Kevlar, the trademark name by DuPont (Sci. & Inv. Enc., 1352), was invented in 1965 by Stephanie Kwolek. A Kevlar woven millibar (shown on project board) has 18,000 pounds of strength, which is the strongest material in the world! Kevlar can be five through fifteen times stronger than steel, depending on the form of the product. Kevlar is also in body armor, meaning it is saving lives. This is definitely a very important composite (New Necessities).
There are three types of Kevlar: rubber industry use, Kevlar 29, and Kevlar 49 (Sci. & Inv. Enc., 1352). The rubber industry uses Kevlar for reinforcement. When Kevlar was first produced in 1972, it was used for the rubber products. One example would be the radial tire belts. Instead of using steel cord, Kevlar cord replaced it. The results were very satisfying. A reduction in weight meant that the fuel economy was better, and the tires were also much quieter. Kevlar was the answer to the challenges of designing rubber hoses and belts for agricultural, industrial, and automotive equipment (DuPont).
Kevlar 49 is used in mainly body armor and making architectural structures stronger (Sci. & Inv. Enc., 1354). Kevlar 49 is mainly made out of coal, corn, air, and water; making it rot and rust resistant. Compared to steel and concrete, Kevlar 49's psi (pressure per square inch) is 525,000, steel's is 36,000, and concrete's is 3,000 (New Necessities). The blast suppression, or body armor, is strong enough to endure machine gun fire (up to .3 caliber), land mines, terroristic weapons, and a chainsaw (New Necessities). It does not melt, can stand temperatures up to 7,000 degrees Fahrenheit, absorbing vibration and energy, and will not stretch. Bullriders, military personnel in war, peace officers, racecar drivers, and many other people use this excellent invention (DuPont). DuPont makes flameproof suits out of Kevlar 49 for fire fighters and high-speed drivers (Consumer's Research Mag.).
Kevlar 29 is not as strong as Kevlar 49, but still has many uses. It is the oldest version of Kevlar, excluding the rubber industry. Kevlar 29 is used basically for the same things of Kevlar 49. Kevlar 49 has higher tenacity, stretching property, tensile strength, and decomposition temperature (DuPont).
Kevlar is resistant against many chemical agents such as acids, bases, salt solutions, organic solvents, and other chemicals. This high-strength synthetic fiber is put in the aramid fiber group. The substances used for fiber forming are long strands, and produced by p-phenylenterephthalamine and terephtyl chloride reaction. The polymer is then put through a process of spinning (Sci. & Inv. Enc., 1352). So as you can see Kevlar is a very complicated material.
There are many applications for Kevlar. One of the most known uses is armored protection. Just a few layers of Kevlar can stop a 9mm bullet. The military has found many uses for Kevlar and is bound to find more. About 75 percent of all fiber-optic cables have an outer covering of Kevlar to increase strength and provide insulation since it is non-conductive. One type of rope, called Parafil, has a Kevlar core and another material on the outside, capable of holding 2.972 million pounds with a stretch elongation of 2.5 percent. This is one of the strongest synthetic cables over made. Kevlar, being flame-proof, is used by people with jobs needing this protection (New Neccessities).
Kevlar is a very important invention of this century. It has many uses and is resistant to chemicals, corrosion, rust, aging, and much more. Kevlar can hold up to 1,486 tons and stand the temperatures of the sun (DuPont). It has saved many lives and will keep doing so. Thank you for taking time to read my report about Kevlar.
1) "Kevlar" The New Illustrated Science and Invention Encyclopedia. . 10 ed. 1987,1989
2) DuPont "Kevlar." Brochure, 1999
3) New Necessities "Culver." Brochure, 1999
4) "The Search for a Fireproof Plastic." Consumers' Research Magazine Mar. 1999