Simultaneously improved mechanical and electromagnetic interference shielding properties of carbon fiber fabrics/epoxy composites via interface engineering

Abstract Carbon fiber reinforced composites (CFRC) are in huge demand in aviation industry for reducing the fuel consumption, despite the unfavorable electromagnetic interference (EMI) shielding property. In this work, carbon fiber fabrics (CF) were coated by a thin layer of nickel (Ni) using electroless plating to increase the electrical conductivity of the composites. Dopamine was then self-polymerized on Ni coated CF (CF-Ni) surfaces to enhance the interfacial interactions between fibers and epoxy matrix. The results showed that the introduction of 0.39 wt% of polydopamine (PDA) content leads to a significant increase of interlaminar shear strength (ILSS), tensile strength and modulus by 70.7%, 22.7% and 15.3%, respectively, compared with CF-Ni/epoxy composites with free of PDA. The dominant facture mechanisms changed from fiber pulling-out and/or debonding to fiber breakage after the introduction of PDA. Compared with CF/epoxy composites, the EMI shielding effectiveness (SE) of CF-Ni/epoxy composites increased by 77.2% and slightly decreased with the increase of the PDA content. In order to further optimize the overall performances of the composites, the laminates structures were specially designed by replacing 2 plies of CF-Ni-PDA with CF-PDA in the middle according to EMI shielding mechanisms. The composites with special laminate stacking exhibited outstanding ILSS (61.2 MPa) and EMI SE (31.0 dB), which are dominant over most reported structural composites. The effects of humidity on the mechanical and EMI shielding properties were evaluated as well, indicating that the composites played a huge application potential in aircraft.