A new technique for the measurement of multicomponent gas transport through polymeric films

An apparatus to measure mixed gas permeation through polymer films is described. The system, based on a combination of manometric and gas chromatography techniques, allows straightforward determination of film permeabilities and selectivities over a wide range of feed pressures and compositions. This approach eliminates the need to use a downstream sweep gas and can be implemented by simple modification of pure gas permeation cells. Pure and mixed gas permeation data in polycarhonate films are reported for carbon dioxide and methane to illustrate the use of the equipment. The deviations between the pure and mixed gas results tend to be small and can he explained in terms of current theories of gas transport in glassy polymers.