Sulfonated aromatic polymer membranes

In sulfonated aromatic polymer membranes, therefore, Donnan ion exclusion appears to be an important contributor to performance. In contact with dilute feedwaters, these strongly anionic membranes exclude feedwater anions from entering the membranes by charge repulsion effects, thus inhibiting salt passage. In more concentrated salt solutions, the charge repulsion effects are shielded by the high ionic activity of the feedwater. 

Sgreccia, E., Chailan, J.F., Khadhraoui, M., Di Vona, M.L., Knautha, R, Mechanical properties of proton-conducting sulfonated aromatic polymer membranes Stress-strain tests and dynamical analysis, J. Power Sources, 2010, 195, 7770-7775. 

Sulfonation of aromatic polymers has been explored as a method to produce hydrophilic polymers with water permeability and salt rejection characteristics. These have been of interest because of their potentially high degree of chlorine resistance. The use of sulfonated aromatic polymers for reverse osmosis membranes began in the late 1960 s with the work of Plummer, Kimura and LaConti of General Electric Company.82 Polyphenylene oxide [poly(2,6-di-... 

To prepare new and inexpensive membranes, various trials have been made 196 sulfonated aromatic polyether membrane such as polyether ketones (PEEK),197 sulfonated polysulfone198 and membranes from sulfonated polyphenylene sulfide,199 phosphoric acid-doped polybenzimidazole, (PBI),200 polybenzimidazole having sulfonic acid groups,201 polybenzimidazole with phosphonic acid groups,202 a blend membrane of polybenzimidazole and sulfonated polysulfone,203 sulfonated phosphazene polymer.204... 

Compared to Nafion , a stronger confinement of water in the narrow channels of the sulfonated aromatic polymers leads to a significantly lower dielectric constant of the waters of hydration (20 compared to 64 in fully hydrated Nafion [185,186]). Of particular relevance to macroscopic models are the diffusion coefficients of water. As the amount of water sorbed by the membrane increases and molecular-scale effects are reduced, the properties approach those of bulk water on the molecular scale. Figme 26 shows the trend in proton mobility. Da, and water self-diffusion, Dh20. for Nafion and the sulfonated polyetherketone membrane [134]. 

Sulfonated Aromatic Polymers for Fuel Cell Membranes... 

Among these, acidity of ionic groups and membrane morphol-ogy appear to be crucial, and they are inter-related. Kreuer et al. [23] reported that typical sulfonated aromatic polymers are unable to form defined hydrophilic domains, as the rigid aromatic backbone prevents the formation of continuous conducting channels. Thus, various strategies have been pursued to obtain efficient ionic networks for enhancing the proton conductivity. 

Manufacture of sulfonated aromatic polymers and their use in the production of membranes 285... 

Manufacture of Sulfonated Aromatic Polymers and their Use in the Production of Membranes... 

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