Polytetrafluoroethylene production

DYNEON Hostaflon Polytetrafluoroethylene, Product Comparison Guide (Feb. 1998)... 

Substances other than enzymes can be immobilized. Examples include the fixing of heparin on polytetrafluoroethylene with the aid of PEI (424), the controUed release of pesticides which are bound to PEI (425), and the inhibition of herbicide suspensions by addition of PEI (426). The uptake of anionic dyes by fabric or paper is improved if the paper is first catonized with PEI (427). In addition, PEI is able to absorb odorizing substances such as fatty acids and aldehydes. Because of its high molecular weight, PEI can be used in cosmetics and body care products, as weU as in industrial elimination of odors, such as the improvement of ambient air quaHty in sewage treatment plants (428). 

Chloroform was used chiefly as an anesthetic and in pharmaceutical preparations immediately prior to World War II. However, these uses have been banned. Annual output in both the United States and the United Kingdom was between 900 and 1350 metric tons. During the war, chloroform production in the United States tripled, largely to meet the requirement for penicillin manufacture. Demand for chloroform continued to increase in the postwar period as its technical appHcations were extended. Consumption continues to increase at a comparatively rapid rate. Chloroform is now used primarily in the manufacture of HCFC-22, monochlorodifluoromethane, a refrigerant, and as a raw material for polytetrafluoroethylene plastics. 

About 90% of the chloroform produced goes into the production of HCFC-22 (chlorodifluoromethane [75-45-6]). Of this 90% about 70% is used as a refrigerant and about 30% is used as a starting material in the production of fluoropolymers, such as polytetrafluoroethylene (PTFE). Of the remaining 10% of the chloroform production about 8% is exported and 2% is used in other ways. 

Gaskets uti1i2ed in ethyleneamine service generally are made of Grafod flexible graphite or polytetrafluoroethylene (TEE). There is no single elastomer that is acceptable for the entire product line, although TEE may be considered as an alternative to elastomers across the product line. However, because TEE is not a tme elastomer, it may not always prove suitable as a replacement. 

New materials also emerged. Nylon, developed brilliantly by W. H. Carothers and his team of research workers for Du Pont as a fibre in the mid-1930s, was first used as a moulding material in 1941. Also in 1941 a patent taken out by Kinetic Chemical Inc. described how R. J. Plunkett had first discovered polytetrafluoroethylene. This happened when, on one occasion, it was found that on opening the valve of a supposedly full cylinder of the gas tetrafluoroethylene no gas issued out. On subsequently cutting up the cylinder it was found that a white solid, polytetrafluoroethylene (PTFE), had been deposited on the inner walls of the cylinder. The process was developed by Du Pont and, in 1943, a pilot plant to produce their product Teflon came on stream. 

Polytetrafluoroethylene decomposition products thermal decomposition of the fluorocarbon chain in air leads to the formation of oxidized products containing carbon, fluorine and oxygen. Because these products decompose in part by hydrolysis in alkaline solution, they can be quantitatively determined in air as fluoride to provide an index of exposure. No TLV is recommended pending determination of the toxicity of the products, but air concentration should be minimal. (Trade names Algoflon, Fluon, Teflon, Tetran.)... 

Plaster of Paris Platinum, soluble salts (as Pt) Polychlorobiphenyls, see Chlorodiphenyls Polytetrafluoroethylene decomposition products Propane... 

Polytetrafluoroethylene and fluorinated ethylene-propylene are the only resins composed wholly of fluorine and carbon. The polymer consists of fluorine atoms surrounding the carbon chain as a sheath, giving a chemically inert and relatively dense product from the strong carbon-fluorine bonds. Polytetrafluoroethylene must be molded at high pressure. Fluorinated ethylene-propylene c.m be injection molded and extruded as thin fdm. Both plastics have exceptional heat resistance... 

Conveyor systems are applied in a number of areas in the rubber industry. The types used can range from simple canvas belt conveyors used for haul-off from conventional extruders, to systems used for transport and cooling of profile products, both in and emerging from continuous vulcanisation units. The latter types have to be resistant to the temperatures used in such systems and are variously constructed from glass fibre-reinforced polytetrafluoroethylene or a silicone rubber covered belt. 

Compositions whose products of combustion produce energy in the infrared wave band are generally composed of magnesium powder, polytetrafluoroethylene (PTFE) and a binder. For efficient tactical utilization of the energy developed by the combustion process the composition is normally formed into pellets either by press consolidation or by press extrusion. The process being used at Longhorn at the time the electrostatic problem was encountered was press consolidation. The composition was being consolidated into a pellet... 

The product attacks glass slowly on standing, and a moderate increase in pressure takes place. The product can be stored for a period of several days in a polyethylene bottle, but it is best to prepare the material shortly before use. If prolonged storage is required, a stainless steel cylinder or a bottle fabricated from Teflon polytetrafluoroethylene resin is suggested. 

The first report of the cyclodimerization of fluorinated olefins was provided by Lewis and Naylor,3 working at E.I. DuPont de Nemours Co., in 1947. While studying the pyrolysis of polytetrafluoroethylene (PTFE), the compound octa-fluorocyclobutane was isolated from the pyrolysis off-gas stream. The researchers identified the product and speculated that it was formed by the cyclodimerization... 

A liquid perfluorocarbon was being used as solvent in an oxidation by oxygen under pressure more energy was released than expected [1], It is cautioned that fluorocarbons are not inert to oxidation, presumably to carbonyl fluoride. An explosion has been experienced with perfluorotoluene in like circumstances [2], A correspondent reports that perfluorotoluene is flammable in air, more saturated perfluorocarbons in pure oxygen [3], Another detailed the combustion performance of polytetrafluoroethylene 148 kcal/mole ignition temperature not below 465°C at 7000 psi of oxygen [4], the product is mostly carbonyl fluoride. Other oxidants may also present a risk in extreme circumstances. 

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... 

ISO 8829 1990 Aerospace - Polytetrafluoroethylene (PTFE) hose assemblies - Test methods ISO 8913 1994 Aerospace - Lightweight polytetrafluoroethylene (PTFE) hose assemblies, classification 204 degrees C/21000 kPa - Procurement specification ISO 9528 1994 Aerospace - Standard-weight polytetrafluoroethylene (PTFE) hose assemblies, classification 204 degrees C/21000 kPa - Procurement specification ISO 9938 1994 Aerospace - Polytetrafluoroethylene (PTFE) hose assemblies, classification 204 degrees C/28 000 kPa- Procurement specification ISO 10502 1992 Aerospace - Hose assemblies in polytetrafluoroethylene (PTFE) for use up to 232 degrees C and 10 500 kPa - Procurement specification ISO 13000-1 1997 Plastics - Polytetrafluoroethylene (PTFE) semi-finished products -Part 1 Requirements and designation... 

ISO 13000-2 1997 Plastics - Polytetrafluoroethylene (PTFE) semi-finished products -Part 2 Preparation of test specimens and determination of properties... 

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