A membrane including a block copolymer is presented. The block copolymer includes at least one block A including structural units having a formula (I), and at least one block B including structural units having a formula (II). A hollow-fiber membrane for hemodialysis or hemofiltration, and associated block copolymer are also presented.

A membrane including a block copolymer is presented. The block copolymer includes at least one block A including structural units having a formula (I), and at least one block B including structural units having a formula (II). A hollow-fiber membrane for hemodialysis or hemofiltration, and associated block copolymer are also presented.

A method is disclosed for forming a microporous membrane that incorporates an additive having low water solubility at the membrane's active surface from a precipitation fluid. The incorporated additive at the membrane's active surface can improve one or more of the membrane's hydrophilicity, wettability, anti-fouling behavior, blood compatibility, and stability over long periods of use or repetitive use. The microporous membrane with this modified active surface can be a hollow fiber, flat sheet, or other self-supporting shape. The microporous membranes can be used for membrane filtering or a solute and/or solvent exchange process, which involve contacting aqueous-based fluid or blood with the microporous membrane, such processes for dialysis, blood oxygenation, or blood separation filtering, or other processes.

A method is disclosed for forming a microporous membrane that incorporates an additive having low water solubility at the membrane's active surface from a precipitation fluid. The incorporated additive at the membrane's active surface can improve one or more of the membrane's hydrophilicity, wettability, anti-fouling behavior, blood compatibility, and stability over long periods of use or repetitive use. The microporous membrane with this modified active surface can be a hollow fiber, flat sheet, or other self-supporting shape. The microporous membranes can be used for membrane filtering or a solute and/or solvent exchange process, which involve contacting aqueous-based fluid or blood with the microporous membrane, such processes for dialysis, blood oxygenation, or blood separation filtering, or other processes.

An ultrafiltration/nanofiltration membrane with gas-tunable pore size is provided. This membrane comprises an active layer arranged between two porous support layers, wherein the active layer is formed of randomly arranged cellulose nanocrystals, wherein pores are defined in the active layer by the free spaces existing between the randomly arranged cellulose nanocrystals, and wherein chains of a CO.sub.2-responsive polymer are grafted on the surface of the cellulose nanocrystals. There are also provided methods for filtering a feed using the membrane, for tuning the apparent pore size/MWCO/charge of the membrane, for cleaning the membrane, and for manufacturing the membrane.

An ultrafiltration/nanofiltration membrane with gas-tunable pore size is provided. This membrane comprises an active layer arranged between two porous support layers, wherein the active layer is formed of randomly arranged cellulose nanocrystals, wherein pores are defined in the active layer by the free spaces existing between the randomly arranged cellulose nanocrystals, and wherein chains of a CO.sub.2-responsive polymer are grafted on the surface of the cellulose nanocrystals. There are also provided methods for filtering a feed using the membrane, for tuning the apparent pore size/MWCO/charge of the membrane, for cleaning the membrane, and for manufacturing the membrane.

The present invention provides a composition for a CO.sub.2 gas separation membrane containing: at least one compound selected from the group consisting of an alkali metal carbonate, an alkali metal bicarbonate, and an alkali metal hydroxide; a crosslinked polymer in which a polymer having a carboxyl group has been crosslinked; and a non-crosslinked polymer obtained by polymerization of one or more monomers selected from the group consisting of vinyl acetate, acrylic acid, methacrylic acid, and a derivative thereof.

The present invention provides a composition for a CO.sub.2 gas separation membrane containing: at least one compound selected from the group consisting of an alkali metal carbonate, an alkali metal bicarbonate, and an alkali metal hydroxide; a crosslinked polymer in which a polymer having a carboxyl group has been crosslinked; and a non-crosslinked polymer obtained by polymerization of one or more monomers selected from the group consisting of vinyl acetate, acrylic acid, methacrylic acid, and a derivative thereof.

A process for separating hydrogen from a gas mixture having hydrogen and a larger gas molecule is comprised of flowing the gas mixture through a carbonized polyvinylidene chloride (PVDC) copolymer membrane having a hydrogen permeance in combination with a hydrogen/methane selectivity, wherein the combination of hydrogen permeance and hydrogen/methane selectivity is (i) at least 30 GPU hydrogen permeance and at least 200 hydrogen/methane selectivity or (ii) at least 10 GPU hydrogen permeance and at least 700 hydrogen/methane selectivity. The carbonized PVDC copolymer may be made by heating and restraining a polyvinylidene chloride copolymer film or hollow fiber having a thickness of 1 micrometer to 250 micrometers to a pretreatment temperature of 100? C. to 180? C. to form a pretreated polyvinylidene chloride copolymer film and then heating and restraining the pretreated polyvinylidene chloride copolymer film to a maximum pyrolysis temperature from 350? C. to 750? C.

The disclosure relates to crosslinked ion-exchange materials (IEM), related methods of making lEMs, and related articles including IEMs. The IEMs can be formed by providing a reaction solution including a charged vinyl monomer, a polyfunctional vinyl crosslinking monomer, a vinyl polymerization initiator, and water; and then performing vinyl polymerization in the reaction solution to form the IEM as a crosslinked reaction product. The reaction solution contains primarily or only water as a solvent for the vinyl monomers. The resulting crosslinked reaction product has a combination of high ionic-exchange capacity (IEC) values coupled with low water uptake and/or low water mass fraction values, which make it suitable for use in various ion-exchange applications.