The prototype of bulletproof vests appeared very early, at that time called armor, to resist swords and protect soldiers. With the development of military weapons, firearms appeared, and bulletproof vests used to resist bullets were also developed. At the beginning, the materials used to make it were steel plates and natural fibers, but later the superior performance Kevlar material was used extensively. So, how does the Kevlar bulletproof vest play a protective role?
According to military experts, 75% of the total number of casualties on the battlefield are caused by low-speed or medium-speed flow bullets and bomb fragments, and only 25% of the casualties are directly caused by bullets. In order to improve the survival ability of combat personnel, the development of bulletproof clothing has been increasingly valued. The Kevlar bulletproof vest is made of aramid organic fiber material, developed by DuPont Company of the United States. By replacing nylon and glass fibers with aramid organic fibers, the weight of bulletproof clothing can be reduced by 50%: under the same unit area weight, its protective force can be increased by at least one time, and it has good flexibility. Bulletproof clothing made of this material weighs only 2-3 kilograms, and is comfortable to wear and easy to move, which is quickly adopted by the military of many countries in the world.
When a bullet hits the Kevlar bulletproof vest, it will be trapped in a very strong fiber "network". These fibers absorb the impact energy from the bullet and emit it, and the impact force of each layer is constantly decreasing until it is completely dispersed, and the bullet is stopped, having no effect on the human body. Whether it is a single-layer fiber or a multi-layer fiber, Kevlar fibers always work together, so a large area of bulletproof clothing is also beneficial. At the same time, it also helps to scatter the force from a certain point, avoiding damage to organs.
Although metal bulletproof clothing can also play a certain protective role, it is too heavy and inconvenient to move, which is very disadvantageous for soldiers. The weight of the Kevlar bulletproof vest is light, and wearing it will not have a heavy feeling, and it also has good air permeability. Bulletproof clothing is generally made into sleeveless vests, which are often seen in police and gangster dramas. Kevlar is a type of aramid fiber with excellent properties, such as ultra-high strength, high modulus, chemical corrosion resistance, anti-aging, and long service life. In addition to making bulletproof clothing, it can also be used in building materials, fire protection facilities, electronic devices, and other fields.