Upcycling plastic waste into high value-added chemicals under mild conditions

Abstract

Abstract As the largest class of organic thermoplastic polymers, polyolefins generated huge amounts of plastic wastes, which cannot be chemically recycled into their monomers or high-value chemicals in a cost- or energy-efficient way. To address this challenging issue, we develop a novel strategy for upcycling polypropylene (PP) waste. An anionic surfactant-induced oxidative degradation method is developed to transform polypropylene into terminal ketone/carboxylic acid/olefin functionalized long-chain oligomers (mainly average C70), which are important feedstocks used in synthetic surfactants, poly-α-olefin lubricants, and polyesters. The reaction only needs to be heated at 60oC for 5 min, and the subsequent reaction is completed by oxidative self-heating. The fast self-heating temperature up to 280oC triggers the thermal cracking of PP. Coupling exothermic oxidative cracking with endothermic thermal cracking promotes oxygenation and dehydrogenation of PP. Controlling the amount of Sodium dodecyl sulfate could modulate the self-exothermic process, giving the products with different degrees of functionalization. The approach provides a mild, facile, and fast solution to obtain value-added chemicals from waste polyolefins.