Enhanced Electrical Conductivity and Interlaminar Fracture Toughness of CF/EP Composites via Interleaving Conductive Thermoplastic Films

The poor electrical conductivity and interlaminar fracture toughness of carbon fiber reinforced epoxy (CF/EP) composites could reduce their reliability for aerospace applications. In this work, multi-walled carbon nanotubes (MWCNTs) doped polyethersulfone (PES) conductive thermoplastic films (CTFs) were prepared by solution casting method. The as-obtained composites were then interleaved into CF/EP prepregs to yield composite laminates. The effects of CTFs on the electrical conductivity and interlaminar fracture toughness of the as-prepared CF/EP composites were investigated. The results suggested an increase in conductivity of laminates by 104% and 84% in the transverse (Y) and through-thickness (Z) directions, respectively. The Mode I and Mode II interlaminar fracture toughness values were evaluated by double cantilever beam (DCB) and end-notched flexure (ENF) testing. The data revealed that the introduction of CTFs with 10wt% MWCNTs led to enhancement in Mode I and Mode II interlaminar fracture toughness of Composite laminates by 206% and 47%, respectively. The failure mechanism was investigated through microstructural and morphological changes in the composites studied by scanning electron microscopy (SEM). This work provides valuable guidance for the simultaneous enhancement of electrical conductivity and interlaminar fracture toughness of CF/EP composites.