Effect of chemical composition on gas transport properties of ethylene-based ionomers

Transport properties of oxygen and carbon dioxide in three ethylene-acrylic acid ionomers, characterized by different amounts of acrylic acid groups, percentage of neutralization and counterion type, have been investigated. Gas permeation experiments have been performed in the 25-65 degrees C range. Gas permeabilities, diffusivities and solubilities were evaluated along with activation energies and heats of solution. The transport properties have been analysed in order to correlate the effect of counterion type and its concentration on macromolecular mobility and on polymer-gas interaction, which in turn are the factors determining permeation rate.