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Solvent-resistant microporous polymide membranes

United States Patent

5,725,769
March 10, 1998
View the Complete Patent at the US Patent & Trademark Office
An asymmetric microporous membrane with exceptional solvent resistance and highly desirable permeability is disclosed. The membrane is made by a solution-casting or solution-spinning process from a copolyamic acid comprising the condensation reaction product in a solvent of at least three reactants selected from certain diamines and dianhydrides and post-treated to imidize and in some cases cross-link the copolyamic acid. The membrane is useful as an uncoated membrane for ultrafiltration, microfiltration, and membrane contactor applications, or may be used as a support for a permselective coating to form a composite membrane useful in gas separations, reverse osmosis, nanofiltration, pervaporation, or vapor permeation.
Miller; Warren K. (Bend, OR), McCray; Scott B. (Bend, OR), Friesen; Dwayne T. (Bend, OR)
Bend Research, Inc. (Bend, OR)
08/ 503,809
July 18, 1995
This invention was made with government support under Contract Nos. DE-FG0392ER81420 and DE-FG0391ER81230, awarded by the U.S. Department of Energy. The government has certain rights in this invention.