Importance

Loading Importance Indicators...

Abstract

A semipermeable membrane made of a polyaryl ether sulfone comprised of recurring units represented by the general formula (I): ##STR1## wherein X, X', X' and X'' are non-dissociative substituents, and l, m, n and o are integers of from 0 to 4. The membrane, which is composed of a single continuous polymer phase, has pores of a diameter increasing progressively and continuously from the surface layers to the center portion thereof. The membrane is prepared by the process wherein: the polyaryl ether sulfone is dissolved in a mixed solution to form a dope of the polyaryl ether sulfone; the polyaryl ether sulfone dope is extruded to form a fiber or film and, then; both sides of the fiber or film are contacted with a liquid miscible with the mixed solvent but incapable of dissolving the polyaryl ether sulfone to remove substantially all the mixed solvent from the fiber or film.

Loading the Abstract Image...

First Claim