Accessing Degradable Polyethylene Materials with In-chain Ester Units via Mechanochemical Backbone Editing

Incorporating a low density of ester units into the backbone of polyethylene materials enhances their sustainability and recyclability while maintaining the main material properties of polyethylenes. Here we report a new way to access degradable polyethylene materials with a low content of in-chain ester units via mechanochemical backbone editing. Initially, ester groups are incorporated as side groups through catalytic copolymerization of ethylene with a cyclobutene-fused lactone monomer (CBL), yielding polyethylene materials with high molecular weights and adjustable thermomechanical properties. Subsequent solid-state ball-milling treatment selectively introduces side-chain ester groups into the main chain of the polyethylene materials via force-induced cycloreversion of the cyclobutane units. Under acidic conditions, hydrolysis of the resultant polyethylene materials with in-chain ester units facilitates further degradation into oligomers.