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Improved Pulp PropertiesImproved Pulp Properties thru Fiber Modificationthru Fiber Modification

Art J. RagauskasSchool Chemistry & BiochemistrySchool Chemistry & Biochemistry

Institute of Paper Science & TechnologyGeorgia Institute of TechnologyGeorgia Institute of Technology

Atlanta, GA

Fiber Modification: Addressing the Challenge

Fiber Modification: The World is not Flat

What is Needed to Make Stable Complex Curved Paper StructuresB Fib Fib B di• Better Fiber-Fiber Bonding

• Moisture insensitivity• Nano coatings

C li ki• Crosslinking• Grafting• Resins• LbL• LbL

• Better Stress Transfer• Engineered fiber surfaces• Fibers reinforced with bio-composites• Fibers reinforced with bio-composites

• Thermo/chemical responsive green composites/resins

Fiber Modification: Southern SW Fiber vs Northern

SW/Tropic HW for Tissue/TowelSW/Tropic HW for Tissue/TowelSouthern Fiber Suffers from fiber coarseness

Ti d i d i b l f lTissue and tissue products requires a balance of several competing effects including tensile strength, absorbency and softness. Of these three parameters, the strength of the sheet and its corresponding softness often exhibit a

ftnes

s

sheet and its corresponding softness often exhibit a dependency on each other. For example, mechanical treatments that enhance softness also decrease tensile strength which for many applications is not a preferred

Sof strength, which for many applications is not a preferred

outcome.

StrengthFiber Notching of SW Fibers

- Yields a ‘softer feel fiber’- Fibers with reduced dry zero-span

tensile have improved hand feel

Fiber Modification: Southern SW Fiber vs Northern

SW/Tropic HW for Tissue/TowelSW/Tropic HW for Tissue/TowelFiber Notching of SW Fibers

ZÜxtàxÜ Y|uxÜ YÄxåtu|Ä|àç

Chemical/Physical Approachesy pp- Chemical etching- Hot blow kraft cooks- Chemical/physical treatments

Fiber Modification: Green Paper & Packaging

Need to Develop Enhanced Moisture/O2/BacterialNeed to Develop Enhanced Moisture/O2/BacterialBarrier Properties

• Consumer driven to be green• Replace plastic/metal barriersp p• Replace petroleum based papermaking additives with biobased materials

Development Opportunities:H i ll l b i f i t d O2• Hemicellulose barriers for moisture and O2

• Functional fibers for antibacterial• Nano-particles

Grafted/LbL/antibacterial agents• Grafted/LbL/antibacterial agents• Nanocellulose/starch/lignin strength/crosslinking

• Coatings/films • Wet end applications

200

300

400Water Vapour Transmission/h

• Wet-end applications• Fire resistant fibers

• Green home insulation market & structural market0

100

0% 5 10

% Sulfonated Whiskers

Fiber Modification: Green Paper & Packaging

Need to Develop Enhanced Moisture/O2/BacterialNeed to Develop Enhanced Moisture/O2/BacterialBarrier Properties

• Consumer driven to be green• Replace plastic/metal barriersp p• Replace petroleum based papermaking additives with biobased materials

35.0

15.0

20.0

25.0

30.0

Tens

ile In

dex

Hot Pressing With Resins 0.0

5.0

10.0

Control 2% PVA 5% PVA 20% PVA

Control and PVA TMP Sheets Hot Pressed

• Hydrophobic Bonding• Dry Formingy g• Air-laid Papermaking

Fiber Modification: Enhanced Water Absorption

Water Absorption of SW Kraft Fibers/Fluff

Cross-linked Fibers

Water RetainedWater Absorbed

120

140

teria

l

Milled Pine Water Retained

Pine Water Retained150

175

200

ial

Milled Pine Thermal

Pine Pulp Thermal

40

60

80

100

wat

er/ g

dry

mat

75

100

125

150

wat

er/ g

dry

mat

eri Pine Pulp Thermal

0

20

40

0 10 20 30 40 50 60 70

% PMVEMA

g w

0

25

50

0 10 20 30 40 50 60 70

g w

% PMVEMA% PMVEMA

Fiber Modification: Enhanced Water Absorption

Water Absorption of SW Kraft Fibers/Fluff

189.2180

210

240

Uncrosslinked

Crosslinked

Cross-linked Fibers

Functionalized Fluff• Develop new crosslinking agents• New oxidation protocols

137.9

86.5

60

90

120

150

WA

AR

V (g

/g)

p• Greater Water Absorbency• Reduced Bonding

4.97 4.72 3.820

30

2.41 0.97 0.50Fiber length (mm)

Functionalized Fibers

Fiber Modification: Fiber – Fiber Bonding

Benefits of Fiber Charge/Hemicellulose Retention/GenerationBenefits of Fiber Charge/Hemicellulose Retention/Generation• Enhanced Strength

• Tensile/Burst/(STFI)• Refinability Peroxidey• Fold • Recyclability

12Tensile stiffnessUltrasonic in Plane specific stiffness:longitudial

5.0

60

70

80

ol/g

,Hol

oPul

p

21.42

21

22

9

10

11

Ultrasonic in Plane specific stiffness:longitudial Ultrasonic in Plane specific stiffness:shear

or k

m2 /s

ec2 4.5

sec2

30

40

50

Car

boxy

lic a

cid,

m

o

18.35

16

17

18

19

20Tensile index

(N.m/g)

44.82 61.79Carboxylic acid, mol/g Holopulp

7

8

9

Stif

fnes

s,kN

/mm

2 o3.5

4.0

Shea

r,km

2 /s

0.0 0.1 0.2 0.3 0.4 0.520

Catalyst, %44.8 67.02 80.04

6

Carboxylic acid, mol/g HoloPulp

3.0


55

60

50

55

60

ex

40

45

50

Tens

ile In

dex

35

40

45

50

Tens

ile In

de

ControlBirchOat Hulls

30

35

100% SW 1% Birch 2% Birch 4% Birch 8% Birch 2% Oats 5% Oats 8% Oats

30

35

8.0% 8.5% 9.0% 9.5% 10.0% 10.5%

Xylan %

Oat Hulls

5.9

6

Burst Index

5 6

5.7

5.8

5.9

5 3

5.4

5.5

5.6

5.2

5.3

Control 2% Ag 5% Ag 8% Ag


46 150 3.4

Birch Xylan on Eucalyptus BKP - Virgin

44

45 Tensile index TEA Strain

m/g

)

141

144

147

3.2

4.3

4.4

4.5

Tear index Retention of tear index 54

55

56

R

42

43

ensi

le in

dex

(Nm

135

138

141 TEA (J/m2)

3.0

Strain(%

)

3 9

4.0

4.1

4.2

ndex

( m

N.m

2 /g)

50

51

52

53

Retention of tear in

-1 0 1 2 3 4 5 6 7 8 9 10 1140

41

Te

126

129

132

2.6

2.8

3.6

3.7

3.8

3.9

Tear

i

46

47

48

49

dex (%)

-1 0 1 2 3 4 5 6 7 8 9 10 11Xylan dosage(%) -1 0 1 2 3 4 5 6 7 8 9 10 11

Xylan dosage(%)

Birch Xylan on E l t BKP O D i dEucalyptus BKP – Once DriedResearch Opportunities

• Oxidative treatments of linerboard – bleach grades• Profiling hemicellulose retention during kraft pulping• Co-pulping with Ag resources• Recovery of hemicelluloses from black liquor


90

Starch Grafting on Bleached SWKP

60

70

80

Nm

/g

30

40

50

le in

dex,

10

20

30

Tens

il

00 1 3 5 10

Starch content, %

Hornification Can be MinimizedHornification Can be Minimized190 Dried in H-form

Fiber Charge

160170180190 Dried in H-form

Dried in ionized formNever dried

120130140150

WR

V, %

8090

100110

0 5 10 15 20 25 30 35 40Carboxyl Group Content, meq/100 g

• Bleached sulfate pulp that was enriched in acid groups• The H-form has fully protonated acid groups• The ionized forms are negative with accompanying

metal

Dry Kraft Pulping at Ambient Pressure for Cost Effective Energy Saving and PollutionCost Effective Energy Saving and Pollution

DeductionFunded by DOE Grand Challenge Program PI: Yulin Deng, Co-PI: Art Ragauskas

Goals: Develop a novel pulping technology that can replace the current Kraft

l i t h i b t ith i ifi t l ti (>30%)pulping technique but with significant less energy consumption (>30%), reduced process cost (>20%), environmental pollution and CO2 emission (>20%).

Significance: The success of the new technique may revolutionarily change the current Kraft process and pulp quality reducing the capital investment andKraft process and pulp quality, reducing the capital investment and improve the operation safety by eliminating the high cost pulp digester.

Our Approach: Dry-Pulping P i i lPrinciple

Filtration to remove the extra liquid Baking the woodchips at

120-140 oC at ambient pressure

Soaking the woodchips in NaOH and Na2S solution

p

Soaking in water and di i t ti i tdisintegrating into fibers

Kraft pulp

Comparison of conventional Kraft pulping and dry-pulping proposed

Pulping l ti

NaOH consumed

Na2S Amount of black liquor

Major chemicals in the black lisolution liquor

Conventional Kraft pulping

4 liters/kg of woodchips

17% 7% ~3.5 litters ~17% NaOH ~7%Na2SKraft pulping woodchips 7%Na2S

Dry pulping 1 liters/kg of woodchips

~7% 5% ~ 3.5 litters ~3% NaOH~3% Na2Sp 2

Lower chemical consumptionLower chemical consumptionNo need for pressure vessel for pulping – incremental production increasesLess water usage

Pentose Green Material Applications

FilmsSurface- and Bulk-Modified Galactoglucomannan Hemicellulose Films and Film Laminates for Versatile Oxygen Barriers. Hartman, Jonas; Albertsson, Ann-Christine; Sjoeberg, John. Biomacromolecules (2006), 7(6), 1983-1989.

Use of xylan, an agricultural by-product, in wheat gluten based biodegradable films : mechanical, solubility and water vapor transfer rate properties. Kayserilioglu, Betul S.; Bakir, Ufuk; Yilmaz, Levent; Akkas, Nuri. Bioresource Technology (2003),

87(3), 239-246. Separation, characterization and hydrogel-formation of hemicellulose from aspen wood. Gabrielii, I.; Gatenholm, P.; Glasser, W. G.; Jain, R. K.; Kenne, L. Carbohydrate Polymers (2000) 43(4) 367 374(2000), 43(4), 367-374.

Warty Inner Layer (S3)

Lignin

Filmsy ( ) Middle Layer (S2)

Hemicellulose

Cellulose

Films

XylanOuter Layer (S1) Primary Wall Middle Lamella

Cell Wall Composition

Cellulose

ML S1 S2 S3

Cellulose Whiskers

Xylan Cellulosics Filmsy

• Preparation Bleached kraft pulp p p H2SO4 or HCl

Birch xylan composite films were formed by adding an aqueous

AFM of Cellulose Nanowiskers

Birefringence of Cellulose Nanowiskers

TEM of Cellulose Nanowiskers1AFM of Cellulose

NanowiskersBirefringence of

Cellulose Nanowiskers

TEM of Cellulose Nanowiskers1

Birch xylan composite films were formed by adding an aqueous suspension neutral or sulphonated whisker suspension to xylan

0.0, 5.0, 10.0, 16.0, 25.0, 50.0 wt% of the total mixture of xylan, whisker and sorbitolwhisker and sorbitol

Solution cast

SEM Images of Films

(A) (B)( )

50 nm

SEM facture images of the (A) control xylan (B) xylan reinforced withSEM facture images of the (A) control xylan, (B) xylan reinforced withsulfonated whisker

Effect of Whiskers on Tensile Strength of Xylan Films

Effect of Whiskers on TEA of Xylan FilmsEffect of Whiskers on TEA of Xylan Films

Effect of Sulfonated Whisker Specific Water VaporEffect of Sulfonated Whisker Specific Water Vapor Transmission Rate of Xylan Films

0.25

0 15

0.2

nce

(g)/h Control, Xylan

l i f d ith 10% lf t d

0 05

0.1

0.15

ht d

iffer

e xylan reinforced w ith 10% sulfonatedw hisker

Xylan reinforced w ith 50% hydrochloride

0

0.05

0 2 4 6 8 10 12 14 16

wei

gh w hisker

0 2 4 6 8 10 12 14 16

time (h)

Effect of Sulfonated Whisker Specific Water VaporEffect of Sulfonated Whisker Specific Water Vapor Transmission Rate of Xylan Films

Effect of Sulfonated Cellulose Whiskers Dosage on Oxygen Transmission Rate of Xylan FilmsOxygen Transmission Rate of Xylan Films

Sample Specific oxygen transmission rate ( 3 / 2d )(cm3 /m2day)

Control 354.950

Xylan + 5% sulfonated cellulose whiskers 1.442

Xylan + 10% sulfonated cellulose whiskers 1 364Xylan + 10% sulfonated cellulose whiskers 1.364



X lan + 70% s lfonated cell lose hiskers 1 178Xylan + 70% sulfonated cellulose whiskers 1.178

Effect of Sulfonated Cellulose Whiskers on Density & Porosity& Porosity

Mercury Porosimetry Measurements

Sample Average Bulk density Porosity Tortuosity factor pore diameter pore diameter

(μm) g/mL %

C l (X l ) 0 1730 0 6165 53 0161 1 258Control (Xylan) 0.1730 0.6165 53.0161 1.258

Xylan + 25% sulfonated 0.1301 0.8705 40.8501 1.700 cellulose whiskers Xylan + 50% sulfonated 0.0581 1.1513 22.8906 2.005 cellulose whiskers

Conclusions• Addition of 7 % of sulphonated whisker the tensile energy

adsorption of the film increases by 445 % and tensile strength of the film increases by 141 %.

• Reinforced with 10% sulphonated cellulose whiskers 74% reduction in specific water transmission properties with respect to films prepared solely from xylan

• Oxygen transmission rate tests demonstrated that films made with xylan, sorbitol and 50% sulfonated cellulose whiskers

d d bilit f 0 1799 3 2 d 1 kP 1 ithreduced permeability of 0.1799 cm3 μm m-2 day-1 kPa-1 with respect to control films with a permeability of 189.1665 cm3 μm m-2 day-1 kPa-1μm m day kPa .

Fundamentals for New GradesNew Grades

Improved Strength PropertiesTensile, Stiffness, Burst, Refinability

Fiber ModificationSTFi Retention of Wet-End Chemicals Pulping/Bleaching

Fiber ModificationFiber Fiber Bonding

Strength RecoveryM k /R l d

Improved TMP Southern Pine

Pulping - Bleaching

Market/Recycledp

- Bonding- Yield

- Softness- Reduced Bonding

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