Synthesis of Diels‐Alder Reaction‐Based Remendable Epoxy Matrix and Corresponding Self‐healing Efficiency to Fibrous Composites

Abstract A Diels‐Alder (DA) thermo‐reversible compound consisting of a furan (FA) and a bismaleimide (BMI) is synthesized and grafted to a general low‐viscosity epoxy to prepare a self‐healable epoxy matrix system. Results prove that the synthesized epoxy can completely self‐heal its own cracks and the interlaminar shear cracks of a fiber reinforced plastic (FRP) due to the dissociation and reassociation of DA thermo‐reversible covalent bonds under proper thermal excitations. Self‐healing efficiencies of 108.5% for the first healing and 130.5% for the second healing are obtained to the mode II interlaminar fracture toughness (GIIC) of the FRP. Moreover, the obtained first and second healing efficiencies of interlaminar shear strength (ILSS) can also reach 105.8 and 102.4%, respectively. Most importantly, the obtained original mechanical properties, with GIIC of 0.82 kJ m−2 and ILSS of 41.6 MPa, of the FRP are much closer to those of traditional structural FRPs. Therefore, this study reveals that the synthesized epoxy system can be used to prepare structural FRPs possessing high self‐healing capability.