Visible-Light HAT Photocatalysis for Switchable Polyethylene Degradation and C-H Functionalization

We report a hydrogen atom transfer (HAT)-mediated photocatalytic platform that switches between oxidative degradation and precision C-H functionalization of polyethylene (PE) by simple control of the reaction conditions. Under O₂, anthraquinone (AQ) catalyzes rapid chain scission under visible light at room temperature, resulting in ∼90% reduction in molecular weight (M_n) and oxidized compounds. In contrast, under anaerobic conditions, the reaction is redirected toward functionalization of PE, enabling grafting of maleimide and maleic anhydride onto the PE backbone without chain degradation. Grafting efficiency is tunable and verified by NMR, FTIR, and DOSY, while anhydride handles enable downstream derivatization to amide-functionalized materials.