Rheological behaviours of silica/water, silica/PEG systems and mechanical properties of shear thickening fluid impregnated Kevlar composites

Evolution in armour materials is critical to improve the protection abilities together with the properties of flexibility and lightness. Silica colloidal suspensions are important candidates to improve strength of the armour materials. The dispersing medium of the silica particles acts as an important role in the formation of shear thickening fluids (STF). STF has the ability to have increased viscosity by increasing the shear rate. Rheological, impact, flexibility and yarn pull-out tests were performed during the study. This study demonstrated that STF did not occur in the case of dispersing silica in water, but increased the impact resistance when Kevlar treated by the silica dispersed in water as compared to neat Kevlar. Fumed silica distribution in polyethylene glycol (PEG) led to STF creation confirmed by the rheological tests. The impact resistance of STF-treated Kevlar was found to be improved when compared to silica-dispersed water-impregnated Kevlar. It was observed that the pull-out force values of STF-fertilized Kevlar were increased compared to neat Kevlar.