A promising solution to address the challenges in plastics sustainability is to replace current polymers with chemically recyclable ones that can depolymerize into their constituent monomers to enable the circular use of materials. Despite some progress, few depolymerizable polymers exhibit the desirable thermal stability and strong mechanical properties of traditional polymers. Here we report a series of chemically recyclable polymers that show excellent thermal stability (decomposition temperature >370 °C) and tunable mechanical properties. The polymers are formed through ring-opening metathesis polymerization of cyclooctene with a trans-cyclobutane installed at the 5 and 6 positions. The additional ring converts the non-depolymerizable polycyclooctene into a depolymerizable polymer by reducing the ring strain energy in the monomer (from 8.2 kcal mol^–1 in unsubstituted cyclooctene to 4.9 kcal mol^–1 in the fused ring). The fused-ring monomer enables a broad scope of functionalities to be incorporated, providing access to chemically recyclable elastomers and plastics that show promise as next-generation sustainable materials.

应对塑料可持续性挑战的一个有前途的解决方案是用可化学回收的聚合物取代当前的聚合物，这些聚合物可以解聚成其组成单体，从而实现材料的循环使用。尽管取得了一些进展，但很少有可解聚聚合物表现出传统聚合物所需的热稳定性和强机械性能。在这里，我们报告了一系列具有出色热稳定性（分解温度 > 370 °C）和可调机械性能的化学可回收聚合物。这些聚合物是通过环辛烯与反式的开环复分解聚合形成的-安装在5和6位的环丁烷。附加环通过降低单体中的环应变能（从未取代的环辛烯中的 8.2 kcal mol ^–1到稠合环中的4.9 kcal mol ^{–1 ）将不可解聚的聚环辛烯转化为可解聚的聚合物。}稠环单体能够整合广泛的功能，提供化学可回收弹性体和塑料的途径，这些弹性体和塑料有望成为下一代可持续材料。