Fluoropolymers chlorotrifluoroethylene

Many vinyl monomers were reported to have been grafted onto fluoropolymers, such as (meth)acrylic acid and (meth)acrylates, acrylamide, acrylonitryl, styrene, 4-vinyl pyridine, N-vinyl pyrrolidone, and vinyl acetate. Many fluoropolymers have been used as supports, such as PTFE, copolymers of TFE with HFP, PFAVE, VDF and ethylene, PCTFE, PVDF, polyvinyl fluoride, copolymers ofVDF with HFP, vinyl fluoride and chlorotrifluoroethylene (CTFE). The source of irradiation has been primarily y-rays and electron beams. The grafting can be carried out under either direct irradiation or through the use of preliminary irradiated fluoropolymers. Ordinary radical inhibitors can be added to the reaction mixture to avoid homopolymerization of functional monomers. 

Multilayer sheets containing poly(chlorotrifluoroethylene) and COC for blister packaging applications have been described (63). In the production of the multilayered film, the fluoropolymer layer is joined with the thermoplastic polymer layer and an adhesive tie layer. 

The major commercial fluoropolymers are made by homopolymerization of tetrafluoroethylene (TFE), chlorotrifluoroethylene (CTFE),vinyhdene fluoride (VF2), and vinyl fluoride (VF), or by co-polymerization of these monomers with hexafluoropropylene (HFP), perfluoro(propyl vinyl ether) (PPVE), per-fluoro(methyl vinyl ether) (PMVE), or ethylene. The polymers are formed by free-radical polymerization in water or fluorinated solvents. 

Very little work has been reported on the effects of irradiation of PCTFE. One source claims that the resistance of PCTFE to ionizing radiation is superior to that of other fluoropolymers [42], Another work reports that poly(chlorotrifluoroethylene) degrades when exposed to ionizing radiation in a similar fashion as PTFE at ambient... 

In this entry, fluoropolymer means a polymer that consists of partially or fully fluorinated olefinic monomers, such as vinylidene fluoride (CH2=CF2) and tetrafluor-oethylene (CF2=CF2). Commercial fluoropolymers include homopolymers and copolymers. Homopolymers contain 99wt.% or more one monomer and lwt.% or less of another monomer according to the convention by American Society for Testing Materials. Copolymers contain 1 wt.% or more of one or more comonomers. The major commercial fluoropolymers are based on tetrafluoroethylene, vinylidene fluoride, and to a lesser extent chlorotrifluoroethylene. Examples of comonomers include perfluoromethyl vinyl ether (PMVE), perfluoroethyl vinyl ether (PEVE), perfluoro-propyl vinyl ether (PPVE), hexafluoropropylene (HFP), chlorotrifluoroethylene (CTFE), and perfluorobutyl ethylene (PFBE). 

Fluoropolymers discussed include polytetrafluoro-ethylene (PTFE), perfluoroalkoxy polymer (PFA), fluorinated ethylene-propylene polymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), and polyvinyl fluoride (PVF). 

Commercial fluoropolymers are based on tetrafluo-roethylene, vinylidene fluoride, and, to a lesser extent, chlorotrifluoroethylene. Examples of comonomers include perfluoromethyl vinyl ether, perfluoroethyl... 

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. Melt processable fluoropolymers such as Teflon FEP, Tefzel ETFE, poly(vinylidene fluoride) (Kynar), and ethylene-chlorotrifluoroethylene copolymer (Halar) are suitable for wire insulation in special applications because they combine good physical properties with low flammability. They are used for instrumentation cable in process-control rooms, as well as for computer and aircraft wiring and in military applications. The... 

Chlortrifluorathylen CTFE Daiflon EINECS 201-201-8 Ethene, chlorotrifluoro- Ethylene, chlorotrifluoro- Ethylene, trifluorochloro- Fluoroplast 3 Genetron 1113 HSDB 2806 Monochlorotri-fluoroethylene Trifluorchlorethylen Trifluorochloro-ethylene Trifluoromonochloroethylene Trifiuorovinyl chloride Trithene UN 1082, Used as a monomer in production of fluoropolymers, particularly Ethylene-Chlorotrifluoroethylene Copolymer (ECTFE). Gas mp -158° bp = -27.8° d = 1.54 soluble in CeHe, CHCI3. Allied Signal Fluorochem Ltd. 

Hyflon AD amorphous fluoropolymer is used in optical devices, pellicles in semiconductor manufacture, as a dielectric and as a separation membrane. Small amounts of TDD have been used as a modifier in ethylene-chlorotrifluoroethylene polymers to increase stress crack resistance. Minute amounts of TDD are used also as a modifier in polytetrafluoroethylene to improve elastic modulus, reduce creep and permeability and increase transparency. It has been suggested that the much higher reactivity of TDD and other fluorinated dioxoles relative to other modifiers gives a more uniform distribution of the modifier in the polymer chain that results in a greater increase in the desired properties at lower concentration of modifier in the polymer. 

In the addition to homo-PVF2, a large number of copolymers have also been synthesized which allow to optimize the mechanical properties of fluoropolymers. Most common are copolymers with vinyl fluoride, trifluoroethylene, tetrafluoroethylene, hexafiuoropropy-lene, hexafluoroisobutylene, chlorotrifluoroethylene, and pentafiuoro-propene [521,535, 559-562]. Copolymerization with nonfluorinated monomers is possible [563] in principle but has not yet found commercial use. Fluorocarbon monomers that can help to retain or enhance the desirable thermal, chemical, and mechanical properties of the vinylidene structure are more interesting comonomers. Copolymerization with hexafluoropropylene, pentafluoropropylene, and chlorotrifluoroethylene results in elastomeric copolymers [564]. The polymerization conditions are similar to those of homopoly(vinylidene fluoride) [564]. The copolymers have been well characterized by x-ray analysis [535], DSC measurements [565], and NMR spectroscopy [565,566]. 

In photovoltaic industry fluoropolymers are used in the envelope of the panel, mainly to protect the active elements of the panel from the aggression of the environment so as to grant 25 years lifetime. Figure 17.2 shows a sketch of a PV panel highlighting potential fluoropolymers usage. In the figure, ECTFE is ethylene-chlorotrifluoroethylene, ETFE is ethylene-tetrafluoroethylene, PVE is polyvinylfluo-ride, and PVDF is polyvinylidenefluoride. 

The following sections describe selected applications of various methodologies involving combined use of the multidimensional NMR experiments described in section 24.2. The sections are divided based on the major classes of fluoropolymers which have commercial and/or scientific significance. These include PVDFs, perflu-orinated polyethers, poly(chlorotrifluoroethylene)s, fluorinated ionomeric polymers, and PTFEs. The applications serve as examples of how multidimensional NMR experiments can be combined to solve stmcture problems in each of these fluoropolymer classes. 

Poly(chlorotrifluoroethylene) (PCTFE, Kel-F fluoropolymer) is a thermoplastic semicrystalline polymer with (-CF2CCIF-) repeating units [49], Typically, PCTFE is synthesized via a free radical polymerization using bulk, suspension, or emulsion techniques [50]. Compared with PTFE (Teflon fluoropolymer), which has similar chemical properties, there is asymmetry in the CTFE monomer unit due to the presence of the chlorine atom in CFCl groups. Consequently, the NMR features of PCTFE are more complicated due to the possible monomer- and stereo-sequence variations. Since PCTFE has various distinguished properties, including thermal, chemical, and radiation resistance, low vapor permeability, and electrical insulation [51,52], it has... 

The commercial production of polymers containing fluorine is very small compared to the output of many other synthetic polymers. Nevertheless, several fluoropolymers are used in various important specialized applications. The principal commercial fluoropolymers at the present time are the homopolymers of tetrafluoroethylene (I), chlorotrifluoroethylene (II), vinyl fluoride (III) and vinylidene fluoride (IV) and vinylidene fluoride-chlorotrifluoroethylene, vinyli-dene fluoride-hexafluoropropylene (V) and tetrafluoroethylene-hexafluoropro-pylene copolymers. These materials, together with a few other fluoropolymers of interest, form the contents of this chapter. 

Polymerization of fluorine-containing olefins was first described in 1934 in a patent to I. G. Farbenindustrie (Germany) which related to poly chlorotrifluoroethylene. However, this polymer was of limited value and it was not until 1938, when Plunkett in the United States prepared poly tetrafluoroethylene, that commercial interest quickened. This polymer has found a great number of uses and probably accounts for at least 90% of the current ouput of fluoropolymers. The first pilot plant for poly tetrafluoroethylene came into operation in 1943 and large scale production began in 1950 (E.I. du Pont de Nemours and Co.) (U.S.A.). In addition to poly tetrafluoroethylene, many other fluoropolymers have been investigated and a few have reached commercial status. In these investigations, attention has centered particularly on copolymers with rubbery characteristics. 

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

Figure 3.1 Evolution of fluoropolymer development over time. PCTFE, Polychlorotrifluoroethylene PVDF, poly-vinylidene fluoride PVF, polyvinyl fluoride FEP, fluorinated ethylene propylene copolymer ECTFE, ethylene-chlorotrifluoroethylene copolymer ETFE, ethylene-tetrafluoroethylene copolymer PFA, perfluoroalkoxy copolymer AF, amorphous fluoropolymer.

There are two distinct families of fluoropolymers perfluorinated (like PTFE) and the partially fluori-nated (like PVDF) polymers. The major types that are rotationally molded are polyvinylidene fluoride (PVDF), ethylene-tetrafluoroethylene (ETFE), ethyl-ene-chlorotrifluoroethylene (EC IFF), andperfluoro-alkoxy (PFA). 

This book is the second of two volumes about fluoropolymers. The division of the volumes is based on the processing techniques of commercial fluoropolymers. Volume One covers the homopolymers of tetrafluoroethylene (TFE) or polytetrafluoroethylene plastics, which are processed by nontraditional techniques. The extremely high melt viscosity of TFE homopolymers precludes its processing by conventional melt processing methods such as injection molding and melt extrusion. The copolymers of TFE and other fluorocarbon polymers, which are processed by melt-processing methods, have been covered in Volume Two. This book is devoted to exploring the various perflu-orinated and partially fluorinated copolymers of tetrafluorethylene and chlorotrifluoroethylene. Polymers of vinyl fluoride and vinylidene fluoride that are, for the most part, melt-processible have been discussed in the second volume. 

The other major monomers, in addition to TFE, are chlorotrifluoroethylene (CTFE, CC1F=CF2), vi-nylidene fluoride (VDF, CFj CHj) and vinyl fluoride (VF, CH2=CHF). These monomers are polymerized and copolymerized by different methods to produce commercial fluoropolymers. TFE, CTFE, and VDF have associated families of polymers and copolymers. Only one commercial VF polymer is known (Tedlar by DuPont). 

Other fluoropolymers are produced in small quantities and for specific applications, including copolymers of ethylene with chlorotrifluoroethylene and TFE. 

Ethylene Chlorotrifluoroethylene Copolymer (ECTFE) 2-8 Ethylene Tetrafluoroethylene Copolymer (ETFE) 8 Fluorinated Ethylene Propylene Copolymer (FEP) 8-9 Fluoropolymer 9... 

Metal-organic complexes and amorphous fluoropolymers used as catalysts in many organic syntheses exhibit excellent solubility in ScCO [9]. Fluoropolymers such as poly(chlorotrifluoroethylene), fluorinated polyacrylates, copolymers of fluorinated acrylates with methacrylate, n-butyl acrylate, styrene, ethylene, etc. which are used to enhance the solubility of the catalyst are also reported to be highly soluble in SCCO2 [9]. Temperature and pressure dependent catalyst solubility not only enhances its activity, but also permits easy recovery and recycle of the catalyst at the end of the reaction. It is possible to precipitate the catalyst and sometimes the product by suitable adjustments in temperature and pressure, and integrate reaction and separation. 

The commercially important fluorocarbon polymers are poly(tetrafluoroethylene) (PTFE), poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP), poly[tetrafluoroethylene-co-(perfluoroaJkylvinyl ether)] (PFA), and amorphous fluoropolymer (AF), typically copolymers of tetrafluoro-ethylene and fluorinated dioxole. The second group of fluoropolymers includes modified poly(tetrafluoroethylene-co-ethylene) (ETFE), poly(vinylidene fluoride) (PVDF) (sometimes referred to as PVF2), and copolymers of vinylidene fluoride, poly(chlorotrifluoroethylene) (PCTFE), poly(chlorotrifluorethylene-co-ethylene) (E/CTFE) and poly(vinyl fluoride) PVF. 

Poly(chlorotrifluoroethylene) (PCTFE) was the first of the fluoropolymers to be made (Ref. 3). It was not imtil the watk of W. T. Miller and his eolle ues during flie research for the Manhattan (atom bomb) project (Ref. 8), however. 

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