INVENTION OF KEVLAR

Invention of Kevlar

Invention of Kevlar

The Kevlar or polyparaphenylene terephthalamide is a polyamide first synthesized in 1965 by chemist Stephanie Kwolek, who worked for DuPont. Obtaining Kevlar fibers was complicated, highlighting the contribution of Herbert Blades, who solved the problem of what solvent used for processing. Finally, DuPont began marketing in 1972. It is very tough and very difficult machining. There are essentially two types of Kevlar fibers: Kevlar 29 and Kevlar 49. Kevlar fiber 29 is obtained as its manufacture. Is typically used as reinforcement strips for their good mechanical properties, or tissues. Typical applications are the manufacture of cables, resistant clothing (protective) or body armor .

Kevlar 49 is used when the fibers are to be imbibed into a resin to form a composite material. Kevlar fibers 49 are surface treated to promote bonding with the resin. The Kevlar 49 is used as equipment for sports ends to speakers and industry aviation, aircraft and communications satellites and motorcycle helmets (Afuah, 2003). This polyamide contains aromatic groups (this is an aramide) and there are interactions between these groups as well as interactions by hydrogen bonds between amide groups. For these interactions, the fibers obtained have a high performance to be perfectly oriented macromolecules in the same direction and very well packaged.

The synthesis of this polymer is carried out through a polymerization step from p-phenylenediamine and terephthalic acid dichloride. The aramids are a family of nylons, including Nomex and Kevlar. Kevlar is used to make bulletproof vests and puncture resistant tires. Blends of Nomex and Kevlar are used to make flame-resistant clothing, which is why they employ firefighters (Carnall, 2002; Christensen & Raynor, 2002). Kevlar is a polyamide, in which all the amide groups are separated by para-phenylene groups. Ie, the amide groups are attached to the phenyl ring in positions opposite each other, at carbons 1 and 4. Kevlar is a highly crystalline polymer. It took time to find a useful application for Kevlar, because it was not soluble in any solvent. Therefore, processing in solution was discarded. No melting below 500 ° C. The poly (p-phenylene terephthalamide; PPD-T) is a polymer thermoplastic aromatic rings consisting of groups separated by amide. It belongs to the family of fibers of aramids. The poly-para-phenylene terephthalamide was discovered and marketed under the trade name Kevlar. This material was discovered in 1965 by Stephanie Kwolek and Herbert Blades, society researchers Du Pont de Nemours. Society chooses to call this polymer Kevlar. It was marketed in 1972. Since the patent has expired and competing products have emerged as of Twaron Teijin (Christiansen, 2000; Davila, Epstein & Shelton, 2006).

Before the 1970s, most body armor were steel, making them heavy and bulky. The appearance of Kevlar company Du Pont has allowed the development of a new type of flexible body armor and much lighter. However, this material was originally intended for tire reinforcement, and its actual capabilities were unknown ballistic (Ettlie, 2006; Fischer, 2006; Hippel, 2006; Leonard-Barton, 1998). The great potential of this new polymer pushed the ...