Oxidative degradation and upcycling of polyethylene wastes

Plastics have become omnipresent in modern life due to their versatility and durability. However, this convenience comes at the cost of substantial waste generation. The inherent chemical stability of plastics complicates its recycling, leading to environmental pollution and ecological threats. This mini-review highlights recent advancements in addressing this challenge by oxidative transformation of polyethylene (PE) into new functional polymers, value-added chemicals, and carbon-based materials. We first discuss the introduction of hydroxyl, carbonyl groups onto PE with a focus on the functionalization degree and selectivity. Subsequently, approaches for PE oxidation into dicarboxylic acids and short-chain oxidized PE are described and compared, with an emphasis on the tandem reactions for converting mixed dicarboxylic acids into other value-added chemicals. We also briefly discuss the oxidative transformation of PE into carbon-based materials and summarize the progress in qualitative and quantitative analysis of oxidation products. Finally, we conclude this mini-review by highlighting the challenges and opportunities in the field.