Carbon Fiber-Bismaleimide Composites Filled with Nickel-Coated Single-Walled Carbon Nanotubes for Lightning-Strike Protection

Multifunctional carbon fiber composites are imperative for next-generation lightweight aircraft structures. However, lightning-strike protection is a feature that is lacking in many modern carbon fiber high-temperature polymer systems, due to their high electrical resistivity. This work presents a study on processing, materials optimization, and property development of high-temperature bismaleimide (BMI)-carbon fiber composites filled with nickel-coated single-walled carbon nanotubes (Ni-SWNTs) based on three key factors: i) dispersion of Ni-SWNTs, ii) their surface coverage on the carbon plies and, iii) the composite surface resistivity. Atomic force microscopy analysis revealed that coating purified SWNTs with nickel enabled improved dispersion which resulted in uniform surface coverage on the carbon plies. The electrical resistivity of the baseline composite system was reduced by ten orders of magnitude by the addition of 4 wt% Ni-SWNTs (calculated with respect to the weight of a single carbon ply). Ni-SWNT-filled composites showed a reduced amount of damage to simulated lightning strike compared to their unfilled counterparts, as indicated by the minimal carbon fiber pull-out.