Carboxylated and Sulfonated Poly(arylene-co-arylene sulfone)s:  Thermostable Polyelectrolytes for Fuel Cell Applications

Abstract

The synthesis of novel soluble copolyarylenes, their functionalization with sulfonic and carboxylic acid groups, and the determination of fuel cell relevant parameters (swelling behavior, methanol permeation, and ionic conductivity) are described. The Ni(0)-catalyzed homocoupling reaction of aryl chlorides was employed for the polymerizations. Carboxylic acid groups were incorporated by copolymerization of methyl 2,5-dichlorobenzoate and subsequent hydrolysis. The composition was varied from 53 to 100 mol % carboxylic acid groups. Sulfonic acid groups were introduced by sulfonation with chlorosulfonic acid. Flexible and transparent membranes with sulfonic and/or carboxylic acid groups were prepared that exhibited higher proton conductivities (values in the range of σ ) 0.11-0.23 S/cm) compared to those of Nafion and sulfonated PEEK as a result of higher ion exchange capacity and water content. Incorporation of carboxylic acid groups led to a reduced water uptake but lower conductivities.

Preparation and Properties of Cross‐linked Sulphonated Poly(sulphide sulphone) Membranes for Fuel Cell Applications

“…However, some drawbacks such as their high cost and high gas and methanol permeability seriously limit their industrial application. In the past decade a large number of sulphonated hydrocarbon polymers such as sulphonated poly(ether sulphone)s [1][2][3], sulphonated poly(ether ether ketone)s [4,5], sulphonated polyphenylenes [6][7][8], sulphonated poly(sulphide sulphone)s (SPSSF) [9] and sulphonated polyimides (SPI) [10][11][12][13][14][15][16][17] have been developed in order to replace Nafion. These materials are much cheaper and many of them have been reported to have comparable or even high-…”

Catalytic Polymerization and Post Polymerization Catalysis Fifty Years After the Discovery of Ziegler's Catalysts

“…[247] These crosscoupling routes have been applied to prepare a wide variety of polyarylenes and polyarylenevinylenes [248,249] useful as electrically conducting polymers, [250] thin films for the surface emitting circular grating polymer laser, [251] polymer semiconductors, [252] conjugated polymers with band gap design for light emitting LEDs, [253] water-soluble rigid rod polyelectrolytes, [254] and novel polyelectrolyte membranes for fuel cells. [255] Polymer architectures have been tuned to achieve improved processing and novel property profiles. Although copolyarylenes, copolyarylenesulfones and copolyaryleneketones are attractive as thermally and hydrolytically stable engineering plastics, the very large amount of salts produced as byproducts represents an important ecological and economical drawback of this technology.…”

Synthesis of a new sulfonated monomer for poly(aryl ether)s

“…High performance polymers have been examined as PEM candidates because they offer the potential of better performance at higher temperatures. Examples of sulfonated, high-performance polymers that have been investigated include polyimides [2], poly(ether sulfones) [3,4], and poly(aryl ether ether nitrile)s [5].…”