Biocomposites Based on Poly (Lactic Acid) and Their Recyclability

Abstract

Biodegradable poly (lactic acid) (PLA) based biocomposites reinforced with rice hulls were prepared by compression molding and their properties were compared to those of commonly used thermoplastic based-polymer, polypropylene (PP) containing the same reinforcements.
Rice hulls from rice processing plants represent renewable sources that could be utilized for production of new class of eco-materials. In this study, rice-hulls-filled poly (lactic acid) (PLA) biocomposites were prepared through addition of 5 wt. % PLA-grafted-MA (CA) for enhancement of adhesion between polymer matrix and natural filler. The composites containing 30% wt. rice hulls (RH) were prepared and the possibility of recycling and reuse of these biocomposites were investigated. For all biocomposites, the mechanical and thermal properties were analyzed and compared to those of commonly used thermoplastic based-polymer, polypropylene (PP) containing the same reinforcement. Thermal stability of neat biocomposites and of the new composites produced from recycled ones was practically unchanged. Utilization of the mixture obtained after the thermal-mechanical recycling of the whole biocomposite has resulted into composite with slightly increased flexural modulus and decreased flexural strength.
The obtained results have shown that rice-hull-filled poly(lactic acid) biocomposites could be recycled and utilized for production of new eco-materials with acceptable thermal and mechanical properties. Namely, the results for flexural strength and modulus of the recycled biocomposite samples are comparable to those of conventional formaldehyde wood medium density fiberboards used as construction elements for indoor applications.