Lifecycle of dynamic covalent polar-olefin macrocycles via entropy-driven ring-opening polymerization and closed-loop chemical recycling

Abstract The global plastic pollution crisis urgently demands closed-loop chemical recycling strategies. While recyclable polymers via olefin metathesis have been widely explored, the development of metal-free methods operating under mild conditions remains a significant challenge. Here, we present the lifecycle design of polar-olefin-derived macrocycles as novel monomers capable of undergoing reversible entropy-driven ring-opening polymerization (ED-ROP) through organic base-catalyzed metathesis of polar olefin bonds. High-molecular-weight polymers were efficiently produced via bulk melt polymerization. Kinetic studies and mass analyses indicated the formation of cyclic polymer topologies through insertion and ring expansion, with polymerization thermodynamically driven by an increase in conformational entropy. By shifting the equilibrium of polar-olefin metathesis in dilute solution, these polymers enable efficient closed-loop depolymerization and monomer recovery. This approach establishes a versatile platform based on polar olefin chemistry, advancing the design of recyclable materials with tailored dynamic functionalities.