Cost-efficient and recyclable epoxy vitrimer composite with low initial viscosity based on exchangeable disulfide crosslinks

Epoxy (EP) vitrimer with excellent processing and recyclability is of great potential for industrial application. In this study, we prepared an EP vitrimer based on the low viscosity homogenous mixture of diglycidyl ether of bisphenol A (DGEBA) and a liquid hardener dimethyl 3,3′-dithiodipropionate (DTDP) catalyzed by 2,4,6-tris (dimethylaminomethyl) phenol (DMP30). The optimal curing condition was determined to be 110 °C × 12 h for the original EP vitrimer. Owing to the exchangeable disulfide crosslinks, rapid stress relaxation was found for the vitrimer with a relaxation time of 1.9 s at 160 °C. Moreover, the prepared EP vitrimer possessed excellent self-healing ability and recyclability, with recovery ratio of at least 94.1% during 3 times recycling. The self-healing ability, recyclability and processing performance remain excellent for the vitrimer even after incorporating 30 wt% boron nitride (BN), which can be recycled using DMF as a solvent.