Synthesis and self-healing behavior of thermoreversible epoxy resins modified with nitrile butadiene rubber

Cracks may generate in epoxy resins, which can affect the comprehensive property and shorten service life. The problem is expected to be resolved by endowing epoxy resin with self-healing performance. Herein, a new kind of self-healing epoxy resin containing both Diels–Alder (DA) bonds and nitrile butadiene rubber (NBR) has been developed. The self-healing performance and mechanical properties of as-prepared epoxy resins are investigated by qualitative observation and quantitative measuring. Results reveal that the as-prepared epoxy resins exhibit excellent self-healing performance and multiple repair ability, and the self-healing behavior is based on dual actions of thermal reversibility of DA reaction and thermal movement of molecular chains. Furthermore, the thermoreversible DA bonds contribute much to the recovery of mechanical property, while the incorporated thermoplastic NBR accelerates the whole healing process. The self-healing efficiency of epoxy resins can be enhanced markedly by introducing thermoplastic NBR. In addition, the self-healing epoxy resins also exhibit outstanding reprocessing performance, which makes it possible of recycling waste epoxy resin. POLYM. ENG. SCI., 59:1603–1610 2019. © 2019 Society of Plastics Engineers