Towards high-performance sustainable polymers via isomerization-driven irreversible ring-opening polymerization of five-membered thionolactones

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 degrees 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 gamma-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.

Automated summary

The study demonstrates that irreversible ring-opening polymerization of biomass-derived thionolactones is an effective strategy for producing sustainable polymers with renewability and high performance properties, which are thermodynamically forbidden under ambient conditions. This strategy allows the conversion of traditionally unachievable five-membered lactones into practical materials with a range of potential applications.