Mechanical and degradation properties of natural fiber-reinforced PLA composites: Jute, sisal, and elephant grass

An experimental study has been carried out to investigate and characterize the properties of elephant grass fiber reinforced fully biodegradable poly lactic acid (PLA) composites. The composites were prepared with various weight fractions of untreated and treated fibers in PLA matrix using injection moulding technique. The tensile strength of PLA composite with treated elephant grass at 20% fiber loading was 18.14% and 24% higher than that of treated jute/PLA composite and plain PLA, respectively. While the flexural strength of treated elephant grass/PLA composite at same fiber loading was 4% and 22% higher than that of treated sisal composite and plain PLA, respectively. The impact strength of composites with untreated elephant grass, sisal and jute fibers were 129.5%, 111.5% and 22.3%, respectively higher when compared with plain PLA. The water absorption rate increased in all the composites as the fiber content increased and the absorption rate reduced with successive alkali treatment on the fibers. The thermal stability of the composite had been reduced with successive alkali treatments as evident from the TGA analysis. The percentage weight loss in all the composites was linearly increasing with number of days of soil burial. The degradation was high in composite with untreated fibers at highest weight fraction. Using enzymatic environment, the degradation was much faster compared to soil burial. Significant effect of surface modification was evident during observing surface morphology of tensile fractured and soil degraded surfaces of the composites using SEM. POLYM. COMPOS., 39:1125-1136, 2018. (c) 2016 Society of Plastics Engineers