Some of the properties of Kevlar are its strength, toughness, high modulus and thermal stability. Kevlar has a wide range of applications and can be found in industrial and advanced-technology settings. Kevlar is also the first organic fiber that can be used for advanced composites.
Kevlar was first introduced to the global market in the 1970s by DuPont. The material was initially developed as a replacement material for steel used in radial tires. Kevlar is classified as an aramid compound and is considered to be part of the nylon family of fiber textiles. Ir is defined from other nylons by its para-aramid chemical distinction which gives it high modulus and structural strength. Kevlar's aramid compound ring also provides it with its thermal stability.
As of 2015, there are three different types of Kevlar available, Kevlar 29, 49 and 149. Each type of Kevlar has a distinct character in either density, tensile modulus, tensile elongation or tensile strength. Kevlar 29 has the same tensile modulus and strength as glass, but has nearly half the density. This allows Kevlar 29 to be used as a lighter weight substitute for glass when needed.
The fibers inside Kevlar are known to absorb moisture. This makes any Kevlar composites more environmentally-sensitive when compared to composites made using glass or graphite.