Ring-opening polymerization (ROP) is a powerful synthetic methodology for the chemical synthesis of technologically important biodegradable aliphatic polyesters from cyclic esters or lactones. However, the bioderived five-membered γ-butyrolactone (γ-BL) is commonly referred as ‘non-polymerizable’ because of its low strain energy. The chemical synthesis of poly(γ-butyrolactone) (PγBL) through the ROP process has been realized only under ultrahigh pressure (20,000 atm, 160 °C) and only produces oligomers. Here we report that the ROP of γ-BL can, with a suitable catalyst, proceed smoothly to high conversions (90%) under ambient pressure to produce PγBL materials with a number-average molecular weight up to 30 kg mol^–1 and with controlled linear and/or cyclic topologies. Remarkably, both linear and cyclic PγBLs can be recycled back into the monomer in quantitative yield by simply heating the bulk materials at 220 °C (linear polymer) or 300 °C (cyclic polymer) for one hour, which thereby demonstrates the complete recyclability of PγBL.

开环聚合（ROP）是一种强大的合成方法，用于从环酯或内酯化学合成技术上重要的可生物降解的脂族聚酯。然而，生物衍生的五元γ-丁内酯（γ-BL）由于其低应变能而通常被称为“不可聚合的”。仅在超高压（20,000 atm，160°C）下，才通过ROP工艺实现聚（γ-丁内酯）（PγBL）的化学合成，并且仅产生低聚物。在这里我们报告说，使用合适的催化剂，γ-BL的ROP可以在环境压力下平稳地进行高转化率（90％），以生产数均分子量高达30 kg mol ^–1的PγBL材料。并具有可控制的线性和/或循环拓扑。值得注意的是，线性和环状PγBLs均可通过简单地将散装物料在220°C（线性聚合物）或300°C（环状聚合物）下加热一小时而以定量收率再循环回单体。 PγBL。