Foaming behaviors of poly (butylene adipate-co-terephthalate) with methyl methacrylate-co-glycidyl methacrylate as chain extender

Abstract

As an important biodegradable polymer, how to achieve stable cell morphology and high cell density in the foam of poly(butylene adipate-co-terephthalate) (PBAT) is challenging due to its low mechanical and melt strength. To address this issue, an innovative methyl methacrylate-co-glycidyl methacrylate (MG) copolymer was designed and used as a chain extender due to its strong affinity with carbon dioxide (CO2) during the supercritical CO2 foaming process. The branching reaction between the carboxyl end groups of PBAT and the epoxy groups in MG enhanced the molecular weight, melt strength, and mechanical properties of PBAT. Therefore, the introduction of MG resulted in a reduced cell size, higher cell density, stronger compression stress for the foamed PBAT. The results prove that the MG copolymer is an effective chain extender for PBAT, which is beneficial to improve the foaming process and properties of PBAT for its application as package cushioning material.