SELECTIVELY PERMEABLE ASYMMETRIC MEMBRANE OF POLYETHERIMIDE

摘要

A gas-selectively permeable membrane and a method of forming said membrane are described. This membrane is an asymmetrical pore diameter structure film made of a polyetherimide having the recurring unit represented by formula (A) or a mixture of said polyetherimide and at least one polymer having the recurring unit represented by formula (B), wherein the mean pore diameter of a dense layer of the asymmetrical pore diameter structure film is 0.5 micron or less and the mean thickness of the dense layer is 10 microns or less: < IMG > wherein x is a natural number including zero, Q is < IMG > This membrane is superior in heat resistance and is suitable for use in the isolation of argon from air, for the concentration of oxygen, for the concentration of hydrogen in twon gas, and so forth.