Effect of nanowire doping and rheological viscosity on novel design of highly concentrated shear thickening fluid for stabbing resistant composites

Abstract

To improve the shear-thickening performance and clarify the relationship between shear-thickening performance and impact resistance, highly concentrated nano-silica-based shear thickening fluids (STF) were prepared. Silica particles with plasma treatment (PT), incorporating nano-reinforcement phases of multi-walled carbon nanotubes (MWCNT) and aramid nanofibers (ANF), were doped into STF systems. The rheological properties of different STF systems and their effects on the stab resistance of composites were studied, and the effects of doped nanowire MWCNT and ANF on the shear-thickening performance and stab resistance were compared. The results show that the STF doped with nanowires can significantly enhance the stab resistance. MWCNT can substantially improve the rigid load-bearing capacity of composite fabrics through strong interfacial bonding and high modulus. At the same time, ANF can enhance the energy-absorbing capacity and the toughness by physical entanglement. Among them, the peak viscosity of 0.3 % M-STF reached 12210 ± 1038 Pa⋅s, which was 8.17 times higher than the undoped STF viscosity, and the critical shear rate was reduced to 0.26 ± 0.07 s⁻¹. There was a nonlinear relationship between peak viscosity and impact resistance. At a viscosity of about 7500∼10500 Pa⋅s, the rigidity and toughness reached an optimal balance. In the dynamic knife-stabbing test, the high-viscosity STF/AFs exhibited a higher peak load (1027 ± 39 N), showing excellent impact resistance. However, when the viscosity exceeds 12000 Pa⋅s, brittle fracture of the material may be induced. Therefore, the optimum viscosity equilibrium point needs to be determined based on the specific mechanical conditions.