The bulk ring-opening polymerization (ROP) of ɛ-caprolactone (ɛ-CL) by various phosphoric acids using phenylmethanol as the initiator was conducted. 1,1′-bi-2-Naphthol (BINOL)-based phosphoric acid was found to be an effective organocatalyst for ROP leading to polyesters at 90°C. The overall conversion to poly(ɛ-caprolactone) was more than 96% and poly(ɛ-caprolactone) with M w of 8400 and polydispersity index of 1.13 was obtained. 1H NMR spectra of oligomers demonstrated the quantitative incorporation of the protic initiator in the polymer chains and showed that transesterification reactions did not occur to a significant extent. The controlled polymerization was indicated by the linear relationships between the number-average molar mass and monomer conversion or monomer-to-initiator ratio. In addition, the present protocol provided an easy-to-handle, inexpensive and environmentally benign entry for the synthesis of biodegradable materials as well as polyesters for biomedical applications.
通过各种
磷酸与
苯甲醇作为
引发剂进行的 ɛ-内酯(ɛ-CL)的大宗开环聚合反应(ROP)研究表明,基于 1,1′-双-
2-萘酚(BINOL)的
磷酸是有效的有机催化剂,在 90°C 条件下能够成功合成聚酯。聚(ɛ-内酯)的整体转化率超过了 96%,得到的聚(ɛ-内酯)分子量为 8400,分散指数为 1.13。寡聚物的 1H NMR 光谱显示原子
引发剂在聚合链中的定量掺入,并表明酯交换反应没有显著发生。受控聚合通过数均相对分子质量与单体转化率或单体与
引发剂比率之间的线性关系得以体现。此外,该方法为合成可
生物降解材料及用于
生物医学应用的聚酯提供了一种易于操作、成本低廉且环保的途径。