1 Cellulose Nanofibers from Wheat Straw NDSU Bernie Steele October 12, 2007
Cellulose Nanofibers from Wheat Straw for High-value Green Nanocomposite Materials Applications 2
Outline Why cellulose nanofibers? Expected benefits Prior work Major tasks ahead State of the project and budget Summary Questions 3
Why Cellulose Nanofibers (CNF)? Raw materials are abundant, cheap, and renewable Biodegradable High aspect ratio. Diameter: from 3 to 20 nm and lengths can reach up to a few micrometers Large surface area High modulus, high strength and low density 4
Cellulose Nanofibers (CNF) Overall expected benefit: A composite that provides twice the mechanical stability with 1/3 less weight when compared to similar composites made using E glass fibers 5
Cellulose Nanofibers (CNF) Specific Fiber Density (g/cm3) Tensile strength (GPa) Young s Modulus (GPa) E glass fiber 2.54 - ~3.4 at 21 C ~72.4 at 21 C 2.62 Jute fiber 1.3-1.45 0.39-0.77 13-26 Cellulose Nanofibers 1.5 ~10 ~150 [1] A.B. Strong,Fundamentals of Composites Manufacturing: Materials, Methods and Applications, Society of Manufacturing Engineers, 1989 [2] A. K. Mohanty, M. Misra, and G. Hinrichsen, Macromolecular Materials and Engineering, 2000, 276/277, 1-24 [3] A. Kelly and N. H. Macmillan, Strong Solids, 3 rd edition, Oxford University Press, New York, 1986 [4] W. Helbert, J. Y. Cavaille, A. Dufresne, Polymer Composites, 1996, 17, 4, 604-611 6 Improved tensile strength compared to jute fiber and E-glass fiber. Superior performance (Young s, stretch and break ) when compared to the jute and E glass fibers. 40% less density than E-glass fiber
CNF From Wheat Straw Cellulose nanowhiskers were successfully extracted from wheat straw using a combined chemical and mechanical extraction TEM micrograph showing the cellulose whiskers extracted from wheat straw (Scale 200 nm) 7 Drzal, MSU Composite Materials and Structures Center USDA-MBI Agreement 2006-34189-17124
CNF Biocomposites from Wheat Straw Cellulose nanofiber/polyvinyl alcohol (PVOH) composite films were prepared by solution film casting. The films containing up to 5 wt% cellulose whiskers were transparent, indicating good dispersion of the fillers. The tensile modulus of the composite films was studied with Dynamic Mechanical Analyzer (DMA). The reinforcement effect of the cellulose nanofibers was more significant at high temperatures. At 25 C, the reinforced films showed a slight increase in storage moduli compared to the neat PVOH films. At 80 C, there was a 36% increase in the storage moduli with only 3wt% cellulose nanofibers The modulus of polymer matrix drops to very low values at high temperatures, which makes the high modulus of the cellulose whiskers more revealing 8 Drzal, MSU Composite Materials and Structures Center USDA-MBI Agreement 2006-34189-17124
CNF Biocomposites from Wheat Straw Comparison of the storage moduli at 80 C Storage modulus (MPa) 180 160 140 120 100 80 60 40 20 0 Neat PVOH film 1wt% WS- CNW/PVOH 3wt% WS- CNW/PVOH The comparison of the storage moduli of the PVOH films with and without cellulose nanowhiskers reinforcement 9 Drzal, MSU Composite Materials and Structures Center USDA-MBI Agreement 2006-34189-17124
MBI Biorefinery Concept Wheat Straw Milling AFEX Chemical Treatment Enzyme Treatment Sizing Cellulose Nanofibers Hemicellulose, Lignin By-Products Fermentation Ethanol t Fermentation Residue Succinic Acid Butanetriol Free-Standing Cellulose Nanofibers Production Process Integrated Cellulose Nanofibers Production Plant with an Ethanol Biorefinery Plant Xylitol 10
MBI Concept Using current enzymes, not all wheat straw cellulose is hydrolyzed in enzymatic hydrolysis. The unhydrolyzed portion is likely the crystalline portion of the cellulose 11
Wheat Straw CNF Cellulose nanofibers from wheat straw hydrolysate using an alkaline pulping process 12
CNF Biocomposites from Wheat Straw Composites with CNF made from the alkaline pulping of fermentation residues have not been consistent enough for testing Further assay work on the hydrolysate and fermentation residues is needed to establish the mixture of compounds present with the CNF and whether these compounds may be causing the lack of success with casting the composite samples. 13
Cellulose Nanofibers Major Tasks Prepare and evaluate cellulose nanofiber samples from wheat straw hydrolysate and fermentation residues Analyze hydrolysate and fermentation residue samples to determine composition Prepare and evaluate composite materials reinforced with CNF Work toward a commercially viable technology package 14
Cellulose Nanofiber Project Michigan State University MBI International Business Partner: TBD Ideas Tech/Com. Feasibility? Product Concept Value Proposition Business Plan Marketing Plan Preliminary Detailed 1 2 Development 4 Validation Investigation Investigation 3 5 Commercial Launch Demonstration of CNF from recycled paper Demonstration of CNF from corn stover & wheat straw Definition of product specifications Established preliminary process economics Evaluate integration with ethanol plant Project Costs = $500,000 15 Pre-Pilot process design and engineering Preparation and evaluation of CNF samples Preparation and evaluation of composite materials Refine process definition, design, engineering and capital and operating costs Pilot plant design and engineering Project Costs = $1,000,000 Pilot plant construction Preparation and evaluation of large scale CNF samples Preparation and evaluation of large scale composite materials Refine process definition, design, engineering and capital and operating costs Validation feedstock assumptions and integration feasibility with an ethanol plant Project Costs = $2,500,000
Cellulose Nanofibers Summary CNF can be found in wheat straw hydrolysate and fermentation residues CNF from wheat straw do reinforce PVOH films Alkaline pulping may be less expensive than acid pulping methods Further work needed on this approach 16
Acknowledgements Professor Larry Drzal and the staff at the Composite Materials and Structures Center, Michigan State University Darold McCalla, MBI Janette Moore, MBI Chris Saffron, MBI This work was supported in part by: USDA CSREES Grant No. 2006-34524-17132 USDA CSREES Grant No. 2006-34189-17124 17
Questions? Thank You! 18