A method relating to a copolymer containing rigid polyamides blocks and flexible blocks including, relative to the total weight of the copolymer: from 55% to 90% by weight of flexible blocks, including at least 35% by weight from polyethylene glycol; from 10% to 45% by weight of rigid polyamide blocks, in which the mean carbon content of the repeating units of the polyamide blocks is greater than or equal to 7. A method also relating to a process for preparing such a copolymer, to a membrane including such a copolymer and to a process for preparing such a membrane.

A platelet filtration membrane and its application for preparing platelets rich plasma and separating platelets from blood samples are disclosed. The platelet filtration membrane comprises a coating layer and a porous substrate. The coating layer composition comprises a first copolymer having a plurality of amide groups and a second copolymer having a plurality of carboxylic acid groups, and the porous substrate comprises PE, PP, PS, PET, PTFE, PVDF, ceramic or rayon. The coating layer is on surfaces of the porous substrate to form the platelet filtration membrane.

A platelet filtration membrane and its application for preparing platelets rich plasma and separating platelets from blood samples are disclosed. The platelet filtration membrane comprises a coating layer and a porous substrate. The coating layer composition comprises a first copolymer having a plurality of amide groups and a second copolymer having a plurality of carboxylic acid groups, and the porous substrate comprises PE, PP, PS, PET, PTFE, PVDF, ceramic or rayon. The coating layer is on surfaces of the porous substrate to form the platelet filtration membrane.

Methods and systems for producing and using multi-layer composite co-polyimide membranes, one method for producing including preparing a microporous or mesoporous membrane support material for coating; applying a sealing layer to the membrane support material to prevent intrusion into the membrane support material of co-polyimide polymer; applying a first permselective co-polyimide layer atop and in contact with the sealing layer; and applying a second permselective co-polyimide layer atop and in contact with the first permselective co-polyimide layer.

Disclosed are copolymers suitable for hydrophilically modifying the surface of porous fluoropolymer supports, for example, a copolymer of the formula (I) or (II): ##STR00001##
wherein Rf, Rh, Ra, Y, m, and n are as described herein. Also disclosed are a method of preparing the copolymers, a method of hydrophilically modifying porous fluoropolymer supports, hydrophilic fluoropolymer porous membranes prepared from the polymers, and a method of filtering fluids through the porous membranes.

Disclosed are copolymers suitable for hydrophilically modifying the surface of porous fluoropolymer supports, for example, a copolymer of the formula (I) or (II): ##STR00001##
wherein Rf, Rh, Ra, Y, m, and n are as described herein. Also disclosed are a method of preparing the copolymers, a method of hydrophilically modifying porous fluoropolymer supports, hydrophilic fluoropolymer porous membranes prepared from the polymers, and a method of filtering fluids through the porous membranes.

Provided are a methane-selective composite membrane comprising: a UiO-66 type organic-inorganic composite nanoporous material, a MIL-100 type organic-inorganic composite nanoporous material, or a ZIF-8 type organic-inorganic composite nanoporous material to which a methane-selective functional group is introduced for selectively separating methane from a gas mixture containing methane/nitrogen, a use thereof, and a method of preparing the same.

The disclosure provides a method for preparing a hollow fiber membrane by melt spinning-stretching and selective swelling, including: preparing a nascent hollow fiber by melt spinning in an inert gas protective atmosphere by using an amphiphilic block copolymer as a film forming material, and stretching the nascent hollow fiber in the cooling process, a stretch rate being controlled at 200-540 mm/min, and a stretch ratio being controlled at 150-600%; immersing the obtained hollow fiber in a swelling solvent, and treating the hollow fiber in a water bath at 65° C. for 1 h; and then transferring the hollow fiber into a long-chain alkane solvent, treating the hollow fiber at the same temperature for 1-12 h, and after the completion of the treatment, immediately taking out the hollow fiber and drying the hollow fiber to obtain the hollow fiber membrane with a bicontinuous porous structure. By combining the melt spinning-stretching and the selective swelling, the method of the disclosure can synchronously and continuously improve the permeability and selectivity of the hollow fiber membrane. The treatment in the long-chain alkane solvent can make the polar chain excessively enriched on the surface of the membrane migrate inward, thereby improving the performance of the hollow fiber membrane.

The disclosure provides a method for preparing a hollow fiber membrane by melt spinning-stretching and selective swelling, including: preparing a nascent hollow fiber by melt spinning in an inert gas protective atmosphere by using an amphiphilic block copolymer as a film forming material, and stretching the nascent hollow fiber in the cooling process, a stretch rate being controlled at 200-540 mm/min, and a stretch ratio being controlled at 150-600%; immersing the obtained hollow fiber in a swelling solvent, and treating the hollow fiber in a water bath at 65° C. for 1 h; and then transferring the hollow fiber into a long-chain alkane solvent, treating the hollow fiber at the same temperature for 1-12 h, and after the completion of the treatment, immediately taking out the hollow fiber and drying the hollow fiber to obtain the hollow fiber membrane with a bicontinuous porous structure. By combining the melt spinning-stretching and the selective swelling, the method of the disclosure can synchronously and continuously improve the permeability and selectivity of the hollow fiber membrane. The treatment in the long-chain alkane solvent can make the polar chain excessively enriched on the surface of the membrane migrate inward, thereby improving the performance of the hollow fiber membrane.

A solution is to produce an acid gas separation composite membrane provided with an acid gas separation facilitated membrane on a porous support, including; arranging of a coating liquid for acid gas separation formed through dispersing or dissolving into water a polyvinyl acetal compound formed through crosslinking, by an acetal bond, block copolymers formed through bonding of a polymer block formed of polyvinyl alcohol and a polymer block formed of polyacrylate through a linking group, an acid gas carrier and at least one kind of anion other than hydroxide ion, carboxyl ion, carbonate ion and bicarbonate ion, and coating of the coating liquid for acid gas separation onto a hydrophobic surface of the porous support having hydrophobicity at least on one surface to form the acid gas separation facilitated transport membrane thereon.