Self-healing of delamination cracks in mendable epoxy matrix laminates using poly[ethylene-co-(methacrylic acid)] thermoplastic

This paper investigates the self-healing repair of delamination cracks in a carbon fibre–epoxy laminate using the mendable thermoplastic poly[ethylene-co-(methacrylic acid)] (EMAA). The effects of different types (fibres or particles) and concentrations of the mendable EMAA agent on the self-healing efficiency was measured using mode I interlaminar fracture toughness testing and fractographic analysis. The EMAA was effective in healing delamination damage and increasing the fracture toughness compared to the original laminate. High healing efficiency was achieved by the wide area flow of EMAA (increase of ∼25 times) through delamination cracks under the pressure delivery mechanism. High recovery in the fracture toughness was achieved after healing by the formation of large-scale EMAA-bridging ligaments along the delamination, which is a toughening mechanism unique to this type of self-healing material. EMAA proved effective for the multiple repairs of delamination cracks with some loss in the self-healing efficiency of the mendable laminates.