A dual mechanism single-component self-healing strategy for polymers

A bifunctional single-component healant, glycidyl methacrylate (GMA), is encapsulated and employed for fabricating self-healing epoxy materials. The released GMA is able to rebond cracked portions at room temperature through hydrogen and covalent bonds, and hence recover fracture toughness with high efficiency. The main advances of the healing system lie in the following. (i) It simplifies the conventional approach using two-part healing agent and broadens applicability of the therapy since two healing mechanisms, solvent effect and chemical reactions, are involved. (ii) As GMA contains both epoxide groups and C=C bonds, ring-opening and nucleophilic addition reactions between GMA and the residual amine in the matrix occur during crack healing and help to reconnect the separated faces. The application of nucleophilic addition, which has not yet been reported as a healing measure, might lead to expansion of the spectrum of self-healing agent because the species of organic molecules enabling nucleophilic addition reaction are far more than those with specific functional groups like epoxide.