Abstract: Glassy polymeric gas separation membranes are chemically modified throughout the thickness thereof. Such membranes manifest selectivity for a pair of gases which is greater than the intrinsic selectivity of the glassy polymeric material and which is greater than the equilibrium intrinsic selectivity of the chemically modified glassy polymeric material.

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 process has been developed for effectively purifying compressed air by removing water vapor, carbon dioxide and other impurities through the use of gas separation membrane systems. Gas separation membranes have been found which are capable of purifying air to a suitable level for operation of analytical instrumentation apparatus such as Fourier Transform Infrared analytical spectrometers and related instrumentation equipment. Impurities normally found in compressed air used in operation and purging of instrumentation devices include water vapor and CO.sub.2, which are strong absorbers of infrared radiation at wavelengths which interfere with analytical wavelengths and spectral regions commonly employed for analysis of a variety of organic and inorganic materials.

Abstract: This invention provides an apparatus and process for dehydrating gases, the apparatus comprised of uncoated, asymmetric membranes having controlled porosity. The membranes being formed of polymeric materials which have high transport selectivity for water vapor and sufficient porosity to provide adequate feed gas permeation sweep for the permeated water vapor ensuring conditions of continued effective dehydration. Uncoated asymmetric gas separation membranes have been found to be effective for dehydrating gases such as air, gases containing hydrocarbons, acid gases and admixtures of these gases. The membranes provided by the invention possess a unique combination of properties and characteristics which promote an effective process for the dehydration of gases.

Abstract: Processes utilizing polyphosphazene membranes for separating polar fluids from non-polar fluids are disclosed. Fluid separation membranes comprised of polyphosphazenes having halogenated side groups are disclosed as exhibiting effective preferential selectivity and permeabilities for polar fluids relative to non-polar fluids contained in feedstream mixtures. The polyphosphazenes are in general rubbery polymers having attractive fluids transport properties and improved thermal and chemical stability.

Abstract: Asymmetric gas separation membranes having graded density skins and macrovoid-free morphology comprised of glassy, hydrophobic polymers which when contacted on the graded density skin surface with an effective amount of permeation modifier and a coating in occluding contact, exhibit permeation selectivities greater than the intrinsic permeation selectivities for at least one gas of a gaseous mixture than a bulk sample of the polymers. The permeation modified membranes have increased free volume as evidenced by the membrane first heat T.sub.g which is greater than the T.sub.g of the bulk sample of the glassy, hydrophobic polymers; however the permeation modified membranes having an effective amount of permeation modifier added in non-uniform mode are achieved without significant loss in the physical properties of the membrane, including T.sub.g.

Abstract: Multicomponent membranes for gas separation having polyphosphazene coatings in occluding contact with a porous separation membrane are disclosed which are effective for separating at least one gas from gaseous mixtures and which exhibit improved stability when exposed to aromatic and aliphatic hydrocarbons contained in the gaseous mixtures. In addition multicomponent membranes for gas separations having a polyphosphazene coating in occluding contact with a porous separation membrane of polar material are disclosed which exhibit relative preferential permeation of polar gases from mixtures containing polar and non-polar gases.

Abstract: Polyphosphazenes are disclosed as gas separation membranes which exhibit effective preferential selectivity and permeabilities for acid gases relative to non-acid gases contained in feed gas stream mixtures, particularly where the acid gases are mixed with gaseous hydrocarbons. The polyphosphazenes are rubbery polymers having attractive acid gases transport properties and improved thermal and chemical stability. Processes utilizing polyphosphazene membranes for separating acid gases from gasous mixtures containing non-acid gases are also disclosed.