Polytetrafluoroethylene Teflon

If all the hydrogen atoms in ethylene are replaced by fluorine atoms, tetrafluoro ethylene results. Tetrafluoroethylene is polymerized to form polytetrafluoro ethylene. Polytetrafluoroethylene, known as teflon, is used in the production of nonstick cooking ware. 

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Electrical Properties. AH polyolefins have low dielectric constants and can be used as insulators in particular, PMP has the lowest dielectric constant among all synthetic resins. As a result, PMP has excellent dielectric properties and alow dielectric loss factor, surpassing those of other polyolefin resins and polytetrafluoroethylene (Teflon). These properties remain nearly constant over a wide temperature range. The dielectric characteristics of poly(vinylcyclohexane) are especially attractive its dielectric loss remains constant between —180 and 160°C, which makes it a prospective high frequency dielectric material of high thermal stabiUty. 

A pyrotechnic composition contains one or more oxidizers in combination with one or more fuels. Oxidizers used in pyrotechnics, such as potassium nitrate, KNO, are soflds at room temperature and release oxygen when heated to elevated temperatures. The oxygen then combines with the fuel, and heat is generated by the resulting chemical reaction. Chemicals that release fluorine or chlorine on heating, such as polytetrafluoroethylene (Teflon)... 

Polytetrafluoroethylene (Teflon) (PTFE) is the most corrosion-resistant thermoplastic polymer. This polymer is resistant to practically every known chemical or solvent combination and has the highest useful temperature of commercially available polymers. It retains its properties up to 500°F (260°C). Because of its exceedingly high molecular weight PTFE is processed by sintering. The PTFE resin is compressed into shapes under high pressure at room temperature and then heated to 700°F (371°C) to complete the sintering process. 

Tetrafluoroethylene. Emulsion polymerisation of tetrafluoroethylene, catalysed by oxygen, yields polytetrafluoroethylene (Teflon) as a very tough horn-like material of high melting point. It possesses excellent electrical insulation properties and a remarkable inertness towards all chemical reagents, including aqua regia. 

PA PCP PCR PFA PGB PHA PID PLC PMACWA PMD POTW ppm PRH PRR psi psig PTFE PVDF PWS picric acid pentachlorophenol propellant collection reactor perfluoroalkoxy product gas burner preliminary hazards analysis proportional integral differential controller programmable logic control Program Manager for Assembled Chemical Weapons Assessment projectile mortar demilitarization (machine) publicly owned treatment works parts per million projectile rotary hydrolyzer propellant removal room pounds per square inch pounds per square inch gauge polytetrafluoroethylene (Teflon) polyvinylidene fluoride projectile washout system... 

World War II helped shape the future of polymers. Wartime demands and shortages encouraged scientists to seek substitutes and materials that even excelled those currently available. Polycarbonate (Kevlar), which could stop a speeding bullet, was developed, as was polytetrafluoroethylene (Teflon), which was super slick. New materials were developed spurred on by the needs of the military, electronics industry, food industry, etc. The creation of new materials continues at an accelerated pace brought on by the need for materials with specific properties and the growing ability to tailor-make giant molecules macromolecules—polymers. 

Polytetrafluoroethylene Teflon Polyurethane Polyvinyl alcohol Polyvinyl acetate Polyvinyl butyral Polyvinyl chloride Polyvinylidene chloride Polyvinylidene fluoride... 

The characteristics of a covalent bond formed by two atoms are due mainly to the properties of the atoms themselves and vary only a little with the identities of the other atoms present in a molecule. As a result, some characteristics of a bond can be predicted with reasonable certainty once the identities of the two bonded atoms are known. For instance, the length of the bond and its strength are approximately the same regardless of the molecule in which it is found. Thus, to understand the properties of a large molecule, such as the resistance of polytetrafluoroethylene (Teflon ) to chemical attack, we can study the character of C—F bonds in a much simpler compound, such as tetrafluoromethane, CF4, and expect the C—F bonds in the polymer to be similar. 

D. Fluorocarbon Polymers. Four different fluorocarbons account for the bulk of the laboratory applications polytetrafluoroethylene, Teflon PTFE po-ly(chlorotrifluoroethylene), KEL-F tetrafluoroethylene-hexafluoropropylene copolymer, Teflon FEP and tetrafluoroethylene-perfluorovinyl ether copolymer, PFA. These polymers are inert with most chemicals and solvents at room temperature and exceptionally inert with oxidizing agents. They also have an exceptional resistance to temperature extremes. However, they are decomposed by liquid alkali metals, solutions of these metals in liquid ammonia, and carban-ion reagents such as butyllithium. Teflon retains some of its compliance at liquid hydrogen temperature. The maximum temperature which is recommended for continuous service is 260°C for Teflon PTFE and PFA, and about 200°C for Kel-F and Teflon FEP. 

Beecroft, R. I., and C. A. Swenson Behavior of polytetrafluoroethylene (Teflon) under high pressures. J. Appl. Phys. 30, 1793—1798 (19S9). 

Various polymeric materials were tested statically with both gaseous and liquefied mixtures of fluorine and oxygen containing from 50 to 100% of the former. The materials which burned or reacted violently were phenol—formaldehyde resins (Bakelite) polyacrylonitrile—butadiene (Buna N) polyamides (Nylon) polychlor-oprene (Neoprene) polyethylene polytrifluoropropylmethylsiloxane (LS63) polyvinyl chloride—vinyl acetate (Tygan) polyvinylidene fluoride—hexafluoropro-pylene (Viton) polyurethane foam. Under dynamic conditions of flow and pressure, the more resistant materials which burned were chlorinated polyethylenes, polymethyl methacrylate (Perspex) polytetrafluoroethylene (Teflon). 

Filters can be grouped on the basis of different characteristics. For example, they can be grouped on the basis of the design capacity of the filters according to the particle concentration or loading [Svarovsky, 1981] or they can be grouped on the basis of the materials of the filters, e.g., fabric or nonfabric [Cooper and Freeman, 1982], Most filters in use are bag filters, which are fabric. The common fabric materials include cotton, polyester, wool, asbestos, glass, acrylic, polytetrafluoroethylene (Teflon), poly (m-phenylene isophthalate) (Nomex), polycaprolactam (Nylon), and polypropylene. 

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