Development of highly electrically conductive composites for aeronautical applications utilizing bi-functional composite interleaves

With the wide application of composite materials in modern aerospace industry, multifunctional carbon fibre composites are likely to play an important role in next generation aircraft. Here, carbon fibre reinforced epoxy composites were produced by using Functionalized Interleaf Technology (FIT). The electroless copper-nickel plated polyester veils (CNPV) were used as the interleaves to replace the initial resin-rich interlaminar regions with functional interlayers. The latter shows useful toughening efficiency, in which the G_Ic and G_IIc values for interleaved specimens increased by 59% and 31%, respectively. At the same time, the in-plane (σ_xy) and through-thickness (σ_z) electrical conductivities were also improved from 74.12 S/cm to 1079.6 S/cm and 1.5×10⁻³ S/cm to 5.29 S/cm, respectively. Moreover, it is found that the effective electric contact area at electrodes was increased by incorporating additional functionalized veils. Therefore, the interleaf material can be characterized by its bi-functionality as it provides both toughening efficiency in the interlaminar region and the ability to form an electrically conductive path crossing the resin-rich interlaminar layer, perpendicular to the laminate plane.