Efficacy of carbon nanotubes and polydimethylsiloxane interlayer in augmenting the impact strength of glass fiber/epoxy composites

Abstract

An experimental investigation is carried out to explore the possibility of carbon nanotubes addition and incorporation of polydimethylsiloxane soft interlayer in improving the impact strength and energy-absorbing capability of conventional glass fiber-reinforced plastics. To this end, deformation behavior of glass fiber-reinforced plastics, carbon nanotube-modified glass fiber-reinforced plastics, and glass fiber-reinforced plastics-polydimethylsiloxane sandwich coupons under high strain rate loading are compared using the split-Hopkinson pressure bar testing technique. While neat epoxy is used to process conventional glass fiber-reinforced plastics, the carbon nanotubes-modified glass fiber-reinforced plastics samples are fabricated using 0.5 wt. % carbon nanotube-modified epoxy. The split-Hopkinson pressure bar testing reveals that the addition of carbon nanotubes improves the peak stress and energy-absorbing capacity of the epoxy matrix. The improved impact response of carbon nanotube-modified epoxy translates into enhanced peak stress and energy-absorbing capability of carbon nanotubes-modified glass fiber-reinforced plastics in comparison to conventional glass fiber-reinforced plastics under impact loading. The microscopy analysis of failed composite samples reveals that while glass fiber-reinforced plastics primarily fails at the fiber/epoxy interface, the failure initiates in the epoxy matrix in carbon nanotubes-modified glass fiber-reinforced plastics samples. The impact testing of sandwich samples shows that the insertion of neat and 0.05 wt. % carbon nanotube-modified polydimethylsiloxane interlayer helps to distribute the impact load in a wider domain and thus delays the failure of glass fiber-reinforced plastics sandwich coupons. Moreover, the carbon nanotube-modified polydimethylsiloxane interlayer is better suited to increase the damage resistance and energy-absorbing ability of glass fiber-reinforced plastics. The present study provides a feasible strategy to enhance the failure strength and energy-absorbing capacity of conventional composites using carbon nanotube-modified epoxy and polydimethylsiloxane-based interlayer.