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Bulletproof material application

Kevlar

In the early 1970s, Kevlar, a synthetic fiber with ultra-high strength, ultra-high modulus and high temperature resistance, was successfully developed by DuPont of the United States, and was quickly applied in the field of bulletproof.

The emergence of this high-performance fiber greatly improves the performance of soft textile body armor, while also improving the comfort of the body armor to a large extent. The U.S. military took the lead in using Kevlar to make body armor, and developed two models of light and heavy. The new body armor is made of Kevlar fiber fabric as the main material and bulletproof nylon cloth as the envelope. The lightweight body armor is composed of 6 layers of Kevlar fabric, and the medium weight is 3.83 kg. Compared with nylon and glass fiber bulletproof vests, the weight is reduced by 50%; in the case of the same mass per unit area, its protective force can be at least doubled, and it has good flexibility.

UHMWPE

UHMWPE is a fiber spun from polyethylene with a relative molecular mass of 1 million to 5 million. It is currently the world’s strongest and lightest fiber. Its strength is 15 times higher than that of steel wire. Very light, up to 40% lighter than materials such as aramid.

In terms of national defense equipment, because the fiber has good impact resistance and greater energy absorption, it can be made into protective clothing, helmets, and bulletproof materials in the military, such as armored protective panels for helicopters, tanks and ships, and radar Protective shells, missile covers, body armor, stab-resistant vests, shields, parachutes, etc., among which the application of body armor is the most eye-catching.

It has the advantages of lightness and softness, and has now become the main fiber occupying the US bulletproof vest market. In addition, the specific impact load value U/p of the ultra-high molecular weight polyethylene fiber composite material is 10 times that of steel, and more than twice that of glass fiber and aramid. Bulletproof and riot helmets made of fiber-reinforced resin composite materials abroad have become substitutes for steel helmets and aramid-reinforced composite helmets.

Liquid bulletproof material

The main component of liquid bulletproof material (TBS) is a special "shear thickening liquid (STF)", this liquid is generally composed of dispersed particles SiO2 and organic dispersion medium vinyl alcohol, polyethylene glycol, local propylene glycol or mineral oil One or more mixtures. Particles are freely suspended in the "shear thickening liquid". When the liquid is disturbed by a violent impact, the special particles in it collide with each other to form resistance to such agitation.

When the stirring force is large enough, these particles are actually "locked" with each other. When the bullet hits this material at high speed, the "shear thickening fluid" body armor will attract the impact energy and quickly become extremely hard, thereby absorbing the impact energy of the bullet.

Carbon nanotubes

Carbon nanotubes are one of the materials with the best mechanical properties found so far, with extremely high tensile strength and elongation at break. Its density is only one-sixth to one-fourth that of steel, and its tensile strength per unit mass is 276 times that of steel. The elastic modulus parameter of carbon nanotubes is 2.4 times stronger than Kevlar, and the overall performance is far More than any other materials currently discovered and manufactured by humans.

The bulletproof effect is mainly reflected in the modulus of elasticity, which means that the resistance strength of carbon nanotube fiber helmets or body armor is at least 2.4 times higher than that of Kevlar.

This body armor is made of carbon nanotubes made by nanotechnology. It was originally designed and developed for the 19th Special Forces of the US Army in Iraq. The patented material is thinner and softer, and the weight is only that of Kevlar, which is used in traditional body armor. Half, but also can prevent stab wounds, through the hardening of carbon nanotubes to prevent the tool from penetrating.

Graphene

As a new type of nanomaterial with the thinnest, strongest, and strongest electrical and thermal conductivity discovered so far, graphene is called "black gold" and is the "king of new materials". Scientists even predict that graphene will "completely change the 21st century." ". It is very likely to set off a disruptive new technology and new industrial revolution sweeping the world.

Scientists studying graphene body armor said that the body armor made of graphene has twice the protection capacity of the existing body armor technology (Kevlar). Although graphene still cannot be made into a powerful material alone, it can be composited into structural materials in multiple layers, so that it can stop the process of breaking outwards after being bombarded.

Graphene bulletproof materials can be widely used in military products such as armed helicopter protective armor, body armor, light protective armor, and explosion-proof equipment. It has broad market prospects in the civilian and military bulletproof materials market.

Compressed glassy carbon

Compressed glassy carbon is a new type of carbon material with the bonding characteristics of graphite and diamond. It is a mixed hybrid composed of sp2 and sp3. It has strange properties, density and conductivity similar to graphite.

Its compressive strength is significantly higher than that of metal and ceramic materials, and its specific strength is more than twice that of carbon fiber, polycrystalline diamond, silicon carbide and boron carbide ceramics. Its hardness is equivalent to that of gemstones and can be used to scribe silicon carbide single crystals. The compression elastic recovery rate of its local deformation is more than 70%, which is significantly higher than that of metal and ceramic materials, and even higher than shape memory alloys and organic rubbers.

Compressed glassy carbon combines light weight, super strength, high rigidity, high elasticity and good electrical conductivity. It has excellent comprehensive performance and many potential applications, such as military armor and aerospace.

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