Polyethylene Recycling via Water Activation by Ball Milling

Polyethylene (PE) is the most prevalent type of plastic waste and also the most challenging to depolymerize because of its inert carbon-carbon (C-C) bonds.^[1] High temperature and noble metals are usually required for depolymerization.^[2] To avoid using noble metals, costly reagents and harsh reaction conditions, it is worthwhile but challenging to explore new reaction pathways.^[3] We report an unprecedented mechanochemical reaction of PE and water to result in shorter-chain alkanes, alkenes, alcohols, and ketones (C_n, where n≲50), with above 80 % of starting carbon converted into these products, which could be a valuable feedstock for re-entering chemical value chains. This reaction is driven solely by ball milling, without heating and pressurizing. No costly catalysts are used. Instead, only earth-abundant Al₂O₃ was milled with reactants.