Abstract: A polysulfone membrane for purifying blood having excellent compatibility with blood and the process producing the membrane are disclosed. The membrane comprises a mixed polymer phase of a graft copolymer and/or block copolymer having a molecular weight of 3.times.10.sup.5 daltons or more and comprising (A) a hydrophilic segment and (B) a hydrophobic segment (exclusive of polysulfone) in a total amount of from 0.5 to 30 parts by weight per 100 parts by weight of polysulfone, with the monomer unit ratio (A/B) between the segments A and B being from 0.5 to 5. The copolymer is preferably a graft copolymer where the hydrophilic segment is a polyvinylpyrrolidone segment and the hydrophobic segment is a polystyrene segment. The membrane can be prepared by applying a wet film formation process to a dope containing an appropriate solvent of the mixed polymer, such as N,N-dimethylacetamide.

Abstract: A bundle of permselective hollow fibers is disclosed, containing a plurality of filaments having a fineness of from 0.05 to 20 denier at a filament-to-hollow fiber ratio of from 2 to 3000. The filaments intermingle with the hollow fibers substantially lengthwise over the length of the hollow fibers, and substantially all of the filaments each engage with at least one of the hollow fibers, thereby placing the hollow fibers into an inseparable bundle. The bundle has not only a high packing ratio of hollow fibers, but also an effective arrangement for efficiently exerting a high performance of each hollow fiber. The bundle can be constructed into a fluid separator, which is useful for dialysis, ultrafiltration, osmosis, reverse osmosis, pressure separation of gas mixtures and the like.

Abstract: A novel hydrophilic composite porous membrane is obtained by applying a specific copolymer solution onto the overall surface of an oriented polyolefin membranous matrix comprising a plurality of microfibrils and a plurality of knotted portions cross-connected to the microfibrils, followed by drying. The copolymer is water-insoluble and is comprised of hydrophilic monomeric units and hydrophobic monomeric units in a specific ratio. In the obtained composite porous membrane, the microfibrils are bonded together by means of the copolymer, thereby forming bundles and a coat of the copolymer is formed on the overall surface of the bundles and knotted portions. The membrane has therewithin pores which are substantially elliptic in the cross section taken along the same direction as the longitudinal direction of the microfibril bundles and has on both surfaces thereof openings which are substantially elliptic as viewed against the surface of the membrane.

Abstract: A plasma separator containing porous hollow fibers composed of a polyolefin having elliptic pores defined by microfibrils and knotted portions, in which the pores of the hollow fibers, together with the spaces between the inner surface of the vessel and the fibers and between and inside the fibers, are filled with a sterile water or sterile solution and which has been sterilized with a sterilizing gas before the filling operation of the sterile water or solution. Incorporation of the water or solution into the pores is attained by applying a pressure to the water or solution. The incorporation of the water or solution causes the limiting pore diameter of the pores of the precursor hollow fibers to expand, thereby changing the pore characteristics of the precursor hollow fibers. The plasma separator, exhibiting high plasma component permeabilities, can be used safely, without troubles of hemolysis and residual chemical or solvents, and readily, without troubles of priming and washing.

Abstract: A linear polydivinylbenzene having recurring units of Formula (A), ##STR1## and a number average molecular weight of about 500 to about 1,000,000; a linear copolymer having at least about 1% by weight of recurring units of Formula (A) as described above and at most about 99% by weight of recurring units of at least one of Formulae (B) and (C), ##STR2## wherein R.sub.1 and R.sub.2 may be the same or different and each represents a hydrogen atom, a C.sub.1-20 alkyl group, a C.sub.3-10 cycloalkyl group, a C.sub.7-12 arylalkyl group, a C.sub.3-8 alkenyl group, a C.sub.6-15 aryl group, a H.sub.2 N--CH.sub.2).sub.n group wherein n is an integer of 1 to 15 or a H--(NH--CH.sub.2 --CH.sub.2).sub.n group wherein m is an integer of 2 to 8; and R.sub.3 represents a hydrogen atom, a C.sub.1-12 alkyl group, a C.sub.3-10 cycloalkyl group, a C.sub.7-12 arylalkyl group or a C.sub.