|Orts, William - Bill|
|Glenn, Gregory - Greg|
Submitted to: Society of Plastics Engineers Proceedings
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/25/2004
Publication Date: 4/29/2004
Citation: Orts, W.J., Imam, S.H., Shey, J., Glenn, G.M., Inglesby, M.K., Guttman, M.E., Nguyen, T.T., Revol, J.F. 2004. Effect of fiber source on cellulose reinforced polymer nanocomposites. Society of Plastics Engineers Proceedings. p. 2427-2431. Interpretive Summary: In the early 1990's, researchers at Toyota revolutionized nanocomposite technology by showing that adding clay nanoparticles to polymers increased their stiffness, impact resistance, heat-distortion temperature, and aging properties. Since then, we have worked on the exciting hypothesis that natural cellulose microfibrils can act in a fashion similar to the clay nanocomposites in reinforcing polymers. The promise behind cellulose-derived composites lies in the fact that the axial Young's modulus of the basic cellulose crystalline microfibril has been reported as 137 GPa, similar to Kevlar and "stronger than steel". Sources of cellulose microfibrils, including wood, straw, bagasse, bacteria, and sea animals, are widely diverse, providing a wide range of potential nanoparticle properties. The addition of cotton-derived microfibrils at 10.3% (w/w) concentration to extruded starch plastics increased stiffness by more than 5-fold relative to a control sample with no cellulose reinforcement. Fibrils from different agricultural sources were compared.
Technical Abstract: Cellulose microfibrils obtained by the acid hydrolysis of cellulose fibers obtained from different gricultural sources were added at low concentrations (2-10% w/w) to polymer gels and films as reinforcing agents. Significant changes in mechanical properties, especially maximum load and tensile strength, were obtained for fibrils derived from several cellulosic sources, including cotton, softwood, and bacterial cellulose. For extruded starch plastics, the addition of cotton-derived microfibrils at 10.3% (w/w) concentration increased Young's modulus by 5-fold relative to a control sample with no cellulose reinforcement. Preliminary data suggests that shear alignment significantly improves tensile strength. However, addition of microfibrils does not always change mechanical properties in a predictable direction. Whereas tensile strength and modulus were shown to increase during addition of microfibrils to an extruded starch thermoplastic and a cast latex film, these parameters decreased when microfibrils were added to a starch-pectin blend, implying that complex interactions are involved in the application of these reinforcing agents.