Aramid

They are used in aerospace and military applications, for ballistic-rated body armor fabric and ballistic composites, in marine cordage, marine hull reinforcement, as an asbestos substitute,[1] and in various lightweight consumer items ranging from phone cases to tennis rackets.

As a result, a higher proportion of the chemical bond contributes more to fiber strength than in many other synthetic fibres in the world.

It was introduced in 1972,[3] accepted in 1974 by the Federal Trade Commission of the USA as the name of a generic category of fiber distinct from nylon,[4][5] and adopted by the International Standards Organisation in 1977.

Aromatic polyamides were first introduced in commercial applications in the early 1960s, with a meta-aramid fiber produced by DuPont as HT-1 and then under the trade name Nomex.

It is used extensively in the production of protective apparel, air filtration, thermal and electrical insulation, as well as a substitute for asbestos.

Based on earlier research by Monsanto Company and Bayer, para-aramid fiber with much higher tenacity and elastic modulus was also developed in the 1960s and 1970s by DuPont and AkzoNobel, both profiting from their knowledge of rayon, polyester and nylon processing.

In 1978, Akzo introduced a similar fiber with roughly the same chemical structure calling it Twaron.

[citation needed] During the 1990s, an in vitro test of aramid fibers showed they exhibited "many of the same effects on epithelial cells as did asbestos, including increased radiolabeled nucleotide incorporation into DNA and induction of ODC (ornithine decarboxylase) enzyme activity", raising the possibility of carcinogenic implications.

[9] However, in 2009, it was shown that inhaled aramid fibrils are shortened and quickly cleared from the body and pose little risk.

Well-known aramid polymers such as Kevlar, Twaron, Nomex, New Star, and Teijinconex) are prepared from diamine and diacid (or equivalent) precursors.

Aramids share a high degree of orientation with other fibers such as ultra-high-molecular-weight polyethylene, a characteristic that dominates their properties.