A dual-layer membrane and a method for preparing thereof. By adding a modifying monomer containing an active group and a characteristic group to a dope solution or spinning solution during the preparation of the dual-layer membrane, the grafting reaction occurs between the active group of the monomer and the polymer in the dope solution or spinning solution, and the intermolecular interaction with other polymers is enhanced by the characteristic group of the monomer, to improve the miscibility between the polymers. The method is suitable for preparing both a dual-layer flat sheet membrane and a dual-layer hollow fiber membrane, and can realize the preparation of a dual-layer membrane with an interpenetrated structure at the interface under mild preparation conditions.

An article that includes a functionalized copolymer and the use thereof, particularly in a process for binding biomaterials, such as in a process for separating aggregated proteins from monomeric proteins in a biological solution; wherein the article includes: a) a porous substrate; and b) a copolymer covalently attached to the porous substrate, the copolymer comprising a hydrocarbon backbone and a plurality of pendant groups attached to the hydrocarbon backbone, wherein 1) each of a first plurality of pendant groups comprises: (a) at least one acidic group or salt thereof; and (b) a spacer group that directly links the at least one acidic group or salt thereof to the hydrocarbon backbone by a chain of at least 6 catenated atoms; and 2) each of a second plurality of pendant groups comprises: (a) at least one acidic group or salt thereof; and (b) a spacer group that directly links the at least one acidic group or salt thereof to the hydrocarbon backbone by a chain of at least 6 catenated atoms; and wherein the first plurality of pendant groups are different than the second plurality of pendant groups; and wherein a mole ratio of the first plurality of pendant groups to the second plurality of pendant groups is in a range of 95:5 to 5:95.

An article that includes a functionalized copolymer and the use thereof, particularly in a process for binding biomaterials, such as in a process for separating aggregated proteins from monomeric proteins in a biological solution; wherein the article includes: a) a porous substrate; and b) a copolymer covalently attached to the porous substrate, the copolymer comprising a hydrocarbon backbone and a plurality of pendant groups attached to the hydrocarbon backbone, wherein 1) each of a first plurality of pendant groups comprises: (a) at least one acidic group or salt thereof; and (b) a spacer group that directly links the at least one acidic group or salt thereof to the hydrocarbon backbone by a chain of at least 6 catenated atoms; and 2) each of a second plurality of pendant groups comprises: (a) at least one acidic group or salt thereof; and (b) a spacer group that directly links the at least one acidic group or salt thereof to the hydrocarbon backbone by a chain of at least 6 catenated atoms; and wherein the first plurality of pendant groups are different than the second plurality of pendant groups; and wherein a mole ratio of the first plurality of pendant groups to the second plurality of pendant groups is in a range of 95:5 to 5:95.

A method for producing a gas separation membrane, including the following steps: step (a): treating the surfaces of silica nanoparticles dispersed in a first solvent with a reactive functional group-containing compound, while nanoparticles are being dispersed in the solvent, to thereby prepare a first solvent dispersion of reactive functional group-modified silica nanoparticles; step (b): replacing the first solvent dispersion's dispersion medium of reactive functional group-modified silica nanoparticles prepared in step (a) with a second solvent without drying of dispersion medium, and then reacting functional group-modified silica nanoparticles with dendrimer-forming monomer or hyperbranched polymer-forming monomer in the second solvent's presence so that dendrimer or hyperbranched polymer is added to reactive functional group, to thereby prepare dendrimer- or hyperbranched polymer-bound silica nanoparticles; step (c): mixing dendrimer- or hyperbranched polymer-bound silica nanoparticles prepared in step (b) with a matrix resin; and step (d): applying mixture prepared in step (c) to a substrate, and then removing the solvent.

A method for producing a gas separation membrane, including the following steps: step (a): treating the surfaces of silica nanoparticles dispersed in a first solvent with a reactive functional group-containing compound, while nanoparticles are being dispersed in the solvent, to thereby prepare a first solvent dispersion of reactive functional group-modified silica nanoparticles; step (b): replacing the first solvent dispersion's dispersion medium of reactive functional group-modified silica nanoparticles prepared in step (a) with a second solvent without drying of dispersion medium, and then reacting functional group-modified silica nanoparticles with dendrimer-forming monomer or hyperbranched polymer-forming monomer in the second solvent's presence so that dendrimer or hyperbranched polymer is added to reactive functional group, to thereby prepare dendrimer- or hyperbranched polymer-bound silica nanoparticles; step (c): mixing dendrimer- or hyperbranched polymer-bound silica nanoparticles prepared in step (b) with a matrix resin; and step (d): applying mixture prepared in step (c) to a substrate, and then removing the solvent.

A gas separation membrane containing a matrix resin and hyperbranched polymer- or dendrimer-bound, heteromorphous shaped silica nanoparticles, which are formed of heteromorphous shaped silica nanoparticles having surfaces onto which a hyperbranched polymer or a dendrimer is chemically added.

A gas separation membrane containing a matrix resin and hyperbranched polymer- or dendrimer-bound, heteromorphous shaped silica nanoparticles, which are formed of heteromorphous shaped silica nanoparticles having surfaces onto which a hyperbranched polymer or a dendrimer is chemically added.

Described is a polyethylene membrane and in particular an ultra-high molecular weight polyethylene member that provides a high air permeability and is hydrophobic. The membranes have small pores and are suitable for sterilization by exposure to gamma radiation. The membranes can be made by methods that involve one or more of stretching the membrane and grafting hydrophobic monomers onto the membrane surface. A perfluorinated monomer, such as perfluoro-n-octyl acrylate, can be grafted to one or more surfaces of the membrane. The membrane have a high flow rate compared to unstretched or ungrafted membranes.

Described is a polyethylene membrane and in particular an ultra-high molecular weight polyethylene member that provides a high air permeability and is hydrophobic. The membranes have small pores and are suitable for sterilization by exposure to gamma radiation. The membranes can be made by methods that involve one or more of stretching the membrane and grafting hydrophobic monomers onto the membrane surface. A perfluorinated monomer, such as perfluoro-n-octyl acrylate, can be grafted to one or more surfaces of the membrane. The membrane have a high flow rate compared to unstretched or ungrafted membranes.

A graft copolymer including zwitterionic repeat units and hydrophobic repeat units, in which the zwitterionic repeat units constitute 2-60 wt % of the graft copolymer and each of the hydrophobic repeat units is characterized in that a homopolymer formed thereof is miscible with polyvinylidene fluoride, polysulfone, poly ether sulfone, polyvinyl chloride, or polyacrylonitrile, each of the hydrophobic repeat units not being a repeat unit of polyvinylidene fluoride. Also disclosed is a filtration membrane containing such a graft copolymer or a statistical copolymer that includes the same composition of repeat units as the graft copolymer. Further disclosed are methods of preparing the graft copolymer and the filtration membrane.