Aramid
From Wikipedia, the free encyclopedia
Aramid fibre is a fire-resistant and strong synthetic fiber, developed by Stephanie Kwolek in 1961. It is used in aerospace and military applications, for "bullet-proof" body armor fabric, and as an asbestos substitute. The term is a shortened form of "aromatic polyamide".
A well-known type of aramid fiber (a para-aramid nylon) is Kevlar created by DuPont, or Twaron from the Teijin company. An especially fireproof variant is Nomex created by DuPont.
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[edit] Production
The Federal Trade Commission definition for aramid fibre is "A manufactured fiber in which the fiber-forming substance is a long-chain synthetic polyamide in which at least 85% of the amide linkages are attached directly to two aromatic rings."
Aramid fiber is produced by spinning a solid fiber from a liquid chemical blend. This relies on a co-solvent with an ionic component (calcium chloride) to occupy the hydrogen bonds of the amide groups, and an organic solvent (N-methyl pyrrolinidone) to dissolve the aromatic polymer; prior to DuPont's invention of this process, no practical means of dissolving the polymer was known.
[edit] Aramid fiber characteristics
- sensitive to degradation from ultraviolet radiation
- good resistance to abrasion, organic solvents, and thermal degradation
- sensitive to moisture and salts
- nonconductive
- no melting point
- low flammability
- good fabric integrity at elevated temperatures
- para-aramid fibers such as Kevlar and Twaron, which have a slightly different molecular structure, also provide outstanding strength-to-weight properties, and have high tenacity, and high Young's modulus.
- difficult to dye - usually solution dyed [1]
- prone to static build-up unless finished [1]
[edit] Major industrial uses
- flame-resistant clothing
- protective clothing and helmets
- body armor, although it is being surpassed by stronger ultra-high molecular weight polyethylene products such as Dyneema and Spectra.
- composite materials
- asbestos replacement
- hot air filtration fabrics
- tire and mechanical rubber goods reinforcement
- ropes and cables
- sail cloth (not necessarily racing boat sails)
- sporting goods
- drumheads
- speaker woofers
- Boathull material
[edit] See also
[edit] References
[1] Kadolph, Sara J. Anna L. Langford. Textiles, Ninth Edition. Pearson Education, Inc 2002. Upper Sadddle River, NJcs:Aramid de:Aramidfaser nl:Aramide pl:Aramid
