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Abstract: Proton exchange membranes of sulfonated crosslinked polystyrene (SXLPS) particles dispersed in crosslinked poly(dimethyl siloxane) matrix were investigated. Three different sizes of particles—25, 8 and 0.08μm—were used at loadings from 0 to 50wt% and the influence of these variables on the water and methanol uptake and proton conductivity were observed. With the reduction in particle size in the composite membrane, more water or methanol uptake was observed. Three different states of water were revealed in the composite membranes by differential scanning calorimetry (DSC). The number of bound water molecules per SO3H group was 11–15 in membranes with 8- and 25-μm SXLPS. The ratio of bound to unbound water molecules was more than one in these membranes, whereas it was less than one in membranes with 0.08-μm SXLPS. The proton conductivities of the membranes increased with the increase in particle loading. At particle loadings above 35wt%, membranes containing 8-μm SXLPS had higher conductivity compared to 25-μm SXLPS at room temperature. The conductivity of membranes containing 0.08-μm SXLPS was restricted to 10−3 S/cm because of the inherently low IEC of the particles. Increasing the temperature from 30 to 80°C drastically enhanced the conductivity of the composite membranes compared to Nafion® 112. At 80°C, conductivities as high as 0.11±0.04S/cm were observed for membranes containing more than 30wt% of 25-μm SXLPS particles. [Copyright &y& Elsevier]

Describes the fabrication of a rheo-light scattering instrument for investigating the influence of shear on the phase behavior of polymer blends from a commercial parallel-plate rheometer. Projection of the laser light scattering; Angular velocities generated by the rheometer; Performance and accuracy of the light-scattering instrument.