Film Permeability Determination Using Static Permeability Cells

The permeability of a plastic film to a gaseous compound depends on the nature of the film, the property of the chemicals, and environmental conditions. There are several terms that can be used to describe the permeability of a film to a compound, including flux, diffusion coefficient, and mass transfer coefficient (MTC). Flux and diffusion rate depend on the concentration gradient across the film. Mass transfer coefficient, however, is considered to be independent of the concentration gradient and dependent only on the properties of the film and the chemical, in addition to environmental conditions, such as temperature. Mass transfer coefficient is therefore a good parameter to represent the permeability of the film to a specific compound.