Multi-scale reinforcement of epoxy composites - Use of carbon fibre fabrics coated with an epoxy binder containing MWCNTs for improved interlaminar fracture resistance

Epoxy multi-scale composites were produced using woven carbon fibre (CF) fabric coated with an aqueous dispersion of multiwall carbon nanotubes (MWCNT) in an epoxy binder. The reinforcement of the CF-epoxy interface increased inter-laminar fracture toughness (ILFT) in mode I by 234 ± 13% and in mode II by 106 ± 2%. These increases were attributed to both the binder, which alone (cured without MWCNT) increased ILFT by 87 ± 8% for mode I and 40 ± 10% for mode II, and to MWCNT pull-out and fracture. The uncured binder caused plasticisation of the matrix, which was addressed somewhat by crosslinking of the binder and further by the addition of MWCNTs.