The invention is an improved method of making a carbon molecular sieve (CMS) membrane in which a precursor polymer is pyrolyzed to form a carbon molecular sieve membrane that is then exposed to a conditioning atmosphere comprised of a target permeate gas molecule such as ethylene when the membrane is desired to separate it from a light hydrocarbon gas stream. The exposure to the ethylene desirably occurs prior to the CMS permeance and selectivity combination substantially changing (e.g., within 5 days) of cooling from the pyrolyzing temperature. The CMS membranes have shown an improved combination of selectivity and permeance as well as stability and are useful to separate gases in gas streams such methane from natural gas, oxygen from air and ethylene or propylene from light hydrocarbon streams.

A carbon molecular sieve (CMS) membrane is made by pyrolyzing, to a peak pyrolysis temperature T.sub.P, a hollow fiber membrane having a polymeric sheath surrounding a polymeric core, anti-substructure collapse particles present in pores formed in the polymeric core help prevent collapse of pores formed in the hollow fiber membrane before pyrolysis. The anti-substructure collapse particles are made of a material or materials that either: i) have a glass transition temperature T.sub.G higher than T.sub.P, ii) have a melting point higher than T.sub.P, or ii) are completely thermally decomposed during said pyrolysis step at a temperature less than T.sub.P. The anti-substructure collapse particles are not soluble in a solvent used for dissolution of the polymeric material of the core.

Microporous polymer membranes and related methods of fabrication are provided. An asymmetric microporous membrane embodiment includes, but is not limited to, a thermoplastic polymer substrate defining a plurality of micropores, the thermoplastic polymer including one or more of polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), and a combination thereof; and a polymethylpentene (PMP) polymer skin positioned on the thermoplastic polymer substrate, wherein when the thermoplastic polymer substrate includes PMP, the PMP polymer skin has a crystallinity that differs from a crystallinity of the PMP in the polymer substrate.

A homogeneous fiber reinforced PVDF hollow fiber membrane and a preparation method thereof are provided. The membrane includes a hollow tubular reinforcement made of PVDF fibers and a polymer separation layer made of PVDF casting solution; wherein the polymer separation layer casting solution comprises 4-25% PVDF resin, 5-20% pore-forming agent, 0-3% inorganic particles and 52-91% solvent according to mass fraction. The preparation method includes steps of: (1) preparing a hollow tubular reinforcement made of PVDF fibers; (2) preparing a PVDF polymer separation layer casting solution; and (3) obtaining the homogeneous fiber reinforced PVDF hollow fiber membrane.

A method of manufacturing a hollow fiber carbon membrane, the method includes heating a polymeric precursor to a pyrolysis temperature that is greater than or equal to 900? C. and less than or equal to 1200? C., and pyrolyzing the polymeric precursor at the pyrolysis temperature in a pyrolysis atmosphere that comprises oxygen in an amount that is greater than 0 ppm and less than 200 ppm.

A polyimide random copolymer has a structure represented by formula (I). A method for preparing the polyimide random copolymer, a membrane made of the polyimide random copolymer, and a method for preparing a polyimide-based hollow fiber membrane are also provided. A system for purifying helium gas and a method for purifying helium gas are related to the membrane made of the polyimide random copolymer.

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Synthetic membranes for the removal, isolation, or purification of substances from a liquid. The membranes include at least one hydrophobic polymer and at least one hydrophilic polymer. 5-40 wt.-% of particles having an average particles size of between 0.1 and 15 ?m are entrapped. The membrane has a wall thickness of below 150 ?m. Methods for preparing the membranes in various geometries, and use of the membranes for the adsorption, isolation, and/or purification of substances from a liquid are explored.

A spinning nozzle is provided for the extrusion of a hollow fiber from one or more spinning masses. An apparatus that includes a spinning nozzle, and a method for extruding a hollow fiber using the spinning nozzle, are also provided. The spinning nozzle has an inlet port for each spinning mass to be extruded. The inlet port is for introducing the spinning mass into the spinning nozzle. An outlet port for the exit of a spinning mass along an outlet axis, is also provided. A spinning mass flow channel is used to guide the spinning mass from the inlet port to the outlet port. The spinning mass flow channel includes a flow manipulation section having an inlet and an outlet and includes a flow-guiding structure for influencing a spinning mass through the spinning mass flow channel.

Microporous polymer membranes and related methods of fabrication are provided. An asymmetric microporous membrane embodiment includes, but is not limited to, a thermoplastic polymer substrate defining a plurality of micropores, the thermoplastic polymer including one or more of polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), and a combination thereof; and a polymethylpentene (PMP) polymer skin positioned on the thermoplastic polymer substrate, wherein when the thermoplastic polymer substrate includes PMP, the PMP polymer skin has a crystallinity that differs from a crystallinity of the PMP in the polymer substrate.

The invention relates to a virus filter membrane which can be used for the removal of virus particles including parvovirus. The invention further relates to a method for producing the membrane. The membrane comprises polyacrylonitrile and polyvinylpyrrolidone.