The development of sustainable polymers that possess useful material properties competitive with existing petroleum-derived polymers is a crucial goal but remains a formidable challenge for polymer science. Here we demonstrate that irreversible ring-opening polymerization (IROP) of biomass-derived five-membered thionolactones is an effective and robust strategy for the polymerization of non-strained five-membered rings—these polymerizations are commonly thermodynamically forbidden under ambient conditions, at industrially relevant temperatures of 80–100 °C. Computational studies reveal that the selective IROP of these thionolactones is thermodynamically driven by S/O isomerization during the ring-opening process. IROP of γ-thionobutyrolactone, a representative non-strained thionolactone, affords a sustainable polymer from renewable resources that possesses external-stimuli-triggered degradability. This poly(thiolactone) also exhibits high performance, with its key thermal and mechanical properties comparing well to those of commercial petroleum-based low-density polyethylene. This IROP strategy will enable conversion of five-membered lactones, generally unachievable by other polymerization methods, into sustainable polymers with a range of potential applications.

开发具有与现有石油衍生聚合物相竞争的有用材料特性的可持续聚合物是一个重要目标，但对聚合物科学来说仍然是一个艰巨的挑战。在这里，我们证明了生物质衍生的五元硫醇内酯的不可逆开环聚合 (IROP) 是一种有效且稳健的非应变五元环聚合策略——这些聚合在环境条件下、在工业上通常是热力学禁止的相关温度为 80–100 °C。计算研究表明，这些硫醇内酯的选择性 IROP 是由开环过程中的 S/O 异构化热力学驱动的。γ-硫代丁内酯的 IROP，一种代表性的非应变硫代内酯，从具有外部刺激触发的可降解性的可再生资源中提供可持续的聚合物。这种聚硫内酯还表现出高性能，其关键的热性能和机械性能与商业石油基低密度聚乙烯的性能相当。这种 IROP 策略将使其他聚合方法通常无法实现的五元内酯转化为具有一系列潜在应用的可持续聚合物。