Exploring the effects of silica particles size on soft body armour panels for stab resistance application in advanced protective textiles

Abstract

Stab-resistant armours are a critical component of personal protective equipment for law enforcement officers and security forces who face various sort of threats in the line of duty. This research focuses on the development and evaluation of advanced, flexible soft-body armour for stab-resistance applications. Multi-layer armour panels were fabricated using neat para-aramid fabrics and impregnated with a shear thickening fluid (STF) made from three mono-dispersed silica particles of sizes ranging from the nano to sub-micron level, i.e., 100 nm, 300 nm, and 500 nm. The performance of these panels was rigorously assessed using a P1 and S1 knife at 24 J and 36 J energy levels, as specified by the National Institute of Justice (NIJ) Standard 0115.00. It was observed that a panel containing 20 layers of STF-impregnated (300 nm and 500 nm Silica particles) para-aramid fabrics successfully met the performance benchmarks for the P1 Knife. Whereas, in the case of the S1 knife, the STF-500 impregnated panel met the requirements at normal and over-test conditions, showing penetration depths lower than 7 mm and 20 mm, respectively. The present research work shows that the application of STF to para-aramid fabric results in a significant enhancement of its stab-resistant performance. STF treatment on the woven fabric significantly reduced penetration depth by 42–63% for the P1 knife and 40–54% for the S1 knife at 24 J and 36 J impact energies, without increasing the areal density of the panel.