Oxidative depolymerization of polyethylene (PE), polypropylene (PP) and polystyrene (PS) wastes to value-added chemicals

Polymer materials are essential in modern applications such as packaging, construction, and textiles, however, their widespread use generates substantial waste. Due to the complex depolymerization processes, this polymeric waste is becoming an environmental burden. Oxidative depolymerization of polymer wastes has a potentially great impact on the economy, environment, and health. This comprehensive study reviews the latest updates on oxidative depolymerization of polystyrene, polypropylene, and polyethylene. These three polymers were selected due to their extensive commercial use and substantial contribution to plastic waste. The review also addresses the commercial and ecological implications of the oxidative depolymerization of these polymers. Besides, it explores the impact of environmental conditions, additive availability, and polymer molecular structure on oxidative depolymerization. Oxidative depolymerization mechanisms such as chain scission, cross-linking, and chain termination reactions are also discussed. Comparisons are drawn between the three polymers of interest to identify the differences in the factors affecting depolymerization and depolymerization mechanisms. This review is relevant to industries that depend on polymers, underscoring the need to understand the factors driving oxidative depolymerization.