Vinylidene fluoride tetrafluoroethylene copolymer

Vinylidene fluoride-tetrafluoroethylene copolymers exhibit chemical resistance similar to that of PCTFE and/or PTFE. They are resistant to acids, alkalis, aqueous solutions of inorganic salts and oxidants. Resistance to solvents is very good across the board [32]. 

The equimolar copolymer of ethylene and tetrafluoroethylene is isomeric with poly(vinyhdene fluoride) but has a higher melting point (16,17) and a lower dielectric loss (18,19) (see Fluorine compounds, organic-poly(VINYLIDENE fluoride)). A copolymer with the degree of alternation of about 0.88 was used to study the stmcture (20). Its unit cell was determined by x-ray diffraction. Despite irregularities in the chain stmcture and low crystallinity, a unit cell and stmcture was derived that gave a calculated crystalline density of 1.9 g/cm. The unit cell is befleved to be orthorhombic or monoclinic (a = 0.96 nm, b = 0.925 nm, c = 0.50 nm 7 = 96%. 

E/TFE = ethylene/tetrafluoroethylene, E/CTFE = ethylene/chlorotrifluoroethylene, EPE = oxide, E/VAL = ethylene/vinyl alcohol, FEP = tetrafluoroethylene/hexafluoropropylene, FU = furan, pA = polyamide, PCTFE = polychlorotrifluoroethyl-ene, HDPE = high-density polyethylene, PF = propylene formaldehyde, PFA = perfluoro alkoxyalkane, PP = polypropylene, PTFE = polytetrafluoroethylene, PUR = polyurethane, PVC = polyvinyl chloride, PVDF = polyvinylidene fluoride, UP = unsaturated polyester, UP-GF = fiberglass-reinforced unsaturated polyester, VE-GF = fiberglass-reinforced vinyl ester, FU-GF = fiberglass-reinforced furane, EP-GF = fiberglass-reinforced ester, CR = chloroprene rubber, CSM = chlo-rosulfonyl polyethylene, FPM = vinylidene fluoride/hexafluoropropylene copolymer, HR = isobutane-isoprene rubber, NBR = nitrile-butadiene rubber, NR = natural rubber, SBR = styrene-butadiene rubber. 

Fiuorei FE-5840Q. See Hexafluoropropylene/vinylidene fluoride/tetrafluoroethylene terpolymer Fiuorei FG-5630Q] Fiuorei FG-5690Q] Fiuorei FLS-2530] Fiuorei FLS-2650. See Hexafluoropropylene/vinylidene fluoride copolymer... 

Acetal homopolymer Animal glue Calcium resinate 1-Decene, homopolymer, hydrogenated Glyceryl rosinate Hydrogenated rosin Methyl rosinate Pentaerythrityl rosinate Polyethylene, chlorosulfonated Polyphenylene ether Potassium rosinate Sodium rosinate Tall oil rosin Vinylidene chloride/methyl acrylate/methyl methacrylate copolymer food-contact articles, for repeated use Butadiene/acrylonitrile copolymer EPM rubber Epoxy, bisphenol A/epichlorohydrin Ethylene/propylene/dicyclopentadiene terpolymer Hexafluoropropylene/vinylidene fluoride copolymer Hexafluoropropylene/vinylidene fluoride/tetrafluoroethylene terpolymer Hydrogenated butadiene/acrylonitrile... 

Copolymers of propylene and tetrafluoroethylene were introduced in the early 1980s by Asahi Glass Co., Japan (21-26). 3M introduced bisphenol/onium cured copolymers of vinylidene fluoride, tetrafluoroethylene, and propylene in the late 1980s (27-30). 

Of these materials the most widely used and most studied are the vinylidene fluoride/hexafluoropropylene copolymers and the terpoly-mers which also contain tetrafluoroethylene. They are generally superior in heat and fluid resistance to the other types. The copolymer of vinylidene fluoride and chlorotrifluoroethylene has superior resistance of oxidizing acids such as fuming nitric acid. The copolymer containing 70 mole% vinylidene fluoride (Kel F 3700) has good low temperature flexibility. 

Investigations in the 1970s were extended to include copolymers of vinylidene fluoride (VDF) with related fluorinated vinyl monomers vinyl fluoride (VF), trifluoroethylene (TrFE) and tetrafluoroethylene (TeFE) [7, 8]. The latter two copolymers were found to crystallize into polar form without the stretching stage required by PVDF. This facilitates processing, and thus offers a wider range of potential device structures. Research in the 1980s has therefore focused on the ferroelectric behaviour and piezoelectric activity of vinylidene fluoride-trifluoroethylene copolymers. 

Fluorinated ethylene-propylene resin Poly(vinylidene fluoride) Ethylene-tetrafluoroethylene copolymer Ethylene- chlorotrifluoro- ethylene copolymer Cellulose- filled Glass-fiber- reinforced... 

The most chemical-resistant plastic commercially available today is tetrafluoroethylene or TFE (Teflon). This thermoplastic is practically unaffected by all alkahes and acids except fluorine and chlorine gas at elevated temperatures and molten metals. It retains its properties up to 260°C (500°F). Chlorotrifluoroethylene or CTFE (Kel-F, Plaskon) also possesses excellent corrosion resistance to almost all acids and alkalies up to 180°C (350°F). A Teflon derivative has been developed from the copolymerization of tetrafluoroethylene and hexafluoropropylene. This resin, FEP, has similar properties to TFE except that it is not recommended for continuous exposures at temperatures above 200°C (400°F). Also, FEP can be extruded on conventional extrusion equipment, while TFE parts must be made by comphcated powder-metallurgy techniques. Another version is poly-vinylidene fluoride, or PVF2 (Kynar), which has excellent resistance to alkahes and acids to 150°C (300°F). It can be extruded. A more recent development is a copolymer of CTFE and ethylene (Halar). This material has excellent resistance to strong inorganic acids, bases, and salts up to 150°C. It also can be extruded. 

The inability to process PTFE by conventional thermoplastics techniques has nevertheless led to an extensive search for a melt-processable polymer but with similar chemical, electrical, non-stick and low-friction properties. This has resulted in several useful materials being marketed, including tetrafluoro-ethylene-hexafluoropropylene copolymer, poly(vinylidene fluoride) (Figure 13.1(d)), and, most promisingly, the copolymer of tetrafluoroethylene and perfluoropropyl vinyl ether. Other fluorine-containing plastics include poly(vinyl fluoride) and polymers and copolymers based on CTFE. 

Silastic LS 420, possessing approximately Q.6%-0.9% pendant vinyl groups, was blended with Kynar 7201, a vinylidene fluoride copolymer with tetrafluoroethylene (Atochem), in the presence of triallylisocyanurate (TAIC) and DAP containing a small amount of benzoyl peroxide in the DAP fraction. 

Poly(vinylidene fluoride) (PVDF) Ethylene-chlorotrifluoroethylene copolymer Ethylene-tetrafluoroethylene copolymer Poly(vinyl fluoride) (PVF)... 

The processability of fluorine-containing polymers is improved by replacement of one or more of the fluorine atoms. Replacing one of the eight fluorine atoms with a trifluoromethyl group gives a product called FEP or Viton, actually a copolymer of tetrafluoroethylene and hexafluoropropylene (Equation 6.53). Polytrifluoromonochloroethylene (PCTFE, Kel F) (Equation 6.54), in which one fluorine atom has been replaced by a chlorine atom, has a less regular structure and is thus more easily processed. Poly(vinylidene fluoride) (PVDF, Kynar) (Equation 6.55) is also more easily processable but less resistant to solvents and corrosives. 

Abbreviations for plastics ABS, acrylonitrile-butadiene-styrene CPVC, chlorinated poly vinyl chloride ECTFE, ethylene-chlorotrifluoroethylene ETFE, ethylene-tetrafluoroethylene PB, polybutylene PE, polyethylene PEEK, poly ether ether ketone PFA, perfluoroalkoxy copolymer POP, poly phenylene oxide PP, polypropylene PVC, polyvinyl chloride PVDC, poly vinylidene chloride PVDF, poly vinylidene fluoride. 

A study has been conducted on PBXs based on TATB using various binders such as polyurethane (Estane 5703-Goodrich), Viton-A (copolymer of vinylidene fluoride and hexafluoropropylene Du Pont), silicone resin (Chemlok), Kel-F800 [copolymer (3 1) of chlorotrifluoroethylene and vinylidene fluoride 3M Company] and Teflon [poly (tetrafluoroethylene), PTFE Du Pont] etc. and it was concluded that... 

Screening tests were conducted on potential construction materials. The candidate materials evaluated included the following polytetrafluoroethylene (PTFE, TFE), fluorinated ethylene-propylene copolymer (FEP), perfluoroalkoxy-alkanes (PFA), ethylene-tetrafluoroethylene copolymer (ETFE), ethylene-chlorotrifluoroethylene copolymer (E-CTFE), poly vinylidene fluoride (PVDF), polypropylene (PP), and polyvinyl chloride (PVC). These materials were chosen based on cost, availability, and information from manufacturers on compatibility with acid solutions. 

Ferroelectricity has also been found in certain copolymer compositions of VF2 with trifluoroethylene, F3E, [6-11] and tetrafluoroethylene, F4E, [12-15] and in nylon 11 [16]. Specifically, copolymers of vinylidene fluoride and trifluoroethylene (VF2/F3E) are materials of great interest because of their outstanding ferroelectricity [9,17-18], together with a parallel strong piezo- [7] and pyroelectricity [19]. These copolymers exhibit, in addition, an important aspect of ferroelectricity that so far has not been demonstrated in PVF2 the existence of a Curie temperature at which the crystals undergo reversibly a ferroelectric to a paraelectric phase transition in a wide range of compositions [9, 17-18],... 

Using the same method Akutin (7) was able to produce block and graft copolymers from several systems containing methyl methacrylate monomer and polydimethyl siloxane, polytrifluoroethylene or a copolymer tetrafluoroethylene-vinylidene fluoride. 

PS PSF PSU PTFE PU PUR PVA PVAL PVB PVC PVCA PVDA PVDC PVDF PVF PVOH SAN SB SBC SBR SMA SMC TA TDI TEFE TPA UF ULDPE UP UR VLDPE ZNC Polystyrene Polysulfone (also PSU) Polysulfone (also PSF) Polytetrafluoroethylene Polyurethane Polyurethane Poly(vinyl acetate) Poly(vinyl alcohol) poly(vinyl butyrate) Poly(vinyl chloride) Poly(vinyl chloride-acetate) Poly(vinylidene acetate) Poly(vinylidene chloride) Poly(vinylidene fluoride) Poly(vinyl fluoride) Poly(vinyl alcohol) Styrene-acrylonitrile copolymer Styrene-butadiene copolymer Styrene block copolymer Styrene butadiene rubber Styrene-maleic anhydride (also SMC) Styrene-maleic anhydride (also SMA) Terephthalic acid (also TPA) Toluene diisocyanate Ethylene-tetrafluoroethylene copolymer Terephthalic acid (also TA) Urea formaldehyde Ultralow-density polyethylene Unsaturated polyester resin Urethane Very low-density polyethylene Ziegler-Natta catalyst... 

Figure 7.2. Comparison of the cloud-point behavior of poly(vinylidene fluoride) (PVDF), 78 mol % vinylidene fluoride and 22 mol % hexafluoropropylene (VDF-HFP22), and 81 mol % tetrafluoroethylene and 19 mol % hexafluoropropylene (TFE-HFP19) in C02. The polymer and copolymer concentrations are 5 wt % in each case. The demarcations L + L and FLUID denote a two-phase and a one-phase region, respectively.

The first commercial fluoroelastomer, Kel-F, was developed by the M. W. Kellog Company in the early to mid-1950s and is a copolymer of vinylidene fluoride (VDF) and chlorotrifluoroethylene (CTFE). Another fluorocarbon elastomer, Viton A, is a copolymer of VDF and hexafluoropropylene (HFP) developed by du Pont was made available commercially in 1955. The products developed thereafter can be divided into two classes VDF-based fluoroelastomers and tetrafluoroethylene (TFE)-based fluoroelastomers (perfluoroelastomers).72 The current products are mostly based on copolymers of VDF and HFP, VDF and MVE, or terpolymers of VDF with HFP and TFE. In the combination of VDF and HFP, the proportion of HFP has to be 19 to 20 mol% or higher to obtain amorphous elastomeric product.73 The ratio of VDF/HFP/TFE has also to be within a certain region to yield elastomers as shown in a triangular diagram (Figure 2.2).74... 

The compilation of such data constituted a firm basis that was used to study a specific and more complicated system the elucidation of the electronic structure of a copolymer of ethylene (48%) and tetrafluoroethylene (52%) whose synthesis was conducted in order to maximize the alternating sequences. The valence band spectrum of such a compound (Figure 8) was found very similar to the one measured e.g. for poly(vinylidene fluoride). But, by looking to the fine details of the spectrum, by simulating the valence band of a block copolymer (by addition of PE and PTFE spectra), and by comparison with model calculations, it was possible to show that the C-C band width and the distance F2s-top of the C-C band were characteristic of an ethylene-tetrafluoro-ethylene copolymer with dominant alternant structure (28). 

Note ETFE, copolymer of ethylene and tetrafluoroethylene ECTFE, copolymer of ethylene chlo-rotrifluoroethylene PFA, copolymer of perfluoropropylvinylether and tetrafluoroethylene PVDF, poly(vinylidene fluoride) PCTFE, poly(chlorotrifluoroethylene). 

Daikin Industries DuPont Fluoroproducts Note PTFE, polytetrafluoroethylene CTFE, chlorotriflua oethylene EFEP, per-fluorinated copolymer of ethylene and propylene ETFE, copolymer of ethylene tetrafluoroethylene PFPE, perfluorinated polyether EClFE, copolymer of ethylene and chlorotrifluoroethylene HIE, ter-polymer of hexafluoropropylene, tetrafluoroethylene, and ethylene MFA, copolymer of perfluoromethyMnylether and tetrafluoroethylene PEA, copolymer of perfluoropropylvinylether and tetrafluoroethylene FEP, fluorinated ethylene-propylene copolymer PVDF, poly(vinylidene fluoride) THV, terpolymer of tetrafluoroethylene, hexafluoroprqjylene, and vinyUdene fluoride PCTFE, poly(chlorotriflua oethylene). 

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). 

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. 

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