AbstractRandom copolymers of l-lactic acid (LLA) and glycolic acid (GA) [P(LLA-GA)] with 0–100 mol% LLA units in the polymers were synthesized and their crystallization behavior was investigated by two representative crystallization methods of precipitation or melt-crystallization. P(LLA-GA) copolymers with LLA unit contents in the ranges of 0–20 and 73–100 mol% were crystallizable during precipitation or melt-crystallization. Surprisingly, these crystallizable ranges are similar to those reported for P(LLA-GA) copolymers synthesized by ring-opening polymerization of cyclic dimers (l-lactide and glycolide), which should have monomer sequence lengths twice those of the P(LLA-GA) copolymers synthesized by polycondensation of the monomers (LLA and GA) in the present study and are expected to have wider crystallizable ranges. The GA units of the LLA-rich P(LLA-GA) copolymers were incorporated in a lattice of LLA unit segments, whereas the LLA units of the GA-rich P(LLA-GA) copolymers were incorporated in a lattice of GA unit segments. Even the incorporation of relatively small-sized GA units in relatively large-sized LLA unit segments strongly induced structural disorder in the crystalline lattice. The crystalline size and melting temperature of the P(LLA-GA) copolymers decreased dramatically as the LLA unit content deviated from 0 to 100 mol%.Random copolymers of l-lactic acid (LLA) and glycolic acid (GA) [P(LLA-GA)] with LLA unit contents in the ranges of 0–20 and 73–100 mol% were crystallizable during precipitation or melt-crystallization. The GA units of the LLA-rich P(LLA-GA) copolymers were incorporated in a lattice of LLA unit segments, whereas the LLA units of the GA-rich P(LLA-GA) copolymers were incorporated in a lattice of GA unit segments. Even the incorporation of relatively small-sized GA units in relatively large-sized LLA unit segments strongly induced structural disorder in the crystalline lattice.

中文翻译：

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生物基和可生物降解的聚（l-乳酸-共-乙醇酸）无规共聚物单体单元的共结晶

摘要合成了 L-乳酸 (LLA) 和乙醇酸 (GA) [P(LLA-GA)] 的无规共聚物，聚合物中含有 0-100 mol% LLA 单元，并通过两种代表性的沉淀结晶方法研究了它们的结晶行为。或熔融结晶。LLA 单元含量在 0-20 和 73-100 mol% 范围内的 P(LLA-GA) 共聚物在沉淀或熔融结晶过程中可结晶。令人惊讶的是，这些可结晶范围与通过环状二聚体（l-丙交酯和乙交酯）开环聚合合成的 P(LLA-GA) 共聚物报道的相似，其单体序列长度应是 P(LLA-GA) 的两倍) 在本研究中通过单体 (LLA 和 GA) 缩聚合成的共聚物，预计具有更宽的结晶范围。富含 LLA 的 P(LLA-GA) 共聚物的 GA 单元结合在 LLA 单元链段的晶格中，而富含 GA 的 P(LLA-GA) 共聚物的 LLA 单元结合在 GA 单元链段的晶格中. 即使在相对大尺寸的 LLA 单元片段中加入相对小尺寸的 GA 单元也会强烈诱导晶格中的结构无序。当 LLA 单元含量从 0 到 100 mol% 偏离时，P(LLA-GA) 共聚物的结晶尺寸和熔融温度显着降低。 l-乳酸 (LLA) 和乙醇酸 (GA) [P(LLA) 的无规共聚物-GA)] 在沉淀或熔融结晶过程中，LLA 单元含量在 0-20 和 73-100 mol% 范围内可结晶。富含 LLA 的 P(LLA-GA) 共聚物的 GA 单元被纳入 LLA 单元链段的晶格中，而富含 GA 的 P(LLA-GA) 共聚物的 LLA 单元被纳入 GA 单元链段的晶格中。即使在相对大尺寸的 LLA 单元片段中加入相对小尺寸的 GA 单元也会强烈诱导晶格中的结构无序。