A comprehensive study on the oxidative pyrolysis of epoxy resin from fiber/epoxy composites: Product characteristics and kinetics

Highlights: • Various O₂ concentrations on the oxidative pyrolysis of epoxy resin were investigated. • The product characteristics of epoxy resin were studied. • A multi-DEAM was employed to elucidate the oxidative pyrolysis kinetics of epoxy resin. • The predicted values under various atmosphere agreed well with experimental data. Thermal treatment has been the most feasible process to recycle valuable carbon fibers and obtain fuel and chemicals from waste fiber/epoxy composites. The present work studied the oxidative pyrolysis behaviors of epoxy resin from fiber/epoxy composites using a thermogravimetric apparatus and a fixed-bed reactor, respectively. The effects of various O₂ concentrations on the thermal behaviors of epoxy resin were investigated and the product characteristics were analyzed. Furthermore, a multi distributed activation energy model (multi-DAEM) was first developed to determine the oxidative pyrolysis kinetics of epoxy resin under various atmospheres. Results showed that the degradation behaviors of epoxy resin were largely altered by the O₂ concentrations. High O₂ concentrations accelerated the primary decomposition of epoxy resin and shifted the oxidation of resin residue into lower temperatures. High contents of methylcyclohexene and phenolic derivatives were detected in liquid products. In air atmosphere, high yields of CO and CO₂ were generated and distributed in several stages. The kinetic analysis indicated that the multi-DAEM method can well explain the oxidative pyrolysis behaviors of epoxy resin. A minimum six-reaction fitting process can perfectly simulate the oxidative pyrolysis of epoxy resin. The predictions for various O₂ concentrations were in good agreement with the experimental tests.