Bidirectional Disulfide Metathesis Enables Recycling of High-Performance Thermoset Networks

Polydicyclopentadiene (pDCPD) is a high-performance thermoset valued for its exceptional mechanical properties, chemical resistance, and thermal stability, enabling broad industrial application. However, its permanent carbon-carbon crosslinked network has long hindered efforts toward sustainable recycling. To overcome this limitation, we present a recycling strategy for pDCPD by incorporating a cyclic disulfide comonomer through ring-opening metathesis polymerization. The introduction of dynamic disulfide bonds enables thermal reprocessing via associative bond exchange and chemical depolymerization into disulfide-terminated oligomers that can be repolymerized without loss of performance. In addition to enabling recyclability, the disulfide monomer containing an aromatic ring enhances mechanical performance of pDCPD network in toughness and stiffness. This work provides a route to dual-mode recyclable, high-performance hydrocarbon thermosets and establishes bidirectional disulfide metathesis as a practical tool for thermoset circularity.