Synergistic toughening in the interleaved carbon fibre reinforced epoxy composites by thermoplastic resin and nanomaterials

Abstract

The nanomaterials and thermoplastic resin both can enhance the fracture toughness of epoxy matrix composite. In this paper, the nanomaterials of different dimensions (zero-dimensional nano-silica and one-dimensional carbon nanotubes (CNTs)) and the thermoplastic resin Polyetherketone-cardo (PEK-C) were applied to prepare the hybrid films to interleave carbon fibre reinforced epoxy composites. The influence of synergistic combination on mechanical properties was investigated. The interaction between nanomaterials and PEK-C, and the way the nanomaterials of different dimensions exert toughening effect were highlighted. The results showed that introducing nanomaterials into PEK-C film could further enhance the crack propagation resistance and compensate the decrease in bending strength and modulus with respect to the neat PEK-C film. The layered structure formed in the interlaminar region due to the phase separation between epoxy matrix and PEK-C resin contributed to the improvement of fracture toughness. The zero-dimensional nano-silica enhanced the compatibility between epoxy and PEK-C in phase structure by functional groups. The pulling-out and breakage of one-dimensional CNTs and the resultant ductile deformation of resin contributed to the toughness improvement.