Characterization of the rheological behaviors and mechanical properties of fabrics impregnated by different shear thickening fluids at changing temperatures

Liquid armor prepared with shear thickening fluid (STF) and high-performance fiber fabric is a novel body protection material which possesses both anti-impact performance and improved wearing comfort. In this work, the rheological behaviors of STFs with different features and mechanical properties of STF impregnated fabrics at different temperatures were characterized. Three kinds of STFs were prepared by mixing silica particles and polyethylene glycol with different particle concentrations and/or particle-fluid interaction. Their rheological behaviors show remarkable differences in viscosity, loss modulus and storage modulus. High solid concentrations and strong particle-fluid interaction are considered to be important factors to obtain high viscosity and high modulus. The rheological properties of STFs are also very sensitive to temperature, as we have found that the viscosity and the modulus values at -40 degrees C are three orders of magnitude higher than those at 55 degrees C. However, the mechanical properties of the aramid fabrics impregnated with these STFs do not change significantly with the STF types and temperature. Yarn pull-out and dynamic impact tests results show that fabrics impregnated with STFs possess excellent energy absorption effects, but the friction resistance and energy absorption capacity of the fabrics are not positively related to the STF viscosity and modulus. Our findings will provide guidance to the design of STF composites in the field of low-speed impact.