Water Absorption and Thermomechanical Characterization of Extruded Starch/Poly(lactic acid)/Agave Bagasse Fiber Bioplastic Composites

Water absorption and thermomechanical behavior of composites based on thermoplastic starch (TPS) are presented in this work, wherein the concentration of agave bagasse fibers (ABF, 0-15wt%) and poly(lactic acid) (PLA, 0-30wt%) is varied. Glycerol (G) is used as starch (S) plasticizer to form TPS. Starch stands as the polymer matrix (70/30wt/wt, S/G). The results show that TPS hygroscopicity decreases as PLA and fiber content increase. Storage, stress-strain, and flexural moduli increase with PLA and/or agave bagasse fibers (ABF) content while impact resistance decreases. The TPS glass transition temperature increases with ABF content and decreases with PLA content. Micrographs of the studied biocomposites show a stratified brittle surface with a rigid fiber fracture.