The CNT/PSt-EA/Kevlar composite with excellent ballistic performance

This work reports a new type of ballistic composite which is prepared by integrating the carbon nanotubepolystyrene ethyl acrylate (CNT/PSt-EA) based shear thickening fluid (C-STF) with Kevlar fabric. Because the rheological property of the PSt-EA based STF is significantly enhanced by the CNT, the C-STF/Kevlar offers better ballistic property than Kevlar fabric. The ballistic test indicated that the ballistic limit velocity (v(bl)) of Kevlar could be improved from 84.6 m/s to 96.5 m/s by impregnating the C-STF. Here, the optimum addition of CNT for C-STF/Kevlar is 1.0% and excessive CNT addition reduces the reinforcement effect. Besides, as the volume fraction of dispersed phase in STF increased from 53.5% to 58.5%, the v(bl) increased from 92.9 m/s to 99.5 m/s. The fabric layer number also plays a critical role in the ballistic property of C-STF/Kevlar. By combining the finite element analysis (FEA) results of ballistic impact with the quasi-static puncture and yarn pull-out results, the enhanced anti-impact mechanism is obtained. It is found that the friction coefficient between the yarns is strengthened and the bearing area of the fabric is increased by doping STFs, thereby the ballistic performance of Kevlar is improved. This work achieves the regulation of ballistic performance of Kevlar composites.