Abstract Poly(l-lactide)-b-polyethylene glycol-b-poly(l-lactide) (PLLA-PEG-PLLA) is found to be more flexible than PLLA due to the flexibility of PEG middle blocks. Melt flow and mechanical properties of PLLA-PEG-PLLA were improved through post melt blending with a chain extender (CE). In this work, in situ chain-extended PLLA-PEG-PLLAs were synthesized by ring-opening polymerization in the presence of Joncryl® CE. The influence of CE content (1.0, 2.0, and 4.0 phr) on the gel content, melt flow index (MFI), thermal properties, and mechanical properties of the obtained in situ chain-extended PLLA-PEG-PLLAs was investigated. The gel content of in situ chain-extended PLLA-PEG-PLLA increased while the MFI and degree of crystallinity significantly decreased with increasing CE content. The in situ chain-extended PLLA-PEG-PLLA with 1.0 phr CE showed the best tensile properties. The extensibility of in situ chain-extended PLLA-PEG-PLLA films decreased when the CE contents were higher than 1.0 phr. These in situ chain-extended PLLA-PEG-PLLA films can be used as highly flexible bioplastics.

中文翻译：

---

在扩链剂存在下通过开环聚合合成柔性聚（l-丙交酯）-b-聚乙二醇-b-聚（l-丙交酯）生物塑料

摘要 聚（l-丙交酯）-b-聚乙二醇-b-聚（l-丙交酯）（PLLA-PEG-PLLA）由于PEG中间嵌段的柔韧性而被发现比PLLA更柔韧。PLLA-PEG-PLLA 的熔体流动性和机械性能通过与扩链剂 (CE) 的熔体后共混得到改善。在这项工作中，在 Joncryl® CE 存在下，通过开环聚合合成了原位扩链的 PLLA-PEG-PLLA。研究了 CE 含量（1.0、2.0 和 4.0 phr）对获得的原位扩链 PLLA-PEG-PLLA 的凝胶含量、熔体流动指数 (MFI)、热性能和机械性能的影响。随着CE含量的增加，原位扩链PLLA-PEG-PLLA的凝胶含量增加，而MFI和结晶度显着降低。原位链延长的 PLLA-PEG-PLLA 与 1。0 phr CE 表现出最好的拉伸性能。当 CE 含量高于 1.0 phr 时，原位扩链 PLLA-PEG-PLLA 薄膜的延展性降低。这些原位链延长的 PLLA-PEG-PLLA 薄膜可用作高度灵活的生物塑料。