Poly(ethylene-co-methacrylic acid) coated carbon fiber for self-healing composites

We describe a simple and scalable method for incorporating thermoplastic agents into fiber reinforced polymers (FRPs). Poly(ethylene-co-methacrylic acid) (EMAA) nanoparticles were successfully deposited on the surface of carbon fibers via spray coating. EMAA was finely distributed and exhibited strong adhesion to the fibers. The EMAA-coated carbon fibers improved the fracture toughness and provided the FRPs with self-healing ability. The resulting healing efficiency, based on the recovery of the interlaminar fracture toughness, was above 40 % and gradually decreased after three repair cycles. The repair mechanism of the system involves the inherent flow capacity of the thermoplastic and formation of interfacial bridging between the two damaged interphases. This methodology allows pure resin to be used without any chemical modification or adverse effects on its viscosity, and the coated fiber can be stored until use.