Abstract: Disclosed is a hollow fiber that contains an outer layer made of a first polymer and an inner layer made of a second polymer, the inner layer including at its outer surface a macrovoid-free thin interface sublayer in contact with the inner surface of the outer layer. The first polymer is immiscible with the second polymer. Also disclosed is a process of preparing the above-described hollow fiber.

Abstract: The present invention relates to a forward osmosis-based separation membrane based on a multilayer thin film, using crosslinking between organic monomers, and a preparation method therefore, and in the preparation of the forward osmosis-based separation membrane including a support layer and a selective layer, a middle layer is provided between the support layer and the selective layer so as to prevent a phenomenon in which the selective layer is filled in a pore of the support layer, such that the thickness of a multilayer thin film constituting the selective layer is optimized, and excellent water permeability, salt removal rate and pollution resistance properties are exhibited through the support layer having a structure of uniform surface pores and minimized pore distortion.

Abstract: A hollow fiber type reverse osmosis membrane including cellulose acetate, characterized in that the filtration rate and the salt rejection rate when an aqueous solution having sodium chloride concentration of 1,500 mg/L is filtered from outer side to inner side of the hollow fiber type reverse osmosis membrane at 25° C. and 1.5 MPa pressure are 180 to 350 L/m2/day and 90.0 to 99.0%, respectively and the outer diameter, the inner diameter and the hollow rate of the hollow fiber type reverse osmosis membrane are 100 to 280 ?m, 50 to 200 ?m and 24 to 42%, respectively. The hollow fiber type reverse osmosis membrane preferably has a dense layer near the outer surface, and thickness of the dense layer is 0.1 to 7 ?m.

Abstract: A method of producing a porous membrane, the method comprising: casting a polymer solution, in which a polymer is dissolved in a mixture of a good solvent, a poor solvent and a non-solvent, over a support, so as to form a casted polymer solution; drying the casted polymer solution, so as to form a cast film; and subjecting the cast film to a phase separation, wherein the porous membrane is produced under a condition where a temperature of a casted surface is lower than a temperature of the polymer solution, and each of a temperature change of the polymer solution and a temperature change of the casted surface is kept within ±3.0° C.

Abstract: A method of forming a two-layered membrane by immersion precipitation including: depositing a first hydrophilic polymer solution with a formulation optimized to produce a high performance porous layer; depositing on top of the first hydrophilic polymer solution a second, different hydrophilic polymer solution optimized to produce a high performance dense layer; and forming the two-layer polymer solution into one of a forward osmosis membrane and a pressure retarded osmosis membrane by bringing the second, different hydrophilic polymer solution into contact with water to form the dense layer. A two-layered membrane formed by immersion precipitation includes: a porous layer formed from a first hydrophilic polymer solution with a formulation optimized to produce a high performance porous layer; and a dense layer on top of and supported by the porous layer, the dense layer formed from a second, different hydrophilic polymer solution optimized to produce a high performance dense layer.

Abstract: The present invention discloses fluoropolymer coated membranes and methods for making and using these membranes. The fluoropolymer coated membranes described in the current invention are prepared by coating a porous asymmetric membrane layer with a thin layer of fluoropolymer coating. The porous asymmetric membrane layer comprises an asymmetric cellulosic membrane, an asymmetric polymer membrane, or an asymmetric molecular sieve/polymer mixed matrix membrane with a low selectivity and high permeance. The fluoropolymer coating improves the selectivity of the porous asymmetric membrane layer and maintains the membrane performance with time.

Abstract: A method for preparing polymeric membranes is disclosed, which has the following steps: (a) forming a casting solution by dissolving cellulose triacetate (CTA) and polyether-sulfone (PES) in a solvent mixture containing n-methyl pyrroridone (NMP) and hydrogen chloride (HCl); (b) forming a membrane from said casting solution; and (c) recovering said membrane. The method of present invention provides an asymmetrical, microporous, polymeric membrane with a high recovery rate of nucleic acids and desirable bulk and surface properties. Also, the membrane so-produced is useful to the application of material separations by filtration and the like, especially the condensation of nucleic acids from a crude sample by filtration.

Abstract: There is disclosed a process for the production of cellulose hydrate ultrafiltration membranes having improved filtration performance and the ultrafiltration membranes produced by the process.

Abstract: There is disclosed a cellulosic microporous filtration membrane with upper and lower porous protective layers with a porous sponge-type intermediate layer between the two protective layers, wherein the sponge-type structure consists of two isotropic regions having different pore sizes.

Abstract: The invention relates to charged filtration membranes and their use for separation of a protein from solvent, low molecular weight solutes or a mixture of proteins. Modification of the membranes to generate charge includes modification of membrane pores to alter charge within a pore and alter the size of a pore. Consequently, the protein is separated from other solutes in a mixture based on size as well as net protein charge and membrane charge.

Abstract: The present invention relates to a cellulose compound hollow fiber membrane having high mechanical strength and is hardly degraded by microorganisms, wherein a cellulose compound is comprised as a membrane material, the thickness of the membrane is 50 to 500 &mgr;m, a dense membrane surface having an average pore diameter of 0.001 to 0.05 &mgr;m exists on the internal and/or external surface thereof, the inside of the membrane is composed of a three-dimensional network-like porous structure having voids with an average pore diameter of 0.05 to 2 &mgr;m, and 70% by weight or more of the membrane material is cellulose acetate propionate or cellulose acetate butyrate.

Abstract: A pore plugging material, for pH dependent membrane diffusion, in which cyclic olefins having phosphazene-functional moieties provide predictable erosion properties when used to plug pores in separation barriers and other porous membranes. Specific properties of the polymers are dependent on several factors, including molecular weight and identity of side groups attached to the phosphazene moiety. However, as a class, phosphazene-functional cyclic olefins provide both predictable erodibility and uniformly benign hydrolysis products and are, therefore, uniquely suitable as pore plugging polymers for separation barriers and membranes of all kinds. The invention, therefore, embraces the provision of a pH-sensitive erodible pore plugging material for pores in separation barriers and membranes of all kinds.

Abstract: To provide a cellulose acetate semipermeable membrane having a high filtration rate and high mechanical strength and which is hardly degraded by microorganisms, the present invention provides a cellulose acetate semipermeable membrane containing a cellulose acetate having an &agr;-cellulose content of not less than 99% by weight, a 6 wt/vol % viscosity of 20 to 220 mPa·s at 25±1° C. and an acetylation degree of 58 to 62%. The cellulose acetate semipermeable membrane is suitable particularly as a hollow fiber membrane.

Abstract: Novel solid phase reaction supports are disclosed. The solid phase reaction supports include (a) a solid phase carrier having a multiplicity of NH2 functional groups; (b) a coupling compound covalently bonded to an NH2 group of the solid phase carrier; and (c) a receptor compound coupled to the solid phase carrier through the coupling compound. The coupling compound is preferably ascorbic acid, dehydroascorbic acid or a diketo compound structurally similar to ascorbic acid or dehydroascorbic acid. The solid phase carrier is preferably made of cellulose.

Abstract: Novel solid phase reaction supports are disclosed. The solid phase reaction supports include (a) a solid phase carrier having a multiplicity of NH2 functional groups of the Formula (I): in which R1 and R2 are each H, or R1 is H and R2 is an alkyl or acyl substituent with a degree of substitution ≦1 or R1 is an alkyl or acyl substituent with a degree of substitution ≦1, and R2 is H, or R1 and R2 are each a substituent with a degree of substitution ≦2 and R3 is an aromatic substituent containing at least one free amino group having a substitution degree ≦1; (b) a coupling compound covalently bonded to an NH2 group of the solid phase carrier; and (c) a receptor compound coupled to the solid phase carrier through the coupling compound.

Abstract: A porous cellulose sheet which has a structure less likely to develop curl and twist, and which can be continuously and stably manufactured, and a method for manufacturing such a sheet. The sheet has pores inside and formed with skin layers on both sides. The difference in thickness between the skin layers is not more than 50%.