Spontaneous Amino-Acetoacetate Click Polymerization: A Powerful Tool toward Closed-Loop Recyclable Poly(vinylogous urethane)s

The development of click polymerization toward the creation of structurally diverse closed-loop recyclable polymers is challenging yet desirable in modern polymer chemistry. In this work, we report a modular amino-acetoacetate click polymerization, which proceeds under mild conditions and produces H2O as the only byproduct. Through systematic optimization of reaction parameters, we successfully synthesized 22 poly(vinylogous urethane)s possessing high molecular weights (Mw up to 93.7 kDa) and well-defined structures in outstanding yields (up to 98%). The diacetoacetate monomers are derived from diols, and both diols and diamine monomers are common chemicals that can be produced from renewable biomass. Notably, these poly(vinylogous urethane)s exhibit the ability to depolymerize back to their respective monomers under mild conditions, highlighting excellent closed-loop recyclability. This click polymerization enables the synthesis of poly(vinylogous urethane)s with diverse structures, providing a versatile platform for the fabrication of closed-loop recyclable materials such as plastics, elastomers, and carbon fiber-reinforced polymer composites. The polymerization methodology and material innovations discussed in this work may benefit the promotion and application of closed-loop recyclable polymers toward greatly diverse demands and scenarios.