This invention relates to a process for the formation of a neutralized sulfonated polymer having about 10 to about 60 meq. sulfonate groups, wherein the sulfonate groups are neutralized with a zinc counterion. A cement of a polymer having olefinic functional groups and a non-reactive solvent is contacted with a sulfonated agent such as an acyl sulfate. The sulfonated polymer is then neutralized with a solution of zinc acetate dissolved in a solvent system of methanol alone or methanol and water, wherein the volume percent of methanol based on non-reactive solvent is less than about 10. A carboxylic acid can be then added to the cement of the neutralized sulfonated polymer thereby forming a zinc salt of the carboxylic acid in situ, wherein the zinc salt of the carboxylic acid is a preferential plasticizer for the zinc sulfonate groups. The Brookfield viscosity at 0.6 rpm at room temperature of the cement of the zinc neutralized sulfonated polymer is less than about 50,000 cps.