Abstract Polymer blends of polylactide (PLA) with poly(butylene adipate-co-terephthalate) (PBAT) to improve properties of PLA has been researched widely. But very few researches focus on the degradation of the blend, which is very important for biodegradable material. Herein, PLA and PBAT blends are prepared through solution casting, and the impact of degradation on thermal and mechanical properties of the blend are analyzed. Young’s modulus of the blend tends to keep steady, while tensile strain decreases drastically with degradation going on. Degradation also leads to poor thermal stability of the blend. Positron annihilation lifetime spectroscopy (PALS) is applied for the first time to investigate degradation process of PLA/PBAT blend, it shows that free volume holes have an increase in quantity and a decrease in size at the beginning of degradation, then show a decrease in quantity and an increase in size as the degradation going on. These findings give fundamental information for PLA/PBAT degradation process and the impact on properties, which helps the further development of PLA blend modification.

中文翻译：

---

可生物降解 PLA/PBAT 混合物的降解研究：热稳定性、机械性能和 PALS 分析

摘要 聚丙交酯 (PLA) 与聚对苯二甲酸丁二醇酯 (PBAT) 的聚合物共混物已被广泛研究以改善 PLA 的性能。但是很少有研究关注共混物的降解，这对于可生物降解的材料非常重要。在此，PLA和PBAT共混物是通过溶液浇铸制备的，并分析了降解对共混物热性能和机械性能的影响。共混物的杨氏模量趋于保持稳定，而拉伸应变随着降解的进行而急剧下降。降解还导致共混物的热稳定性差。首次应用正电子湮没寿命光谱（PALS）研究PLA/PBAT共混物的降解过程，它表明自由体积孔在退化开始时数量增加和尺寸减小，然后随着退化的进行而数量减少和尺寸增加。这些发现为 PLA/PBAT 降解过程及其对性能的影响提供了基本信息，有助于进一步开发 PLA 共混改性。