The present invention relates to a separation membrane including a thermoplastic polymer selected from a cellulose ester and a polyamide, in which, when regions obtained by dividing a cross-sectional surface perpendicular to a longitudinal direction of the separation membrane into 5 at an equal interval are defined as regions 1 to 5, all the regions 1 to 5 have a number average pore diameter changing rate α.sub.i of −0.25 to 0.25, and at least one of the regions 1 to 5 is a region P that satisfies conditions (a) and (b): (a) a value of area average pore diameter D.sub.s/number average pore diameter D.sub.n is 2.50 to 6.00; and (b) a number average W of fine pores that are located at a distance smaller than L.sub.a from a center of respective coarse pores is 10 to 30.

A porous membrane includes a polymer which includes one or more structural units selected from the group consisting of a structural unit represented by Formula (I) and a structural unit represented by Formula (II), in which a content of the structural unit represented by Formula (II) is 1% by mass or more and less than 10% by mass with respect to a total mass of the structural unit represented by Formula (I) and the structural unit represented by Formula (II) ##STR00001##

A porous membrane includes a polymer which includes one or more structural units selected from the group consisting of a structural unit represented by Formula (I) and a structural unit represented by Formula (II), in which a content of the structural unit represented by Formula (II) is 1% by mass or more and less than 10% by mass with respect to a total mass of the structural unit represented by Formula (I) and the structural unit represented by Formula (II) ##STR00001##

A process is provided of making facilitated transport membrane comprising a relatively hydrophilic, very small pore, nanoporous support membrane, a hydrophilic polymer inside the very small nanopores on the skin layer surface of the support membrane, a thin, nonporous, hydrophilic polymer layer coated on the surface of the support membrane, and metal salts incorporated in the hydrophilic polymer layer coated on the surface of the support membrane and the hydrophilic polymer inside the very small nanopores. In addition, the process provides a new method of making facilitated transport membrane spiral wound elements or hollow fiber modules for olefin/paraffin separations, particularly for C3=/C3 and C2=/C2 separations.

A process is provided of making facilitated transport membrane comprising a relatively hydrophilic, very small pore, nanoporous support membrane, a hydrophilic polymer inside the very small nanopores on the skin layer surface of the support membrane, a thin, nonporous, hydrophilic polymer layer coated on the surface of the support membrane, and metal salts incorporated in the hydrophilic polymer layer coated on the surface of the support membrane and the hydrophilic polymer inside the very small nanopores. In addition, the process provides a new method of making facilitated transport membrane spiral wound elements or hollow fiber modules for olefin/paraffin separations, particularly for C3=/C3 and C2=/C2 separations.

A gas detector comprises a gas detection unit and a filter introducing surrounding atmosphere to the gas detection unit. The filter comprises a gas-permeable organic polymer membrane having an acidic group or a basic group.

A gas detector comprises a gas detection unit and a filter introducing surrounding atmosphere to the gas detection unit. The filter comprises a gas-permeable organic polymer membrane having an acidic group or a basic group.

Provided is a hydrophilic porous membrane including a porous membrane and a hydroxyalkyl cellulose (preferably, hydroxypropyl cellulose) retained in the porous membrane, the hydroxyalkyl cellulose having a weight-average molecular weight of 10,000 or more and less than 110,000. The hydrophilic porous membrane of embodiments of the invention has high water permeability and can pass an integrity test in the case of being used as a filtration membrane of a filter cartridge. Also provided is a method for producing the above-mentioned hydrophilic porous membrane, the method comprising causing a hydrophilizing liquid including 0.005% to 0.500% by mass of a hydroxyalkyl cellulose having a weight-average molecular weight of 10,000 or more and less than 110,000, to permeate a porous membrane.

Provided is a hydrophilic porous membrane including a porous membrane and a hydroxyalkyl cellulose (preferably, hydroxypropyl cellulose) retained in the porous membrane, the hydroxyalkyl cellulose having a weight-average molecular weight of 10,000 or more and less than 110,000. The hydrophilic porous membrane of embodiments of the invention has high water permeability and can pass an integrity test in the case of being used as a filtration membrane of a filter cartridge. Also provided is a method for producing the above-mentioned hydrophilic porous membrane, the method comprising causing a hydrophilizing liquid including 0.005% to 0.500% by mass of a hydroxyalkyl cellulose having a weight-average molecular weight of 10,000 or more and less than 110,000, to permeate a porous membrane.

A porous membrane includes a polymer which includes one or more structural units selected from the group consisting of a structural unit represented by Formula (I) and a structural unit represented by Formula (II), in which a content of the structural unit represented by Formula (II) is 1% by mass or more and less than 10% by mass with respect to a total mass of the structural unit represented by Formula (I) and the structural unit represented by Formula (II)

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