Recent progress in degradation and recycling of epoxy resin

Epoxy resin is widely used in electrical equipment and electronic devices fields due to its excellent electrical, thermal, and mechanical properties. However, its internal three-dimensional covalent interconnection structure brings barriers to its degradability and recycling because covalent bonds cannot be broken easily. With the replacements of power equipment and electronic devices, there will be more and more epoxy resins and their composites in them to be treated and effective recycling is of great significance for resource conservation and environmental protection. In this review article, recent progress in degradation and recycling of epoxy resin is introduced and the effect of three traditional degradation methods is discussed. The drawbacks of these methods are thought to come from the intrinsic properties of these epoxy resins. So the urgency of developing new kinds of degradable epoxy resins is proposed. Then different types of new degradable epoxy resins are reviewed. Degradation mechanisms of the opened-loop recycling and recycling methods of the closed-loop recycling are summarized in detail. Finally, the challenges and perspectives are discussed based on their current developments. This review comprehensively considers both traditional degradation methods and new methods for developing degradable epoxy resins. It covers not only an overview of the state-of-the-art advances of degradation and recycling of epoxy resin but also the prospects that provide reference for the synthesis of degradable epoxy resin materials.