Study on mechanical and thermal properties of coir fibers reinforced thermoplastic starch/poly(butylene adipate-co-terephthalate) composites

In this study, a novel biodegradable coir fiber (CF) reinforced thermoplastic starch (TPS) and poly(butylene adipate-co-terephthalate) (PBAT) composites (CF/TPS/PBAT) with a constant TPS: PBAT weight ratio of 70:30 and 5, 10, 15, and 20 wt% additions of CF were prepared by the melt blending and injection molding. The effects of fiber content and fiber surface modification on the mechanical and thermal properties of the prepared biocomposites were investigated. The incorporation of fibers effectively enhanced the mechanical and thermal properties of TPS/PBAT blends. Due to the removal of hemicellulose and impurities on the fiber surface after alkali treatment, the interfacial adhesion of the fiber was enhanced, thus improving the compatibility between the fibers and the matrix. At 20 wt% CFs with alkali treatment, the tensile strength exhibited 393% improvement and flexural strength exhibited 536% improvement over TPS/PBAT blends. Thermal analysis showed that the thermal stability, storage modulus, and glass transition temperature of the composites increased with the increase of fiber content. This work is significant for the development of biodegradable materials.