Perfluorinated polymer poly

In fact, commercial polymeric optical fibers prepared from the perfluorinated polymer poly(perfluorobutenyl vinyl ether), of the structure shown in Chart 3.23, exhibit an attenuation of 15 dBkm at 1 = 1310 nm. 

A large variety of newer poly(ether imide)s has been described. Included among these are perfluorinated polymers (96), poly(ester ether imide)s (97), poly(ether imide)s derived from A/,Ar-diamino-l,4,5,8-naphthalenetetracarboxyHcbisimide (98), and poly(arylene ether imide ketone)s (99). In addition, many other heterocyHc groups have been introduced into polyether systems, eg, poly(pyrazole ether)s (100) and poly(aryl ether phenylquinoxaLine)s (101) poly(aryl ether oxazole)s with trifluoromethyl groups (102) and polyethers with other heterolinkages, eg, poly(arylether azine)s (103). 

Perfluorinated polymers, 18 288-353. See also Perfluorinated ethylene-propylene (FEP) copolymers poly tetr afluoroethylene, 18 288—306 tetrafluoroethylene-ethylene copolymers, 18 316-329 tetrafluoroethylene-perfluorodioxole copolymers, 18 339-342 tetrafluoroethylene-perfluorovinyl ether, 18 329-339... 

Initially, poly(styrenesulfonic acid) (PSSA) and sulfonated phenol-formaldehyde membranes were used for PEFCs, but the useful life of these materials was limited because of significant degradation under fuel-cell operating conditions. A critical breakthrough was achieved with the introduction of Nafion , a perfluorinated polymer with side chains... 

Highly branched polymers such as polypropylene and polymers with other links, e.g. poly(oxymethylene), are most readily attacked by atomic oxygen. Perfluorinated polymers, rubber vulcanized with sulfur, and highly aromatic polymers are the most resistant. 

Among the proton-conducting membranes, Nafion or Nafion-like sulfonated perfluorinated polymers should also be mentioned. These materials are used for polymer electrolyte membrane (PEM) FCs, and in addition to being chemically very stable, they exhibit high proton conductivity at temperatures lower than 100°C. It is believed that permeability and thermal stability may be increased if tailor-made lamellar nanoparticles are added to a proton-conducting polymer. The sulfonated poly(ether ether ketone) (S-PEEK) type of polymers is also widely reported as an alternative to fluorinated polymers such as Nafion or Hyflon [51]. 

The development of polyaryls, in particular polyetherketones (PEEK), as a substitute of perfluorinated polymers was mainly based on cost and stability considerations [1]. Sulfonated polyetherketones has been found to be durable under fuel cell operation conditions over several thousand hours [185]. Victrex Company is the main producer of PEEK polymer and its sulfonation can be performed directly on the polymer backbone or by polymerization of sulfonated monomers [7]. Hoechst-Aventis and Eumatech commercialize sulfonated PEEK (sPEEK) and sulfonated poly(phtalazinone ether ketone) (sPPEK) membranes for fuel cell applications [3]. 

Perfluorinated Polymers, Polytetrafluoroethylene Polyamides, Aromatic Polyamides, Plastics Polyarylates Poly(arylene sufide)s Polycarbonates Cyclohexanedimethanol Polyesters Polyesters, Main Chain Aromatic Polyesters, Thermoplastic Polyethers, Aromatic Poly(ethylene naph-thanoate) Polyimides Polyketones Poly(phenylene ether) Polysulfones Poly(trimethylene terephthalate) Rigid Rod Polymers Syndiotactic Polystyrene . 

Biomedical Applications. Dillon (114) synthesized IPN membranes from polytetrafluoroethylene (PTFE) and poly(dimethyl siloxane) (PDMS) (see Perfluorinated Polymers, Polytetrafluoroethylene Silicones). These flexible membranes are used for a variety of medical purposes, especially second-degree bum care. These materials are commercially available under the trade name Silon. The PDMS component rapidly transports body fluids away from the bum site, while the PTFE provides mechanical strength. The PTFE is also waterproof, so that when the woimd area is washed, water beads up on the film. An additional valuable feature is that the Aims are highly transparent, so that the doctor can observe the wound area easily, making early treatment of any infection or other problem possible. 

Because ablation is carried ont at high temperatures it is possible to examine thermally static polymers snch as poly-p-methylstyrene. Other recent applications of ToF-SIMS include the examination of PS [182-184], PE [185], carbon fibre-reinforced epoxy resins [186], polyalkylacrylates [187], alkylketene dimers [188], perfluorinated polymers [189],... 

Traditional organic polymers such as poly(vinyl chloride), poly(ethylene), poly(propylene), and poly(styrene) are well-known to decompose completely around 400—500° C however, perfluorinated polymers such as poly(tetrafluoroethylene) (PTFE) decompose at higher temperatures (around 600° C) due to the bondstrengthening effect of fluorine for C—C and C—F bonds in highly fluorinated compounds [1,2, 4-6]. Hybridization of PTFE with silica gels is of particular interest... 

Perfluoropolymers The manufacturing of TFE/HFP monomers consumes large amounts of energy (>10,000 kWh/ton TFE). In the past, there were many efforts to recover perfluorinated monomers from scrap materials. All of the approaches were based on the findings that perfluorinated polymers can be pyrolyzed under high temperature conditions into TFE/HFP [90-95] (Scheme 21.13). The pyrolysis back to monomers of perfluorinated polymers is a rare property in the materials industry there are only a few other polymer classes [e.g.. Polystyrene, Poly(methylmethacrylate)] which can be converted into monomers upon heating. 

Time of flight static secondary ion mass spectroscopy (SSIMS) has been applied to perfluorinated polymers, polystyrene, polyacylacrylates (including poly cyclo-hexylmethacrylate, polybenzyl methacrylate, polyphenyl methacrylate, poly n-hexyl methacrylate, poly n-butyl methacrylate, polymethylmethacrylate, poly n-propyl methacrylate, polyisopropyl methacrylate and poly secbutyl methacrylate). Blends of polystyrene and polyvinyl chloride, bisphenol A and polystyrene, polycarbonate and polystyrene and tetramethyl bisphenol A and polycarbonate have also been studied by this technique. 

Other recent applications of ToF-SIMS without XPS include the examination of PS [6, 17-19], polyethylene (PE) [20], carbon fibre reinforced epoxy resins [21], polyalkyl methacrylates [22], alkylketene dimers [23], perfluorinated polymers [24], perflnorinated ethers [25], polyethylene glycol (PEG) oligomers [15, 25-29], rubber [30], ethylene-tetrafluoroethylene copolymer [30], Nylon-6 [31], PC [32,33], PDMS [34], polypyrrole coated PS [35], poly-p-phenylene vinylene [36], butyl rubber [37], poly(4-vinyl phenol)/poly(4-vinyl pyridine blends) [38], polypyrrole-silica gel composites [39], y-glycidoxypropyl trimethoxy silane [40], triblock copolymer poly(ethylene glycol)- 3 poly(phenylene ethylene)- 3 poly(ethylene glycol) [41], ethylene-terephthalate-hydroxybenzoate copolymer [42], PS-polyvinyl methyl ether, polycarbonate - PS blends [43] and PDMS-urethane [44],... 

FIGURE 6.3 Chemical structures of the three types of SPP copolymers sulfonated poly (p-benzoyl-phenylene) (sPPBP), grafted sulfonated poly(p-benzoyl-phenylene) (GS), and grafted perfluorinated sulfonated poly(p-benzoyl-phenylene) (GPS). (From Ninivin, C.L. et al., J. Appl. Polym. Sci., 101,944, 2006.)... 

Other SSIMS studies of polymer surfaces have included perfluorinated polyether [3.21], low-density polyethylene [3.22], poly(ethylene terephthalate) [3.23], and the oxidation of polyetheretherketone [3.24]. 

In spite of the high effort focused on the carbon electrochemistry, very little is known about the electrochemical preparation of carbon itself. This challenging idea appeared in the early 1970s in connection with the cathodic reduction of poly(tetrafluoroethylene) (PTFE) and some other perfluorin-ated polymers. The standard potential of the hypothetical reduction of PTFE to elemental carbon ... 

We are going to discuss the syntheses of fluoropolymers, poly(carbon monofluoride), perfluoropolyethers, perfluorinated nitrogen-containing ladder polymers, and surface fluorination of polymers by direct fluorination. 

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