Abstract: The present invention discloses a new type of high performance polymer membranes prepared from aromatic polyimide membranes by thermal treating and crosslinking and methods for making and using these membranes. The polymer membranes were prepared from aromatic polyimide membranes by thermal treating under inert atmosphere followed by crosslinking preferably by using a UV radiation source. The aromatic polyimide membranes were made from aromatic polyimide polymers comprising both pendent hydroxy functional groups ortho to the heterocyclic imide nitrogen and cross-linkable functional groups in the polymer backbone. The membranes showed significantly improved selectivity and permeability for gas separations compared to the aromatic polyimide membranes without any treatment. The membranes can be fabricated into any convenient geometry and are not only suitable for a variety of liquid, gas, and vapor separations, but also can be used for other applications such as for catalysis and fuel cell applications.

Abstract: The present invention discloses a new type of high performance mixed matrix membranes (MMMs) and methods for making and using the same. The MMMs comprise a continuous polymer matrix and at least two types of molecular sieves dispersed therein. The continuous polymer matrix in the MMM contains at least one type of polymer. The MMM in the form of a dense film, asymmetric flat sheet membrane or otherwise prepared exhibits simultaneously improved selectivity and permeability for gas separations compared to polymer membranes made from a continuous polymer matrix without any molecular sieves or with only one type of molecular sieve. MMMs of the present invention are suitable for a wide range of gas, vapor, and liquid separations such as alcohol/water, CO2/CH4, H2/CH4, O2/N2, CO2/N2, olefin/paraffin, iso/normal paraffins, and other light gases separations.

Abstract: The present invention is for crosslinked membranes and in particular for crosslinked poly(ethylene oxide)-cellulose acetate-silsesquioxane (PEO-CA-Si) organic-inorganic hybrid membranes and their use in gas separation. These crosslinked PEO-CA-Si membranes were prepared by in-situ sol-gel co-condensation of crosslinkable PEO-organotrialkoxysilane and CA-organotrialkoxysilane polymers in the presence of acetic acid catalyst during the formation of membranes. The crosslinkable PEO- and CA-organotrialkoxysilane polymers were synthesized via the reaction between the hydroxyl groups on PEO (or on CA) and the isocyanate on organotrialkoxysilane to form urethane linkages under mild conditions. The crosslinked PEO-CA-Si membranes exhibited both increased selectivity of CO2/N2 and CO2 permeability as compared to a CA membrane, suggesting that these membranes are very promising for gas separations such as CO2/N2 separation.

Abstract: A gas separation membrane comprises a blend of polyethersulfone (PES) and aromatic polyimide polymers that may comprise a plurality of first repeating units of formula (I), wherein X1, X 2 and X3 are herein defined.

Abstract: Hollow fiber membranes, such as those used in air separation modules, are generally made from solution spinning. Typically, solvent is present in the bore of the fiber for the spinning process. This solvent, in addition to the solvent already present in the polymer dope solution, may cause voids in the fiber material. By adding citric acid to the polymer dope material, these voids may be reduced or eliminated.

Abstract: New ionic liquid-solid-polymer mixed matrix membranes were proposed for gas separations such as CO2 removal from natural gas or N2. For the new mixed matrix membranes, the solids such as carbon molecular sieves, microporous molecular sieves, MCM-41 type of mesoporous molecular sieves, or polymer of intrinsic microporosity (PIM) are coated (or impregnated) with ionic liquids such as 1-butyl-3-methyl imidazolium bis[trifluoromethylsulfonyl]amide. The ionic liquids coated or impregnated solids are then dispersed in the continuous polymer matrix to form mixed matrix membranes. These hybrid mixed matrix membranes will combine the properties of the continuous polymer phase, the ionic liquids, and the dispersed ionic liquids coated or impregnated solids phase, which will possibly open up new opportunities for gas separation processes such as CO2 separation from natural gas or flue gas.

Abstract: The present invention discloses a novel method to improve the selectivities of polybenzoxazole (PBO) membranes prepared from aromatic polyimide membranes for gas, vapor, and liquid separations. The PBO membranes that were prepared by thermal treating aromatic polyimide membranes containing between 0.05 and 20 wt-% of a poly(styrene sulfonic acid) polymer. These polymers showed up to 95% improvement in selectivity for CO2/CH4 and H2/CH4 separations compared to PBO membranes prepared from corresponding aromatic polyimide membranes without a poly(styrene sulfonic acid) polymer.

Abstract: The present invention discloses a blends of an aromatic polyimide polymer and a polymer containing aromatic sulfonic acid groups that can be converted into polybenzoxazole (PBO) membranes for gas, vapor, and liquid separations. The PBO membranes that were prepared by thermal treating aromatic polyimide membranes containing between 0.05 and 20 wt-% of a poly(styrene sulfonic acid) polymer. These polymers showed up to 95% improvement in selectivity for CO2/CH4 and H2/CH4 separations compared to PBO membranes prepared from corresponding aromatic polyimide membranes without a poly(styrene sulfonic acid) polymer.

Abstract: A new family of silicon-based polymers has been prepared in which organic host components are bound covalently. The polymer is a polysilsesquioxane matrix comprising, for example, hosts such as cyclodextrins (CD) or calixarenes (CX).

Abstract: Nano-molecular sieve-polymer mixed matrix membranes (MMMs) for CO2 removal from natural gas have been prepared by incorporating dispersible template-free nano-molecular sieves into polymer matrices such as Matrimid 5218 polyimide matrix or Ultem 1000 polyetherimide matrix. The nano-molecular sieves used in this invention include template-free nano-AlPO-18, nano-AlPO-5, nano-Silicalite, nano-SAPO-34, and PEG-functionalized nano-Silicalite. These template-free nano-molecular sieves were synthesized by an organic ligand grafting method.

Abstract: Mixed matrix membranes that are capable of separation and purification of gas mixtures are disclosed. These membranes comprise polymers that include dispersed therein nanomolecular sieve particles. In a preferred embodiment, the nanomolecular sieve particles contain attached functional groups to prevent their agglomeration.

Abstract: The present invention discloses high performance polybenzoxazole membranes prepared from aromatic poly(o-hydroxy amide) membranes by thermal cyclization and a method for using these membranes. The polybenzoxazole membranes were prepared by thermal treating aromatic poly(o-hydroxy amide) membranes in a temperature range of 200° to 550° C. under inert atmosphere. The aromatic poly(o-hydroxy amide) membranes used for making the polybenzoxazole membranes were prepared from aromatic poly(o-hydroxy amide) polymers comprising pendent phenolic hydroxyl groups ortho to the amide nitrogen in the polymer backbone. In some embodiments of the invention, the polybenzoxazole membranes may be subjected to an additional crosslinking step to increase the selectivity of the membranes.

Abstract: The present invention discloses high performance polybenzoxazole membranes prepared from aromatic poly(o-hydroxy amide) membranes by thermal cyclization and a method for using these membranes. The polybenzoxazole membranes were prepared by thermal treating aromatic poly(o-hydroxy amide) membranes in a temperature range of 200° to 550° C. under inert atmosphere. The aromatic poly(o-hydroxy amide) membranes used for making the polybenzoxazole membranes were prepared from aromatic poly(o-hydroxy amide) polymers comprising pendent phenolic hydroxyl groups ortho to the amide nitrogen in the polymer backbone. In some embodiments of the invention, the polybenzoxazole membranes may be subjected to an additional crosslinking step to increase the selectivity of the membranes.

Abstract: This invention discloses a composition of, a method of making, and an application of high plasticization-resistant chemically cross-linked organic-inorganic hybrid membranes such as cross-linked cellulose acetate-cellulose triacetate-polyurethanepropylsilsesquioxane membranes. These cross-linked membranes with covalently interpolymer-chain-connected hybrid networks were prepared via a sol-gel condensation polymerization of cross-linkable organic polymer-organosilicon alkoxide precursor membrane materials. CO2 plasticization tests on these cross-linked membranes demonstrate extremely high CO2 plasticization resistance under CO2 pressure up to 5516 kPa (800 psig). These new cross-linked membranes can be used not only for gas separations such as CO2/CH4 and CO2/N2 separations, O2/N2 separation, olefin/paraffin separations (e.g. propylene/propane separation), iso/normal paraffins separations, but also for liquid separations such as desalination.

Abstract: The present invention discloses microporous aluminophosphate (AlPO4) molecular sieve membranes and methods for making and using the same. The microporous AlPO4 molecular sieve membranes, particularly small pore microporous AlPO-14 and AlPO-18 molecular sieve membranes, are prepared by three different methods, including in-situ crystallization of a layer of AlPO4 molecular sieve crystals on a porous membrane support, coating a layer of polymer-bound AlPO4 molecular sieve crystals on a porous membrane support, and a seeding method by in-situ crystallization of a continuous second layer of AlPO4 molecular sieve crystals on a seed layer of AlPO4 molecular sieve crystals supported on a porous membrane support.

Abstract: Mixed matrix membranes that are capable of separation and purification of gas mixtures are disclosed. These membranes comprise polymers that include dispersed therein nanomolecular sieve particles. In a preferred embodiment, the nanomolecular sieve particles contain attached functional groups to prevent their agglomeration.

Abstract: The present invention involves the use of a multi-stage membrane system for gas, vapor, and liquid separations. In this multi-stage membrane system, high selectivity and high permeance or at least high selectivity polybenzoxazole membranes or cross-linked polybenzoxazole membranes are applied for a pre-membrane or both the pre-membrane and the secondary membrane. A primary membrane can be from conventional glassy polymers. This multi-stage membrane system can reduce inter-stage compression cost, increase product recovery and product purity for gas, vapor, and liquid separations. It can also save the cost compared to the system using all the high cost polybenzoxazole membranes or cross-linked polybenzoxazole membranes.

Abstract: The present invention is for crosslinked membranes and in particular for crosslinked poly(ethylene oxide)-cellulose acetate-silsesquioxane (PEO-CA-Si) organic-inorganic hybrid membranes and their use in gas separation. These crosslinked PEO-CA-Si membranes were prepared by in-situ sol-gel co-condensation of crosslinkable PEO-organotrialkoxysilane and CA-organotrialkoxysilane polymers in the presence of acetic acid catalyst during the formation of membranes. The crosslinkable PEO- and CA-organotrialkoxysilane polymers were synthesized via the reaction between the hydroxyl groups on PEO (or on CA) and the isocyanate on organotrialkoxysilane to form urethane linkages under mild conditions. The crosslinked PEO-CA-Si membranes exhibited both increased selectivity of CO2/N2 and CO2 permeability as compared to a CA membrane, suggesting that these membranes are very promising for gas separations such as CO2/N2 separation.

Abstract: A gas separation membrane comprises a blend of polyethersulfone (PES) and aromatic polyimide polymers that may comprise a plurality of first repeating units of formula (I), wherein X1, X 2 and X3 are herein defined.

Abstract: This invention discloses a composition of, a method of making, and an application of high plasticization-resistant chemically cross-linked organic-inorganic hybrid membranes such as cross-linked cellulose acetate-cellulose triacetate-polyurethanepropylsilsesquioxane membranes. These cross-linked membranes with covalently interpolymer-chain-connected hybrid networks were prepared via a sol-gel condensation polymerization of cross-linkable organic polymer-organosilicon alkoxide precursor membrane materials. CO2 plasticization tests on these cross-linked membranes demonstrate extremely high CO2 plasticization resistance under CO2 pressure up to 5516 kPa (800 psig). These new cross-linked membranes can be used not only for gas separations such as CO2/CH4 and CO2/N2 separations, O2/N2 separation, olefin/paraffin separations (e.g. propylene/propane separation), iso/normal paraffins separations, but also for liquid separations such as desalination.