(338d) Green Poly (lactic acid) Composites Reinforced with Sugarcane Bagasse Residues

Poly (lactic acid) (PLA) composites reinforced by sugarcane bagasse residues were prepared using twin-extrusion.  By using near zero-value bio-based residues, these composites are not only 100% renewable and biodegradable, but also have the competitive cost in comparison with petroleum-based composites.  The sugarcane bagasse residues (10-30 wt.%), containing different content of fibers and all the remaining lignin, were used to prepare lignocelluloses reinforced PLA composite with desirable physical and chemical properties. In this study, the sugarcane bagasse residues include the residues originally from the sugar extraction process, after pretreatment, and after fermentation of biorefinery processes. The varieties of different bagasse residues include the composition, particle size and its surface reactivity during the chemical and biological (enzymes, microbes) treatments that the biomass is subjected to. The effect of these varieties on the morphologies, thermal properties, mechanical properties and the molecular weight of PLA composites was studied. Furthermore, a coupling agent (Desmodur® VKS 20) was used to increase the interfacial bonding of PLA with lignocelluloses.  Desmodur® VKS 20 is a mixture of diphenylmethane-4, 4’-diisocyanate (MDI) with isomers and higher functional homologues (PMDI). The microstructure and the properties of the composites in the presence of couple agents were also investigated in this study.  It was found that this coupling agent could extend the polymer chain and therefore improved the mechanical properties of the composites.