Fracture toughness and overall characterization of PLA based biocomposites with natural fibers: a comparative study.

Biocomposites based on commercial polylactic acid (PLA) matrix reinforced with three different short natural fibers (coir, fique and sisal) at 1; 3, and 5 % wt, were obtained by compression molding. The idea of keeping additional processing steps as low as possible, thus reducing costs, prevailed. Then, no chemical treatment was performed on natural fibers. Overall performance of composites was evaluated by means of fracture tests along with FTIR and thermal characterization, SEM micrographs, and tensile tests. Results show that the incorporation of short sisal fibers increased more than 130 % the fracture toughness of composite materials, by inducing additional mechanisms of energy dissipation prior to crack growth. This improvement in behavior was observed even though there was no good adhesion between fibers and matrix. Sisal fibers' composites exhibited the best fracture and mechanical properties compared to coir and fique composites, without a detriment in degradation behavior.