(576c) Gas Permeation In Cation-Exchange Polymer Membranes

The effect of monovalent and divalent cations and sulfonate content on gas permeability of sulfonated polymers including PFSA and pentablock copolymer composed of poly[t-butyl styrene-b-ethylene-co-propylene-b-styrene –co-styrene sulfonate-b- ethylene-co-propylene-b-t-butyl styrene] (PBC) was investigated.  Their physical properties were as well evaluated using Dynamic Mechanical Analysis (DMA) in order to determine how transport properties correlated with polymer chain motion behavior.  Additionally, thermal responses of these materials were explored from a temperature range of 30^oC to 90^oC permitting the determination of activation energies of permeation, diffusion, and the heat of sorption.  The cross link density increase with the increasing sulfonate group content in polymers was expected to improve polymer gas barrier properties. Electrostatic network existing in cationic exchange membranes lead to significant changes of  polymer physical properties which was well correlated with transport properties.