Fluoropolymers polytetrafluoroethylene PTFE

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. 

While on the subject of fluoroorganic compounds, one cannot overstate the importance of fluoropolymers in modem industry and science. There is hardly anyone around today who has never heard of polytetrafluoroethylene (PTFE) [CF2—CF2] . Housewives who know nothing about fluorine use PTFE-coated frying pans or pots, and know that PTFE makes washing up easier, because virtually nothing sticks to a PTFE-coated utensil. 

The fluoropolymer family consists of polymers produced from alkenes in which one or more hydrogens have been replaced by fluorine. The most important members of this family are polytetrafluoroethylene (PTFE) (XLVII), polychlorotrifluoroethylene (PCTFE) (XLVIII), poly(vinyl fluoride) (PVF) (XLIX), poly(vinylidene fluoride) (PVDF) (L) copolymers of... 

Teflon is the brand name for the chemical compound called polytetrafluoroethylene (PTFE). One molecule of PTFE contains two carbon atoms bonded to four fluorine atoms. Many molecules of PTEE can form polymer chains known as fluoropolymers. 

Polymer fume fever An illness characterized by temporary flu-like symptoms caused by inhaling the products released during the decomposition of fluoropolymers, mainly polytetrafluoroethylene (PTFE). Tobacco smoke enhances the severity of this condition. 

Tetrafluoroethylene (TFE) A perfluorinated monomer used as a feedstock for the production of polytetrafluoroethylene (PTFE) and as a comonomer for the production of a variety of other fluoropolymers. 

Fluoropolymers are technical polymers with very special properties and apphcations. Their properties are derived mainly from the strong carbon-fluorine bond energy of 507 kJ moU compared with typical energies of 415 kJ moU for C-H or 348 kJ moU for C-C bonds. The most important fluoropolymer is polytetrafluoroethylene (PTFE). In... 

PVDF is the third most widely used fluoropolymer, after polytetrafluoroethylene (PTFE) and fluorinated ethylene-propylene (FEP). The worldwide consumption of PVDF was approximately 15,000 metric tons in 2001 and is growing at an annual rate of 6-8%. PVDF applications have been expanded over the past 40 years because of its unique physical properties, and have over 30 years of proven and field performance data on thermal, chemical, radiation, and weathering applications. PVDF applications include, but are not limited to, chemical processing of pipes and components, semiconductor, architectural finishes and coatings, electrical plenum, cable jacketing. 

Polytetrafluoroethylene (PTFE Teflon) was discovered accidently by PlunkettCZ nd commercialized by DuPont in the 1940 s. This polymer has a solubility parameter of about 6H and a high melting point of 327°C and is not readily moldable. Poly-chlorotrifluoroethylene (CTFE, Kel-F), the copolymer of tetrafluoroethylene and hexafluoropropylene (FEP), polyvinylidene fluoride (PVDF, Kynar), the copolymer of tetrafluoroethylene and ethylene (ETFE), the copolymer of vinylidene fluoride and hexafluoroisobutylene (CM-1), perfluoroalkoxyethylene (PFA) and polyvinyl fluoride (PVF, Tedlar) are all more readily processed than PTFE. However, the lubricity and chemical resistance of these fluoropolymers is less than that of PTFE. 

Fluoropolymers are polytetrafluoroethylene (PTFE) and ethylene tetrafluoroethylene (ETFE). They can assist as redundant insulation and are primarily used as a coating to defend conductor wires from corrosion. The advantages of those materials are their inert and biocompatible behavior and high tensile strength. Otherwise, their stiffness, creep. 

Polytetrafluoroethylene (PTFE) polymer is an example of a linear fluoropolymer. Its structure in simplistic form is shown in Figure 9.2. The CAS number for PTFE is 9002-84-0. 

A wide variety of fluoropolymers are available, including polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), fluorinated ethylene propylene (FEP), ethylene chlorotiifluoroethylene (ECTFE), ethylene tetrafluoroethylene (ETFE), polyvinylin-dene fluoride (PVDF), and polyvinyl fluoride (PVF). 

PFCA is another important PFC group. The main use of perfluorooctanoate (PFOA) is as a process aid in the manufacture of various fluoropolymers, such as polytetrafluoroethylene (PTFE). These polymers are among other things, used to coat cookware intended for stovetop cooking and baking. 

Lubricants such as fluoropolymers [e.g., polytetrafluoroethylene (PTFE)], molybdenum disulfide, or graphite have also been blended with PEI polymers to achieve enhanced tribological properties, particularly improved lubricity, and reduced friction and wear. 

D 3297 Practice for Molding and Machining Tolerances for PTFE Resin Parts D 3308 Specification for PTFE Resin Skived Tape D 3369 Specification for TFE Fluorocarbon Resin Cast Film D 4441 Specification for Dispersions of Polytetrafluoroethylene D 4591 Method for Determining Temperatures and Heats of Transitions of Fluoropolymers by Differential Scanning Calorimetry E 911 Specification for Glass Stopcocks with Polytetrafluoroethylene (PTFE) Plugs... 

In this chapter, we describe a variety of methodologies for applying multidimensional NMR (mostly 2D- and some 3D-NMR) for the characterization of fluoropolymers. Space limitations preclude a comprehensive survey of the literature. Instead, a few of the primary methodologies are described involving combined use of multidimensional NMR methods for structure elucidation. Then, a selected group of papers were reviewed to illustrate the applications of these methodologies to the characterization of some of the most common classes of fluoropolymers, including homo- and copolymers with poly(vinylidene fluoride), fluorinated polyethers, fluori-nated ionomers, poly(vinyl fluoride) and its copolymers, and polytetrafluoroethylene (PTFE) and its copolymers. 

Fluoropolymers — polyethylene-tetrafluoro-ethylene (ETFE), polytetrafluoroethylene (PTFE), and chlorotrifluoroethylene (CTFE)— possess outstanding chemical and radiation... 

Inappropriate matching of the physicochemical properties of the binder with the carbon material may influence dramatically upon the electroactive area via blocking of the SPE film or simply decreasing the electroactive surface area. Another point to be considered is the cost of the binders. For example, fluoropolymers such Nafion, polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE) are commonly used as binder in electrode preparation in the field of lithium-ion batteries or fuel cells. However, the curing process has to be soft in most cases... 

Fluoropolymers have excellent heat, chemical and corrosion resistance. The most common is polytetrafluoroethylene (PTFE), often known by the Dupont trademark, Teflon . Other tradenames include Dyneon (3M) and Fluon (Asahi Glass). The invention of PTFE is often used as an example of serendipity, but it was actually a combination of serendipity, curiosity, and hard work. Roy Plunkett was working on experimental refrigerants when a cylinder that had been filled withtetrafluoroethylene (TFE) gas did not deliver gas when the valve was opened. Often, when something does not occur as planned, people discard the results and move on, but Plunkett was curious. When the cylinder was cut open, a white lubricious solid was discovered. Further investigation revealed the solid to be a polymer of tetrafluoroethylene [28]. 

Fluoropolymers have evolved over six decades. New monomers have allowed the synthesis of new polymers with new methods of processing. Most newer perfluoropolymers have the same basic properties as polytetrafluoroethylene (PTFE) but they offer new methods of processing. These new techniques have greatly increased the range of parts that can be fabricated from fluoropolymers at reduced cost. Today, fluoropolymers are processed by methods almost identical to those used a half century ago as well as by state of the art molding technologies. 

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