(632b) Biodegradable Nanocomposites from Wheat Straw

The objective of this work is to investigate the mechanical and thermal properties of cellulose nanofiber reinforced starch based thermoplastic composites. The cellulose nanofibers were isolated from wheat straw by a chemo-mechanical technique. The morphology, physico-chemical and thermal properties of the resulting fibers were investigated to examine their potential use as reinforcement fibers in biocomposite applications. Transmission electron microscopy results showed the wheat straw nanofibers have diameters in the range of 10-120 nm and lengths of a few thousand nanometers. Their average aspect ratio was found to be 95. Chemical characterization of the nanofibers confirmed that the cellulose content was increased from 75% to 95% by an applied alkali and acid treatment. FT-IR spectroscopic analysis of the fibers demonstrated that this chemical treatment also led to partial removal of hemicelluloses and lignin from the nanofibers' structure. PXRD measurements revealed that this resulted in improved crystallinity of the fibers. After mechanical treatments, thermal properties of the nanofibers were studied by the TGA technique and found to increase dramatically. The nanofibers were pre-dispersed in a compatibilizing agent and dried before being used to produce reinforced thermoplastic composites by compounding method. The tensile strength and modulus of the reinforced starch films were compared with those of pure starch and were found to be exhibited considerably improved even at 5% nanofiber loading.