Ketones and poly

The effect of a second polymer blended with PPS which causes enhanced nucleation of PPS has been previously observed. It was found that low concentrations (1—2 wt %) of poly(phenylene sulfide ketone) and poly(ether ether ketone), when melt-blended with PPS, function effectively to increase the nucleation density of PPS (149). 

Poly(arylene ether ketone) and poly(arylene ether sulfone) were also tried to be incorporated into the hybrids with silica gel by means of the sol-gel procedure [19, 20], For example, triethoxysilyl-terminated organic polymer was subjected to co-hydrolysis with tetraethoxysilane. A systematic change in mechanical and physical properties of the hybrid glass has been found with the content of organic polymer and the annealing temperatures. 

Thermooxidative stability of the fluorine-containing poly(ether ketone) (11) and poly(sulfide ketone) (13) from 15 is very high. The 5% weight-loss temperatures (DT5) are 391 and 436°C for poly(ether ketone) and poly(sulfide ketone) analogues having no fluorine atoms, whereas those of poly(ether ketone) (11) and poly(sulfide ketone) (13) are higher than 500°C. 

Another concern for polystyrene- and some aromatic-based PEMs is hydrolysis of fhe sulfonic acid group from aromatic rings as well as hydrolytic cleavage of polymer backbone under fuel cell conditions for aromafic polymers including polyimides, poly(arylene ethers), poly(ether ketones), and poly(ether sulfones). It is well known that the sulfonation of aromafic rings is a reversible process especially at low pH and at elevated temperature (Scheme 3.3). The reversibility of sulfonation, for example, is used in fhe preparafion of trinitrotoluene or picric acid. Por the simplest membrane of the class of arylsulfonic acids (i.e., benzenesulfonic acid), fhe reacfion occurs upon freatment with a stream of superheated steam at 180°C.i ... 

Swier, S., Ramani, V., Fenton, J. M., Kunz, H. R., Shaw, M. T. and Weiss, R. A. 2005. Polymer blends based on sulfonated poly(ether ketone ketone) and poly(ether sulfone) as proton exchange membranes for fuel cells. Journal of Membrane Science 256 122-133. 

CD are very rigid molecules and polyrotaxanes derived from them are expected to be more rigid than the starting backbone. Poly(methyl methacrylate side chain rotaxane) 56 had a Tg 20°C higher than the backbone itself. The same observation was also seen in side chain poly(ether ketone) and poly(ether sulfone) systems [96-102]. 

In earlier investigations, the author developed catalytic methods for preparing ketones and poly ketones using acetylacetonato-vanadium(III) (1). Oxidative process for ethers using acetylacetonatocobalt(II) are also described by the author (2). 

The largest body of experimental work on the photochemistry of solid polymers relates to the study of the photolysis of homo- and copolymers of vinyl ketones. In early work, Guillet and Norrish (20) and Wissbrun (21) showed that polymeric ketones such as poly(methylvinyl ketone) and poly(methylisopropenyl ketone) underwent the same classical photochemical reactions as their low-molecular-weight analogs. The photophysical and photochemical processes which occur are summarized below ... 

A suitable polymer material for preparation of carbon membranes should not cause pore holes or any defects after the carbonization. Up to now, various precursor materials such as polyimide, polyacrylonitrile (PAN), poly(phthalazinone ether sulfone ketone) and poly(phenylene oxide) have been used for the fabrication of carbon molecular sieve membranes. Likewise, aromatic polyimide and its derivatives have been extensively used as precursor for carbon membranes due to their rigid structure and high carbon yields. The membrane morphology of polyimide could be well maintained during the high temperature carbonization process. A commercially available and cheap polymeric material is cellulose acetate (CA, MW 100 000, DS = 2.45) this was also used as the precursor material for preparation of carbon membranes by He et al They reported that cellulose acetate can be easily dissolved in many solvents to form the dope solution for spinning the hollow fibers, and the hollow fiber carbon membranes prepared showed good separation performances. 

With respect to hydrogen-bonded supramolecular diblock copolymers, pioneering investigations were carried out by Binder and coworkers [87, 88] and by Gong and coworkers [89]. Initially, Binder and colleagues functionalized poly(ether ketone) and poly(isobutylene) chains with complementary hydrogen-bonding... 

The most studied Nafion composite membranes with organic fillers include blends of Nafion with polypyrrole, polybenzimidazole, poly(vinyl alcohol), polyvinylidene fluoride, polyanfline, sulftmated poly(ether ether ketone), and poly(tetrafluoroethylene). 

Gohil GS, Nagarale RK, Binsu W, Shahi VK. Preparation and characterization of monovalent cation selective sulfonated poly(ether ether ketone) and poly(ether sulfone) composite membranes. J Colloid Interface Sci 2006 298(2) 845-53. 

Jung, H.-Y. and Park, J.-K. 2007. Blend membranes based on sulfonated polyfether ether ketone) and poly(vinylidine flouride). 52 7464—7468. 

A number of techniques, including addition of stabilizers and crosslinking, are used to extend thermal stability. Some polymers, for example PEEK (polyaryletherether ketone) and poly(phenylene sulfide), gain their thermal stability by virtue of their high degree of crystallinity. Other... 

Ma CCM, Lee CL, Tai NH, Chemical resistance of carbon fibre reinforced poly(ether ether ketone) and poly(phenylene sulfide) composites. Polymer Composites, 13(6), 435-440, 1992. Enomoto M, Ohashi T, Hata T, Susuki Y, Maeda M, Sato H, Evaluation of corrosion resistance of carbon fibres in hot phosphoric acid, Denki Kagaku, 65(4), 320-325, 1997. 

Due to fluorination, PFSA materials are relatively more costly than non-fluorinated hydrocarbon membranes. The latter such as poly (ether ether ketone) and poly (arylene ether sulfone) have also been widely investigated for fuel cell applications. In addition to lower cost, some of them also have better dimensional stability with regard to hydration levels. The problem is their lower chemical stability in the fuel cell environment. 

Raman spectra of poly(aryl ether ether ketone) and poly(aryl ether ketones). 

New Polymers and Other Modes of Deformation.—Three relatively new polymers have become available recently poly (ether ketones), poly (ether ether ketones) and poly(ether sulphones). Poly(ether ether ketones), (PEEK), have good electrical insulating properties and very good abrasion resistance. This combination makes the polymer an attractive coating for electrical conductors. The same polymer is also attractive as a load bearing material for moving parts. Poly(phenylene sulphide) continues to be developed for this purpose but the PEEKS are much simpler to fabricate. Linear low-density polyethylenes are expected to be widely available in the near future. These materials have many attractive features, particularly as packaging materials. 

Poly(arylene ether)s are one of the most studied aromatic polymers for the sulfonation reactions. Poly(arylene ether)s include poly(phenylene ether), poly(arylene ether ketone), poly(arylene ether ether ketone), and poly(arylene ether sul-fone). These polymers contain electron-rich phenylene rings linked by ether bonds, which are susceptible for the sulfonation reactions with typical sulfonating reagents such as sulfuric acid, chlorosulfonic acid, or sulfur trioxide. The first attempt was the sulfonation of poly(2,6-dimethyl-phenylene ether) (PPO) by General Electric in 1960s [4]. Since then, a number of... 

In summary PVA can be oxidized in controlled manner to form poly(enol-ketone) and poly(hydroxy-ketone). These polymers undergo biodegradation faster than PVA. They also exhibit interesting chemical reactivities. 

Barnard M. Marks, Boron-trifluoride hydrogen fluoride catalyzed synthesis of poly (aromatic ketone) and poly(aromatic sulfone)polymers. US Patent 3441538. April 29,1969. 

Poly(methyl vinyl ketone) and poly(methyl vinyl ketone-co-styrene)... 

T. Kobayashi, M. Rikukawa, K. Sanui, N. Ogata, Proton-conducting polymers derived from poly(ether-ether-ketone) and poly(4-phenoxybenzoyl-l,4-phenylene). Solid State Ionics 106, 219-225 (1998). 

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