Ambient‐Temperature Depolymerization and Closed‐Loop Recycling of Waste Epoxy Thermosets

ABSTRACT Pervasive reliance on anhydride‐cured epoxy across diverse sectors, especially the electrical industries, has created a severe crisis in waste management. The rigid crosslinked structure necessitates aggressive disposal methods, including landfilling and incineration in industrial practice, as well as high‐temperature processes widely adopted in research. A low‐barrier, easy‐to‐implement approach is in pressing need. Here, we present an efficient depolymerization method for traditional anhydride‐cured epoxy at ambient temperature (viable even at −38°C) using all commercially available and easy‐to‐recycle chemicals. This method is suitable for various post‐industrial goods (including 50‐year‐old end‐of‐life items and decommissioned devices in landfill), to salvage intact non‐epoxy components like carbon fibers and transformer winding. It can also be generalized to depolymerize plastics other than epoxy, including post‐consumer polyesters and smart liquid crystal elastomers. Moreover, the dissolved epoxy can be repolymerized back to pristine thermoset or vitrimer, filling the gap in closed‐loop recycling of traditional epoxy. This method establishes a simple but practical route for recycling traditional epoxy thermosets and related industrial products.