Kevlar – a polymer from the group of polyamides (more precisely aramids), from which artificial fibers with high tensile strength are spun. Kevlar was invented in the DuPont laboratories in 1965 by a team of researchers led by the an American chemist of Polish origin Stephanie Kwolek. Kevlar is a trade name of DuPont. The Kevlar synthesis is obtained by the reaction of the polycondensation of dicarboxylic acid chlorides with aromatic amines. The synthesis reaction proceeds as follows:
Kevlar properties are not dissolved in organic solvents, but in concentrated sulfuric acid. Kevlar is about 5.5 times lighter than steel – its density is 1.44 g / cm³. It owes its strength mainly to the way the fibers are spun. These fibers are extracted from a solution of Kevlar in sulfuric acid, in which a liquid crystalline phase is formed. As a result, the extracted fiber has a high degree of molecular organization that is unattainable when spinning normal polyamide fibers. After the sulfuric acid has been removed, the liquid-crystalline order is “frozen” in the solid state, since there are numerous hydrogen bonds that are formed spontaneously between the polar amide groups (-CO-NH-) when the fibers solidify.
The fibers made from Kevlar are used, among other things, in bulletproof vests, helmets, hard hats, trampolines, inner shells of skis, tennis rackets, canoes and parts of the armor of aircraft carriers. Kevlar is also used to increase the breaking strength and tensile strength of fiberglass cables. It is used to protect particularly vulnerable elements of shoes and clothing. (It is used in the automotive industry to reinforce the rims and other components of bicycles and motorcycles, as well as to make lightweight motorcycle clothing.)
Directions: Ready to use. Apply with paint brush or sponge.