Low‐cost and high‐performance poly(butylene adipate‐co‐terephthalate)/thermoplastic starch blends prepared by an eccentric rotor extruder: Morphology, rheological behavior, thermal and mechanical properties

Abstract

Due to similar processing and mechanical properties, poly(butylene adipate‐co‐terephthalate) (PBAT) is expected to be a fully‐biodegradable alternative to low‐density polyethylene (LDPE) packaging films, thereby alleviating environmental pollution caused by waste packaging films. However, the higher price of PBAT limits its large‐scale practical application in the packaging field. Blending with thermoplastic starch (TPS) to prepare PBAT/TPS blends can reduce the cost. In this work, the PBAT/TPS blends with different compositions were prepared using a novel eccentric rotor extruder dominated by an extensional flow field. With increasing the TPS content, a transition from the sea‐island phase structure to the bicontinuous phase structure occurred near the composition ratio of 50/50. Moreover, the dynamic mechanical analysis results showed that the compatibility between PBAT and TPS first improved and then deteriorated as the TPS content increased. As a result, the elongation at break first decreased slightly from ~1585% for the PBAT/TPS(90/10) blend to ~1263% for the PBAT/TPS(70/30) blend and dropped sharply to ~130% for the PBAT/TPS(40/60) blend. The knowledge obtained from this study will help us further understand the effect of the TPS phase on the micro‐morphology and macro‐properties of the PBAT/TPS blends, which is important for the future preparation of high‐performance PBAT/TPS blends.