Abstract: The present invention provides an asymmetric modified CMS hollow fiber membrane having improved gas separation performance properties and a process for preparing an asymmetric modified CMS hollow fiber membrane having improved gas separation performance properties. The process comprises treating a polymeric precursor fiber with a solution containing a modifying agent prior to pyrolysis. The concentration of the modifying agent in the solution may be selected in order to obtain an asymmetric modified CMS hollow fiber membrane having a desired combination of gas permeance and selectivity properties. The treated precursor fiber is then pyrolyzed to form an asymmetric modified CMS hollow fiber membrane having improved gas permeance.

Abstract: The present invention provides an asymmetric modified CMS hollow fiber membrane having improved gas separation performance properties and a process for preparing an asymmetric modified CMS hollow fiber membrane having improved gas separation performance properties. The process comprises treating a polymeric precursor fiber with a solution containing a modifying agent prior to pyrolysis. The concentration of the modifying agent in the solution may be selected in order to obtain an asymmetric modified CMS hollow fiber membrane having a desired combination of gas permeance and selectivity properties. The treated precursor fiber is then pyrolyzed to form an asymmetric modified CMS hollow fiber membrane having improved gas permeance.

Abstract: The present disclosure describes a process for separating at least a first gas component and a second gas component by contacting a gas stream comprising the first and second gas components with a carbon molecular sieve (CMS) membrane under aggressive gas separation conditions in which the partial pressure of the selectively sorbed gas component in the gas stream is high. Despite the high partial pressure of the sorbed gas component, the selectivity of the carbon molecular sieve membrane is not substantially reduced by plasticization or saturation. In some embodiments, the aggressive gas separation process may include contacting a gas stream at supercritical conditions with a CMS membrane to separate at least first and second gas components. The process may be useful for, among other things, the separation of CO2 from a natural gas stream.

Abstract: Disclosed herein are asymmetric multilayer carbon molecular sieve (“CMS”) hollow fiber membranes and processes for preparing the membranes. The processes include simultaneously extruding a core dope containing a polymer and suitable nanoparticles, a sheath dope, and a bore fluid, followed by pyrolysis of the extruded fiber.

Abstract: Embodiments of the present disclosure relate to methods of treating carbon molecular sieve (CMS) membranes, and in particular CMS hollow fiber membranes, that have undergone aging-induced permeance/permeability loss. By treating aged CMS membranes in accordance with embodiments of the present disclosure, the CMS membranes may be regenerated such that the aging-induced permeance/permeability loss is reversed and the permeance/permeability of the CMS membrane is increased. In some embodiments, the permeance/permeability of the treated CMS membrane may be increased to such a degree that the permeance/permeability of the regenerated CMS membrane is at least as high as the original permeance/permeability of the CMS membrane prior to aging-induced permeance/permeability loss.

Abstract: In embodiments of the present disclosure, a CMS hollow fiber membranes may be prepared to have an ultrathin (e.g. 2 microns or less) separation layer. A precursor hollow fiber may be prepared as dual layer fibers having a thin sheath layer and a core layer. During pyrolysis, the sheath layer is transformed into an ultrathin separation layer. Porosity of the core layer substrate is well-maintained during pyrolysis, thereby enabling high permeance of the CMS hollow fiber membrane. Additionally, in some embodiments, the sheath layer of the precursor hollow fibers may be hybridized prior to pyrolysis. By hybridizing the sheath layer prior to pyrolysis, a CMS hollow fiber may having an improved separation factor, including for example increased carbon dioxide/methane selectivity, may be provided.

Abstract: Ventilating face masks and methods and systems for face mask ventilation are disclosed. In some embodiments, a mask ventilation system can comprise an expandable base layer comprising side edges and a ventilation layer external to the expandable base layer comprising side edges. When the expandable base layer is in an expanded state, the side edges of the ventilation layer and the side edges of the expandable base layer can define one or more ventilation gaps between the expandable base layer and the ventilation layer for diverting at least a portion of the wearer's breath away from the surface, wherein the diversion can decrease the relative humidity on the surface.

Abstract: The present disclosure describes a process for separating at least a first gas component and a second gas component by contacting a gas stream comprising the first and second gas components with a carbon molecular sieve (CMS) membrane under aggressive gas separation conditions in which the partial pressure of the selectively sorbed gas component in the gas stream is high. Despite the high partial pressure of the sorbed gas component, the selectivity of the carbon molecular sieve membrane is not substantially reduced by plasticization or saturation. In some embodiments, the aggressive gas separation process may include contacting a gas stream at supercritical conditions with a CMS membrane to separate at least first and second gas components. The process may be useful for, among other things, the separation of CO2 from a natural gas stream.

Abstract: The various embodiments of the disclosure relate generally to carbon molecular sieve membranes (CMSM) and their associated fabrication processes for the separation of nitrogen/methane gas mixtures, and more particularly to CMSM that maintain high nitrogen-methane selectivity and high gas permeabilities. Methods for removing nitrogen from a nitrogen methane mixture gas via the use of the CMS membranes and gas enrichment devices using the same are also disclosed.

Abstract: The present invention provides an asymmetric modified CMS hollow fiber membrane having improved gas separation performance properties and a process for preparing an asymmetric modified CMS hollow fiber membrane having improved gas separation performance properties. The process comprises treating a polymeric precursor fiber with a solution containing a modifying agent prior to pyrolysis. The concentration of the modifying agent in the solution may be selected in order to obtain an asymmetric modified CMS hollow fiber membrane having a desired combination of gas permeance and selectivity properties. The treated precursor fiber is then pyrolyzed to form an asymmetric modified CMS hollow fiber membrane having improved gas permeance.

Abstract: A syntactic foam of a host matrix and inclusions dispersed in the host matrix, wherein at least a portion of the inclusions include microspheres containing a charge gas and having an internal pressure of greater than 0.1 MPa.

Abstract: The present invention provides an asymmetric modified CMS hollow fiber membrane having improved gas separation performance properties and a process for preparing an asymmetric modified CMS hollow fiber membrane having improved gas separation performance properties. The process comprises treating a polymeric precursor fiber with a solution containing a modifying agent prior to pyrolysis. The concentration of the modifying agent in the solution may be selected in order to obtain an asymmetric modified CMS hollow fiber membrane having a desired combination of gas permeance and selectivity properties. The treated precursor fiber is then pyrolyzed to form an asymmetric modified CMS hollow fiber membrane having improved gas permeance.

Abstract: Disclosed herein are asymmetric multilayer carbon molecular sieve (“CMS”) hollow fiber membranes and processes for preparing the membranes. The processes include simultaneously extruding a core dope containing a polymer and suitable nanoparticles, a sheath dope, and a bore fluid, followed by pyrolysis of the extruded fiber.

Abstract: One method as described herein relates to making a high molecular weight, monoesterified polyimide polymer using a small amount of bulky diamine. These high molecular weight, monoesterified polyimide polymers are useful in forming crosslinked polymer membranes with high permeance that are useful for the separation of fluid mixtures. Another method as described herein relates to making the crosslinked membranes from the high molecular weight, monoesterified polyimide polymer containing a small amount of bulky diamine. The small amount of bulky diamine allows for formation of both the high molecular weight polyimide polymer and for covalent ester crosslinks via reaction of the carboxylic acid groups with a diol crosslinking agent. This small amount of bulky diamines reduces chain mobility or segmental motion during crosslinking and reduces large loss of permeance. As such, this method provides a crosslinked membrane with good permeance and selectivity.

Abstract: One method as described herein relates to making a membrane comprising an uncrosslinked high molecular weight, monoesterified polyimide polymer with a small amount of bulky diamine. These uncrosslinked high molecular weight, monoesterified polyimide polymers with a small amount of bulky diamine are useful in forming polymer membranes with high permeance and good selectivity that are useful for the separation of fluid mixtures. Also as described herein is a hollow fiber polymer membrane comprising an uncrosslinked high molecular weight, monoesterified polyimide polymer with a small amount of bulky diamine. The small amount of bulky diamine allows for formation of a membrane comprising the uncrosslinked polymer that exhibits high permeance and good selectivity.

Abstract: One method as described herein relates to making a membrane comprising an uncrosslinked high molecular weight polyimide polymer with a small amount of bulky diamine. Also as described herein is a hollow fiber polymer membrane comprising an uncrosslinked high molecular weight polyimide polymer with a small amount of bulky diamine. The polyimide polymers include monomers comprising dianhydride monomers, diamino monomers without carboxylic acid functional groups, and optionally diamino monomers with carboxylic acid functional groups, wherein 2 to 10 mole % of the diamino monomers are bulky diamino compounds and the ratio of diamino monomers with carboxylic acid functional groups to diamino monomers without carboxylic acid functional groups is 0 to 2:3. These uncrosslinked high molecular weight polyimide polymers with a small amount of bulky diamine are useful in forming polymer membranes with high permeance and good selectivity that are useful for the separation of fluid mixtures.

Abstract: Disclosed herein is a composite hollow fiber polymer membrane including a porous core layer and a selective sheath layer. The porous core layer includes a polyamide-imide polymer, or a polyetherimide polymer, and the selective sheath layer includes a polyimide polymer, which is prepared from monomers A, B, and C. The monomer A is a dianhydride of the formula wherein X1 and X2 are independently halogenated alkyl group, phenyl or halogen and R1, R2, R3, R4, R5, and R6 are independently H, alkyl, or halogen. The monomer B is a diamino cyclic compound without a carboxylic acid functionality and the monomer C is a diamino cyclic compound with a carboxylic acid functionality. The polyimide polymer further includes covalent ester crosslinks. Also disclosed herein is a method of making the composite polymer membrane and a process for purifying natural gas utilizing the composite polymer membrane.

Abstract: Provided herein are metal organic framework/polymer mixed-matrix hollow fiber membranes and metal organic framework/carbon molecular sieve mixed-matrix hollow fiber membranes. The materials have high MOF particle loading and are easily scalable. The MOF/polymer mixed-matrix hollow fibers are formed using a dry-jet/wet-quench fiber spinning technique and show C3H6/C3H8 selectivity that is significantly enhanced over the pure polymer fiber and that is consistent with the selectivity of mixed-matrix dense films of the same MOF/polymer combination. The MOF/CMS mixed-matrix hollow fibers are formed by pyrolyzing the MOF/polymer mixed-matrix hollow fibers and show increased C3H6 permeance and increased selectivity over the MOF/polymer mixed-matrix hollow fiber membranes.

Abstract: Embodiments of the present disclosure are directed to a process for making a carbon molecular sieve membrane having a desired permselectivity between a first gas species and a second gas species, in which the second gas species has a larger kinetic diameter than the first gas species. The process comprises providing a polymer precursor and pyrolyzing the polymer precursor at a pyrolysis temperature that is effective to selectively reduce the sorption coefficient of the second gas species, thereby increasing the permselectivity of the resulting carbon molecular sieve membrane.

Abstract: One method as described herein relates to making a membrane comprising an uncrosslinked high molecular weight, monoesterified polyimide polymer with a small amount of bulky diamine. These uncrosslinked high molecular weight, monoesterified polyimide polymers with a small amount of bulky diamine are useful in forming polymer membranes with high permeance and good selectivity that are useful for the separation of fluid mixtures. Also as described herein is a hollow fiber polymer membrane comprising an uncrosslinked high molecular weight, monoesterified polyimide polymer with a small amount of bulky diamine. The small amount of bulky diamine allows for formation of a membrane comprising the uncrosslinked polymer that exhibits high permeance and good selectivity.