Impact behaviour of glass fribre /epoxy composites with nano-enhanced resin after water exposure

Impact behaviour of glass fibre /epoxy composites with nano- SiO2 modified resin was studied in terms of low velocity impact after water exposure. Nanocomposites with 1%, 2%, 3% 5% 7% nano-SiO2 (Nanopox- Evonic) were investigated. Peak impact load and impact damage area as a function of nanoparticle contents were compared for dry specimens and for samples exposed to water (0.7 %wt. 1.7% water absorbed) at 1J, 2J 3J impact energies. For unmodified composite peak force was higher than for 3% modified specimens and higher for dry specimens than those exposed to water. Impact damage areas were plotted as a function of water contents for modified and unmodified samples. Failure modes were illustrated using SEM micrographs. Numeropus matrix cracks were the dominating failure mode in dry speciemens both unmodified and the modified. Fibre fracture was observed at 3J impact energy in all dry unmodified samples, however water exposure prevented early fibre fracture in nanocomposites. The proposed energy absorption mechanism is nanoparticles debonding.