Constructing stable “bridge” structures with compatibilizer POE‐g‐GMA to improve the compatibility of starch‐based composites

Abstract

AbstractWith the development of degradation technologies such as chemical‐catalysis and bio‐catalysis, starch‐polyethylene (PE) composites have been revitalized as industrial packaging materials. However, starch and PE suffer from interfacial incompatibility. In this study, poly(octene ethylene) grafted glycidyl methacrylate (POE‐g‐GMA) was added at relatively low amounts (0–7 wt%) to construct robust structures between thermoplastic starch (TPS) and low‐density polyethylene (LDPE). Tensile strength increased by 36.39% with the addition of 1 wt% POE‐g‐GMA. Meanwhile, a smooth surface was observed by SEM, and a fibrillar cross‐linked structure appeared on the fractural surface of the blend. POE‐g‐GMA formed a stable “bridge” at the interface between TPS and LDPE, which increased the thermal stability of the blend as well. The crystallinity of LDPE increased from 20.5% (without addition) to 32.8% (with 1 wt% addition), whereas the average crystallite size decreased slightly. The optimal POE‐g‐GMA content was found to be 1 wt% based on mechanical and thermal measurements. The results of this study can provide a reference for improving the interfacial compatibility of biopolymers and fossil‐fuel‐based polymers.