Perfluoromethyl vinyl ether

Tetrafluoroethylene, perfluoromethyl vinyl ether cure site monomer... 

Perfluoroelastomers, i.e., elastomers based on perfluoromethyl vinyl ether (PMVE) and TFE, exhibit a virtually unmatched resistance to a broad class of chemicals except fluorinated solvents. On the other hand, they are adversely affected by hydraulic fluid, diethyl amine, and fumed nitric acid resulting in swelling of the elastomer by 41, 61, and 90%, respectively.10... 

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). 

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

Figures 3.34 and 3.35 show the relationship of tensile strength and ultimate (break) elongation with temperature for perfluoroalkyl vinyl ether modified perfluoroalkoxy polymer (PFA). Figures 3.36 through 3.38 show a comparison of the properties of PFA with MFA, which is perfluoromethyl vinyl ether (PMVE). The common measurement technique for tensile properties of fiuoropiastics is ASTM D1708.

Figure 3.69 Deformation under load of PFA (MFA, modified by perfluoromethyl vinyl ether) in tensile mode at 200°C.i >...

Similar data for perfluoroalkoxy (PFA), fluori-nated ethylene propylene (FEP), ethylene tetrafluoro-ethylene (ETFE), and perfluoromethyl vinyl ether (MFA) polymers are presented in Figs. 6.6-6.9. 

Perfluoromethyl Vinyl Ether - SqqPerfluoroalkyl vinyl ether. 

A more important use of HFPO is as an intermediate for the syntheses of a wide range of trifluorovinyl ether monomers that are used as comonomers in fluorinated plastics and elastomers. The general synthesis of this class of monomers is exemplified by the synthesis of perfluoromethyl vinyl ether (IV, PMVE) (Eq. 13.6). 

PRA Prabhakar, R.S., DeAngelis, M.G., Sarti, G.C., Freeman, B.D., and Coughlin, M.C., Gas and vapor sorption, permeation, and diffusion in poly(tetrafluoroethylene-co-perfluoromethyl vinyl ether). Macromolecules, 38, 7043, 2005. 

CD can react with the linear polymers including some hydrophilic chemicals, for instance, polyethylene glycol (PEG), polypropylene glycol (PPG), and perfluoromethyl vinyl ether (PMVE), or some lipophilic chemicals, for example, low-density polyethylene (LDPE), polypropylene (PP), polyisobutylene imide (PIBI), polyester for the production of rotaxane and n-rotaxane. PEG is mixed with CD to achieve the precipitation. The yield increases with the increase in... 

Terpolymers of tetrafluoroethylene, perfluoromethyl vinyl ether, and small amounts of a cross-linking termonomer, such as, for example, perfluoro(4-cyanobutyl vinyl ether), are free radically copolymerized in emulsion. Vulcanization occurs by cyclotrimerization of the cyano groups to s-triazine rings. The elastomer has a glass transition temperature of —12 C and a brittle temperature of —39° C. It is very resistant to weathering and possesses a good low-temperature flexibility. 

Data are taken from Refs. [4, 13, 26-29]. HFP, hexafluoropropylene VDF, vinyUdene fluoride MFA, copolymer of TFE and perfluoromethyl vinyl ether (PMVE Hyflon). 

Hexafluoropropylene- co-tetrafluoroethylene Perfluoromethyl vinyl ether-co-tetrafluoroethylene DSC I had 1 mol% hexaflucHopropylene II had 2 mol% perfluOTOTielhyl vinyl ether Pucciariello and Angioletti (1999)... 

A family of copolymers containing TFE and perfluoromethyl vinyl ether modified with PPVE referred to as MFA is produced by Ausimont (24). The relatively small pendant group —0—CF3 seems to have a similar effect on the crystallinity reduction as is exhibited by —CF3 in FEP (perfluoropropylene-tetrafluoroethylene copolymer) however, the higher reactivity of perfiuoromethyl vinyl ether than that of HFP makes the polymerization process more efficient. The performance characteristics are described in References 11 and 25. 

Perfluoro-2-inethylene-l,3-dioxolane monomers copolymerizes with various commercially available fluorovinyl monomers, too. Perfluoro-3-methylene-2,4-dioxabicyclo [3,3,0] octane (Figure 16.5F) was copolymerized with chlorotrifluo-roethylene (CTFE), perfluoropropyl vinyl ether, perfluoromethyl vinyl ether, and vinylidene fluoride [23] by a free radical initiator such as perfluorodibenzoylperox-ide or tert-butyl peroxypivalate in bulk or in solution, respectively (see Figure 16.9). 

Perfluoroelastomer (tetrafluoro-perfluoromethyl vinyl ether copolymer) Introduced by DuPont in 1977 as Kalrez , this elastomer combines the properties of a conventional fluoroelastomer, such as vinylidene fluoride-hexafluoropropylene copolymer, with those of a fluorocarbon resin such as polytetrafluoroethylene. It has found application for O-rings and seals that must withstand strong chemicals and solvents at high temperatures. 

Solubility parameter of poly(tetrafluoroethylene-eo-perfluoromethyl vinyl ether)... 

Perfluroalkoxy polymer or PFA is one of the most important meltprocessible fluoroplastics due to its relative ease of processing and high service temperature equivalent to polytetrafluoroethylene (260°C). It also has the same excellent chemical resistance and low friction properties as PTFE. Perfluroalkoxy polymers are prepared by copolymerization of a perfluoroalkylvinyl ethers (Rf—O—CF=CF2, where Rj is a perfluorinated alkyl group) with tetrafluoroethylene. Examples of commercially utilized ethers include perfluoromethyl-vinyl ether (CFg—O—CF=CF2), perfluoroethylvinyl ether (C2F5—O—CF=CF2) and perfluoropropylvinyl ether (C3F7—O—CF=CF2). Several percent of ether is incorporated in a copolymer. 

TFE = tetrafluoroethylene, PPVE = perfluoropropyl vinyl ether, PMVE = perfluoromethyl vinyl ether, HEP = hexafluoropropylene. HFPO oxide dimer peroxide is the initiator, 1,1,2-trichlorotrifluoroethane is the solvent. 

PFA polymers are fully fluorinated and melt processible. They have chemical resistance and thermal stability comparable to polytetrafluoroethylene (PTFE). Melt viscosity of PFA is over one million times lower than PTFE. Perfluoroalkoxy resins are in general copolymers of tetrafiuoroethylene with one or more of perfluoroalkyl vinyl ether comonomers. Commercial examples of the latter include perfluoromethyl vinyl ether (PMVE), perfluoroethyl vinyl ether (PEVE), and perfluoropropyl vinyl ether (PPVE). PFA resins are specified by ASTM Method D3307, which also provides procedures or references to other ASTM methods for the measurement of resin properties. Commercial PFA resins offered by major manufacturers have been listed in Tables 6.1 through 6.7. 

Polymer Composition Copolymer tetrafluoroethylene eopolymer with 1.5 mole% perfluoropropyl vinyl ether Copolymer tetrafluoroethylene eopolymer with 6.9 mole% hexafluoropropylene Copolymer tetrafluoroethylene eopolymer with 3.5 mole% perfluoromethyl vinyl ether and 0.4 mole% perfluoropropyl vinyl ether... 

Tables 12.1 and 12.2 summarize the effect of a number of representative organic and inorganic compounds on tetrafluoroethylene-perfluoropropyl vinyl ether polymer (PFA). Figure 12.2 gives a comparison of PFA and MFA (copolymer of tetrafluoroethylene and perfluoromethyl vinyl ether).

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