A gas separation membrane for selective separation of hydrogen and helium from gas mixtures containing carbon dioxide includes a porous support layer, an aromatic polyamide layer on the porous support layer, and a coating including a glassy polymer formed on the aromatic polyamide layer. A glass transition temperature of the glassy polymer is greater than 50° C. The gas separation membrane may be formed by contacting a solution including the glassy polymer with an aromatic polyamide layer of a composite membrane and drying the solution to form a coating of the glassy polymer on the aromatic polyamide layer. Separating hydrogen or helium from a gas stream including carbon dioxide includes contacting a gas feed stream including carbon dioxide with the gas separation membrane to yield a permeate stream having a concentration of helium or hydrogen that exceeds the concentration of helium or hydrogen, respectively, in the gas feed stream.

A gas separation membrane for selective separation of hydrogen and helium from gas mixtures containing carbon dioxide includes a porous support layer, an aromatic polyamide layer on the porous support layer, and a coating including a glassy polymer formed on the aromatic polyamide layer. A glass transition temperature of the glassy polymer is greater than 50° C. The gas separation membrane may be formed by contacting a solution including the glassy polymer with an aromatic polyamide layer of a composite membrane and drying the solution to form a coating of the glassy polymer on the aromatic polyamide layer. Separating hydrogen or helium from a gas stream including carbon dioxide includes contacting a gas feed stream including carbon dioxide with the gas separation membrane to yield a permeate stream having a concentration of helium or hydrogen that exceeds the concentration of helium or hydrogen, respectively, in the gas feed stream.

A hollow fiber membrane and methods of making the hollow fiber membrane are described. The membrane includes a hydrophobic polymer such as polysulfone, a hydrophilic polymer such as polyvinylpyrrolidone (PVP), and a fluropolymer additive, and optionally a stabilizer, for instance, to stabilize the fluoropolymer additive in the membrane, particularly during conditioning or E-beam sterilization or both. Further conditioning improvements to membrane manufacturing are disclosed. The membrane may be incorporated into a dialysis filter for use in hemodialysis and related applications. The membrane has improved hemocompatibility, charge stability, or middle molecule clearance compared to conventional membranes. Also disclosed is a method of evaluating membrane charge stability.

Composite membrane tubing includes a porous scaffold support combined with polyether block amide copolymer. The composite membrane tubing has overlapping “fusion areas” that are an artifact of the manufacturing process. The methods of manufacturing above-mentioned composite membrane tubing have also been addressed. The composite membrane tubing can be reinforced with a structural mesh to further provide rigidity and strength. Composite membrane tubing or generally extruded tubing can be integrated into a multi-tube module for various applications.

This disclosure relates to CO.sub.2-philic crosslinked polyethylene glycol membranes useful for natural gas purification processes. Also provided are methods of using the membranes to remove CO.sub.2 and H.sub.2S from natural gas.

This disclosure relates to CO.sub.2-philic crosslinked polyethylene glycol membranes useful for natural gas purification processes. Also provided are methods of using the membranes to remove CO.sub.2 and H.sub.2S from natural gas.

A method of separating gas and a method of making a gas separation membrane. The method of separating gas includes flowing a gas stream through a membrane, in which the membrane comprises a crosslinked mixture of a poly(ether-b-amide) copolymer and an acrylate-terminated poly(ethylene glycol) according to formula (I) or formula (II); and separating the gas stream via the membrane. ##STR00001##
In formulas (I) and (II), each n is of from 2 to 30; and each R is independently —H or —CH.sub.3.

A method of separating gas and a method of making a gas separation membrane. The method of separating gas includes flowing a gas stream through a membrane, in which the membrane comprises a crosslinked mixture of a poly(ether-b-amide) copolymer and an acrylate-terminated poly(ethylene glycol) according to formula (I) or formula (II); and separating the gas stream via the membrane. ##STR00001##
In formulas (I) and (II), each n is of from 2 to 30; and each R is independently —H or —CH.sub.3.

An article that can be used for biomaterial capture comprises (a) a porous substrate; and (b) borne on the porous substrate, a polymer comprising interpolymerized units of at least one monomer consisting of (1) at least one monovalent ethylenically unsaturated group, (2) at least one monovalent ligand functional group selected from acidic groups, basic groups other than guanidino, and salts thereof, and (3) a multivalent spacer group that is directly bonded to the monovalent groups so as to link at least one ethylenically unsaturated group and at least one ligand functional group by a chain of at least six catenated atoms.

An article that can be used for biomaterial capture comprises (a) a porous substrate; and (b) borne on the porous substrate, a polymer comprising interpolymerized units of at least one monomer consisting of (1) at least one monovalent ethylenically unsaturated group, (2) at least one monovalent ligand functional group selected from acidic groups, basic groups other than guanidino, and salts thereof, and (3) a multivalent spacer group that is directly bonded to the monovalent groups so as to link at least one ethylenically unsaturated group and at least one ligand functional group by a chain of at least six catenated atoms.