what exactly is kevlar, aparrently it's 5 times stronger than steel?

Answer 1

Kevlar is DuPont Company's brand name for a particular light but very strong aramid fibre. It was created in DuPont's labs in 1965 by Stephanie Kwolek and Herbert Blades, and was first used commercially in the early 1970s. It can be spun into ropes or sheets of fabric that can either be used as-is, or used in the construction of composite components. It is now used in a wide range of applications - from bicycles to body armor - due to its high strength-to-weight ratio, five times greater than that of steel.
When Kevlar is spun in the same way that a spider spins a web, the resulting fibre has tremendous strength, and is heat- and cut-resistant. The fibres do not rust or corrode, and their strength is unaffected by water. When woven together, they form a good material for mooring lines and other underwater objects. However, unless specially waterproofed, Kevlar's ability to stop bullets and other projectiles is degraded when wet.

There are three common grades of Kevlar: Kevlar, Kevlar 29, and Kevlar 49. Kevlar is typically used as reinforcements in tires and other rubber mechanical goods. Kevlar 29 is used in industrial applications such as cables, asbestos replacement, brake lines, body armour (knife or bullet resistant). Kevlar 49 is considered to have the greatest tensile strength of all the aramids, and is used in applications such as plastic reinforcement for boat hulls, aeroplanes, and bikes.

Kevlar's main weaknesses are that it decomposes under alkaline conditions or when exposed to chlorine or UV light. While it can have a great tensile strength, sometimes in excess of 4.0 GPa, like all fibers it tends to buckle in compression.

Kevlar is synthesized from the monomers 1,4-phenyl-diamine (para-phenylenediamine) and terephthaloyl chloride. The result is a liquid-crystalline behaviour and mechanical drawing causing the polymer chains to orientate in the direction of the fibre.

Kevlar has a high price, in part, due to the difficulties arising from the use of concentrated sulfuric acid in its manufacture. These harsh conditions are needed to keep the highly insoluble polymer in solution during synthesis and spinning.

Fibers of Kevlar consist of long molecular chains produced from poly-paraphenylene terephthalamide. There are many inter-chain bonds making the material extremely strong. Kevlar derives a portion of its improved strength from inter-molecular hydrogen bonds formed between the carbonyl groups and protons on neighboring polymer chains and the partial pi stacking of the benzenoid aromatic stacking interactions between stacked strands. These interactions have a greater influence on Kevlar than van der Waals interactions and chain length that typically influence the properties of other synthetic polymers and fibers like Dyneema. The presence of salts and certain other impurities, especially calcium, could interfere with the strand interactions and caution is used to avoid inclusion in its production. Kevlar's structure consists of relatively rigid molecules, which tend to form mostly planar sheet-like structures that have similarities to silk protein.

Answer 2

Kevlar is an aramid fiber developed by DuPont. It is woven into sheets, much like fiberglass cloth. Besides its use in bulletproof vests, Kevlar is sometimes used as the base material for printed wiring boards (PWBs), which are the boards providing the mounting and interconnection for the microcircuits in your PC as well as virtually every other electronic device. It may be identified by a brown color, whereas fiberglass PWBs are usually green.

Answer 3

It's a synthetic fiber that is very strong in SOME uses. commonly talked about when discussing "bullet proof vests". The fibers can resist breaking froma bullet. But you can't build a bridge out of Kevlar.
do a google or yahho search on Kevlar.
Good luck, Trevor.

Answer 4

Kevlar is the brand name of Dupont's very strong yet lightweight aramid fiber that is woven to make bulletproof vests as well as many other things.

Answer 5

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Answer 6

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Answer 7

Kevlar is exactly a trade name still owned by Du Pont for their aromatic Polyamide fibres.

Answer 8

Its an aromatic polyamide(a plastic) invented by Du Pont. The benzene ring (6 or 8 carbons in a circle) makes it very strong in one direction.

Answer 9

It's a material that is bulletproof and used by the police force and SWAT teams as a vest that protects the vital organs (heart, live, lungs, etc.)

Answer 10

It is a light weight cut resistant material. When in an appropriate amount of multiple layers can be used as a bullet proof protective armor (bullet proof vest).