Search results
Results from the WOW.Com Content Network
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.
The samples demonstrated similar depth, but the neat Kevlar displayed more yarn-pullout and yarn splaying. Observers found that the STF-Kevlar was able to withstand the stab test better than the neat Kevlar. Later on, in a spike impactor stab test, the STF-Kevlar demonstrated significantly better results than the neat Kevlar.
Liquid-crystal polymers are present in melted/liquid or solid form. [7] In solid form, the main example of lyotropic LCPs is the commercial aramid known as Kevlar . The chemical structure of this aramid consists of linearly substituted aromatic rings linked by amide groups.
Structure of Twaron and Kevlar.The aromatic rings appear as hexagons. The rings are attached alternately to either two NH groups or two CO groups. [2] The attachment points on each ring are diametrically opposite each other, a characteristic of the structure called para-aramid.
Eventually you can find out from his graph that the (1) at the end is not part of his formula and instead he is citing his graph. Air and thin air and high tech vacuums, microstructure Formula Values d=1 millimeter Standard Atmospheric Pressure 0.0209 0.0235 0.0260 0.1 atmosphere 0.0209 0.0235 0.0259 0.01 atmospheres 0.0205 0.0230 0.0254 0.001 ...
In 1966, Stephanie Kwolek, a chemist working for E.I. DuPont de Nemours & Co., developed Kevlar; a strong, lightweight liquid polymer that can be spun into a fiber and woven into cloth. [3] Kevlar was initially used as a replacement for steel-belting in tires, and later for use in ropes, gaskets, and automotive and aviation parts.
The conductive fiber is used for electronic textiles, EMI shielding in woven or knit sheets, or as a braid over wires, and for signal transmission or current conduction. This conductive fiber combines the advantages of Zylon (strength, resistance to high temperatures, durability, lightweight, etc.) with the electrical properties of various metals.
(For the polyatomic ideal gas, N o is the number of atoms in a molecule.) In gas, constant-pressure specific heat capacity c p,f has a larger value and the difference depends on the temperature T, volumetric thermal expansion coefficient β and the isothermal compressibility κ [c p,f – c v,f = Tβ 2 /(ρ f κ), ρ f : the fluid density