Performance‐Enhanced PBAT / PBS Foams via Micro‐Opening Microcellular Injection Molding With an ADR Chain Extender

ABSTRACT Poly(butylene adipate‐co‐terephthalate) (PBAT) has attracted considerable attention in the field of porous materials due to its excellent mechanical properties and biodegradability. However, PBAT foams often exhibit poor cell morphology as well as limited cell size and density during batch foaming, which severely restricts their practical applications. In this study, a synergistic modification strategy combining polymer blending and chain extension was proposed based on the mold‐opening microcellular injection molding (MOMIM) process. Under a target weight reduction of 15%, the effects of packing time and supercritical fluid (SCF) content on cell morphology and size distribution were systematically investigated. Meanwhile, poly(butylene succinate) (PBS) was incorporated into PBAT to enhance its crystallization behavior and regulate melt strength, while 1 wt% of chain extender ADR was introduced to improve interfacial compatibility and suppress foam shrinkage. The results demonstrated that when the PBS content reached 40 wt% with 1 wt% ADR, uniform PBAT microcellular foams with an average cell size below 3 μm and a cell density of 10 10 cells/cm 3 were successfully fabricated, representing a two‐order‐of‐magnitude increase in cell density compared with neat PBAT foam. In terms of mechanical performance, the modified foams exhibited a 196.3% increase in Young's modulus and a 77.5% improvement in tensile strength relative to pure PBAT foams. This work provides valuable insights for the industrial‐scale preparation of biodegradable PBAT‐based microcellular foams via injection molding.