Conductivity and methanol permeability of sulfonated polystyrene membrane with dispersed montmorillonite nanoclay

Sulfonated polystyrene membranes with dispersed montmorillonite (MMT) nanoclay were prepared and their conductivities, methanol permeabilities and other characteristics were presented in this study. Sulfonated polystyrene membranes were recast by employing various solvents such as dimethyl sulfoxide (DMSO), chlorobenzene/n-butanol, chlorobenzene/DMSO and toluene/n-butanol. These solvents enhanced the ratio of proton conductivity to methanol permeability (C/P ratio) of sulfonated polystyrene membranes, especially DMSO. To reduce the methanol permeability, surfactant-modified MMT nanoclay, which has a large surface area, was blended with sulfonated polystyrene. The methanol permeability of the sulfonated polystyrene with dispersed nanoclay is 1/10 the value of Nafion (R) and the activation energy of methanol permeability is about 28 kJ/mol. As DMSO was used as a solvent, the conductivity over permeability ratio of the membrane with 14.38% sulfonation was double the value of Nafion (R). POLYM. COMPOS., 2012. (C) 2012 Society of Plastics Engineers