Mechanical properties and structure of mixtures of poly(butylene-adipate-co-terephthalate) (PBAT) with thermoplastic starch (TPS)

Abstract

Mixtures of poly(butylene-adipate-co-terephthalate) (PBAT) with thermoplastic starch (TPS) in a broad concentration range from 70:30 to 30:70 wt.% were prepared in a twin-screw extruder. Mechanical properties were tested, showing that the addition of TPS leads to a substantial decrease in the tensile strength as well as in the elongation at break, while Young’s modulus is rising substantially. Additional data were collected by dynamic mechanical thermal analysis (DMTA) and scanning electron microscopy (SEM), enabling a more detailed discussion on relations between ultimate properties and structural parameters. The application potential of biodegradable PBAT/TPS blends consists mainly in the substitution of polyethylene in packagings, where the material investigated is also economically competitive. The main advantage of adding TPS to PBAT is increasing the biobased carbon content cost-effectively, since most PBAT on the market is fossil-based.