Nanotube Sheet — Graphite Hybrid Nanocomposite for Damage Detection

In this study, we fabricate carbon nanotube (CNT) sheet — graphite powder hybrid nanocomposites and determine their strain dependent electrical resistivity for applications in damage sensing of aerospace composites. CNT sheet — graphite powder nanocomposites are prepared by epoxy resin infiltration under vacuum followed by oven curing. The electrical resistivity of the composites is measured while simultaneously subjecting it to tensile loading. The resistivity of the nanocomposite films without load reduces from about 34.7×10–5Ω·m to 8.1×10–5Ω·m by the addition of varying quantities of graphite powder. Additionally, the change in resistivity with tensile strain shows a significant improvement from 0.85 x10–5Ω·m to 8.9x10–5Ω·m when epoxy resin is modified with 5 wt% graphite powder. There is an associated particle size effect. The improvements are observed only when the second phase is graphitic particles (300 – 1000 µm) and not for fine graphene flakes (0.5 – 3 µm). We propose the application of these nanocomposites in damage sensing of aerospace carbon-fiber composites.