Cumene-mediated aerobic oxidation of polyethylene†

Installing polar functional groups onto the hydrocarbon backbone of polyethylene (PE) can endow it with new properties, such as wettability and adhesion to polar materials. Herein, we report a scalable PE oxidation method that uses cumene as a radical mediator and atmospheric O₂ as an oxidant to obtain oxidized PE with a functionalization degree of up to 3.8 mol%. The oxidized PE exhibits enhanced adhesion to aluminum plates, increased tensile strength and improved elastic modulus compared with pristine PE. The method is applicable to various types of PE and can be easily scaled up. Mechanistic studies demonstrate that cumene alkoxyl radicals abstract hydrogen atoms from PE to initiate PE oxidation, and the use of a binuclear nickel catalyst can accelerate this process and alleviate the C–C bond cleavage by curtailing the undesired chain-scission pathway. This research offers a promising solution for converting accumulated PE waste into functionalized polymers by oxidation.