Patents by Inventor Chung M. Tam

Chung M. Tam has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Method of manufacturing a reverse osmosis membrane and the membrane so produced
    Patent number: 4894159
    Abstract: Reverse osmosis membranes are manufactured by casting a polysulfone casting composition comprising:(i) an aromatic polysulfone derivative having repeat units, at least an average of about 20% of which are carboxylated and are of the formula I: ##STR1## , wherein each R in each formula is ortho to the sulfone, at least one R in each formula is a carboxyl group with any remainder thereof being hydrogen, and(ii) a solvent for the aromatic polysulfone derivative, then evaporating solvent from the casting composition and then gelling the casting composition into a reverse osmosis membrane. The permeability of the reverse osmosis membrane may be increased by the addition of a non-solvent for the aromatic polysulfone derivative to the casting composition.
    Type: Grant
    Filed: June 5, 1989
    Date of Patent: January 16, 1990
    Assignee: National Research Council of Canada
    Inventors: Michael D. Guiver, Andre Y. Tremblay, Chung M. Tam