Selective upcycling of commodity PVC/PET plastic mixture via mechanochemical reaction

Plastic production has surged to over 400 million tons annually, but recycling efforts have lagged, resulting in serious environmental effects. Despite ongoing research, recycling commodity plastics remains a significant challenge. Despite extensive studies on single-component plastics, most discarded plastics exist as mixtures, limiting the real-world applicability of such approaches. Therefore, this study aims to develop a selective upcycling and depolymerization strategy targeting poly(vinyl chloride) (PVC) and poly(ethylene terephthalate) (PET), major components in mixed plastic waste. A sequential dehydrochlorination and epoxidation process were performed on the PVC/PET mixtures using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and m -chloroperoxybenzoic acid ( m CPBA) to incorporate oxirane mechanophores along the polymer backbone. Subsequent hydrolytic degradation using NaOH resulted in the upcycling of PVC into degradable, water-soluble polyols and the depolymerization of PET into terephthalic acid monomers. Finally, the feasibility of this model system was demonstrated on automotive leather waste, underscoring its potential for practical recycling of real-world mixed plastic streams. • Upcycling mixed plastic waste is crucial for advancing the circular economy. • Mechanochemical upcycling strategy for PVC/PET plastic mixtures was developed. • Stepwise ball milling enabled recovery of polyols and TPA from PVC/PET mixtures. • Real-world application to car seat cover yielded 75 % polyols and 58 % TPA. • These results show strong potential of this process for sustainable plastic recycling.