Preparation of Anion Exchange Membranes

Most commercially available anion exchange membranes have quaternary ammonium groups as ion exchange groups. These membranes may be prepared, for example, by the reaction of trimethylamine with a copolymer membrane prepared 

It is impossible to prepare perfluorinated anion exchange membranes due to the strong electron-donor properties of the fluorine atom. For example, a stable 

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T. Sata, Y. Yamane and K. Matsusaki, Preparation of anion exchange membranes having pyridinium groups or pyridinium derivatives as anion exchange groups, J. Polym. Sci., Polym. Chem. Ed., 1998, 36, 49-58. 

For the preparation of anion-exchange membranes positively charged groups are introduced into the polystyrene by chloromethylation and amination with triamine according to the following reaction scheme ... 

High-molecular-weight polymers are obtained with an outstanding solubility in polar aprotic solvents. This polymer is suitable for the preparation of anion exchange membranes by solution casting using dimethylacetamide as solvent [12]. 

Matsuoka, K., Chiba, S., Iiiyama, Y., Abe, T., Matsuoka, M., Kikuchi, K. and Ogumi, Z. 2008. Preparation of anion-exchange membrane by plasma polymerization and its use in alkaline fuel cells. 

Preparation of Anion Exchange Membranes for Fuel Cells... 

Some efforts have also been directed towards the preparation of anion exchange membranes from polymer films (approach b ). Generally, these polymers, e.g., polymer films of hydrocarbon polyethylene and polypropylene or fluorocarbon origin (ETFE, PVDF), are insoluble in solvents. The method most commonly used consists in grafting vinyl monomers, such as styrene, onto polymer films followed by subsequent chemical modifications, such as chloromethylation-amination instead of sulfona-tion [6-8]. 

Siiser A (1973) Preparation of anion exchange membranes from cellulose sheets. US Patent 3714010... 

Recently, some progress in the preparation of anion exchange membranes was reported, leading to the application of the PEFC concept to alkaline fuel cells. However, performance in terms of power output and stabUity/lifetime is far below... 

Hong, J.H., Hong, S.K. (2010) Preparation of anion exchange membrane by amination of chlorinated polypropylene and ethylenediamine and its properties. Journal of Applied Polymer Science, 115, 2296-2301. 

Hwang, G.J., Ohya, H. (1998) Preparation of anion exchange membrane based on block copolymers. Part II the effect of the formation of macroreticular structure on the membrane properties. Journal of Membrane Science, 149, 163 169. 

Geraldine Merle, A. C. de Ven, E. V. Nijmeijer, K., An easy method for the preparation of anion exchange membranes Graft-polymerization of ionic liquids in porous supports. Journal of Applied Polymer Science 2013, 129, 1143-1150. 

Figure 3.4 Effect of divinylbenzene content on properties of anion exchange membrane prepared by the paste method. (O) Transport number (t) ( ) specific conductivity (k). DVB divinylbenzene St styrene MVP 2-methyl-5-vinylpyr-idine. Composition MVP/(St + MVP) — 0.8 (St + MVP + DVB)/PVC = 1.3 DOP/PVC = 0.3 (by weight). The copolymer membrane is quatemized with methyl iodide.

Composite membranes prepared from anion exchange membranes and pyrrole are also effective in preventing the increase in electrical resistance of the... 

K. Takata, Preparation method of anion exchange membrane, Jpn. Pat. JP 56-47213 (examined application). 

T. Sata, Anti-organic fouling properties of composite membranes prepared from anion exchange membrane and polypyrrole, J. Chem. Soc., Chem. Commun., 1993, 1122. 

Figure 5.28 Change in permeability coefficient (D/6) of urea (neutral molecule) with ion exchange capacity of anion exchange membranes and composite membranes (D diffusion coefficient, cm2 s 6 thickness of the membrane, cm). ( ) Commercial anion exchange membranes (NEOSEPTA AM-1, AM-2 and AM-3, strongly basic anion exchange) ( ) Fe-Py membrane (A) Py-Fe membrane. The permeability coefficient was measured by diffusion dialysis of urea solution using a two-compartment cell (2.0 mol l urea solution/membrane/ pure water) for 48 h at 25.0 °C under vigorous agitation). The ion exchange capacity on the horizontal axis represents values before preparation of the composite membranes.

M. Josowitz, J. Janata, K. Ashley and S. Pons, Electrochemical and ultraviolet-visible spectroelectrochemical investigation of selectivity of potentiometric gas sensors based on polypyrrole, Anal. Chem., 1987, 59, 253 T. Sata. Possibility for potentiometric humidity sensor of composite membranes prepared from anion-exchange membrane and conducting polymer, Sensor Actuators, B, 1995, 23, 63 K. Ogura, H. Shiigi, T. Oho and T. Tonosaki, A C02 sensor with polymer composites at ordinary temperature, J. Electrochem. Soc., 2000,147, 4351. 

R. Yamane, Y. Mizutani and Y. Onoue, Comparison of permselectivity of anion exchange membranes for NaCl-Na2S04 system, Denki Kagaku (J. Electrochem. Soc. Jpn.), 1962, 30, 94 R. Yamane, Y. Mizutani H. Motomura and R. Izuo, Preparation of S042- non permeable anion exchange membrane, Denki Kagaku (J. Electrochem. Soc. Jpn.), 1964, 32, 277-280. 

T. Sata and S. Nojima, Transport properties of anion exchange membranes prepared by the reaction of cross-linked membranes having chloromethyl groups with 4-vinylpyridine and trimethylamine, J. Polym. Sci. Polym. Phys. Ed., 1999, 37, 1773. 

T. Sata, T. Yamaguchi and K. Matsusaki, Preparation and properties of composite membranes composed of anion-exchange membranes and polypyrrole, J. Phys. Chem.,... 

In the literature, there are numerous methods reported for the preparation of ion-exchange membranes with special properties, e.g., to be used for the production of table salt, as battery separators, as ion-selective electrodes, or in diffusion and Donnan dialysis. Significant effort has also been concentrated on the development of anion-exchange membranes with low fouling tendencies. 

Four kinds of anion exchange membranes (TMA. TEA. TPA and TBA) with different amine functional groups were prepared by reaction of the membranous copolymer composed of chloromethylstyrenc (CMS typc)and divinylstyrcne with various amines (trimethylaminc. iriethylamine. tri-w-propylaminc and tri-n-butylaminc). The structures of base membrane and anion exchange membrane can be expressed as respectively. The synthesis of base membrane and the procedure of immobilized amine in the base membrane are described in the following. 

In study of ionic exchange membrane, FT-IR method was usually used to analyze the chemical structures of formed membrane. Fang et. al., prepared novel anion exchange membranes based on the copolymer of methyl methacrylate, vinylbenzyl chloride and ethyl acrylate. The structure of membrane was mainly verified by measurement of FT-IR. This study remarkably showed the importance of FT-IR method in analysis of chemical structure of membranes.F I... 

Inasmuch as the use of epichlorohydrin concept, Agel et al. [13] developed a new and cheap type of anion exchange membranes (AEM) by preparing the polyepichlorohydrin (PECH) graft quaternary amines (DABCO, TEA) for use in alkaline cells. It s a quasi-gas impervious polymer membrane. The ionic conductivity was much improved to 10 S cm due to the low crystallinity and the anion exchange between Cf and OH ions on the polymer side chains. For the first time, the alkaline SPE employed in alkaline fuel cell, the test results exhibited good performance and could tolerate at high temperature up to 120°C. 

As it has been pointed out in past years [2], the most critical concerns of the alkaline membrane fuel cell technology are the low conductivity and the relatively poor stability of the anion exchange membranes that exist in the first years of the alkaline membrane fuel cell development. Before discussing these main concerns, a short review of anion exchange membrane preparation methods is presented. 

New versions of anion-exchange membranes were prepared via chlormethy-lation and amination of polysulfone. Amination using different diamines made it possible to investigate the effect of the length of the alkyl chain on membrane properties. The chain with the longest alkyl chain showed better hydroxyl ion conductivity and thermal stability than did those with a shorter chain (Park et al., 2008). 

Xu, T., Liu, Z., Yang, W. (2005) Fundamental studies of a new series of anion exchange membranes membrane prepared from poly(2,6-dimethyl-l,4-phenylene oxide) (PPO) and triethylamine. Journal of Membrane Science, 249, 183-191. 

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