THIN SILICONE MEMBRANES‐THEIR PERMEATION PROPERTIES AND SOME APPLICATIONS

While the permeation of gases through solid materials is often a nuisance and sometimes a hazard, in recent years several useful applications have been found for this phenomenon. For example, H, is purified by diffusion through Pd-Ag foils, 0, partial pressures are measured in instruments dependent on 0, permeating through a plastic membrane, and artificial lungs based on permeation of 0, and CO, through thin polymeric membranes are being developed. These applications are only the beginning, for recent advances in membrane technology portend uses as far afield as water desalination by reverse osmosis and the separation of azeotropes by membrane perm-vaporation. When one wishes to separate noncondensable gases by a membrane technique, his first consideration should be whether a silicone rubber membrane can be used. This stems from the unusually high permeability of silicone rubber, indicated in TABLE 1, a tabulation of 0, permeabilities in various membranes.