Kevlar is a registered trade mark of DuPont™ for a synthetic para-aramid fiber related to other aramids, such as Nomex and Technora. Universal and strong, the Kevlar® fiber is more than a series of filaments. It is strong but relatively lightweight. The specific tensile strength (tension or pull) of Kevlar 29 and Kevlar 49 is over eight times greater than the one of steel wire. Unlike most plastic, it does not melt: it is relatively good in enduring temperatures and decomposes at approximately 450° C (850° F). Like plastic, its continuous exposure to UV light (e.g. sunlight) causes discolouration and some decomposition of the Kevlar fibers. Kevlar is resistant to numerous chemicals though continuous exposure to strong acids or bases degrades its quality in time.
Kevlar® fibers are used in the production of clothing, accessories and equipment, making them safer and more durable. With five times greater strength than steel on a uniform weight basis, it is the fabric of protective clothing and accessories.
It should be noted that Kevlar also has its disadvantages. In particular, although there it boasts very high tensile strength, it is of very poor compression strength (crushing or squeezing resistance). That is why Kevlar cannot substitute steel as the main building material in the construction of buildings, bridges and other structures where compression forces are common.