PREPARATION AND GAS PERMEATION PROPERTIES OF SILICONE-COATED DRY POLYETHERSULFONE MEMBRANES

Flat polyethersulfone membranes of different pore sizes were prepared and characterized by ultrafiltration experiments with polyethylene glycol solutes at operating pressures below 50 psig. The membranes were then air-dried and surface coated with silicone rubber material. The surface coating was repeated, and the permeabilities of hydrogen and nitrogen were determined after each coating at an operating pressure of 50 psig. It was found that the permeation rate decreased rapidly with coating. Furthermore, a maximum in the H2/N2 permeability ratio appeared as the number of coatings was increased. The maximum permeability ratio increased as the pore size of the polyethersulfone sublayer decreased. The change in permeation rate with the operating period was also investigated. © 1990.