What is Kevlar?
poly(p-phenyleneterephtalamide) Kevlar is a man-made organic fiber with many unique properties such as high tensile strength. Kevlar is employed in making bulletproof vests, belts for radial tires, cables, reinforced composites for aircraft panels and boat hulls, flame-resistant garments (in blends with another similar fiber Nomex), sports equipment such as golf club shafts and lightweight bicycles, and in asbestos replacements in clutches and brakes (3). Kevlar is a carbon based aramid, (a term invented as an abbreviation for aromatic polyamide, or aromatic nylon fiber). An aramid is a manufactured fiber related in chemical composition to the nylon family, yet its properties vary greatly from nylon. Aramids are prepared by condensation of a diamine and terephthalic acid, a carboxylic acid that contains a hexagonal benzene ring in its molecules. “The close packing of the aromatic polymer chains produced a strong, tough, stiff, high-melting fiber, good for radial tires, heat- or flame-r
Kevlar is an extremely strong material that derives its strength from its weave. It is woven like tiny spider webs. Stephanie Kwolek and Herbert Blades created this special material in 1965 for the Dupont Company. Since then it has been used in a number of ways. Kevlar is a special way of weaving a liquid into a solid. This is called an aramid weave. Aramid fibers tend to be difficult to corrode, resistant to heat, and have no melting point. Aramid fibers like Kevlar may be slightly corrosive if exposed to chlorine. Because Kevlar is light, it is the premium choice for bulletproof vests. A variant of Kevlar called nomex is fireproof and may be used by fireman or people responding to disaster situations. Kevlar has different types of weaves, and the weave that makes a fabric-like material for vests is called Kevlar 29. Kevlar 29 may also be used in brake pads, or to replace asbestos. It is also is a major part of the composition of body armor. Kevlar has two other types, Kevlar, and Kev
Kevlar is a synthetic material known as a polymer (aren’t you glad you asked?). A Kevlar fiber is an array of molecules that are paralllel to each other like spaghetti in a package. These chains are held together by electrostatic forces between molecules known as hydrogen bonds. The fibers are drawn at a temperature over 750 degrees Fahrenheit. (If you must know, the actual chemical name of Kevlar is poly-para-phenylene terephthalamide, but we didn’t tell you.) All this chemistry stuff leads to a material 5 times stronger per weight than steel and about half the density of fiberglass. It was a lady named Stephanie Louse Kwolek who pioneered the research leading to the marketing of Kevlar by Dupont in the mid-70’s. General features of Kevlar include: High Tensile Strength at Low Weight Low Elongation to Break High Modulus (Structural Rigidity) Low Electrical Conductivity High Chemical Resistance Low Thermal Shrinkage High Toughness (Work-To-Break) Excellent Dimensional Stability High Cu
Dry Friction Product Specifications* – Clutchtex P-7 Description: KEVLAR fiber composite material is a non-molded and non-asbestos, textile-reinforced polymer for industrial clutch and brake applications. Offers uniquely high wear resistance and low opposing surface wear. Available bonded to carrier plates in thicknesses as required (often laminated over a cork-nitrile substrate), or as a flexible laminate up to 10 mm (3/8″) thick. Physical and Mechanical Properties Composition: 100% long KEVLAR fibers and proprietary polymer binders. Includes no metal, no abrasives, no cotton, and no fillers. Density: 0.91 g/cu. cm (0.033 lb./cu.in.) Thermal conductivity: Extremely low Shock resistance: Excellent (does not crack, or break) Lubricant contaminant resistance: Does not degrade Abrasiveness: Non-abrasive to opposing iron, steel, and copper surfaces Operating Conditions Static pressure: Up to 6900 kPa (1,000 p.s.i.), (or as limited by substrate) Dynamic pressure: 140 – 3100 kPa (20-450 p.s.
