Flemion

Asahi Glass Co., Tokyo cation and anion Selemion and Flemion ... 

Polymer-metal composites Cationic mobility activated electrically in membranes of the Nafion (DuPont) and Flemion (Asahi Glass) type leads to a bending response, again mimicking muscle action. 

Nakao, M., Shimohira, T. Takechi, Y. (1998) High performance operation with Flemion membranes and the AZEC-B1 electrolyser. In Modem Chlor-Alkali Technology, Vol. 7 (ed. S. Sealey), pp. 95-104. Society of Chemical Industry, London and Royal Society of Chemistry, Cambridge. 

Sajima, Y., Nakao, M., Shimohira, T. Miyake, H. (1992) Advances in flemion membranes for chlor-alkali production. In Modern Chlor-alkali Technology (ed. T.C. Wellington), Vol. 5, pp. 159-175. Hays Chemical Distribution Ltd., Sandbach, UK. 

Advanced Cell Technology with Flemion Membranes and the AZEC Bipolar Electrolyser... 

AGC has been recently focusing on the development of a new electrolyser and a new membrane for high current density operation, a facility much requested by many users. In July 1998, AGC completed the conversion of its last diaphragm process plant to the then newest Bipolar Electrolyser, the AZEC B-l (hereinafter, B-l) with Flemion F-893 (hereinafter, F-893) membrane and also the then-newest membrane Flemion Fx-8964 (hereinafter, Fx-8964). This conversion was the result of AGC s development efforts. AGC is now on the way to the next stage of its ion-exchange membrane technology, where 6 kA /m-2 operation will be the norm and 8 kA m-2 operation will be made a feasibility. 

Perfluorinated PEMs with sulfonic acid (la = Nafion, Flemion lb = Aciplex 2a = DOW, Hyflon-ion 2b = 3M, 2c = Asahi Kasei 3 = Asahi Glass) and b)s[(perfluoroalkyl sulfonyl] (4) groups for proton conduction. 

The DuPont Nafion materials, both sulfonate and carboxylate varieties, are not entirely unique, as similar perfluorinated ionomers have been developed by others such as the Asahi Chemical Company (commercial name Aciplex) and the Asahi Glass Company (commercial name Flemion). The comonomer chemical structures of and further information on these materials are given in the recent review article by Doyle and Rajendvan. Now commercially unavailable, but once considered a viable alternative, the Dow Chemical Company developed a somewhat similar perfluorinated ionomer that resembled the sulfonate form of Nafion except that the side chain of the former is shorter and contains one ether oxygen, rather than two ether oxygens, that is, —O—... 

Later, Hinatsu et al. studied the uptake of water, from the liquid and vapor states at various temperatures, in acid form Nafion 117 and 125, and Aciplex and Flemion membranes, although the latter two similar products will not be discussed here. These studies were motivated by a concern over the deleterious effects, involving either overly dry or overly wet membranes, on electrical conductivity within the context of polymer electrolyte fuel cells and polymer electrolyte water electrolyzers. 

As discussed above, the most commonly known and studied PEMs are based on nonaromatic perfluori-nated hydrocarbons such as Nation, Aciplex, Flemion, and what are termed the Dow membranes. However, their chemical synthesis is challenging due to the safety concerns of tetrafluoroethylene and the cost/ availability of the perfluoroether comonomers. These issues have relegated detailed synthetic research on polyperfluorosulfonic acid materials to the industrial sector or to a few specialized academic labs. 

Other perfluorinated ionomer membranes, chemically very similar to Nafion, are also available commercially. Aciplex, manufactured by the Asahi Chemical Company, is very similar to Nafion, except that it has perfluoropropanesulfonic acid side chains. Flemion (Asahi Glass Company), in contrast, possesses perfluorobutanoic acid functions. 

Membrane cell (Fig. 15.3c). This is similar to the diaphragm cell, except that a selective membrane, which lets only certain ions through, is employed instead of a physical separator. In this way higher concentrations of caustic soda can be produced than in the diaphragm cell. Membranes used are of Nation (a tetrafluoroethylene copolymer), Flemion , and other similar materials, as well as bilayer membranes which improve selectivity and impede hydroxide diffusion, so that up to 40 per cent sodium hydroxide solution can be produced. The cell potential is —2.95 V (reversible potential —2.20 V). Energy consumption is the lowest of the three processes, and product purity is high. 

In Xuezhong Du etal. (2001), Japanese Aciplex and Flemion and Chinese Shanghai alternatives to Nafion are compared with Nafion in terms of their performance, and none is overwhelming. The latter alternatives have not yet caught on in the international scene. Price comparison is not made available. 

The electrolysis of potassium chloride [7447-40-7], KQ, to produce chlorine and potassium hydroxide in membrane cells requires similar but unique membranes. Commercial membranes currendy employed in high performance membrane electrolyzers include E)u Pont s Nation 900 series and Asahi Glass s Flemion 700 series. 

This process has been used to make functionalized perlluorovinyl ethers [e.g., F2C = CF0CF2CF(CF3)0CF2CF2S02F] which are copolymerized to form fluorinated membrane materials (Nafion, Flemion), which arc important in chloralkali electrolysis. ... 

Flemion (Daikin) CFjCFjX Nafion, X = CO2H Flemion, X = SOjH ... 

PFSA lonomer with PTFE Fibril Reinforcement Asahi Glass Flemion.789... 

PEMFCs generally operate at temperatures <100°C. PFSA-based polymer ionomer membranes like Nafion, Gore, Aciplex, and Flemion are not significantly affected by temperatures up to 150°C where most of the water is lost and membranes may suffer irreversible dry out. Chemical degradation of these membranes in the form usually starts with the loss of sulfonate groups at over 220°C [7]. 

Nation XR resin Nation CR resin Flemion XR resin Flemion CR resin Aciplex XR resin Aciplex XR resin... 

The synthesis of the monomers as well as the polymerization of PFSA membranes involve dangerous reactions under conditions of high pressure and temperature. Additionally, the synthesis of the comonomer that is commonly referred to as perfluorosulfonylfluoride ethyl propyl vinyl ether (PSEPVE) involves numerous steps with low yields. These factors contribute to the cost of these materials. The synthesis routes described in detail by Doyle and Rajendran are summarized here. The synthesis of the long-chain PFSA monomers used in commercial systems like Nafion, Flemion, and Aciplex proceeds through... 

XR (sulfonate) comonomer structures Nafion, Flemion CF2=CF0CF2CF(CF3)0CF2CF2S02F... 

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