The Dow Chemical Company

Jee I Kau

Ritchie A Wessling

Donald L Schmidt

Dale M Pickelman

Richard F Fibiger

Sharon S Whipple

Thomas E Davis

Robert D Mahoney

Dana C Overman, Iii

Roger B Hornby

Ernest A Sharer

This invention relates to a novel composition useful for preparing a semi-permeable cellulose ester gas separation membrane, which composition includes a mixture of a cellulose ester, a solvent selected from the group consisting essentially of glycerol acetate, glycerol diacetate, glycerol triacetate, and mixtures thereof, and optionally the non-solvent glycerol. This invention also relates to a process of fabricating a cellulose ester gas separation membrane from said composition.

Preparing cellulose ester membranes for gas separation

This invention consists of a composition useful for preparing a cellulose ester membrane comprising (1) a cellulose ester, (2) glycerol monoacetate, glycerol diacetate, glycerol triacetate, or mixtures thereof, and (3) optionally glycerol, wherein the cellulose ester membrane prepared from said composition is useful for a membrane liquid separation process such as microfiltration, ultrafiltration, dialysis, or reverse osmosis. In another aspect, this invention is an improved process for using said composition to prepare a cellulose ester membrane by forming a mixture of said composition, heating the mixture to a temperature at which the mixture becomes a homogeneous fluid, and extruding, molding, or casting the homogeneous fluid into a membrane. Another aspect of this invention consists of a cellulose ester membrane wherein the fabricated membrane contains glycerol monoacetate, glycerol diacetate, glycerol triacetate, or mixtures thereof, and optionally glycerol.

Compositions useful for preparing cellulose ester membranes for liquid

A novel reverse osmosis membrane comprising a hydroxyalkyl methacrylate film cross-linked with a vinylaralkyl dialkylsulfonium salt is described. This film, when cast on a compatible substrate, results in a membrane of exceptional chlorine resistance.

Chlorine-stable membrane compositions

A novel composite membrane and methods of making the membrane are described. The discriminating layer of the membrane is prepared by reaction of a reactive cationic compound group with a compound bearing a nucleophilic moiety. At least one of the reactants bears an average of two or more reactive groups. The reaction product contains covalent bonds formed via charge eliminating reactions. In a preferred embodiment of the invention, the nucleophilic group is anionic and a coacervate is formed initially on a microporous substrate. The resulting membrane may be useful for reverse osmosis, gas or ultrafiltration separations.

Semi-permeable membranes prepared via reaction of cationic groups with

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Concord, CA, United States of America

Jee I Kau