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 (CO) during the supercritical CO 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.

中文翻译：

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甲基丙烯酸甲酯-甲基丙烯酸缩水甘油酯扩链剂聚己二酸-对苯二甲酸丁二醇酯的发泡行为

作为一种重要的生物可降解聚合物，由于其机械强度和熔体强度较低，如何在聚己二酸-对苯二甲酸丁二醇酯（PBAT）泡沫中实现稳定的泡孔形态和高泡孔密度具有挑战性。为了解决这个问题，设计了一种创新的甲基丙烯酸甲酯-甲基丙烯酸缩水甘油酯（MG）共聚物，并将其用作扩链剂，因为它在超临界CO发泡过程中与二氧化碳（CO）具有很强的亲和力。 PBAT的羧基端基与MG中的环氧基团之间的支化反应提高了PBAT的分子量、熔体强度和机械性能。因此，MG的引入导致发泡PBAT的泡孔尺寸减小、泡孔密度更高、压缩应力更强。结果表明，MG共聚物是PBAT有效的扩链剂，有利于改善PBAT的发泡工艺和性能，使其应用​​于包装缓冲材料。