Development of self-healing epoxy composites via incorporation of microencapsulated epoxy and mercaptan in poly(methyl methacrylate) shell

Self-healing composites based on epoxy resin containing poly(methyl methacrylate) (PMMA) microcapsules filled with healing agents were prepared. The effect of healing agents microcapsules on mechanical properties and self-healing behavior of epoxy composites were investigated in this work. Epoxy and mercaptan as curing agent were microencapsulated in PMMA shell as two-component healing agent through internal phase separation method, and then, epoxy composites containing 2.5, 5, 7.5 and 10 wt% of healing agent microcapsules were prepared. The fracture toughness and healing efficiency of these composites were measured using a tapered double cantilever beam (TDCB) specimen. The results indicated that about 80% healing efficiency was achieved with 10 wt% PMMA microcapsules at room temperature after 24 h. The tensile strength of the epoxy with 2.5 wt % PMMA microcapsules increased initially and then decreased gradually with increasing microcapsules content up to 10 wt% PMMA microcapsules. DSC results also indicated that this system has good potential for spontaneous self-healing performance at room temperature.