Recyclable Graft Polymer Enabled by RAFT Step-Growth Polymerization and Deconstruction

Graft polymers exhibit unique mechanical and interfacial properties arising from their densely grafted architectures; however, their recyclability remains severely limited and fails to meet current environmental sustainability requirements. Herein, we report a strategy for the synthesis, deconstruction, and reconstruction of recyclable graft polymer through the combination of grafting-through reversible addition-fragmentation chain transfer (RAFT) step-growth polymerization and RAFT interchange. Polystyrene macromonomers bearing symmetrical trithiocarbonate (TTC) units were first synthesized via RAFT polymerization and subsequently polymerized with bismaleimide in an A₂ + B₂-type RAFT step-growth polymerization to yield graft polymer containing a TTC unit in every repeat unit of the backbone. The uniform incorporation of TTC linkages enables efficient main-chain deconstruction under mild conditions, producing well-defined macromonomers with narrow molecular weight distributions. Importantly, the deconstructed products can be efficiently reconstructed into graft polymers via RAFT step-growth polymerization, enabling deconstruction-reconstruction cycles with high yields. This work establishes a simple and effective platform for the circular recycling of graft polymers while preserving precise architectural control, offering new opportunities for sustainable design of advanced macromolecular materials.