Abstract

Two different types of graphene flakes were produced following solution processing methods and dispersed using shear mixing in a bifunctional (A) and a multifunctional (B) epoxy resin at a concentration of 0.8 and 0.6 wt%, respectively. The graphene/epoxy resin mixtures were used to impregnate unidirectional carbon fibre tapes. These prepregs were stacked (seven plies) and cured to produce laminates. The interlaminar fracture toughness (mode-I) of the carbon fiber/graphene epoxy laminates with resin B showed over 56% improvement compared with the laminate without graphene. Single lap joints were prepared using the laminates as adherents and polyurethane adhesives (Sika 7666 and Sika 7888). The addition of graphene improved considerably the adhesion strength from 3.3 to 21 MPa (sample prepared with resin A and Sika 7888) highlighting the potential of graphene as a secondary filler in carbon fibre reinforced polymer composites.

Keywords
GrapheneCarbon fibre reinforced polymer (CFRP)Fracture toughness; Shear lap joints