A process for separating a feed gas comprising polar and non-polar gases into a gas mixture enriched in polar gas(es) and a gas mixture depleted in polar gas(es), the process comprising passing the feed gas through a gas separation unit comprising at least two gas-separation modules in order of decreasing selectivity for the polar gas(es), wherein the feed gas entering the gas separation unit comprises 1 to 35 mol % of polar gas(es).

A composite membrane comprising: a. a porous support; b. a polymeric layer comprising dialkylsiloxane groups and a metal, the polymeric layer being present on the porous support; c. a discriminating layer present on the polymeric layer; and d. optionally a protective layer present on the discriminating layer wherein the polymeric layer has a molar ratio of metal:silicon of at least 0.0005.

A process for preparing a composite membrane comprising the steps: a) applying a radiation-curable composition to a porous support; b) irradiating the composition and thereby forming a gutter layer of cured polymer; and c) forming a discriminating layer on the gutter layer; wherein the radiation-curable composition comprises a partially crosslinked, radiation-curable polymer comprising epoxy groups and siloxane groups, a photoinitiator and is substantially free from mono-epoxy compounds. Composite membranes and gas separation cartridges are also claimed.

A process for preparing a composite membrane comprising the steps of: a) applying a radiation-curable composition to a porous support; b) irradiating the composition and thereby forming a layer of cured polymer of thickness 20 to 400 nm on the support; c) forming a discriminating layer on the layer of cured polymer; and d) optionally forming a protective layer on the discriminating layer; wherein the radiation-curable composition comprises a partially crosslinked, radiation-curable polymer comprises dialkylsiloxane groups. Composite membranes are also claimed.

In a method of fabricating high performance CMS membranes, in which a dual-layer hollow fiber precursor fiber membrane that contains a nano-particle-filler containing core layer is extruded, a sheath layer is co-extruded with the core layer so that at least a portion of the core layer is surrounded by the sheath layer. The nano-particle filler is defect sealed. The dual-layer hollow fiber precursor fiber and the sheath layer are pyrolysed. A CMS membrane includes a core layer, a sheath layer surrounding at least a portion of the core layer and a plurality of nanoparticles disposed in the core layer.

Porous membranes are provided according to the invention having desirable coefficient of thermal expansion and large surface area, for example at least about 4,000 mm.sup.2. These porous membranes may be made according to an exemplary process employing lithographic patterning of a photoresist followed by development of the photoresist and etching. In one aspect, the etch barrier layer is chosen from a material that does not react with or incorporate metal or other contaminants into the membrane layer.

The invention relates to hydrophobic hollow fiber membranes, and in particular, to hydrophobic organic-inorganic composite hollow fiber membranes. Methods for forming the hydrophobic organic-inorganic composite hollow fiber membranes are also disclosed. The hydrophobic organic-inorganic composite hollow fiber membranes may be used in membrane contactor applications such as gas-liquid (G-L) contactor and liquid-liquid (L-L) contactor processes. Applications for G-L membrane contactors include gas streams purification (gas absorption), water ozonation, and water deoxygenation. Applications for L-L membrane contactors include direct contact membrane distillation and liquid-liquid extraction.

The present disclosure relates to a composite membrane in which a rubbery polymer is introduced into a gutter layer to suppress the physical aging of the highly permeable composite membrane, and more particularly, to a composite membrane comprising a porous support layer; a gutter layer on the porous support layer; and an active layer on the gutter layer, wherein the gutter layer comprises a blend of poly(l-trimethlsilyl-l-propyne) (PTMSP) and a rubbery polymer and a method for preparing the same. The composite membrane according to the present disclosure has high permeation performance and a remarkable decline in physical aging leading to a decrease in permeability over time and thus has very high industrial applicability.

In one aspect, the disclosure relates to azide-containing poly(ether imide) polymers (PEIs; N.sub.3-PEI-N.sub.3) synthesized via a heterogenous diazotizationazidation reaction. In one aspect, the azide-containing PEIs can be solution-cast into films and then thermally crosslinked. In a further aspect, the crosslinked PEIs (X-PEIs) exhibit superior thermal and mechanical properties. In a still further aspect, X-PEIs display outstanding resistance to classical solvents for conventional PEI, including THF, DCM, chloroform, DMF, and NMP. In another aspect, with an initial number average molecular weight (M.sub.n) of 8.9 kDa, the disclosed azide-containing PEIs have a high crosslinking density and thus possess desirable thermal, mechanical, and solvent resistance properties.

Various embodiments of a system and method for enriching a concentration of components of interest in an air flow are described. The system includes an apparatus for enriching a concentration of components of interest in an air flow. The apparatus includes a chamber and a tube having a tube wall made of a selectively permeable material positioned within the chamber. A first end of the tube is connected to the inlet port of the chamber and a second end of the tube is connected to the outlet port of the chamber. The selectively permeable material has a lower permeability to components of interest than to inert gases, and the selectively permeable material is non-reactive with components of interest. The apparatus is configured to receive a sample stream and the chamber is maintained at a chamber pressure that is different than a stream pressure of the sample stream.