Aramid fibers

Aramid fibers are a class of synthetic fibers which are heat resistant and / or exhibit good mechanical properties. They are used in aerospace and military applications, for example in the manufacture of bulletproof vests as well as as a substitute for asbestos. The word aramid comes from the contraction of aromatic polyamide. The component chains are strongly oriented in the direction of fiber strength, so that the forces of molecular interactions can be harnessed for thermal and / or mechanical resistance.


Poly-para-phenylene terephthalamide is a polymer made up of aromatic rings (benzene) separated by amide groups. It belongs to the group of aramid fibers. Poly-para-phenylene terephthalamide has been discovered and marketed under the trade name Kevlar.

Poly-para-phenylene terephthalamide was discovered in 1965 by Stéphanie Kwolek and Herbert Blades, researchers at DuPont. Today the patent has expired, hence the appearance of competing products such as Twaron produced by Teijin.

Poly-para-phenylene terephthalamide is a synthetic fiber which has exceptional qualities of tensile strength and elongation. Only the spider web (three times more resistant), and carbon nanotubes (100 times more resistant and 6 times lighter) surpass it.

There are several grades of Kevlar: Kevlar, Kevlar 52, and Kevlar 49. Basic Kevlar is mostly used for reinforcing tires and other rubbers. Kevlar 29 is mainly used in industrial applications such as cables, or to replace asbestos, brake lining, for reinforcing the hull of a boat, or for the manufacture of bulletproof vests. Kevlar 49 is the grade with the highest tensile strength of all aramids and is used in certain plastics, for shell reinforcement, and for the manufacture of certain aircraft parts and bicycle frames.


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Poly-para-phenylene terephthalamide has various valuable properties, such as resistance to heat, elongation or shear. It is therefore used in many fields where these characteristics are sought after:

See Composites
See Laminates (metal/fibreglass/glass)
See Hard or refractory ceramic
See Composites by the RTM process
See RTM composite machining
Cutting and machining of Carbon Kevelar by waterjet cutting