Abstract: A dialysis membrane is made of a regenerated cellulose polymer in the form of a hollow fiber with a continuous internal cavity filled essentially with a gas. The hollow fiber has a porous inner and an outer surface. The outer surface of the hollow fiber is formed by a thin skin which has fine lengthwise grooves. The inner surface of the hollow fiber is positively modified by physical and/or chemical means.The invention also includes a method for manufacturing such a dialysis membrane.

Abstract: A dialysis membrane for hemodialysis in the form of sheet films, tubular films, or hollow fibers is composed of a polysaccharide ether. The polysaccharide ether has a structure given by the formula ##STR1## in which cell is the skeleton of the unmodified cellulose molecule or of the chitin molecule, each with no hydroxyl groups, s is equal to 3 for the unmodified cellulose molecule and 2 for the chitin molecule, and x is the degree of etherification, which is in the range from 0.001 to 0.079, and R is an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, arylalkyl, arylalkenyl, and/or arylalkynyl group with 3 to 25 carbon atoms, and/or the radical of a heterocyclic compound with 3 to 25 carbon atoms, in which the carbon chain may be interrupted by oxygen or sulfur atoms.

Abstract: A dialysis membrane in the form of a hollow fiber with a continuous internal cavity is made of cellulose acetate or a cellulose acetate derivative. The hollow fiber is made by using a gas to form the internal hollow cavity. A dialysis membrane in the form of a hollow fiber with a continuous hollow cavity may be made in a process using a spinning solution containing an organic carboxylic acid. Modification agents can be added to the solution and the solution extruded through a spinneret suitable for manufacturing hollow fibers, while an internal medium is introduced simultaneously into the internal cavity of the forming hollow fiber. The precipitation of the dialysis membrane thus formed and an ordinary further aftertreatment take place subsequently in a precipitation bath. The hollow fiber is made by using a gas as the internal medium to form the internal cavity.

Abstract: A dialysis membrane in the form of a hollow fiber with a continuous internal cavity is made of cellulose acetate or a cellulose acetate derivative. The membrane has a maximum sieving coefficient of 0.04 for albumin with a molecular weight of 68,000. A dialysis membrane in the form of a hollow fiber with a continuous internal cavity may be made in a process using a spinning solution containing an organic carboxylic acid and a cavity-forming liquid. Modification agents and/or water are optionally added and the solution is extruded through a spinneret suitable for the manufacture of hollow fibers. The precipitation of the resultant dialysis membrane and the usual further aftertreatment take place in a precipitation bath. The organic carboxylic acid preferably is acetic acid and the precipitation bath preferably is a diluted acetic acid.

Abstract: Dialysis membranes are disclosed, in the shape of hollow fibers composed of cellulose regenerated from copper-ammonia solution, having a continuous hollow cavity and a closed wall, wherein in any cross-section normal to the direction of the fiber axis the difference of the distance to the outer wall surface and the distance to the inner wall surface, each measured from the fiber midpoint, varies along the periphery, the fiber midpoint being the midpoint of the circle circumscribing the fiber cross-section, and the cross-section normal to the direction of the fiber axis possessing the shape of a circle, a deformed circle, an ellipse, a kidney-shaped deformed ellipse, or a deformed quadrangle.

Abstract: A dialysis membrane used for hemodialysis having a structure comprised of flat films, blown films or tubular threads of substitution-modified cellulose, in which the effects of complement activation and leukopenia are clearly reduced. The average degree of substitution of the modified cellulose is 0.02 to 0.07. Dialysis membranes, which have proven successful within the scope of the invention, contain modified cellulose, having a structure represented by the formula cellulose-Z, wherein Z represents the group --R'--X--Y.X is at least one member selected from the group consisting of ##STR1## Y is at least one member selected from the group consisting of --R, --NR.sub.2, --Si(OR").sub.3, --SO.sub.3 H, --COOH, --PO.sub.3 H.sub.2, --N.sup.+ HR.sub.2, --OR" and the salts thereof.R' is at least one member selected from the group consisting of an alkylenes cycloalkylenes and arylenes having a total of 1 to 25 carbon atoms.R" is a hydrogen atom or R.

Abstract: A single or multilayer dialysis membrane, constructed as a flat film, a tubular foil or especially as hollow fibers, the membrane being made of a regenerated cuprammonium cellulose which may be unmodified or partly modified by alkyl, carboxyalkyl or hydroxyalkyl groups, and said membrane being characterized by an ultrafiltration capacity at 37.degree. C. of 7 to 30 ml/hr.multidot.m.sup.2.mmHg, an average molecular permeability, based upon vitamin B12, of about 3.multidot.10.sup.-3 to 12.multidot.10.sup.-3 cm/min, and a water retention value of more than 145%, calculated according to the German Industrial Standard (DIN) 53814. The new membrane is prepared by the known cuprammonium process but with the addition of a finely ground CuO with a maximum particle size of 20 microns to the standard cuprammonium solution. After casting, extruding or spinning this solution into a coagulating bath, e.g.

Abstract: Dialysis membranes are described in which two or more hollow fibers of cellulose regenerated from cuoxam solution are spun together and connected to each other parallel to the fiber axis. The connection may be in the form of crosspieces, which should be between about 1 and 3 times the thickness of the hollow fiber walls. A novel process for preparation of the dialysis membrane hollow fibers is also disclosed.

Abstract: A multilayer cellulosic membrane for blood dialysis and a method for the production of said membrane by regeneration from separately extruded cuprammonium cellulose solutions brought together to form two or more permanently adhered layers, each layer forming a seal against blood penetration through the leakage points of an adjacent layer, the resulting multilayer membrane thus being substantially free of blood leakage over the total thickness of the membrane. Especially preferred membranes for blood dialysis are those in which the layer arranged on the blood side of the diaphragm contains a modified cellulose chemically bound with an antithrombogenic substance.

Abstract: A dialyzing membrane, especially for hemodialysis, formed as a hollow fiber, tubular foil or flat sheet by regeneration of cellulose from a cuprammonium solution, the membrane comprising at least two firmly adhered cellulosic layers including at least one dialyzing layer consisting essentially of a semipermeable regenerated cellulose and at least one adsorbent layer consisting of said regenerated cellulose containing embedded therein fine particles of an adsorbent material in an amount of up to 95% by weight with reference to the dry weight of the adsorbent layer, preferably 1 to 90% and especially 20 to 70% by weight, when the adsorbent layer is part of a hollow fiber structure.

Abstract: A dialyzing membrane, especially for hemodialysis, formed as a hollow fiber, tubular foil or flat sheet by regeneration of cellulose from a cuprammonium solution, the membrane comprising at least two firmly adhered cellulosic layers including at least one dialyzing layer consisting essentially of a semipermeable regenerated cellulose and at least one adsorbent layer consisting of said regenerated cellulose containing embedded therein fine particles of an adsorbent material in an amount of up to 95% by weight with reference to the dry weight of the adsorbent layer, preferably 1 to 90% and especially 20 to 70% by weight, when the adsorbent layer is part of a hollow fiber structure.