A new paradigm for closed-loop recyclable plastics: the sulfur-substitution strategy

The development of modern society is inseparable from polymer materials, yet the escalating plastic pollution crisis caused by waste accumulation underscores the urgent need for closed-loop recyclable plastics. However, current closed-loop systems remain constrained by limited depolymerization efficiency and insufficient diversity in structure and performance. Recently, recyclable polythioesters derived from the ring-opening polymerization of cyclic thioesters have attracted increasing attention, owing to the unique dynamic characteristics of thioester bonds. Against this backdrop, we propose a sulfur-substitution strategy: by designing and synthesizing thio-analogues of lactones, we have achieved structurally diverse, superior properties, and chemically recyclable polythioesters. This article provides a systematic overview of our group’s progress on sulfur-substitution strategies in the field of closed-loop recyclable polythioesters and discusses both the future applications and the key challenges that remain to be addressed.