Effect of dispersing media and temperature on inter-yarn frictional properties of Kevlar fabrics impregnated with shear thickening fluid

Abstract Shear thickening fluid (STF) treated Kevlar fabrics is a potential method to improve the stab resistance of flexible body armors, whereas the STFs were significantly influenced by the temperature during their practical application. In this study, four kinds of STFs were prepared using constant silica and various dispersing media with different number of hydroxyl groups and chain length. The steady state and dynamic rheological properties of STFs were investigated in the temperature range of 20 to 50 °C. The pull-out test of the STF/Kevlar fabrics were also studied at different speeds and temperatures to evaluate the contribution of shear thickening effect. The results indicated that the STF/Kevlar fabrics had higher inter-yarn friction than the neat fabrics, suggesting a correlation of shear thickening effect. At 50 °C, the STFs with more hydroxyl groups and longer chains could reduce the negative effect of elevated temperature on the inter-yarn friction from 88.94% to 49.23%. Therefore, according to the different environment temperature, it is necessary to choose suitable dispersing medium to design application-specific of STFs.