Improved Pulp Properties

Transcription

1 Improved Pulp Properties thru Fiber Modification Art J. Ragauskas School Chemistry & Biochemistry Institute of Paper Science & Technology Georgia Institute of Technology Atlanta, GA

2 Fiber Modification: Addressing the Challenge

3 Fiber Modification: The World is not Flat What is Needed to Make Stable Complex Curved Paper Structures Better Fiber-Fiber Bonding Moisture insensitivity Nano coatings Crosslinking Grafting Resins LbL Better Stress Transfer Engineered fiber surfaces Fibers reinforced with bio-composites Thermo/chemical responsive green composites/resins

4 Fiber Modification: Southern SW Fiber vs Northern SW/Tropic HW for Tissue/Towel Southern Fiber Suffers from fiber coarseness Sof ftness Tissue 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 dependency on each other. For example, mechanical treatments that enhance softness also decrease tensile strength, which for many applications is not a preferred outcome. Strength Fiber Notching of SW Fibers - Yields a softer feel fiber - Fibers with reduced dry zero-span tensile have improved hand feel

5 Fiber Modification: Southern SW Fiber vs Northern SW/Tropic HW for Tissue/Towel Fiber Notching of SW Fibers ZÜxtàxÜ Y uxü YÄxåtu Ä àç Chemical/Physical Approaches - Chemical etching - Hot blow kraft cooks - Chemical/physical treatments

6 Fiber Modification: Green Paper & Packaging Need to Develop Enhanced Moisture/O2/Bacterial Barrier Properties Consumer driven to be green Replace plastic/metal barriers Replace petroleum based papermaking additives with biobased materials Development Opportunities: Hemicellulose l barriers for moisture and O2 Functional fibers for antibacterial Nano-particles Grafted/LbL/antibacterial agents Nanocellulose/starch/lignin strength/crosslinking Coatings/films Wet-end end applications Fire resistant fibers Green home insulation market & structural market Water Vapour Transmission/h % 5 10 % Sulfonated Whiskers

7 Fiber Modification: Green Paper & Packaging Need to Develop Enhanced Moisture/O2/Bacterial Barrier Properties Consumer driven to be green Replace plastic/metal barriers Replace petroleum based papermaking additives with biobased materials Tensile Index Hot Pressing With Resins Control 2% PVA 5% PVA 20% PVA Control and PVA TMP Sheets Hot Pressed Hydrophobic Bonding Dry Forming Air-laid Papermaking

8 Fiber Modification: Enhanced Water Absorption Water Absorption of SW Kraft Fibers/Fluff Cross-linked Fibers Water Absorbed Water Retained g water/ g dry materi ial Milled Pine Thermal Pine Pulp Thermal g water/ g dry mat terial Milled Pine Water Retained Pine Water Retained % PMVEMA %PMVEMA

9 Fiber Modification: Enhanced Water Absorption Water Absorption of SW Kraft Fibers/Fluff 240 Cross-linked Fibers WAARV (g/g) Uncrosslinked Crosslinked Fiber length (mm) Functionalized Fluff Develop new crosslinking agents New oxidation protocols Greater Water Absorbency Reduced Bonding Functionalized Fibers

10 Fiber Modification: Fiber Fiber Bonding Benefits of Fiber Charge/Hemicellulose Retention/Generation Enhanced Strength Tensile/Burst/(STFI) Refinability Fold Recyclability Peroxide Tensile stiffness Ultrasonic in Plane specific stiffness:longitudial Ultrasonic in Plane specific stiffness:shear 5.0 Carboxylic acid, mo ol/g,holopulp Tensile index (N.m/g) Carboxylic acid, mol/g Holopulp Stiffness,kN/mm 2 or km 2 /sec Shear,km 2 /s sec Catalyst, % Carboxylic acid, mol/g HoloPulp 3.0

11 Fiber Modification: Fiber Fiber Bonding Tensile Index Tensile Inde ex Control Birch Oat Hulls % SW 1% Birch 2% Birch 4% Birch 8% Birch 2% Oats 5% Oats 8% Oats 8.0% 8.5% 9.0% 9.5% 10.0% 10.5% Xylan % Burst Index Control 2% Ag 5% Ag 8% Ag

12 Fiber Modification: Fiber Fiber Bonding Birch Xylan on Eucalyptus BKP - Virgin Te ensile index (Nm m/g) Tensile index TEA Strain Xylan dosage(%) TEA (J/m 2 ) Strain(%) Tear index ( mn.m 2 /g) Tear index Retention of tear index Xylan dosage(%) Retention of tear in dex (%) Birch Xylan on Research Opportunities Eucalyptus BKP Once Dried Oxidative treatments of linerboard bleach grades Profiling hemicellulose retention during kraft pulping Co-pulping with Ag resources Recovery of hemicelluloses from black liquor

13 Fiber Modification: Fiber Fiber Bonding Nm/g Tensil le index, Starch Grafting on Bleached SWKP Starch content, %

14 Hornification Can be Minimized WRV, % 190 Dried in H-form 180 Dried in ionized form 170 Never dried Fiber Charge Carboxyl 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

15 Dry Kraft Pulping at Ambient Pressure for Cost Effective Energy Saving and Pollution Deduction Funded by DOE Grand Challenge Program PI: Yulin Deng, Co-PI: Art Ragauskas Goals: Develop a novel pulping technology that can replace the current Kraft pulping technique but with significant ifi less energy consumption (>30%), reduced process cost (>20%), environmental pollution and CO 2 emission (>20%). Significance: The success of the new technique may revolutionarily change the current Kraft process and pulp quality, reducing the capital investment and improve the operation safety by eliminating the high cost pulp digester.

16 Soaking the woodchips in NaOH and Na 2 S solution Our Approach: Dry-Pulping Pi Principlei Filtration to remove the extra liquid Baking the woodchips at o C at ambient pressure Soaking in water and disintegrating i ti into fibers Kraft pulp

17 Comparison of conventional Kraft pulping and dry-pulping proposed Pulping solution NaOH consumed Na 2 S Amount of black liquor Major chemicals in the black liquor Conventional 4 liters/kg of 17% 7% ~3.5 litters ~17% NaOH Kraft pulping woodchips ~7%Na 2 S Dry pulping 1 liters/kg of woodchips ~7% 5% ~ 3.5 litters ~3% NaOH ~3% Na 2 S p 2 Lower chemical consumption Lower chemical consumption No need for pressure vessel for pulping incremental production increases Less water usage

18 Pentose Green Material Applications Films Surface- and Bulk-Modified Galactoglucomannan Hemicellulose Films and Film Laminates for Versatile Oxygen Barriers. Hartman, Jonas; Albertsson, Ann-Christine; Sjoeberg, John. Biomacromolecules (2006), 7(6), 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), 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), Warty Inner Layer (S3) Middle Layer (S2) Films Xylan Lignin Hemicellulose Outer Layer (S1) Primary Wall Middle Lamella Cellulose Whiskers Cellulose ML S1 S2 S3 Cell Wall Composition

19 Xylan Cellulosics Films Preparation Bleached kraft pulp p H2SO4 or HCl AFM of Cellulose Nanowiskers Birefringence of Cellulose Nanowiskers TEM of Cellulose Nanowiskers 1 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 sorbitol Solution cast

20 SEM Images of Films (A) (B) SEM facture images of the (A) control xylan, (B) xylan reinforced with sulfonated whisker 50 nm

21 Effect of Whiskers on Tensile Strength of Xylan Films

22 Effect of Whiskers on TEA of Xylan Films

23 Effect of Sulfonated Whisker Specific Water Vapor Transmission Rate of Xylan Films w e i g h t d iffe r e n ce (g )/h Control, Xylan xylan reinforced w ith 10% sulfonated whisker Xylan reinforced w ith 50% hydrochloride whisker time (h)

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

25 Effect of Sulfonated Cellulose Whiskers Dosage on Oxygen Transmission Rate of Xylan Films Sample Specific oxygen transmission rate (cm 3 /m 2 day) Control Xylan + 5% sulfonated cellulose whiskers Xylan + 10% sulfonated cellulose whiskers Xylan + 25% sulfonated cellulose whiskers Xylan + 50% sulfonated cellulose whiskers Xylan + 70% sulfonated cellulose lose whiskers

26 Effect of Sulfonated Cellulose Whiskers on Density & Porosity Mercury Porosimetry Measurements Sample Average Bulk density Porosity Tortuosity factor pore diameter (μm) g/ml % Control l(xylan) Xylan + 25% sulfonated cellulose whiskers Xylan + 50% sulfonated cellulose whiskers

27 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 reduced d permeability of cm3 μm m -2 day -1 kpa -1 with respect to control films with a permeability of cm3 μm m -2 day -1 kpa -1.

28 Fundamentals for New Grades Improved Strength Properties Tensile, Stiffness, Burst, Refinability STFi Retention of Wet-End Chemicals Pulping/Bleaching Improved TMP - Bonding - Yield Fiber Modification Fiber Modification Fiber Pulping Fiber - Bleaching Bonding Southern Pine - Softness - Reduced Bonding Strength Recovery Market/Recycled