| Abstract |
Graft polymers, owing to their grafted structures, possess unique properties useful for a broad range of applications. Due to the demand for a circular economy, it is desirable to have graft polymers depolymerizable. However, depolymerizable graft polymers are rare, and existing examples of depolymerizable graft polymers lack the rigor in controlling the size and architecture. Herein, we demonstrate a robust method to synthesize depolymerizable graft polymers by leveraging our recent development of chemically recyclable polymers prepared from controlled ring-opening metathesis polymerization of trans-cyclobutane fused trans-cyclooctenes. The superior reactivity of the highly strained trans-cyclooctene allows grafting-through of macromonomers to be successfully conducted, empowering excellent control in backbone length for various types of sidechains, including a poly(ethylene glycol), a polylactide, and an aliphatic chain. Notably, an ultrahigh molecular weight of 14 000 kDa is achieved with high conversion (>90%) and low dispersity (D < 1.2). The controlled polymerization enables the synthesis of graft polymers of various architectures, including block and statistical copolymers. Kinetic studies of depolymerization show that the graft polymers depolymerize to the cis-cyclooctene macromonomers through an unzipping mechanism. The versatile synthesis of depolymerizable graft polymers opens the door to sustainable thermoplastics with diverse material properties. |