Shear Thickening Processing Bears On Knitted Fabric Of Stab-Resistant Of Performance

Recently, international terrorist activities are increasing. The domestic anti-terrorism and anti-split situation is very grim, personal safety has become a rather important thing around the world, promoting the rapid development of body armours. In many countries including China, the use of gun is prohibited very strictly, yet the threats from knives and stabs are mostly ubiquitous. Therefore, as one of the important part personal protective armours; the exploitation of stab-resistant body armour is getting more and more attention. The traditional stab-resistant protective materials face the contradiction between performance and flexibility. To solve the problem, in this thesis, a new-type stab-resistant material with excellent protective performance and flexibility was prepared by the compound of Ultra-high molecular weight polyethylene (UHMWPE) and Shear thickening fluid (STF).In this thesis, firstly, Weft knitted and Double-sided set circle fabric with three different loop length were made from polyester fiber. Its bursting and quasi-static puncture performance were studied, meanwhile, it were discussed that stitch lengths and fabric structures have an effect on its protective performance. Based on these, the knitting type cloth, which has the optimization of process parameters, were weaved from ultra-high molecular weight polyethylene(UHMWPE) fiber. Shear thickening fluid(STF) was made from nano-meter silica particles that is called the dispersed phase and polyethylene glycol 200 (PEG) known as the dispersion medium by using the mixer. STF-UHMWPE composite was made by static immersion method with STF diluted by ethanol. The composite specimens surface morphology and micro structure were observed by scanning electron microscopy. In the process of the experiment, it were studied that what have SiO2 of quality score, Fabric dipping time and pressure after dipping influenced on quasi-static puncture strength and the dynamic anti-cone performance of composite materials, Lastly, SiO2 of quality score, Fabric dipping time and pressure after dipping were viewed as the three factors, then the three factors of three levels orthogonal test were studied. The stab-resistant performance of the composite materials were evaluated by dynamic tests and quasistatic tests against spike and knife. After analysing the experiment results, the composite technological parameters with excellent stab-resistant performance was found. The weft knitted fabric and STF-UHMWPE composite of the mechanism of stab-resistant was proposed.It could be found from the experiments that loop length and texture of fabric have significant effect on the anti-stab performance of the knitted fabric, the bursting strength and puncture strength of the fabrics were decrease with the growth of the loop length, the both had remarkable linear correlation with loop length. The difference of knitted fabric structures affected the Bursting and Quasi-static puncture performance. The mixer can be used for making STF, SiO2 quality score, dipping time and pressure after dipping have all effect on the STF-UHMWPE composite of performance, among them, SiO2 quality score has the greatest effect on the protective performance, dipping time took second palace, pressure after dipping had minimal impact on the performance.The spite and knife tests showed that STF-UHMWPE composite of anti-stab performance was more excellent than. pure UHMWPE specimens under the same surface density. The same surface density of composite specimens with the layer is less, the more flexible the anti stab-resistant body armour.