentration.

Taurit fillers were compounded with the matrix PE-1 via melt extrusion. This method provides import-ant benefits, which are, on the one hand, a combin-ation in a single extruder of a few processes (disper-sion, mixing, homogenization, thermal treatment) and, on the other hand, continuity and a high productivity of the process.

Mixing was carried out in a laboratory multifunc-tional twin-screw extruder UR-TC (England). The prin-ciple of its operation is fully consistent with the tech-nological process in the production line. The entire complex includes an extruder with modular screws, modular cylinder, feeders, a cooling bath, and a gra-nulator. The components were blended in the ext-ruder at the temperature of 110-120 °C. Polyethylene was fed first, then taurit and gossypol were added to the mixture. After obtaining a homogeneous blend it was dumped out of the extruder at the temperature of 130-140 °C. The extrudates were collected and used to prepare specimens for tensile, bending, impact and wear tests.

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Mechanical tests were performed on dog-bone specimens with dimensions of the working area 80 mm×10 mm×3 mm using a tensile testing machine Instron 1121. Tensile and bending diagrams were recorded at ambient temperature and rate of drawing of 50%/min. In every series, 7-10 specimens were tested and average values of elastic modulus, tensile strength and elongation at break were calculated.

The rate of oxygen adsorption was measured by means of an experimental set-up containing reaction vessels, a vacuum assembly and a pressure gauge.

Impact strength was measured at room tempe-rature using a pendulum impact machine CEAST 9050, dimensions of specimens were 80 mm×10 mm×3 mm, with notch length of 3 mm.

RESULTS AND DISCUSSION

In our previous work [21], we focused on the nature of chemical bonds responsible for the syner-

gistic effect of gossypol resin. Based on the above- -mentioned data and on new IR absorption spectra, we can summarize the data on the decrease in oxy-gen absorption by various combinations of polymer-mineral coating (Table 2).

Data from spectral studies of original resin and a prepared polymer composite with gossypol resin are shown in Figures 1 and 2. The spectra were captured using a Shimadzu-IRPrestige-21 spectrophotometer equipped with a MIRacle ATR accessory (PIKE Tech-nologies) in the regional laboratory of engineering “Constructional and biochemical materials” at the M. Auezov South Kazakhstan State University.

The IR spectra of the chloroform solution of gos-sypol resin show that the stretching vibrations of the carbon skeleton appear in the region of 1250–1160 cm-1 (νC-C). They also occur as a series of weak bands with a frequency range below 650 cm-1 (δC-C, Figure 1). Vibrations that appear in the region of 1165–1107 cm-1 can be attributed to the isopropyl group of gos-

Table 2. Decrease in oxygen absorption by composites with different fillers

Mineral filler Stabilizer

Phenyl-β-naphthylamine 2,6-Di-tert-butyl-4-methylphenol 6-Ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline Gossypol

Talc -6 -8 +1 +4

Barium sulphate -4 -5 -7 -3

Asbestos fibres -11 +2 -21 -1

Feldspar +4 +3 +5 -12

Barite +3 -5 -6 -13

Aluminum oxide -2 +21 +22 +46

Taurit shale +29 +21 +15 +49

Taurit carbonate +27 +22 +24 +52

Carbon black -12 +25 +20 +51

Figure 1. IR spectra of gossypol resin.

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sypol molecules and its derivatives. By contrast, the IR spectra of the composite show a broad band in the region of 3.600–3.000 cm-1 with an absorption peak at 3.360 cm-1 (Figure 2). Strong absorption was also observed in the region of 800-600 cm-1. These bands can be attributed to the methylene group that reacts with the carboxyl group of fatty acids, which can be found in the gossypol resin in a significant amount (40-60%).

Oxygen is one of the major corrosive agents. If the incorporation of filler in the polymer decreases the rate of oxygen absorption, it means improved prot-ective properties of the material. Table 2 and Figure 3 presents data on the oxygen absorption of compo-sites with nine mineral fillers and four different stabil-izers (the values are given in % relative to the original PE-1 matrix). It is found that the fillers talc, barium sulphate, and asbestos fibres have little effect on the value of oxygen absorption. Addition of the reinforce-ments feldspar and barite increases the quantity of absorbed oxygen, thus leading to deterioration of coating properties. The maximum decrease in oxygen absorption (≈50%) is observed for composites con-taining the stabilizer gossypol and four minerals: aluminium oxide, carbon black and both types of tau-rit. We believe that in this case there is a synergistic effect between these minerals and gossypol resin. According to reference [14], the molecule of gossypol has aldehyde and hydroxyl groups, which determine its activity as a compatibilizer. Based on the results of these experiments, the stabilizer gossypol has been selected for further work as providing the best pro-perties of the composites.

Figure 3. Decrease in oxygen absorption by composites with

different fillers.

Materials used as coatings are often subjected to bending deformations during their service, there-fore bending strength is an important parameter for coatings. Values of bending strength for the compo-sites under study are presented in Figure 4. As is seen from the diagram, the strength is greatest for composites with aluminium oxide and both taurits when filler weight content is 10%. For composites with larger concentrations of minerals, bending stress is lowered.

Table 3 summarizes properties of the compo-sites with the four most effective reinforcements. We

Figure 2. IR spectra of coating composite with taurit and gossypol resin.

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can conclude that in this series taurit provides the best combination of properties.

Table 3. Protective characteristics of composites with carbon black, aluminium oxide, taurit shale and taurit carbonate; 1 – elastic modulus, 2 – durability, 3 – increase in viscosity, 4 – catal-ytic effect on the curing process, 5 - the decline in throw-away from deformation, 6 – wear resistance, 7 - availability in Kaz-akhstan; +: improved properties , -: deterioration , n/c: no change

Filler Properties of the composite relative

to the matrix

1 2 3 4 5 6 7

Carbon black - - + - n/c + +

Aluminum oxide + n/c + - + + -

Taurit carbonate + + + + + + +

Taurit shale + + + + + + +

It is important that anticorrosive properties of coatings should be combined with acceptable mech-anical characteristics since the coatings, easily des-troyed under the influence of external stresses, can-not protect the pipeline against mechanical damage.

The pristine polymer binding PE-1 has a tensile strength of 14 MPa, an ultimate elongation of 570% and is deformed with a weakly pronounced neck. Mechanical tests revealed that stress at break of the composites gradually decreases with increasing con-centration of taurit (Figure 5, curve 1). Such depen-dence of strength on filler concentration is typical for composites with mineral additives and is associated with the appearance and growth of pores [22]. It has been observed that filler particles begin to detach from the matrix at stretching, while the largest particle of 80-110 μm separate from the polymer at the elon-gation of 30-40%, and smaller inclusions tend to detach at the region of strain-hardening. The form-ation of voids leads to a reduction of the specimen section, which resists the acting force, and conse-quently the stress at the break is lowered.

Ultimate elongation is also reduced in compo-sites with mineral fillers; this phenomenon is known as “embrittlement”. The criterion for transition between

ductile and brittle deformation is described in public-ations [23-26]. If the composite’s strength is larger than the stress of neck propagation, a neck appears and propagates throughout the working area of a ten-sile specimen (ductile type deformation). Otherwise, steady propagation of neck becomes impossible and the composite fractures at the onset of necking (brittle failure). Figure 5 shows that plots of stress at break and stress of neck propagation come close and inter-sect at the filler fraction around 15%. Indeed, if taurit concentration is less than 15%, the strain at break of the composites is only slightly different from the strain of the neat polymer (Figure 6). At higher contents of taurit, ultimate elongation decreases significantly.

Figure 5. Stress at break (1) and stress of neck propagation (2)

versus taurit concentration.

Besides mechanical characteristics, other pro-perties that are important for protective coatings of pipelines have been determined: impact strength, resistance to temperature changes and to the exter-nal environment, wear and corrosive resistance, and durability. These parameters for composites with tau-rit shale and taurit carbonate are given in Table 4. It

Figure 4. Effect of fillers on bending strength of the composites (concentration, wt.%: 1 - 5; 2 - 10; 3 - 15).

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has been observed that the durability, wear and cor-rosive resistance increase in the whole concentration range from 2 to 20% while the impact strength and resistance to temperature changes achieve the high-est values at φ = 8%. No significant difference has been found between taurit shale and taurit carbonate. Taking into account the data on the mechanical pro-perties, the value of 8% has been chosen as the opti-mal concentration of filler.

Figure 6. Ultimate strain of the composites versus taurit

concentration.

Table 4. Effect of taurit filler on performance behaviour of the composites; 1 - impact strength, 2 - resistance to the external environment, 3 - resistance to temperature changes, 4 – durab-ility, 5 - wear resistance, 6 – corrosive resistance

Concentration of taurit shale/carbo-nate, wt. %

Composite

1 2 3 4 5 6

2 3/3 2/3 8/8 4/3 3/3 8/7

5 9/9 4/5 15/13 6/8 8/9 10/8

8 15/12 7/9 25/22 13/15 14/15 17/15

10 15/12 6/8 22/21 12/12 14/12 20/18

15 10/11 3/5 19/18 17/18 18/14 24/22

20 7/8 - 10/8 22/20 26/23 28/27

CONCLUSIONS

A new composite material has been developed on the basis of taurit, a low-cost, well-available and environmentally friendly mineral. It is shown that per-formance properties of the composite (bending and impact strength, wear and corrosive resistance, res-istance to temperature changes and external environ-ment, and durability) are superior to similar character-istics of the original polymer and the best combination

of properties has been observed at filler concentration of 8 wt.%. The results indicate that the obtained mat-erial can be used as a protective coating of pipelines. In addition, it is worth to underline that the resulting modified composite material, which consists of the LDPE matrix, the gossypol resin and mineral filler, demonstrates a synergetic effect, as well as the pro-perties, which are not only highly competitive with the initial polymer, which was selected as the matrix, but which even surpass properties of this polymer. We can explain this fact with the well-developed surface of taurit and with the development of the connections of chemical nature with the addition of the gossypol resin.

Acknowledgements

Authors express their gratitude to the team of the LLP Neftekhimstroy-YUG and to those working in the Regional Laboratory of Constructional and Bio-chemical Materials at the M. Auezov South Kazakh-stan State University for research assistance.

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KAZIM S. NADIROV MANAP K. ZHANTASOV

AIZHAN A. YESSENTAYEVA GULMIRA ZH. BIMBETOVA

SAULE A. SAKIBAYEVA AINUR S. SADYRBAYEVA

RAZIA A. ISSAYEVA ZHADRA A. SHINGISBAYEVA

ARSLANBEK K. ORYNBASAROV KHAMIT A. SARSENBAYEV

M. Auezov South Kazakhstan State University, Shymkent, Kazakhstan

NAUČNI RAD

POLIMERNI PREMAZI NA BAZI LDPE I TAURITA - PRIPREMA, STRUKTURA I MEHANIČKA SVOJSTVA

U radu se opisuje način pripreme i ponašanje polimernih kompozitnih sistema sa LDPE matricom i tauritom kao agensom za pojačanje. Taurit (vrsta šungita) je jeftin, dobro ras-položiv i ekološki prihvatljiv mineral, kompatibilan sa mnogim polimerima. Kompoziti su pripremljeni ekstruzionim mešanjem, a proučavane su njihove mehaničke i zaštitne oso-bine. Performanse materijala koji sadrže taurit upoređivane su sa svojstvima kompozita sa drugim uobičajenim punilima (čađa, talk, aluminijum-oksid, azbestna vlakna). Taurit se pokazao kao najefikasnija armatura u ovoj seriji. Dobijeni rezultati ukazuju da se dobijeni kompoziti mogu koristiti kao premazi cevovoda koji ih štite od korozije i meha-ničkih oštećenja.

Ključne reči: polimerni kompozitni sistemi; zaštitni premaz; materijali sa tauri-tom; cevovodi.