Self-healing performance of hybrid core-shell nanofibers mat containing epoxy-mercaptan at subroom temperature

Self-healing epoxy composite working at subroom temperature could be useful in aerospace industry and wind turbine blades. In this research, hybrid core-shell nanofibers mat containing epoxy resin and mercaptan was embedded in epoxy matrix to investigate repeated self-healing ability of the fabricated composite at subroom temperature (10 degrees C). The results of three-point bending test illustrated that the release of epoxy resin and mercaptan into cracks and curing reaction between them could restore flexural properties of the composite. In fourth bending cycle, flexural modulus of composite reinforced by hybrid mat and unreinforced epoxy (without nanofiber) was reduced 6% and 24%, respectively. In addition, hybrid mat reinforced composite was broken at fifth bending cycle whereas for unreinforced epoxy specimen occurred at fourth bending cycle. Non-isothermal differential scanning calorimetry thermograms after each three-point bending cycle of hybrid mat reinforced composite showed an exothermic peak centered about 64 degrees C. This peak is related to epoxy and mercaptan reaction that could confirm self-healing ability of hybrid core-shell nanofibers mat. Extraction results, FTIR analysis, and three-point bending test showed the stability of epoxy and mercaptan into nanofibers during 8 months.