Abstract: The present invention discloses a novel method of making high performance mixed matrix membranes (MMMs) using stabilized concentrated suspensions of solvents, uniformly dispersed polymer stabilized molecular sieves, and at least two different types of polymers as the continuous blend polymer matrix. MMMs as dense films or asymmetric flat sheet or hollow fiber membranes fabricated by the method described in the current invention exhibit significantly enhanced permeation performance for separations over the polymer membranes made from the continuous blend polymer matrix. 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 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: This invention relates to a method of making flat sheet asymmetric membranes, including cellulose diacetate/cellulose triacetate blended membranes, polyimide membranes, and polyimide/polyethersulfone blended membranes by formulating the polymer or the blended polymers dopes in a dual solvent mixture containing 1,3 dioxolane and a second solvent, such as N,N?-methylpyrrolidinone (NMP). The dopes are tailored to be closed to the point of phase separation with or without suitable non-solvent additives such as methanol, acetone, decane or a mixture of these non-solvents. The flat sheet asymmetric membranes are cast by the phase inversion processes using water as the coagulation bath and annealing bath. The dried membranes are coated with UV curable silicone rubber. The resulting asymmetric membranes having a skin thickness of less than 100 nm, exhibit excellent permeability and selectivity compared to the intrinsic dense film performances.

Abstract: The present invention discloses a new type of high performance polymer membranes derived from aromatic polyimide membranes and methods for making and using these membranes. The polymer membranes described in the present invention were derived from aromatic polyimide membranes by crosslinking followed by thermal treating. 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 high performance polymer membranes showed significantly improved permeability for gas separations compared to the aromatic polyimide membranes without any treatment. The high performance polymer membranes also showed significantly improved selectivity for gas separations compared to the thermal-treated but non-UV-crosslinked aromatic polyimide membranes.

Abstract: The present invention discloses blend polymer membranes comprising thermally rearranged polymers derived from aromatic polyimides containing ortho-positioned functional groups and methods for making and using these blend polymer membranes. The blend polymer membranes described in the current invention are prepared by heat treatment of blend polymer membranes comprising aromatic polyimides containing ortho-positioned functional groups such as —OH or —SH groups. In some instances, an additional crosslinking step is performed to improve the selectivity of the membrane. These blend polymer membranes have improved flexibility, reduced cost, improved processability, and enhanced selectivity and/or permeability compared to the comparable polymer membranes that comprise a single polymer.

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: In the present invention high performance cross-linked polybenzoxazole and polybenzothiazole polymer membranes and methods for making and using these membranes have been developed. The cross-linked polybenzoxazole and polybenzothiazole polymer membranes are prepared by: 1) first synthesizing polyimide polymers comprising pendent functional groups (e.g., —OH or —SH) ortho to the heterocyclic imide nitrogen and cross-linkable functional groups in the polymer backbone; 2) fabricating polyimide membranes from these polymers; 3) converting the polyimide membranes to polybenzoxazole or polybenzothiazole membranes by heating under inert atmosphere such as nitrogen or vacuum; and 4) finally converting the membranes to high performance cross-linked polybenzoxazole or polybenzothiazole membranes by a crosslinking treatment, preferably UV radiation. The membranes can be fabricated into any convenient geometry.

Abstract: The present invention discloses new types of polybenzoxazole-based mixed matrix membranes and methods for making and using these membranes. The polybenzoxazole-based mixed matrix membranes are prepared by fabricating a polyimide-based mixed matrix membrane by dispersing molecular sieve particles in a continuous aromatic polyimide matrix with pendent hydroxyl groups ortho to the heterocyclic imide nitrogen; and then converting the polyimide-based mixed matrix membrane to a polybenzoxazole-based mixed matrix membrane by heating between 300° and 600° C. under inert atmosphere or vacuum. The polybenzoxazole-based mixed matrix membranes of the present invention can be fabricated into any convenient geometry such as flat sheet (or spiral wound), tube, hollow fiber, or thin film composite.

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: In the present invention high performance cross-linked polybenzoxazole and polybenzothiazole polymer membranes and methods for making and using these membranes have been developed. The cross-linked polybenzoxazole and polybenzothiazole polymer membranes are prepared by: 1) first synthesizing polyimide polymers comprising pendent functional groups (e.g., —OH or —SH) ortho to the heterocyclic imide nitrogen and cross-linkable functional groups in the polymer backbone; 2) fabricating polyimide membranes from these polymers; 3) converting the polyimide membranes to polybenzoxazole or polybenzothiazole membranes by heating under inert atmosphere such as nitrogen or vacuum; and 4) finally converting the membranes to high performance cross-linked polybenzoxazole or polybenzothiazole membranes by a crosslinking treatment, preferably UV radiation. The membranes can be fabricated into any convenient geometry.

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 new types of polybenzoxazole-based mixed matrix membranes and methods for making and using these membranes. The polybenzoxazole-based mixed matrix membranes are prepared by fabricating a polyimide-based mixed matrix membrane by dispersing molecular sieve particles in a continuous aromatic polyimide matrix with pendent hydroxyl groups ortho to the heterocyclic imide nitrogen; and then converting the polyimide-based mixed matrix membrane to a polybenzoxazole-based mixed matrix membrane by heating between 200° and 600° C. under inert atmosphere or vacuum. The polybenzoxazole-based mixed matrix membranes of the present invention can be fabricated into any convenient geometry such as flat sheet (or spiral wound), tube, hollow fiber, or thin film composite.

Abstract: The present invention the manufacture of a membrane for gas and liquid separations in which a polymer layer is applied directly to a tricot fabric instead of the conventional cloth or glass or metal substrate.

Abstract: The present invention discloses fluoropolymer coated membranes and methods for making and using these membranes. The fluoropolymer coated membranes described in the current invention are prepared by coating a porous asymmetric membrane layer with a thin layer of fluoropolymer coating. The porous asymmetric membrane layer comprises an asymmetric cellulosic membrane, an asymmetric polymer membrane, or an asymmetric molecular sieve/polymer mixed matrix membrane with a low selectivity and high permeance. The fluoropolymer coating improves the selectivity of the porous asymmetric membrane layer and maintains the membrane performance with time.

Abstract: This invention relates to a method of making flat sheet asymmetric membranes, including cellulose diacetate/cellulose triacetate blended membranes, polyimide membranes, and polyimide/polyethersulfone blended membranes by formulating the polymer or the blended polymers dopes in a dual solvent mixture containing 1,3 dioxolane and a second solvent, such as N,N?-methylpyrrolidinone (NMP). The dopes are tailored to be closed to the point of phase separation with or without suitable non-solvent additives such as methanol, acetone, decane or a mixture of these non-solvents. The flat sheet asymmetric membranes are cast by the phase inversion processes using water as the coagulation bath and annealing bath. The dried membranes are coated with UV curable silicone rubber. The resulting asymmetric membranes exhibit excellent permeability and selectivity compared to the intrinsic dense film performances.

Abstract: The present invention discloses a novel method of making high performance mixed matrix membranes (MMMs) using stabilized concentrated suspensions of solvents, uniformly dispersed polymer stabilized molecular sieves, and at least two different types of polymers as the continuous blend polymer matrix. MMMs as dense films or asymmetric flat sheet or hollow fiber membranes fabricated by the method described in the current invention exhibit significantly enhanced permeation performance for separations over the polymer membranes made from the continuous blend polymer matrix. 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 discloses a novel method of making high performance mixed matrix membranes (MMMs) using stabilized concentrated suspensions of solvents, uniformly dispersed polymer stabilized molecular sieves, and at least two different types of polymers as the continuous blend polymer matrix. MMMs as dense films or asymmetric flat sheet or hollow fiber membranes fabricated by the method described in the current invention exhibit significantly enhanced permeation performance for separations over the polymer membranes made from the continuous blend polymer matrix. 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 discloses a novel method of making high performance mixed matrix membranes (MMMs) using stabilized concentrated suspensions of solvents, uniformly dispersed polymer stabilized molecular sieves, and at least two different types of polymers as the continuous blend polymer matrix. MMMs as dense films or asymmetric flat sheet or hollow fiber membranes fabricated by the method described in the current invention exhibit significantly enhanced permeation performance for separations over the polymer membranes made from the continuous blend polymer matrix. 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 relates to a process for maintaining the humidity of an enclosed space within an acceptable operational range of relative humidity to minimize static electricity while passively removing at least a portion of organic contaminants from the enclosed space. The invention provides a simple, low cost solution to preventing damage to electronic disk drives using an adsorbent sheet material which requires less than about one-tenth the volume of adsorbent carriers which enclose the adsorbent material in a supporting envelope. The process employs a weak adsorbent such as high silica zeolite which effectively controls humidity at low operating temperatures and as the operating temperature increases is enabled to adsorb contaminants by reduced affinity for water.

Abstract: An apparatus for pressure and temperature swing adsorption processes is described. Such processes include pressure swing adsorption, temperature swing adsorption, and sorption cooling. The apparatus, a spirally wound module, provides high efficiency gas separations by reducing the differential pressure required between the adsorption pressure and the desorption pressure. The apparatus comprises an adsorption zone containing at least one adsorbent paper layer containing a selective adsorbent and an adsorbent spacer spirally wound about a hollow mandrel and in intimate thermal contact with a heat transfer zone. For pressure and temperature swing processes, the adsorption zone is disposed on the outside of the heat transfer zone, and for sorption cooling processes, the heat transfer zone is disposed on the outside of the adsorption zone and the adsorption zone is contained in an envelope-like leaf.