Fluorinated ethylene vinyl ether

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. 

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. 

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). 

PE/Other Commodity Polymer Blends PE s are frequently used as impact modifiers for a variety of other thermoplastics. For example, addition of either PE, CPE, or CSR to PVC improved its moldability, stability, impact strength and chemical resistance [Matsuda et al, I960]. Blends of PO/PVAl were developed to improve the antistatic properties [Minekawa et al, 1969]. LDPE was blended with poly(2-ethyl-2-oxazoline) (PEOX) for improved adhesion, e.g., to PET [Hoenig et al, 1984]. Blends of PE, PP, PS or their copolymers with ethylene-fluorinated vinyl ether copolymer... 

The acid-base Nafion composite membranes include blends of Nafion with polypyrrole (PPy) [98-104], polybenzimidazole (PBI) [105-107], poly (propyleneoxide) (PPO) [108, 109], polyfurfuryl alcohol (PFA) [110], poly(vinyl alcohol) (PVA) [111-115], sulfonated phenol-formaldehyde (sPF) [116], polyvinylidene fluoride (PVdF) [117-122], poly(p-phenylene vinylene) (PPV) [123], poly(vinyl pyrrolidone) (PVP) [124] polyanifine (PANI) [125-128], polyethylene (PE) [129], poly(ethylene-terephtalate) [130], sulfated p-cyclodextrin (sCD) [131], sulfonated poly(ether ether ketone) (sPEEK) [132-135], sulfonated poly(aryl ether ketone) (sPAEK) [136], poly(arylene ether sulfone) (PAES) [137], poly(vinylimidazole) (PVl) [138], poly(vinyl pyridine) (PVPy) [139], poly (tetrafluoroethylene) (PTFE) [140-142], poly(fluorinated ethylene-propylene) [143], sulfonated polyhedral oligomeric silsesquioxane (sPOSS) [144], poly (3,4-ethylenedioxythiophene) (PEDT) [145, 146], polyrotaxanes (PR) [147], purple membrane [148], sulfonated polystyrene (PSSA) [149, 150], polystyrene-b-poly(ethylene-ran-butylene)-bpolystyrene (SEES) [151], poly(2-acrylamido-2-methyl-l-propanesulphonic acid-co-l,6-hexanediol propoxylate diacrylate-co-ethyl methacrylate) (AMPS) [152], and chitosan [31]. A binary PVA/chitosan [153] and a ternary Nafion composite with PVA, polyimide (PI) and 8-trimethoxy silylpropyl glycerin ether-1,3,6-pyrenetrisulfonic acid (TSPS) has also been reported [154]. 

Zhu S-Z, He P, Zhao J-W, Cai X (2004) Reactions of fluoroalkanesulfonyl azides with vinyl ether and tetrakis(dimethylamino)ethylene. J Fluorine Chem 125 445-450... 

Commercial fluoropolymers are based on TFE, vinylidene fluoride, and, to a lesser extent, CTFE. Examples of other comonomers include perfluoro-methyl vinyl ether, perfluoroethyl vinyl ether, PPVE, HFP, CTFE, and perfluorobutyl ethylene. The general consequences of the substitution of fluorine for hydrogen in a polymer include increased chemical and solvent resistance, enhanced electrical properties such as lower dielectric constant, lower coefficient of friction, higher melting point, increased photostability and thermal stability, improved flame resistance and weakened mechanical properties. The ultimate, most useful and sought-after properties are achieved in perfluorinated polymers. 

FEP polymers are fully fluorinated and melt processible. They have chemical resistance comparable to polytetrafluoroethylene (PTFE). Melt viscosity of FEP is over one million times lower than PTFE. Fluorinated ethylene propylene resins are in general copolymers of tetrafluoroethylene with hexafluoropropylene and possibly one or more other comonomers. Commercial examples of the latter include perfluoroalkyl vinyl ether (PAVE), such perfluoroethyl vinyl ether (PEVE). FEP... 

Also FKM elastomers are made from TEE, VF2 and fluorinated vinyl ether as well as a special pentapolymer of TEE, HEP, ethylene, fluorinated vinyl ether and VF2. 

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