Abstract: The present invention provides for the first time ultrafiltration/diafiltration membranes that are capable of excluding 0.02 .mu.m diameter, monodisperse, latex particles and are capable of being dried without loss of such ultrafiltration properties. A rapid, reliable method for integrity testing membranes also has now been discovered. The test has particular applicability to ultrafiltration membranes, although it may also be used for testing microfiltration membranes as well. In accordance with the method, referred to as the K.sub.

Abstract: The present invention provides for the first time ultrafiltration/diafiltration membranes that are capable of excluding 0.02 .mu.m diameter, monodisperse, latex particles and are capable of being dried without loss of such ultrafiltration properties. A rapid, reliable method for integrity testing membranes also has now been discovered. The test has particular applicability to ultrafiltration membranes, although it may also be used for testing microfiltration membranes as well. In accordance with the method, referred to as the K.sub.

Abstract: Asymmetric gas separation membranes having graded density skins and macrovoid-free morphology comprised of glassy, hydrophobic polymers are disclosed which are effective for separation gases with significante increases in permeation while maintaining equal or greater separation electivity. The membranes have increased free volume and the graded density skin exhibits a density gradient which becomes more dense with increasing proximity to the surface, the membrane effectively decouples the interdependency between permeability and separation selectivity.

Abstract: A process for forming high free volume, asymmetric gas separation membranes having graded density skins and macrovoid-free morphology from a solvent system comprising a Lewis acid, Lewis base, and a Lewis acid:base complex which dissolve hydrophobic polymers. The dopes have high total solids, high viscosity and low coagulation (g) values which enhance rapid gelation without the formation of macrovoids and which minimize densification. The dope solvent system complexes are readily disassociated by the coagulation medium and the component molecules are miscible in the medium which provides for rapid desolvation of the formed membrane thus providing a membrane having low residual solvent retention.

Abstract: A casting solution of two nylons in formic acid, e.g., high molecular weight extrusion grade Nylon 66 homopolymer [.eta.] about 2 or higher, and nylon multipolymer 66, 610, 6 as a strengthening polymer and gelation promoter, when cast by either the dry or wet phase inversion processes, results in highly unexpected membranes of superior strength, flexibility, and uniformity, suitable for use in microfiltration and ultrafiltration.

Abstract: A casting solution of two nylons in formic acid, e.g., high molecular weight extrusion grade Nylon 66 homopolymer [.eta.] about 2 or higher, and nylon multipolymer 66, 610, 6 as a strengthening polymer and gelation promoter, when cast by either the dry or wet phase inversion processes, results in highly unexpected membranes of superior strength, flexibility, and uniformity, suitable for use in microfiltration and ultrafiltration.

Abstract: The discovery that highly anisotropic membranes, e.g. with a degree of anisotropy of five can for the very first time be produced by the dry phase inversion process by a very specific combination of polymers, solvent and non-solvent, optionally along with plasticizers and modifiers, all of which separately are known in membrane technology, the polymers consisting essentially of cellulose nitrate and cellulose nitrate-cellulose acetate mixed ester polymers, the solvent being methyl formate, propylene oxide, or mixtures thereof, and the non-solvents being isopropyl alcohol, t-butyl alcohol or mixtures thereof, is disclosed.

Abstract: Membrane forming polymers are converted to hydrophilic polymeric membranes by (a) grafting a polyoxyethylene chain to a membrane forming polymer structure and thereafter forming a membrane; (b) coating a membrane with a polymer to which a polyoxyethylene chain has been grafted; or (c) grafting in situ a polyoxyethylene chain to a formed membrane polymer.

Abstract: Microfiltration membranes are described comprising 10% to 50% cyanoethylated polysaccharide ether polymers blended with 50% to 90% polymers of cellulose nitrate, cellulose acetate or mixtures of the two. These membranes are flexible and strong and can be readily pleated for use in cartridge filters as well as used flat in conventional single- or multi-plate holders. They are also more thermally stable than conventional "mixed ester" (cellulose nitrate/cellulose acetate) membranes.

Abstract: A dense hollow fiber cellulosic membrane which possesses outstanding permeability and strength characteristics and the method of preparation thereof is disclosed.

Abstract: Integral, skinned and unskinned, microporous microfiltration and ultrafiltration, electrophoresis membranes having high void volumes (above 50% void) composed of polycarbonates and copolymers of polycarbonates with polyalkylene oxides and the dry process for producing such membranes are disclosed.

Abstract: A dry-wet process for forming interiorally asymmetric hollow fiber cellulose acetate membranes is disclosed.

Abstract: A new composition, cellulose acetate-chlorobutyrate pyridinium salt, which has superior biodegradation resistance and polymer membrane forming characteristics and related compositions.

Abstract: Microporous membrane filters composed of polyesters derived from aromatic dibasic acids and especially polytetramethylene terephthalate are produced. These membranes are produced by a polymer assisted phase inversion process involving casting a solution of the polyester and assisting polymer to form a film, evaporating the solvent to form a membrane having inchoate micropores filled with the assisting polymer and subsequently at least partially leaching out the assiting polymer.

Abstract: Integral, skinned and unskinned, microporous microfiltration and ultrafiltration, electrophoresis membranes having high void volumes (above 50% void) composed of polycarbonates and copolymers of polycarbonates with polyalkylene oxides and the dry process for producing such membranes are disclosed.