Mechanical properties due to water absorption and fiber chemical treatment of coir fibers reinforced PLA composites

In this study, mechanical properties of coir/PLA composites were studied under different water immersion time. Coir/PLA composite were prepared using coir fiber treated with NaOH and NaOH followed by soaking in acrylic acid (AA) 0.5% solution with varying immersion time. Fraction volume of the fibers in the PLA composites was fixed at 40%. Water absorption, tensile and flexural properties of these composite were analyzed. The tensile and flexural test are conducted according to ASTM standard D3039 and ASTM D790, respectively. The water uptake process for all specimens sharply increased and approach saturation after 169h. Th e composite with NaOH treated of fiber was the highest to absorb the water. Overall, composites with NaOH followed by AA as a chemical treatment of coir fiber have greater tensile and bending strength than those of untreated and NaOH treated fiber. Based on the immersion time for coir in the AA solution, the maximum tensile and bending strength of composites occur at 0.5h for all water immersion time of composites. The flexural properties of PLA/coir composites shows a decrease tendency when 6h water immersion. Tensile fracture surface morphologies of the composites were observed using SEM method.