Polytetrafluoroethylene FIFE

Fluorinated polymers, especially polytetrafluoroethylene (FIFE) and copolymers of tetrafluoroethylene (TFE) with hexafluoropropylene (HEP) and perfluorinated alkyl vinyl ethers (PFAVE) as well as other fluorine-containing polymers are well known as materials with unique inertness. However, fluorinated polymers with functional groups are of much more interest because they combine the merits of pefluorinated materials and functional polymers (the terms functional monomer/ polymer will be used in this chapter to mean monomer/polymer containing functional groups, respectively). Such materials can be used, e.g., as ion exchange membranes for chlorine-alkali and fuel cells, gas separation membranes, solid polymeric superacid catalysts and polymeric reagents for various organic reactions, and chemical sensors. Of course, fully fluorinated materials are exceptionally inert, but at the same time are the most complicated to produce. 

Crushing. Byrskii et al. (8) used a vibration ball mill to study the volatile compounds released from a series of crushed polymers. They chose this method to intensify the mechanical degradation process and thus to increase the rate of volatile evolution from the polymer. For polymers such as polyethylene (PE) and polytetrafluoroethylene (FIFE), compound evolution rates are low from other methods of mechanical deformation hence, it is difficult to obtain mass spectra. Byl skii et al. used this technique to successfully obtain mass spectra of compounds from PE and PTFE and demonstrated the feasibility of the vibration ball mill for performing kinetic studies of mechanical degradation as a function of the amplitude of the vibration and duration of the grinding. 

NHjtorNj + H ) Polypropylene (PP) Poly(Vinyl-chloride) (PVQ Polytetrafluoroethylene (FIFE) Polycarbonate (PC) Polyurethane (PU) Poly (methyl methacrylate) (PMMA) Heparin bonding for improved blood compatibility... 

A general scheme for the production of such functionalized polymers can be presented as follows The polymer support (polyethylene (PE), polypropylene (PP), polystyrene (PS), polytetrafluoroethylene (FIFE), ethylene-propylene copolymers (CEP), etc.) are subjected to mechanical, chemical, radiation-chemical ( -irradiation or with accelerated electrons) or high-frequency (HF), UV-irradiation treatment with a subsequent grafting of the appropriate monomers ... 

Figure 2.36 shows that addition of this plasticizer to tetrafluoroethylene/peifluoro(alkyl vinyl) ether, TFE/PPVE, increases its melt flow index.Figure 2.37 shows that the addition of plasticizer causes almost hnear increase in the tensile strength. "" This is unusual and it is most likely caused by the modification of crystalhne structure and mode of failure. Addition of this plasticizer to polytetrafluoroethylene, FIFE, improves its mechanical performance and processing abilities by sintering. ""... 

Polytetrafluoroethylene (FIFE). A high-temperature fluoropIastic with extremely good chemical resistance. 

For many years a legend has been perpetrated that polytetrafluoroethylene (FIFE) and its perfluorinated copolymers are insoluble. Yet, a patent was issued as early as 1950 covering the plasticization of PTFE. In the mid-1980s. Smith and Gardner reviewed the subject of PTFE-perfluorocarbon solution thermodynamics and... 

For practical purposes there are eight types of fluoropolymers, as summarized in Table F.7. Included in this family of plastics are polytetrafluoroethylene (FIFE), polychlorotrifluoroethylene (PCTFE), polyvinyl fluoride (PVF), fluorinated ethylene propylene (FEP), and others. Depending on which of the fluoropolymers are used, they can be produced as molding materials, extrusion materials, dispersion, film, or tape. Processing of fluoropolymers requires adequate ventilation for the toxic gases (HF) that may be produced. 

The most prominent use of MQ resins is as the tackifying agent for silicone pressure-sensitive adhesives (PSA) (523-525). The other main component of silicone PSA is a silicone gum. This mixture of MQ resin and silicone gum is applied to a tape backing such as polytetrafluoroethylene (FIFE) or poly(ethylene... 

Fluoropolymers possess excellent thermal stability and are nearly completely inert to chemical attack. Polytetrafluoroethylene (FIFE), discovered in 1938 by Roy Plunkett at I.E. du Pont de Nemours and Company, is the world s most used fluoropolymer. PIPE accounts for 59% of the fluoropolymers market and its production amounted to some 79,000 metric tons in 2004 [1], Applications exploiting the extraordinary properties of the material are wide-ranging and include gaskets, thread-seal tape, pipe liners, bearings, gears, slide plates, filter bags, medical prosthetics, and architectural material [2,3]. 

Mainly the improvement of the sliding properties of moving mold elements should be mentioned as areas of application of the above illustrated surface and coating technologies (Figure 5.35). PVD coatings based on carbon, tungsten, or molybdenum, chemical nickel-polytetrafluoroethylene (FIFE) layers, or so-called beam treatments... 

Polytetrafluoroethylene (FIFE), diamond, and SiC particles can also be incorporated into a nickel electroless plating for improved properties. Diamond and silicon carbide are used to enhance abrasion resistance the surface hardness of these composites is reported to be 1300 HVN. Polytetrafluoroethylene is added to the electroless nickel bath to provide a composite coating with enhanced lubrication. Almost any particulate material can be deposited in a metallic matrix, provided the particles are sufficiently small to remain suspended in the bath and that the particles do not react chemically with the bath during electrodeposition. 

Anodizing for protection of aluminum alloys, preferably sealed with a self-lubricating polymer such as polytetrafluoroethylene (FIFE)... 

In a solid polymer electrolyte, such as used in the PEFC, ion mobility is a result of an electrolyte solution integrated into an inert polymer matrix. Early electrolyte membranes developed for the United States space program consisted of treated hydrocarbons, which resulted in poor longevity due to the relatively weaker hydrocarbon bonds [3]. Most modem solid electrolytes are perflourinated ionomers with a fixed side chain of sulphonic acid bonded covalently to the inert, but chemically stable, polymer polytetrafluoroethylene (FIFE) stracture. As a result, the membrane consists of two very different sub-stractures 1) a hydrophilic and ionically conductive phase related to the bonded sulphonic acid groups... 

All samples were filtered with a 0.45pm polytetrafluoroethylene (FIFE) membrane filter before injection into the column. 

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