Self-healing epoxy with ultrafast and heat-resistant healing system processable at elevated temperature

Self-healing system with ultrafast speed and heat-resistance is highly desired in development of intelligent high performance polymer composites. In this work, trifluoromethanesulfonic acid (TfOH), an ultra-strong Bronsted acid, is successfully encapsulated in silica microspheres, which cooperates with epoxy monomer, forming a group of novel self-healing agent having practical value. Impact and fatigue tests demonstrate that mechanical strength of epoxy composite filled with low loading level of microencapsulated epoxy monomer and TfOH can be recovered within seconds at room temperature without manual intervention. Moreover, the present healing system is low-toxic and has acquired significant thermal stability. It can survive the rigorous processing of high Tg epoxy (>240 °C) during composite fabrication and provides the composite that was pre-treated at 180 °C for 5 h with the same healing efficiency as the untreated one. We believe that this work expands the spectrum of self-healing strategies and facilitates future applications.