Bulk depolymerization of graft polymers based on trans-cyclobutane-fused cyclooctene

Polymers capable of undergoing facile and selective depolymerization are highly desired for achieving a fully circular polymer economy. To advance the design of next-generation chemically recyclable polymers, it is essential to understand how the structure and architecture of polymers influence the thermodynamics of depolymerization. In this study, we investigate the structure-depolymerizability relationship of a series of graft polymers with varied sidechain lengths and grafting densities. The precision graft polymers are prepared through ring-opening metathesis polymerization of highly reactive trans-cyclooctene macromonomers and can be depolymerized into the more stable cis-cyclooctene form. Increasing side-chain length or grafting density is found to promote depolymerization. Ball-milling-assisted depolymerization is also pursued but results in significant chain scissions and low monomer yield. The findings here can aid the development of new depolymerizable polymers with useful properties.