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Kevlar (para-aramid) [2] is a strong, heat-resistant synthetic fiber, related to other aramids such as Nomex and Technora. Developed by Stephanie Kwolek at DuPont in 1965, [ 3 ] [ 2 ] [ 4 ] the high-strength material was first used commercially in the early 1970s as a replacement for steel in racing tires.
In contrast, Kevlar derives its strength from strong bonding between relatively short molecules. The weak bonding between olefin molecules allows local thermal excitations to disrupt the crystalline order of a given chain piece-by-piece, giving it much poorer heat resistance than other high-strength fibers.
Aramid fibers, short for aromatic polyamide, are a class of heat-resistant and strong synthetic fibers. They are used in aerospace and military applications, for ballistic-rated body armor fabric and ballistic composites, in marine cordage , marine hull reinforcement, as an asbestos substitute, [ 1 ] and in various lightweight consumer items ...
Molecular structure of Kevlar Molecular structure of the LCP Vectran [5]. Liquid crystallinity in polymers may occur either by dissolving a polymer in a solvent (lyotropic liquid-crystal polymers) or by heating a polymer above its glass or melting transition point (thermotropic liquid-crystal polymers). [6]
Excellent thermal stability at temperature extremes, water repellency, chemical stability and resistance to petroleum products have made Kevlar KM2 an indispensable asset to the military personnel who use it every day." [1] "Kevlar KM2 fiber is a transversely isotropic material. Its tensile stress–strain response in the axial direction is ...
The Improved Outer Tactical Vest (IOTV) in MultiCam, as issued to United States Army soldiers. A bulletproof vest, also known as a ballistic vest or bullet-resistant vest, is a type of body armour designed to absorb impact and prevent the penetration of firearm projectiles and explosion fragments to the torso.
Kevlar Fabric Standard Unidirectional Carbon Fiber Fabric High Modulus Unidirectional Carbon Fiber Fabric E-Glass Unidirectional Fiber Glass Fabric Kevlar Unidirectional Fabric Steel S97 Young's Modulus 0° E1 GPa 70 85 25 30 135 175 40 75 207 Young's Modulus 90° E2 GPa 70 85 25 30 10 8 8 6 207 In-plane Shear Modulus G12 GPa 5 5 4 5 5 5 4 2 80
Terephthaloyl chloride (TCL, 1,4-benzenedicarbonyl chloride) is the acyl chloride of terephthalic acid.It is a white solid at room temperature. It is one of two precursors used to make Kevlar, the other being p-phenylenediamine.