Praxair Technology, Inc.

Union Carbide Industrial Gases Technology Corporation

Union Carbide Corporation

L'air Liquide, Societe Anonyme a Directoire Et Conseil De Surveillance Pour L'etude Et L'exploitation Des Procedes Georges Claude

Joyce K Nelson

Benjamin Bikson

James Timothy Macheras

Yong Ding

Yurdagul F Ozcayir

James E Miller

Gertrud Gotz

Salvatore Giglia

Cheryl Ann Ford

Johann Katz Leroux

Jerry E Perrin

Samuel C Williams

Robert D Burchesky

A method for fabricating a composite membrane includes coating a substrate, such as, for example, an asymmetrical porous hollow fiber substrate, with a solution which includes a perfluorinated polymer and a perfluorinated solvent. Prior to coating, the substrate is impregnated with an impregnation fluid which is immiscible with the perfluorinated solvent. The method of the invention further includes removing the perfluorinated solvent and the impregnation fluid. A composite membrane includes a porous asymmetric hollow fiber substrate having an outer surface coated with a perfluoropolymer coating. Separation devices which include composite membranes and methods of separating a fluid mixture into a fraction enriched in a first component and a fraction depleted in that component also are described.

Method of preparing composite gas separation membranes from perfluoropolymers

Soluble polyamic acid salt (PAAS) precursors comprised of tertiary and quaternary amines, ammonium cations, sulfonium cations, or phosphonium cations, are prepared and fabricated into membranes that are subsequently imidized and converted into rigid-rod polyimide articles, such as membranes with desirable gas separation properties. A method of enhancing solubility of PAAS polymers in alcohols is also disclosed.

Polymide gas separation membranes

A preferred gas separation membrane made from a blend of a copolymer of 2,2-bis(trifluoromethyl)-4,5-difluoro-1,3-dioxole (BDD) and tetrafluoroethylene (TFE) with a 2,2,4-trifluoro-5-trifluoromethoxy-1,3-dioxide based polymer is disclosed, the membrane exhibiting an advantageous combination of gas separation and permeation properties for a number of gas separation applications. In particular, the membrane formed from the blend of these polymers exhibits unexpectedly high gas separation factors for separation of volatile organic hydrocarbon vapors (VOC) from air, compared to the component polymers that form the blends. Fabrication of composite membranes formed from perfluoropolymer blends is further disclosed.

Gas separation using membranes formed from blends of perfluorinated polymers

The invention relates to preparation and uses of novel polymeric materials, polyimide amic acid salts (PIAAS). The use of these materials for the fabrication of fluid separation membranes is further disclosed.

Polyimide amic acid salts and polyimide membranes formed therefrom

A process for preparing polyimide gas separation membranes is disclosed. The process involves preparing polyamic acid salt membrane precursors that are converted into polyimide membranes by mild thermal or chemical treatments. The gas separation processes that utilize these polyimide membranes are further disclosed.

Production and use of improved polyimide separation membranes

Multicomponent hollow fiber membrane tubesheets are disclosed that provide for improved membrane performance, particularly at high operating pressures. The multicomponent tubesheets have an epoxy resin having, when cured, different degrees of hardness in different portions of the tubesheet. Methods for producing such multicomponent tubesheets are also provided.

Hollow fiber membrane tubesheets of variable epoxy composition and hardness

Improved anisotropic fluid separation membranes are prepared from blends of polymers with surface energy differences. The membranes are formulated by processes wherein low surface energy polymer with desirable fluid separation and permeation characteristics is preferentially concentrated in the surface discriminating layer of the membrane.

Method of preparing membranes from blends of polymers

Improved fluid separation membranes are prepared from the blends of polyetherimide with phenylindane containing polyimides, wherein the amount of phenylindane containing polyimide in the blend is low. The present invention provides for highly anisotropic membranes particularly useful for gas separation applications and for preparation of composite membranes thereof.

Method of preparing membranes from blends of polyetherimide and

The present invention relates to fluid separation composite membranes prepared from sulfonated aromatic polymers in lithium salt form with sulfonic acid groups attached to aromatic rings that are incorporated into the main polymeric backbone.

Fluid separation composite membranes prepared from sulfonated aromatic

Multilayer composite membranes are produced in a one-step coating process that provides an interior gas separation layer and an external defect sealing layer.

Production and use of improved composite fluid separation membranes

The present invention relates to composite membranes and membranes which are formed from modified poly(phenylene oxide) polymers having improved film forming properties and separation characteristics. The present invention further relates to poly(phenylene oxide) polymer and modified poly(phenylene oxide) polymer, having improved membrane forming characteristics and processes for producing the same.

Modified poly(phenylene oxide) based membranes for enhanced fluid

A process for producing highly asymmetric hollow fibers useful as permselective gas separation membranes and for producing composite membranes thereof by extruding the spinning dope through a tube-in-orifice spinneret into a gas-filled chamber maintained at reduced pressure and then conveying the extruded hollow fiber through a liquid bath to solidify the extrudate.

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Lexington, MA, United States of America

Joyce K Nelson