A porous membrane comprising a membrane-forming polymer (A) and a polymer (B) containing a methyl methacrylate unit and a hydroxyl group-containing (meth)acrylate (b1) unit. A flux of pure water to permeate the porous membrane is preferably 10 (m.sup.3/m.sup.2/MPa/h) or more and less than 200 (m.sup.3/m.sup.2/MPa/h). The contact angle of the bulk of the membrane-forming polymer (A) is preferably 60? or more. The membrane-forming polymer (A) is preferably a fluorine-containing polymer. The polymer (B) is preferably a random copolymer.

Cation exchange membranes are prepared via facile methods to control sulfonation of polystyrene repeat units. An amount of sulfuric acid is reacted with an acetic anhydride to form an amount of acetyl sulfate. The acetyl sulfate is then added to a known concentration of polystyrene units in boiling dichloromethane (DCM) to form sulfonated polystyrene random copolymers, including a random distribution of sulfonated polystyrene repeats and unsulfonated polystyrene repeats, with sulfonation levels between about 0.07 and about 0.225. The sulfonation level can be controlled by adjusting reaction times, reaction temperatures, and sulfuric acid loading in the reaction mediums. These membranes, neutralized via alkali metals, exhibit high charge densities and low hydration degrees, and maintain high permselectivity under various high solution concentrations. The membranes can expand the operating range of ion-exchange membranes (IEMs) and enable numerous additional applications, including high-salinity electrodialysis, improved efficiency of the chloralkali process, water electrolyzers, fuel cells, etc.

Disclosed are apparatus and methods for blood and other biological fluid purification using a membrane with cell containing vascular channel systems and filtration channel systems. Also disclosed are methods of making the apparatus as well as methods of making membranes.

Process for making membranes M comprising the following steps: a) providing a dope solution D comprising at least one polymer P and at least one solvent S, b) adding at least one coagulant C to said dope solution D to coagulate said at least one polymer P from said dope solution D to obtain a membrane M, wherein said at least one solvent S comprises more than 50% by weight of at least one compound according to formula (I) (I), wherein R.sup.1 and R.sup.2 are independently C.sub.1 to C.sub.20 alkyl, R.sup.3 is selected from H or an aliphatic rest, 20 R.sup.4 is selected from H or an aliphatic rest, AO represents at least one alkylene oxide, n is a number from 0 to 100.

##STR00001##

The present disclosure relates to improved semipermeable membranes based on acrylonitrile copolymers for use in dialyzers for the extracorporeal treatment of blood in conjunction with hemodialysis, hemofiltration or hemodiafiltration. The present disclosure further relates to methods of producing such membranes.

The present invention deals with a method for obtaining membranes in the form of hollow fibers with application in the field of carbon dioxide removal from natural gas. The aforementioned membranes are obtained by means of heat treatment of polymeric membranes. In this method, polymeric membranes are obtained by a phase-inversion technique by immersion-precipitation and are subsequently subjected to a heat treatment, that is, that the membranes effectively become precursor membranes of the heat treatment. The heat treatment process involves the optimization of the heating rate, temperature, and stabilization time variables, aiming at the improvement of the transport properties of the polymeric membranes. After the heat treatment, it becomes possible to use the membranes in separation processes of gases which operate at pressures greater than 30 bar, with selectivity for carbon dioxide (CO.sub.2).

This invention provides a polymeric separation membrane that has excellent durable antibacterial effect and stain resistance, and a preparation method thereof. The polymeric separation membrane can be widely applied for water treatment, which belongs to the field of water treatment and membrane separation science and technology. The polymeric separation membrane containing quaternary ammonium salt is prepared by the immersion precipitation phase inversion method, using quaternary ammonium salt mixed with polymer and additives. This modification method effectively improves the antibacterial and antifouling ability of the polymeric separation membrane prolongs the service life of membranes and significantly inhibits the reproduction of bacterial and microbial. The preparation method has the advantages of simple process, easy operation, easy for promotion, and also avoids expensive equipment. The polymeric separation membrane has great antibacterial ability and stain resistance, therefore, it has potential application in the field of water treatment.

A separation membrane for blood processing, wherein the separation membrane for blood processing includes: a separation membrane containing polysulfone-based polymer and polyvinylpyrrolidone; and a coating film provided on at least a part of the surface of the separation membrane and containing a polymer material having a structure represented by the following general formula (1):

##STR00001##

wherein R.sup.1 is a hydrogen atom or a methyl group; R.sup.2 is a methyl group or an ethyl group; n is 2 to 6 and m is 1 to 3; P denotes the number of repetition; and a plurality of each of R.sup.1, R.sup.2, n, and m present in one molecule may be the same or different.

The present invention provides a method for the preparation of an asymmetric membranes. More particularly, the new method relates to the use of a crosslinker contacted via vapour or liquid phase with the surface layer of a cast polymer film, followed by the immersion of said film in a coagulation bath. The formation of a crosslinked skin layer and the solidification of the membrane bulk can thus be decoupled in time.

The invention provides a blood purifier which shows a decreased amount of hydrogen peroxide extracted from its selectively permeable separation membranes, and thus is highly reliable in its safety in use for hemecatharysis. The blood purifier comprises selectively permeable separation membranes as a main component and is characterized in that the amount of hydrogen peroxide which is extracted from the selectively permeable separation membrane removed from the blood purifier after 3 months or longer has passed since the sterilization of the blood purifier by exposure to a radioactive ray and/or an electron ray is not larger than 10 ppm.