Effect of Soy Waste/Cellulose on Mechanical, Water Sorption, and Biodegradation Properties of Thermoplastic Starch Composites

Thermoplastic starch (TPS)/soy pulp (soy waste) composites (TSS) with varying compositions are successfully prepared in an internal mixer followed by compression molding. The mechanical, water absorption, and biodegradable properties of the developed composites are studied and compared with virgin TPS and cellulose reinforced TPS composites (TSC). Optimum tensile and flexural strength is observed for TSS and TSC composites with 10 wt.% soy waste and cellulose. Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscope (SEM) analyses indicated the interaction occurred between soy pulp/cellulose and TPS. Water absorptivity is found to increase from 6.2% to as high as 42.3% with the addition of 0 to 25 wt.% cellulose filler to the TPS matrix. Moreover, the soil burial degradation study shows higher degradability of the composites with a higher amount of soy pulp/cellulose. The developed composites show moderate mechanical properties with a hydrophobic and biodegradable nature. Therefore, there is a great possibility for these biocomposites to be utilized in applications such as disposable items, packaging materials, office cuboids, and transport sectors.