Depolymerization Strategies Valorizing Commercial Thermoplastic Polyesters: Perspective Proposing Efficient and Convenient Chemical Recycling and Upcycling

Abstract

Commercial thermoplastic materials are used across several material fields, which increasingly employ recycling pathways in their production to reduce waste, minimize environmental impact, and reprocess their products to lower overall costs. Mechanical recycling and circular reprocessing within the unified polymer production are the most optimal circular solutions, achieving the sustainable demands of modern society. This work focuses on chemical recycling and upcycling opportunities, employing complex, heterogeneous, and substantially impure mixtures of plastic waste or multicomponent systems that cannot be reprocessed and used directly. Three major and most widely applied depolymerization strategies at the industrial scale were discussed: hydrolysis (acidic/alkaline), alcoholysis (also known as transesterification), and aminolysis. The main aim is to summarize the essential positive and negative factors regarding each chemical approach. The future applications of the upcycled products are introduced, and the quality and overall utility of the chemically recycled thermoplastic macromolecular compounds are meticulously evaluated.