Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Improved composite gas separation membranes from perfluoropolymers are disclosed. The membranes are formed by depositing an ultrathin, dense separation layer of a soluble amorphous perfluoropolymer on top of a porous polyethersulfone substrate. The membranes are particularly useful for the separation and recovery of volatile organic hydrocarbon vapors.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.