2025-05-08 作者：wff 来源：文献：
Crystallization Studies on the Stereocomplexation of Poly(ʟ-lactide) / 4-Armed Poly(ϵ-caprolactone-co-d,ʟ-lactide)- block-poly(d-lactide) Blends.
文献链接：
https://chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/slct.202301769
作者：
Tingting Jin, Suyang Dai, Xiangyu Wang, Ni Jiang, Zhenbo Ning, Zhihua Gan
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原文摘要：
A series of four-armed poly(ϵ-caprolactone-co-d,ʟ-lactide)-block-poly(d-lactide) (4a-CDL-D) copolymers with different poly(d-lactide) (PDLA) block lengths (Mn,PDLA) were synthesized via ring opening polymerization using pentaerythritol as initiator. They were blended with poly(ʟ-lactide) (PLLA) to improve its crystallization rate and mechanical properties. It was found that the crystallization of PLLA in the PLLA/4a-CDL-D blend was affected differently when Mn,PDLA changed. In the PLLA/4a-CDL blend without PDLA blocks, the crystallization was retarded obviously because of the dilution effect of 4a-CDL on PLLA crystallization. Interestingly, a crystallization acceleration effect was found when Mn,PDLA was 0.5k although no stereocomplex (SC) crystallites existed. When Mn,PDLA was 1k or higher (1.5k and 2k), SC crystallites could be formed in the PLLA/4a-CDL-D blends. However, when Mn,PDLA was 1k or 1.5 k, the formation of SC crystallites was difficult and they showed weaker acceleration effect on PLLA crystallization. While when Mn,PDLA was 2k, the crystallization of PLLA was accelerated markedly due to the significant increase of nucleation sites.
ʟ-丙交酯（L-lactide, L-LA）和d-丙交酯（D-lactide, D-LA）是乳酸的两种光学异构体，通过开环聚合（ROP）可合成聚乳酸（PLA）。4a-CDL-d 是一种由 ʟ-丙交酯（L-LA）与d-丙交酯（D-LA） 共聚形成的嵌段共聚物，其名称中的 “4a” 可能指代特定的嵌段结构或合成方法（如催化剂、引发剂或聚合条件），而 “CDL-d” 可能表示共聚物中 L-LA和D-LA的嵌段排列方式（如交替、梯度或无规嵌段）。
该共聚物结合了 L-PLA（结晶性高、降解慢） 和 D-PLA（结晶性低、降解快） 的特性，通过调节嵌段比例和长度，可实现材料性能的调控，满足生物医学、药物递送、组织工程等领域的需求。
图为：聚（d-丙交酯）（PDLA）嵌段长度（Mn，PDLA）的聚（ε-己内酯-co-d，ʟ-丙交酯-嵌段聚（d-乳酸）（4a-CDL-d）共聚物，并与聚（ʟ-乳酸）（PLLA）共混。
以季戊四醇为引发剂，通过开环聚合合成了一系列具有不同嵌段长度（Mn，PDLA）的四臂聚己内酯-co-d，ʟ-丙交酯-嵌段聚d-丙交酯（4a-CDL-d）共聚物。将它们与聚丙交酯（PLLA）共混以提高其结晶速率和机械性能。当Mn、PDLA发生变化时，PLLA/4a-CDL-D共混物中PLLA的结晶受到不同的影响。在没有PDLA嵌段的PLLA/4a-CDL共混物中，由于4a-CDL对PLLA结晶的稀释作用，结晶明显延迟。
当Mn，PDLA为0.5k时，尽管不存在立体络合物（SC）晶粒，但发现了结晶加速效应。当Mn，PDLA为1k或更高时（1.5k和2k），PLLA/4a-CDL-D共混物中可以形成SC晶粒。然而，当Mn、PDLA为1k或1.5k时，SC晶粒的形成很困难，并且它们对PLLA结晶的加速作用较弱。当Mn，PDLA为2k时，由于成核位置的增加，PLLA的结晶明显加速。这些共混物比纯PLLA具有更长的断裂伸长率。
