Self-Healing of an Epoxy Resin Using Scandium(III) Triflate as a Catalytic Curing Agent

A novel Lewis acid-catalysed self-healing system is investigated for implementation into epoxy-based fibre reinforced polymer (FRP) composite materials. The catalyst, scandium(III) triflate, is selected using a qualitative approach and subsequently embedded with pre-synthesised epoxy-solvent loaded microcapsules, into an epoxy resin. Healing is initiated when microcapsules are ruptured at the onset of crack propagation. The epoxy monomer healing agent contained within actively undergoes ring-opening polymerisation (ROP) on contact with the locally dispersed catalyst, forming a new polymer to bridge the two fractured crack planes. Self-healing performance is quantified using a tapered double cantilever beam (TDCB) test specimen and the effects of microcapsule content and healing temperature and time are all independently considered. As an initial proof of concept study, results show that a material recovery value of greater than 80% fracture strength is achieved for this novel Lewis acid-catalysed self-healing epoxy resin.