Asahi Glass Flemion

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

Typically, the membranes for low-temperature PEM fuel cells are made of perfluoiocaibon-sulfonic acid ionomers (PFSA). The best material known is Nafion produced by DuPont, though similar materials have been developed for commercial or development purposes by other manufacturers such as Asahi Glass (Flemion) or As Chemical (Aciplex). In the electrode part, the catalyst is generally dispersed as small particles on a conductive support (carbon powders). Despite many attempts to develop a non-noble-metal catalyst, platinum remains the best known electrocatalyst for ORR in PEM fuel cells. The most extensive limitations to large-scale commercial use of these materials arise from the fact that... 

Fig. 17.2 Structures of some perfluorinated sulfonic acid containing polymers (PFSAs). Polymer 1 is available from DuPont (Nafion ), Asahi Glass (Flemion ), and others Polymer 2 is the short-side-chain ionomer developed at Dow, currently available from Solvacore and Polymer 3 is the ionomer available from 3M Company...

Nafion ionomer is not the only perfluorosulfonic membrane material to be considered for PEMFCs. There are many other commercial perfluorinated ionomers, such as Asahi Glass (Flemion ), Asahi Kasei (Aciplex ), 3M (3M polymer), and Solvay Solexis (Hyflon ), all of which share some structural similarities with the polytetrafluoroethylene-based Nafion but use different perfluorinated vinyl ethers, as shown in Table 4.1. 

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. 

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—... 

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. 

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. 

We will briefly introduce some important ionomers (see Fig. 1), but for a thorough treatment of ionomer chemistry, see, e.g., Refs. . The simplest classification of ionomers is semicrystalline vs. amorphous ionomers. The prototypical semicrystalline ionomer is EMAA (Surlyn, DuPont) neutralized with various cations. Also from DuPont, Nafion is a perfluorinated polyethylene with sulfonic acid or sulfonate groups on short side chains. Other commercial ionomers like Aciplex (Asahi Chemical Company), Flemion (Asahi Glass Company), and Neosepta (Tokuyama) are structurally similar to Nafion. For a recent review on Nafion see Mauritz and Moore. ... 

Other perfluorinated cation exchange membrane materials have also been produced for chlor-alkali cell and other applications. These are the Flemion membrane products (Asahi Glass Co. 

Asahi Glass Co., has announced the improvement of its Flemion membrane, Flemion 723, which reduces electrolysis power from 2500 to 2300 KWH/M Ton NaOH, operating at 35% NaOH and 2.0 KA/M current density. Cell voltage is 3.23 volts at 2 KA/M with 94% current efficiency (75). 

Asahi Glass, "The Flemion Membrane Chlor-Alkali Process,"... 

A novel perfluorocarboxylate membrane named Flemion was developed by Asahi Glass Co., Ltd. in 1975, resulting from its long experience both with manufacture of various fluorochemicals and with electrodialysis using membranes. 

Perfluorocarboxylate ionomer Flemion Asahi Glass Chloralkali membrane... 

Polymers with a polytetrafluoroethylene (PTFE) backbone and pendant perfluorosulfonate or perfluor-ocarboxylate groups have become commercially important materials, although they are expensive. The sulfonates were introduced as Nafion by Du Pont in the early 1970s and the carboxylates as Flemion by Asahi Glass in 1978. They are made by free-radical copolymerization of tetrafluoroethylene and perfluorovinyl monomers giving precursor copolymers, (XXII) and (XXIII), which can be post-functionalized by hydrolysis to generate sulfonic and carboxylic acid groups. The perfluorovinyl... 

MAJOR APPLICATIONS Nafion is the DuPont trademark for its family of perfluorinated ionomers, that is, resins and membranes. Asahi Chemical Industry Company produces Aciplex and Asahi Glass Company, Ltd., Japan, produces Flemion both are competitive products to Nafion in form and function. These perfluorinated ionomers are used in a variety of applications, the largest of which are as an ion exchange resin and in membrane separators in the commercial electrolysis of brine to produce caustic and chlorine. Nafion membranes are also being used in the development of fuel cells and as heterogeneous super acid catalysts in supported, cubed, or powdered form. 

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