Energy-Efficient Conversion of Amine-Cured Epoxy Resins into Functional Chemicals Based on Swelling-Induced Nanopores

Abstract

Rapid growth of discarded or landfilled thermosetting plastics has caused serious environmental issues and significant waste of energy. Selective degradation of thermosetting plastics into useful chemicals under mild conditions may provide a sustainable approach to address this challenge. In this study, we developed a green and efficient method to cleave the cross-links of amine-cured epoxy resin (EP) to produce new functional chemicals. Complete degradation was achieved using 4 mol/L HNO3 incubated at 60 °C for 3 h, and it has a higher efficiency than conventional methods. The C–N bonds of EP were selectively cleaved without breaking the skeletal bonds. The swelling-induced nanopores in EP caused by microwave processing exposed the cross-links that resulted in milder degradation conditions. The porous products could be readily separated and recovered. This study demonstrates a feasible approach for the recycling of thermosetting polymers under mild conditions.