Chemically recyclable polyester materials

Synthetic polymers are fundamental materials indispensable for human survival and life. The application of these polymers on a large scale has greatly improved living standards and promoted social and civilizational development. However, traditional polymer materials rely on limited petrochemical resources, and due to the chemical inertness of their carbon-carbon chains, they cause serious environmental pollution after disposal. The continued growth in global polymer production poses a dual challenge to human resources and the environment. Researching and developing chemically recyclable polymer materials is an important route to overcome this challenge. This mini review discusses three pathways of polymer chemical cycling: closed-loop chemical cycling of monomer-polymer-monomer (e.g., polyesters, polythioesters, poly(thio)carbonates, polyamides, and polyacetals), open-loop chemical cycling (e.g., PET, poly(thioether-ester)s, poly(thiocarbonate-ester)s), and the conversion of polymer A into another polymer B. The corresponding chemical cycling mechanisms are summarized, and the main challenges in developing chemically recyclable polymer materials are discussed.