美国弗吉尼亚理工学院Rong Tong团队报道了通过可扩展的立体顺序控制聚合合成高强度和延展性的弹性聚（α羟基酸）。相关研究成果于2021年9月28日发表在《美国化学会杂志》。

尽管聚（α-羟基酸）具有可降解性和生物相容性，但其用途仍然有限，因为其热性能和机械性能不如商品聚烯烃，这可归因于聚酯主链上缺乏侧链功能。从邻羧基酸酐合成高分子量功能化聚（α-羟基酸）的尝试因需要外部能源（如光或电）而产生的可扩展性问题而受阻。

该文中，研究人员报告了一种操作简单、可扩展的方法，通过由高氧化还原活性锰络合物和醇锌介导的邻羧基酸酐的受控开环聚合来合成立体规整、高分子量（>200kDa）官能化聚（α-羟基酸）。机理研究表明，开环过程可能是通过锰介导的脱羧作用和烷氧基的形成进行的。与相应的均聚物和嵌段共聚物相比，该方法直接从两种邻羧基酸酐混合物中制备的梯度共聚物表现出更好的延展性和韧性，因此突出了功能化聚（α-羟基酸）作为延展性和弹性聚合物材料的潜在可行性。

附：英文原文

Title: Resilient Poly(α-hydroxy acids) with Improved Strength and Ductility via Scalable Stereosequence-Controlled Polymerization

Author: Xiaoqian Wang, Ai Lin Chin, Jingyi Zhou, Hua Wang, Rong Tong

Issue&Volume: September 28, 2021

Abstract: Despite the degradability and biocompatibility of poly(α-hydroxy acids), their utility remains limited because their thermal and mechanical properties are inferior to those of commodity polyolefins, which can be attributed to the lack of side-chain functionality on the polyester backbone. Attempts to synthesize high-molecular-weight functionalized poly(α-hydroxy acids) from O-carboxyanhydrides have been hampered by scalability problems arising from the need for an external energy source such as light or electricity. Herein, we report an operationally simple, scalable method for the synthesis of stereoregular, high-molecular-weight (>200 kDa) functionalized poly(α-hydroxy acids) by means of controlled ring-opening polymerization of O-carboxyanhydrides mediated by a highly redox reactive manganese complex and a zinc-alkoxide. Mechanistic studies indicated that the ring-opening process likely proceeded via the Mn-mediated decarboxylation with alkoxy radical formation. Gradient copolymers produced directly by this method from mixtures of two O-carboxyanhydrides exhibited better ductility and toughness than their corresponding homopolymers and block copolymers, therefore highlighting the potential feasibility of functionalized poly(α-hydroxy acids) as ductile and resilient polymeric materials.

DOI: 10.1021/jacs.1c08802

Source: https://pubs.acs.org/doi/10.1021/jacs.1c08802