Structure and property of biodegradable soy protein isolate/PBAT blends

Abstract

In this study, the structure and properties of biodegradable plastic blends from soy protein isolate (SPI) and poly(butylene adipate-co-terephthalate) (PBAT) was studied. Using scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), mechanical test, and biodegradation test, the compatibility and phase behavior of the components were investigated. In the blends, SPI acted as a filler in the PBAT matrix, which exhibited a reinforcing effect on the PBAT matrix. With increasing SPI content, the tensile strength and elongation at break of SPI/PBAT blends reduced; the thermal stability decreased at 200–400°C and increased at higher temperatures. However, the blends with as high as 28.6wt% SPI still possessed a good ductility. Soy protein was easily degraded in the soil and thus made the blends biodegradable as a whole.