Enhanced electrical properties of carbon fiber reinforced composites obtained by an effective infusion process

Carbon fiber reinforced composites (CFRCs) panels were manufactured with a Resin Film Infusion (RFI) approach by mixing a tetrafunctional epoxy precursor with a reactive diluent which allows to reduce the viscosity of the matrix and facilitate the dispersion in it of 0.5 wt.% multiwall carbon nanotubes (MWCNTs). The proper choice of the viscosity value and the infusion technique allows to obtain high electrical conductivity of panels composed by 7 plies of carbon fiber (crossing at 90°) cloths. The anisotropic electrical behavior is characterized by two in-plane electrical conductivities of 11.34 kS/m (in the direction parallel to the fibers) and 9.57 kS/m (at 45° with respect to the fibers), whereas a value of 1.75 S/m was achieved for the out of plane (through the thickness) value. The DC measurements confirm that the fibers govern the conduction mechanisms in the in-plane direction, whereas the percolating path created by the effective distribution of MWCNTs, favoured by resin formulation and adopted processing approach, leads to a significant enhancement of the overall electrical performance of the CFRCs.