Tailoring the Rheology of Shear Thickening Fluids by Regulating the Particle Size of Dispersed Phase for Enhancing the Impact Resistance of Aramid Fabrics

Rheological behaviour of shear thickening fluid (STF) is influenced by particle size, particle shape, concentration of particles etc. This study deals with the effect of particle size and its distribution on the rheological behaviour of STFs and ensuing impact resistance of Kevlar® fabrics treated with them. Synthesis of submicron sized silica particles of three different sizes was carried out by following the Stöber method. Corresponding STFs consisting of 67 % silica particles were prepared and their rheological behaviour was evaluated. Decrease in particle size coupled with particle size uniformity significantly contributes to enhancement in dilatancy of STFs. Further, Kevlar® fabric was impregnated with these STFs for assessing their impact resistance performance. Fabric impregnated with STF prepared from the finest and uniform silica particles, having the highest peak viscosity, exhibited the best impact resistance performance among all STF impregnated fabrics. These findings show that the particle size and its distribution decisively influence the thickening behaviour of STF which in turn plays a critical role in determining the impact energy absorption by high-performance fabrics.