Removal of residual solvent and monomers from a polymer through devolatilization can be the limiting step in production throughput. The process may be made more efficient by the addition of a cosolvent. In this work, the effects of two soluble gases, carbon dioxide, and ethylene, on the solubility and diffusivity of a number of solvents in poly(vinyl acetate) and poly(styrene) have been evaluated. The results indicate that in general the solubilities are reduced by the presence of the soluble gases and the diffusivity is significantly increased, with ethylene having the most pronounced effect. Larger solvent molecules benefit more by the presence of the added gas. The implications of this work are that replacement of noninteracting gases such as air or nitrogen with soluble gases can reduce solvent removal times and increase production rates. (C) 2008 Wiley Periodicals, Inc.