SURFACE SULPHONATED POLYETHERIMIDE PERMEABLE MEMBRANE

摘要

PURPOSE:To obtain a permselective polyetherimide membrane with sulphonated surface so as to provide hydrophilic surface without impairing the mechanical strength of the membrane by sulphonating and adjusting the electric resistance of the surface to <=10<13>OMEGA. CONSTITUTION:The external surface layer and the surface of the internal tissue of a permselective polyetherimide membrane are sulphonated to reduce the surface electric resistance to <=10<13>OMEGA. The sulphonating reaction is carried out by allowing gaseous SO3 or chlorosulphonic acid to contact with the membrane or by allowing the membrane to contact with a dilute soln. of a sulphonating agent. Useful polyetherimide is one expressed by the formula and having >=30,000 average mol.wt.