A membrane contains a polymer composition is described. The polymer composition contains a) at least one polymer of PA, PVA, Cellulose CA, CTA, CA-triacetate blend, cellulose ester, cellulose nitrate, regenerated cellulose, aromatic, aromatic/aliphatic or aliphatic polyamide, aromatic, aromatic/aliphatic or aliphatic polyimide, PBI, PBIL, PAN, PAN-PVC copolymer, PAN-methallyl sulfonate copolymer, PEI, PEEK, sulfonated SPEEK, PPO, poly-carbonate, polyester, PTFE, PVDF, PP, a polyelectrolyte complex, PMMA, PDMS, aromatic, aromatic/aliphatic or aliphatic polyimide urethane, aromatic, aromatic/aliphatic or aliphatic polyamidimide, crosslinked polyimide or poly-arylene ether, PSU, PPSU and PESU, and b) at least one dope polymer DP1, which is a polyalkylene oxide with a molecular mass Mw of more than 100,000 g/mol and/or a K-value of 60 or 20 more.

An asymmetric membrane having a substantially non-porous surface layer is made by a method including: dissolving a poly(phenylene ether) copolymer in a solvent mixture including a first solvent and a second solvent to provide a membrane-forming composition; and phase-inverting the membrane forming composition in a first non-solvent to form the membrane comprising a substantially non-porous surface layer. The first solvent is a water-miscible polar aprotic solvent, and the second solvent is a polar solvent having two to eight carbon atoms.

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).

A method of manufacture of crosslinked, edible, porous hollow fibers and sheet membranes suitable for the manufacture of clean meat products, the hollow fibers and sheet membranes made therefrom and methods of use thereof.

The further advancement of membrane separation processes requires the development of more selective membranes. In this study, membranes that take inspiration from biological systems and use multiple functionalities of unique chemical design to control solute transport through chemical factors in addition to steric factors are detailed. Specifically, copolymer materials tailor-made for the generation of nanofilters that possess a high density of well-defined pores lined by azido moieties allowed for the generation of chemically-patterned mosaic membranes in a rapid manner through the use of printing devices. By engineering the composition of the reactive ink solutions used for chemical functionalization, large areas of patterned membranes were generated in seconds rather than hours. Charge mosaic membranes were used as an example of this novel platform.

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.

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.

An method of making a porous asymmetric membrane involves dissolving a poly(phenylene ether), poly(phenylene ether) copolymer, polyethersulfone, polysulfone, polyphenylsulfone, polyimide, polyetherimide, polyvinylidene fluoride, or a combination thereof in a water-miscible polar aprotic solvent to provide a membrane-forming composition; and phase-inverting the membrane-forming composition in a first non-solvent composition composed of water, a water-miscible polar aprotic solvent, or a mixture thereof, and a polymer additive dissolved in the first non-solvent composition. The method can be a method of making a hollow fiber by coextrusion through a spinneret having an annulus and a bore, including coextruding the membrane-forming composition through the annulus, and the first non-solvent composition through the bore, into a second non-solvent composition composed of water, a water-miscible polar aprotic solvent, or a mixture thereof to form the hollow fiber.

Provided is a microporous membrane which has an asymmetric structure and which exhibits higher permeability while keeping a high particle rejection. This microporous membrane is an asymmetric microporous membrane that is provided with: a skin layer in which micropores have been formed; and a support layer which supports the skin layer and in which pores larger than the micropores have been formed. The material of the microporous membrane is a polyvinylidene fluoride-based resin. In the skin layer, multiple spherical bodies (1) are present, and multiple linear joining parts (2) extend three-dimensionally from each of the spherical bodies (1), each pair of adjacent spherical bodies (1) being linked to each other by one or more of the linear joining parts (2). Thus, the skin layer has a three-dimensional network structure wherein the spherical bodies (1) act as nodes.

[Problem] The purpose of the present invention is to provide a polyamide hollow fiber membrane having such properties that the transmission of fine particles through the membrane can be prevented effectively, the membrane has an excellent water transmissibility, the entire surface of the membrane has excellent hydrophilicity, and impurities such as metal elements are rarely eluted through the membrane. [Solution] A polyamide hollow fiber membrane produced by a TIPS method under specific production conditions has the following characteristic properties: (1) the contact angle of water on the surface of the membrane is 80? or less; (2) the external pressure water transmissibility of the membrane is 50 L/(m.sup.2.Math.atm.Math.h) or more; and (3) the 50 nm-particles blocking ratio of the membrane is 90% or more.