Reinforcement Effects of Shear Thickening Fluid over Mechanical Properties of Nonwoven Fabrics

Conventional personal protective equipment is usually made in multilayer stacks, and appears clumsy and uncomfortable, offering limited protection. In recent years, a newly-developed nanosuspension, shear thickening fluids (STFs), has been commonly applied to buffer and shock absorption. In this study, nonwoven fabrics are impregnated with 30 wt%, 35 wt%, or 40 wt% STF in order to strengthen the interaction among fibers. The resultant STF composite nonwoven fabrics are observed for their morphology, and tested for their tensile strength, tearing strength, bursting strength, and dynamic impact resistance, thereby examining the damage resistance of the materials. The SEM images indicate that the fibers are adhered with a tremendous amount of silicon dioxide (SiO₂) particulates with a rise in the STF concentration, due to which the smooth fibers become rough. Moreover, the mechanical test results indicate that a rise in the STF concentration improves the frictional force during the relative motion of fibers, which subsequently mechanically strengthens the STF composite nonwoven fabrics. The dynamic impact test results show that when the STF concentration increases from 30 wt% to 35 wt%, the materials exhibit dynamic impact strength that is significantly improved to 51.9%. Nonetheless, significant improvement in dynamic impact strength is absent when the STF concentration increases to 40 wt%. To sum up, a critical value of STF concentration has a positive influence over the mechanical strengths of STF composite nonwoven fabrics.