Non‐destructive self‐healing design for carbon fiber/epoxy composites

Abstract Self‐healing composites are promising for engineering, but self‐healing structures or components usually induce reduction in the composite's mechanical properties. In this paper, core‐shell nanofibers which accommodating healing agent in the core and incorporating carbon nanotubes (CNTs) in the shell were produced to develop non‐destructive self‐healing carbon fiber/epoxy (CF/EP) composites. The epoxy resin and curing agent were encapsulated in CNTs‐reinforced polyacrylonitrile (PAN) core‐shell electrospinning nanofiber mats and the mats were placed on carbon fibers to fabricate CF/EP composite laminates by the vacuum‐assisted resin transfer molding (VARTM) process. The results indicated that the flexural strength, flexural modulus, tensile strength, tensile modulus, and Mode II interlaminar fracture toughness of composites with suitable self‐healing components increased by 49%, 44%, 8%, 13%, and 43%, respectively, compared to the pristine CF/EP. The healing flexural strength of the composite with 1 wt% CNTs recovered up to 93.57%, observed 24 h after the bending fracture, which is higher than the initial strength of CF/EP composites without self‐healing components. The research indicates that self‐healing composites can be developed without mechanical properties degrade and even achieve stronger mechanical properties.