Abstract: The polyimide blend membrane in the present invention was prepared by blending a first aromatic polyimide with high permeability and a second aromatic polyimide with high selectivity for gas separation. The polyimide blend membrane in the present invention showed improved permeability compared to membranes made from the second aromatic polyimide and improved selectivity compared to membranes made from the first aromatic polyimide.

Abstract: An asymmetric integrally-skinned flat sheet membrane comprising a miscible blend of an aromatic polyethersulfone (PES) polymer and an aromatic polyimide polymer is used for gas separations such as hydrogen purification, separation of hydrogen and methane and to separate other gases and liquids. UV radiation may be applied to the surface of the membrane for improved properties.

Abstract: The polyimide blend membrane in the present invention was prepared by blending a first aromatic polyimide with high permeability and a second aromatic polyimide with high selectivity for gas separation. The polyimide blend membrane in the present invention showed improved permeability compared to membranes made from the second aromatic polyimide and improved selectivity compared to membranes made from the first aromatic polyimide.

Abstract: An asymmetric integrally-skinned flat sheet membrane comprising a miscible blend of an aromatic polyethersulfone (PES) polymer and an aromatic polyimide polymer is used for gas separations such as hydrogen purification, separation of hydrogen and methane and to separate other gases and liquids. UV radiation may be applied to the surface of the membrane for improved properties.

Abstract: A polyimide polymer having hydroxyl and acetoxy function groups is provided together with a membrane made from the polymer. Also provided is a process for separating at least one gas from a mixture of gases using a polyimide membrane comprising a polyimide polymer with hydroxyl and acetoxy functional the process comprising: (a) providing the polyimide membrane comprising the polyimide polymer with hydroxyl and acetoxy functional groups which is permeable to the at least one gas; (b) contacting the mixture on one side of the polyimide membrane to cause said at least one gas to permeate the membrane; and (c) removing from the opposite side of the membrane a permeate gas composition comprising a portion of said at least one gas which permeated the polyimide membrane.

Abstract: The present invention involves a type of nanoporous macrocycle-containing cross-linked polymeric membrane, a method of making the membrane, and the use of such a novel membrane system for natural gas liquids (NGL) recovery, fuel gas conditioning, natural gas pre-treatment, sulfur removal from fluidized catalytic cracking (FCC) and other naphtha streams, as well as aromatic separations such as aromatic/paraffin separation and xylene separation. The nanoporous macrocycle-containing cross-linked polymeric membrane is prepared from a diisocyanate-terminated polyether or a diisocyanate-terminated polyester, that is crosslinked with a nanoporous macrocycle comprising hydroxyl functional groups such as ?-, ?-, and ?-cyclodextrins.

Abstract: A polyimide polymer having hydroxyl and acetoxy function groups is provided together with a membrane made from the polymer. Also provided is a process for separating at least one gas from a mixture of gases using a polyimide membrane comprising a polyimide polymer with hydroxyl and acetoxy functional the process comprising: (a) providing the polyimide membrane comprising the polyimide polymer with hydroxyl and acetoxy functional groups which is permeable to the at least one gas; (b) contacting the mixture on one side of the polyimide membrane to cause said at least one gas to permeate the membrane; and (c) removing from the opposite side of the membrane a permeate gas composition comprising a portion of said at least one gas which permeated the polyimide membrane.

Abstract: A copolyimide membrane is provided by the present invention that is effective in separating olefins and paraffins. The membrane with very high selectivity and permeability in the present invention is used in a process for separating olefins from a mixture of olefins and paraffins, the process comprising providing a copolyimide membrane with very high selectivity and high permeability described in the present invention which is permeable to said olefin; (b) contacting the olefin/paraffin mixture on one side of the copolyimide membrane with very high selectivity and high permeability described in the present invention to cause the olefin to permeate the membrane; and (c) removing from the opposite side of the membrane a permeate gas composition comprising a portion of the olefin which permeated through the membrane. Ethylene, propylene, butene, or pentene is separated from ethane, propane, butane, or pentane, respectively with up to 99 mole % olefin content in the permeate.

Abstract: The present invention involves a type of nanoporous macrocycle-containing cross-linked polymeric membrane, a method of making the membrane, and the use of such a novel membrane system for natural gas liquids (NGL) recovery, fuel gas conditioning, natural gas pre-treatment, sulfur removal from fluidized catalytic cracking (FCC) and other naphtha streams, as well as aromatic separations such as aromatic/paraffin separation and xylene separation. The nanoporous macrocycle-containing cross-linked polymeric membrane is prepared from a diisocyanate-terminated polyether or a diisocyanate-terminated polyester, that is crosslinked with a nanoporous macrocycle comprising hydroxyl functional groups such as ?-, ?-, and ?-cyclodextrins.

Abstract: Cross-linked rubbery polyurethane-ether polymeric membranes are made from cross-linked rubbery polyurethane-ether polymers that are synthesized from a diisocyanate-terminated polyether and a tetrol with four hydroxyl functional groups. The hydroxyl groups on the tetrol react with the isocyanate groups on the diisocyanate-terminated polyether to form urethane bonds. The cross-linked rubbery polyurethane-ether polymeric membrane selectively permeate condensable vapors such as C3 to C35 hydrocarbons, aromatics, water vapor, carbon dioxide, and hydrogen sulfide and rejects methane and ethane. The cross-linked rubbery polyurethane-ether polymeric membrane have high permeance for condensable vapors, high selectivity for condensable vapors over methane and ethane, and high resistance to liquid chemicals.

Abstract: Cross-linked rubbery polyurethane-ether polymeric membranes are made from cross-linked rubbery polyurethane-ether polymers that are synthesized from a diisocyanate-terminated polyether and a tetrol with four hydroxyl functional groups. The hydroxyl groups on the tetrol react with the isocyanate groups on the diisocyanate-terminated polyether to form urethane bonds. The cross-linked rubbery polyurethane-ether polymeric membrane selectively permeate condensable vapors such as C3 to C35 hydrocarbons, aromatics, water vapor, carbon dioxide, and hydrogen sulfide and rejects methane and ethane. The cross-linked rubbery polyurethane-ether polymeric membrane have high permeance for condensable vapors, high selectivity for condensable vapors over methane and ethane, and high resistance to liquid chemicals.

Abstract: The present invention discloses high performance cross-linked polyimide asymmetric flat sheet membranes and a process of using such membranes. The cross-linked polyimide asymmetric flat sheet membranes have shown CO2 permeance higher than 80 GPU and CO2/CH4 selectivity higher than 20 at 50° C. under 6996 kPa of a feed gas with 10% CO2 and 90% CH4 for CO2/CH4 separation.

Abstract: A fluorinated ethylene-propylene polymeric membrane comprising a copolymer comprising 2,3,3,3-tetrafluoropropene and vinylidene fluoride is disclosed. The fluorinated ethylene-propylene polymeric membranes of the invention are especially useful in gas separation processes in air purification, petrochemical, refinery, and natural gas industries.

Abstract: A fluorinated ethylene-propylene polymeric membrane comprising a copolymer comprising 2,3,3,3-tetrafluoropropene and vinylidene fluoride is disclosed. The fluorinated ethylene-propylene polymeric membranes of the invention are especially useful in gas separation processes in air purification, petrochemical, refinery, and natural gas industries.

Abstract: The present invention discloses new types of poly(amidoamine) (PAMAM) dendrimer-cross-linked polyimide membranes and methods for making and using these membranes. The membranes are prepared by cross-linking of asymmetric aromatic polyimide membranes using a PAMAM dendrimer as the cross-linking agent. The PAMAM-cross-linked polyimide membranes showed significantly improved selectivities for CO2/CH4 compared to a comparable uncrosslinked polyimide membrane. For example, PAMAM 0.0 dendrimer-cross-linked asymmetric flat sheet poly(3,3?,4,4?-diphenylsulfone tetracarboxylic dianhydride-3,3?,5,5?-tetramethyl-4,4?-methylene dianiline) (DSDA-TMMDA) polyimide membrane showed CO2 permeance of 135.2 A.U. and CO2/CH4 selectivity of 20.3. However, the un-cross-linked DSDA-TMMDA asymmetric flat sheet membrane showed much lower CO2/CH4 selectivity (16.5) and higher CO2 permeance (230.8 GPU).