Investigating the Dimensional, Mechanical, and Morphological Properties of Composites Reinforced with Sisal Fibers and Polylactic Acid in Response to Water Absorption

Biocomposites are promising candidates for some engineering applications owing to the growing environmental and economic challenges to replace petrochemical-based polymers with biodegradable polymers. Herein, sisal fiber reinforced polylactic acid (PLA) composite specimens were fabricated using an injection molding machine with and without plasticizer. The weight percentage (wt%) of the sisal fiber varied between 5% and 20%. The effect of the sisal fiber wt% on water absorption resistance and mechanical properties was investigated experimentally using water ageing, mechanical, and morphological studies. The results revealed that tensile and flexural specimens after water ageing exhibited lower tensile and flexural strengths with higher water absorption behavior at 20 wt% sisal fiber than 5 wt% sisal fiber, while the impact strength increased after water ageing. In addition, the sisal fiber/PLA composites exhibited higher water absorption behavior and lower strength and modulus at 20 wt% sisal fiber after water ageing. Moreover, the water absorption decreased with the incorporation of the plasticizer.