A lattice-based activity coefficient model for gas sorption in glassy polymers

Abstract

The glassy polymer lattice sorption model (GPLSM) recognizes the presence of holes on the lattice and determines how the number of holes changes by taking into account swelling due to penetrant gas molecules. The GPLSM equation has a composition-dependent energy term similar to that in the Flory-Huggins theory and an entropic term based on the mixing of gas molecules and holes. A good representation of the experimental data is obtained for the carbon dioxide- and methane-polycarbonate systems