GAS-PERMEABILITY OF COMPOSITE MEMBRANES

The permeability of a composite membrane consisting of a homogeneous layer and a porous layer has been derived theoretically by assuming that the permeation through the homogeneous layer obeys Fick's law and that permeation through the porous layer is free molecular flow. The permeabilities of various gases through homogeneous polycarbonate membrane, neutron-irradiated, nonsodium hydroxide-etched polycarbonate membrane, and their composite membrane were tested. A two-layer series model, incorporating the effect of neutron irradiation which produces some non-penetrating pores in the porous membrane layer, is proposed and agreed quite well with the experimental data.