Hollow fiber membrane containing poly(aryl ether sulfone) and water-soluble polymer additives

Abstract

This invention relates to a hollow fiber membrane made from a blend of poly(aryl ether sulfone) and a water-soluble polymer additive, a method for producing the same, and its use.

Description

[Technical Field]

[0001] This invention relates to hollow fiber membranes made from a blend of poly(aryl ether sulfone) and a water-soluble polymer additive, a method for producing the same, and its use. Furthermore, this invention relates to separation elements, membrane modules, separation systems, membrane cartridges, and fuel cell membrane humidifiers containing such membranes.

[0002] In hydrogen fuel cells, electricity is generated by the reaction of hydrogen and oxygen, which in turn forms water. Polymer electrolyte membrane (PEM) fuel cells (FCs), in particular, are used for transport applications with no carbon dioxide emissions, and ambient air serves as the oxygen source necessary for the fuel cell reaction. For efficient operation and performance of the fuel cell, the PEM membrane requires a certain level of humidification. Therefore, a gas-to-gas humidifier is used to transfer water vapor from the cathode exhaust gas to the intake gas. To provide humidification, for example, lightweight and miniaturized membrane humidifiers are used, and the humidifier may include a hollow fiber membrane that selectively supplies water vapor to the fuel cell membrane.

[0003] Various materials are used for hollow fiber membranes. Examples include perfluorinated sulfonic acid polymers (PFSA) (e.g., Nafion®, DuPont), polyimides or polyarylsulfones, such as polyethersulfone (PESU) or polysulfone (PSU). U.S. Patent Application Publication No. 2021154624 relates to a composite hollow fiber membrane comprising a hollow fiber membrane and a contaminant trapping layer coated on the inner surface of the hollow fiber membrane, which can be used in membrane humidifiers for fuel cells. From an environmental standpoint, halogen-containing polymer membrane materials are undesirable.

[0004] In the method for producing polyarylsulfone hollow fibers by non-solvent-induced phase separation (NIPS), hydrophilic water-soluble polymers such as polyvinylpyrrolidone (PVP) are used as additives to adjust the viscosity of the polymer solution. Such additives can also act as placeholders for the pores in the filtration layer of the hollow fiber membrane (e.g., S. Munari, Desalination 1988, 70, 265-275). In a subsequent post-treatment step, the filtration layer is formed by removing the hydrophilic polymer from the polyarylsulfone matrix. This can be selectively removed by chemical treatment with hypochlorite (IMWienk et al., Journal Polymer Science: Part A: Polymer Chemistry 1995, 33, 49-54).

[0005] With the growing demand for environmentally friendly electricity, optimized fuel cell assemblies, including membrane humidifiers, are required for efficient and long-term sustainable operation of fuel cells.

[0006] Therefore, an object of the present invention was to find a membrane suitable for a fuel cell humidifier that can selectively suppress gases and transfer water vapor to the fuel cell membrane. A further object was to provide a selective and halogen-free membrane having a high water vapor permeability useful for fuel cell membrane humidifiers.

[0007] The purpose is to create a porous support structure and an inner membrane surface layer (SL). in ) and the outer film surface layer (SL out This is achieved by using a hollow fiber membrane comprising a hollow fiber membrane comprising at least one polymer (P) selected from poly(arylene ethersulfone) and sulfonated poly(arylene ethersulfone), and a water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP), in a fuel cell membrane humidifier, and by using such a membrane to selectively suppress nitrogen gas and selectively allow water vapor to pass through a gaseous mixture containing water vapor and nitrogen.

[0008] Furthermore, within the framework of the present invention, surprisingly, a porous support structure and an inner membrane surface layer (SL) in ) and the outer film surface layer (SL out The hollow fiber membrane of the present invention, comprising at least one polymer (P) selected from poly(arylene ethersulfone) and sulfonated poly(arylene ethersulfone), and a water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP) having a solution viscosity characterized by a K value of at least 80, at least 10% by weight based on the total weight of the membrane, has been found to exhibit a high water transfer rate while selectively suppressing undesirable gases contained in the gaseous exhaust composition supplied to a fuel cell. The membrane of the present invention and assemblies comprising the membrane of the present invention are particularly useful in humidifiers for polymer electrolyte membrane fuel cells.

[0009] In the context of this invention, the term "membrane" means a semipermeable structure that acts as a selective barrier, allowing some particles, substances, or chemicals to pass through while retaining others. Generally, membranes are applied in various liquid and gas separations.

[0010] The membrane of the present invention is a hollow fiber membrane, which may be a single-bore hollow fiber membrane or a multiple-bore hollow fiber membrane. In the hollow fiber membrane, a semipermeable barrier exists in the form of hollow fibers.

[0011] Multiple channel membranes, also called multi-bore membranes, contain two or more longitudinal channels, which are also called "channels" or "bores."

[0012] The number of channels is typically 2 to 19. In one embodiment, the multiple-bore hollow fiber membrane includes 2 or 3 channels. In another embodiment, the multiple-bore hollow fiber membrane includes 5 to 9 channels. In a particular embodiment, the multiple-bore hollow fiber membrane includes 7 channels. In yet another embodiment, the multiple-bore hollow fiber membrane includes 20 to 100 channels.

[0013] The shapes of one or more bores may vary. Typically, the film according to the present invention has a diameter that is essentially circular, elliptical, or rectangular. Preferably, the film according to the present invention is essentially circular, i.e., the bore has a diameter that is essentially circular.

[0014] In another embodiment, such a bore has an essentially elliptical diameter. In yet another embodiment, the channel has an essentially rectangular diameter. In some cases, the actual form of such a channel may deviate from the ideal circular, elliptical, or rectangular form.

[0015] A hollow fiber membrane channel has an inner diameter and an outer diameter. The difference between the outer diameter and the inner diameter is the thickness of the hollow fiber membrane.

[0016] Typically, such channels have an outer diameter of 0.05 mm to 3 mm, preferably 0.5 mm to 2 mm, more preferably 0.9 mm to 1.5 mm (for essentially circular diameters), a smaller outer diameter (for essentially elliptical diameters), or a smaller outer supply size (for essentially rectangular diameters). In another preferred embodiment, such channels have an outer diameter in the range of 0.2 to 0.9 mm (for essentially circular diameters), a smaller outer diameter (for essentially elliptical diameters), or a smaller outer supply size (for essentially rectangular diameters).

[0017] In a preferred embodiment, the hollow fiber membrane according to the present invention or the hollow fiber membrane used in accordance with the present invention has an outer diameter of 2 to 10 mm, preferably 3 to 8 mm, more preferably 4 to 6 mm (for essentially circular diameters), a smaller outer diameter (for essentially elliptical diameters), or a smaller outer supply size (for essentially rectangular diameters).

[0018] In another preferred embodiment, the hollow fiber membrane according to the present invention or the hollow fiber membrane used in accordance with the present invention has an outer diameter of 2 to 4 mm (for an essentially circular diameter), a smaller outer diameter (for an essentially elliptical diameter), or a smaller outer supply size (for an essentially rectangular diameter).

[0019] The hollow fiber membrane can have any thickness. For example, the membrane thickness is in the range of 20 to 150 μm, preferably in the range of 20 to 100 μm, and most preferably in the range of 30 to 60 μm.

[0020] If the multi-bore hollow fiber membrane contains channels that are essentially rectangular in shape, these channels can be arranged in a row. If the channels of the multi-bore hollow fiber membrane are essentially circular in shape, these channels are preferably arranged such that the central channel is surrounded by the other channels. In one preferred embodiment, the membrane includes one central channel and, for example, four, six, or eighteen further channels arranged in a ring around the central channel. The wall thickness of such a multiple-channel membrane is typically 0.02 to 1 mm, preferably 30 to 500 μm, and more preferably 100 to 300 μm at its thinnest point.

[0021] The hollow fiber membranes of the present invention and the hollow fiber membranes used in accordance with the present invention each comprise at least one polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone). Poly(arylene ethersulfone) is unsulfonated unless expressly stated otherwise.

[0022] Poly(arylene ether sulfone) polymers belong to a group of high-temperature resistant polymers that exhibit high heat resistance, excellent mechanical properties, and inherent flame retardancy (EMKoch, H.-M. Walter, Kunststoffe 80 (1990) 1146, E. Doring, Kunststoffe 80 (1990) 1149, N. Inchaurondo-Nehm, Kunststoffe 2008 190). Polyarylene (ether) sulfones are generally known to those skilled in the art.

[0023] In the context of this invention, "non-sulfonated" means that the poly(arylene ethersulfone) polymer does not contain a -SO2X group, where X is a cation equivalent combined with Cl - and O- is selected from the group consisting of. "One cation equivalent" within the context of the present invention refers to one cation of a single positive charge, or a cation having two or more positive charges, such as H + , Li + , Na + , K + , Mg 2+ , Ca 2+ or NH4 + and means one charge equivalent thereof.

[0024] The terms "sulfonated poly(arylene ether sulfone)" or "poly(arylene ether sulfone)" in the present application are understood to mean exactly one sulfonated poly(arylene ether sulfone) polymer or poly(arylene ether sulfone) polymer, respectively, and are also understood to mean a mixture of two or more sulfonated poly(arylene ether sulfone) polymers or a mixture of two or more poly(arylene ether sulfone) polymers, respectively.

[0025] According to one embodiment, the hollow fiber membrane of the present invention or the hollow fiber membrane used according to the present invention contains a poly(arylene ether sulfone) polymer (P) that is defined or preferably defined herein, respectively. In a specific embodiment thereof, the hollow fiber membrane contains no sulfonated poly(arylene ether sulfone) at all.

[0026] According to these embodiments, the hollow fiber membrane preferably contains at least 50% by weight of the poly(arylene ether sulfone) polymer (P), more preferably at least 60% by weight, and most preferably at least 70% by weight of the poly(arylene ether sulfone) polymer (P) based on the total weight of the hollow fiber membrane.

[0027] According to further embodiments, the hollow fiber membrane of the present invention or the hollow fiber membrane used in accordance with the present invention each comprises a defined, or preferably herein defined, sulfonated poly(arylene ethersulfone) polymer (P). In specific embodiments, the hollow fiber membrane contains no (unsulfonated) poly(arylene ethersulfone) at all.

[0028] According to these embodiments, the hollow fiber membrane preferably comprises at least 50% by weight of sulfonated poly(arylene ethersulfone) polymer (P), more preferably at least 60% by weight, and most preferably at least 70% by weight of sulfonated poly(arylene ethersulfone) polymer (P), based on the total weight of the hollow fiber membrane.

[0029] In further embodiments, the hollow fiber membrane of the present invention or the hollow fiber membrane used in accordance with the present invention each comprises a defined or preferably herein defined sulfonated poly(arylene ethersulfone) and a defined or preferably herein defined poly(arylene ethersulfone).

[0030] When both sulfonated poly(arylene ethersulfone) and unsulfonated poly(arylene ethersulfone) are included in the hollow fiber membrane, the hollow fiber membrane contains preferably 5 to 90% by weight, more preferably 7.5 to 80% by weight, of the sulfonated poly(arylene ethersulfone) polymer (P) based on the total weight of the membrane. The membrane also contains preferably 10 to 95% by weight, more preferably 20 to 92.5% by weight, of the poly(arylene ethersulfone) polymer (P) based on the total weight of the membrane.

[0031] Therefore, in a preferred embodiment, the hollow fiber membrane comprises, in each case, 5 to 90% by weight of a sulfonated poly(arylene ethersulfone) polymer and 10 to 95% by weight of a poly(arylene ethersulfone) polymer, based on the total weight of the membrane.

[0032] In preferred embodiments, the sulfonated poly(arylene ethersulfone) polymer is of formula (I) [ka] Includes units of, In the formula, the symbols t, q, Q, T, Y, Ar and Ar 1 The definition is as follows: t and q are independent of each other and can be 0, 1, 2, or 3. Q, T, and Y are independent of each other, and are chemically bonded, or -O-, -S-, -SO2-, S=O, C=O, -N=N-, and -CR. a R b - is a base selected from, where R a and R b These are, independently of each other, hydrogen atoms, (C1~C 12 ) Alkyl, (C1~C 12 )alkoxy, (C3~C 12 )Cycloalkyl or (C6~C 18 ) an aryl group, where at least one of Q, T, and Y is present and -SO2-, Ar and Ar 1 They are independent of each other, (C6~C 18 ) It is allerene, At least one unit (I) comprises an arylene group substituted with at least one -SO2X group, where X is Cl and O combined with one cation equivalent. - Selected from the group consisting of, the cation equivalent is H + Li + kaNa + , K + Mg 2+ Ca 2+ or NH4 + That is the case.

[0033] Of the above conditions, if Q, T, or Y is a chemical bond, this is understood to mean that the adjacent group on the left and the adjacent group on the right are directly bonded to each other via a chemical bond. It will be easily understood that if at least one of the groups consisting of Q, T, and Y is -SO2-, then at least one of the groups in equation (I) is -SO2-. Thus, when q=0, at least one of T and Y is -SO2-, for example, when t=0, at least one of Q and Y is -SO2-, and when q=0 and t=0, Y is SO2.

[0034] According to one preferred embodiment, t and q are independently 0 or 1.

[0035] According to one preferred embodiment, Q, T, and Y in formula II are independently chemical bonds, -O-, -SO2-, and -CR. a R b -Selected from, where at least one of Q, T, and Y exists and is -SO2-. Furthermore, R a and R b These elements may preferably be hydrogen or (C1-C4) alkyl, independently of each other.

[0036] -CR a R b -In R a and R b Preferably, independently, hydrogen, (C1~C 12 ) Alkyl, (C1~C 12 )alkoxy and (C6~C 18 ) Selected from the arrow.

[0037] (C1~C 12 Alkyl refers to a linear or branched saturated hydrocarbon group having 1 to 12 carbon atoms. The following parts, (C1-C6) alkyl, e.g., methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, 2- or 3-methylpentyl, and (C7-C 12Alkyl groups, such as unbranched heptyl, octyl, nonyl, decyl, undecyl, lauryl, and their monobranched or polybranched analogs, are particularly included.

[0038] "C1~C 12 The term "alkoxy" refers to a linear or branched alkyl group having 1 to 12 carbon atoms bonded via oxygen at any position within the alkyl group, such as methoxy, ethoxy, n-propoxy, 1-methylethoxy, butoxy, 1-methyl-propoxy, 2-methyl-propoxy, or 1,1-dimethylethoxy.

[0039] (C3~C 12 Cycloalkyl refers to a monocyclic saturated hydrocarbon group having 3 to 12 carbon ring members, and in particular includes (C3-C8) cycloalkyl groups, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclopropylmethyl, cyclopropylethyl, cyclopropylpropyl, cyclobutylmethyl, cyclobutylethyl, cyclopentylethyl, -propyl, -butyl, -pentyl, -hexyl, cyclohexylmethyl, -dimethyl, and -trimethyl.

[0040] Ar and Ar 1 They are independent of each other, (C6~C 18 )-Arylene group. According to a particular embodiment, Ar 1 is non-substitutable (C6~C 12 ) In some cases, it is preferable that the group be an arylene group.

[0041] Ar and Ar 1 It may be preferable to independently select from phenylene, bisphenylene and naphthylene groups, as well as arylene groups derived from anthracene, phenanthrene, or naphthacene. For example, Ar and Ar 1These are independently selected from 1,2-phenylene, 1,3-phenylene, 1,4-phenylene, 1,6-naphthylene, 1,7-naphthylene, 2,6-naphthylene and 2,7-naphthylene, 2,7-dihydroxynaphthylene and 4,4'-bisphenylene.

[0042] In particular, Ar and Ar 1 The group is independently selected from phenylene and naphthylene groups, for example, independently selected from 1,2-phenylene, 1,3-phenylene, 1,4-phenylene, 1,6-naphthylene, 1,7-naphthylene, 2,6-naphthylene and 2,7-naphthylene, and more specifically, it may be preferable to independently select from 1,4-phenylene, 1,3-phenylene and naphthylene. Furthermore, according to another embodiment of the present invention, Ar and Ar 1 The following are independently selected from anthracene, phenanthrene, or arylene groups derived from naphthacene. Furthermore, according to a further embodiment, Ar and Ar 1 These are independently selected from 2,7-dihydroxynaphthylene and 4,4'-bisphenylene.

[0043] A preferred sulfonated poly(arylene ethersulfone) polymer is a polymer containing at least one of the following units Ia to Io as repeating structural units, where at least one unit (I) contains an arylene group substituted with at least one -SO2X group, where X is Cl and O combined with one cation equivalent. - Selected from the group consisting of, the cation equivalent is H + Li + kaNa + , K + Mg 2+ Ca 2+ or NH4 + That is the case. [ka] [ka]

[0044] In addition to the preferred units Ia to Io, units in which one or more 1,4-phenylene units derived from hydroquinone are replaced by 1,3-phenylene units derived from resorcinol or naphthylene units derived from dihydroxynaphthalene are also preferred.

[0045] Particularly preferred units of general formula (I) are units Ia, Ig, and Ik. It is also particularly preferred that the sulfonated poly(arylene ethersulfone) polymer is essentially formed from one type of unit of general formula (I), particularly a unit selected from Ia, Ig, and Ik.

[0046] In a particularly preferred embodiment, Ar = 1,4-phenylene, t = 1, q = 0, T is a chemical bond, and Y = SO2. A particularly preferred sulfonated poly(arylene ether sulfone) polymer (A) formed from the above repeating units is called sulfonated polyphenylene sulfone (PPSU) (formula Ig).

[0047] In a particularly preferred embodiment, Ar=1,4-phenylene, t=1, q=0, T=C(CH3)2, and Y=SO2. A particularly preferred sulfonated poly(arylene ethersulfone) polymer (A) formed from the above repeating units is called sulfonated polysulfone (PSU) (formula Ia).

[0048] In a particularly preferred embodiment, Ar=1,4-phenylene, t=1, q=0, and T=Y=SO2. A particularly preferred sulfonated poly(arylene ethersulfone) polymer (A) formed from the above repeating units is called sulfonated poly(ethersulfone) (PESU) (formula Ik).

[0049] In the context of this invention, abbreviations such as PPSU, PESU, and PSU are used in accordance with DIN EN ISO 1043-1 (Plastics - Symbols and abbreviated terms - Part 1: Basic polymers and their special characteristics (ISO 1043-1:2001); German version EN ISO 1043-1:2002).

[0050] In preferred embodiments, the sulfonated poly(arylene ethersulfone) polymer is a copolymer formed from poly(ethersulfone) (PESU) units and poly(phenylenesulfone) (PPSU) units, where at least one unit comprises an arylene group substituted with at least one -SO2X group, where X is Cl and O combined with one cation equivalent. - Selected from the group consisting of, the cation equivalent is H + Li + kaNa + , K + Mg 2+ Ca 2+ or NH4 + This copolymer may be, for example, a random copolymer or a block copolymer. A random copolymer formed from poly(ethersulfone) (PESU) and poly(phenylenesulfone) (PPSU) is preferred because it yields a more homogeneous material that shows little to no phase separation in the dissolved or solid state.

[0051] If the sulfonated poly(arylene ethersulfone) polymer is a copolymer formed from poly(ethersulfone) (PESU) units and poly(phenylenesulfone) (PPSU) units, then the sulfonated poly(arylene ethersulfone) polymer in either case contains poly(phenylenesulfone) (PPSU) units in the range of 1 to 20 mol% and poly(ethersulfone) (PESU) units in the range of 80 to 99 mol%, based on the sum of all repeating units.

[0052] In a particularly preferred embodiment, the sulfonated poly(arylene ethersulfone) polymer is of formula (III) [ka] The units of, and / or formula (IV) [ka] Includes units of.

[0053] In a particularly preferred embodiment, the sulfonated poly(arylene ethersulfone) polymer is of formula (V) [ka] Includes units of.

[0054] The sulfonated poly(arylene ethersulfone) polymer may also contain units of formula (III) and / or formula (IV) and / or formula (V).

[0055] The number average molecular weight (M) of the sulfonated poly(arylene ether sulfone) polymer is preferably determined by gel permeation chromatography in dimethylacetamide as a solvent against a narrowly distributed polymethyl methacrylate as a standard, with a number average molecular weight of 10,000 to 35,000 g / mol. N ) has.

[0056] Furthermore, the sulfonated poly(arylene ethersulfone) polymer preferably has a free acid content of less than 3 mg KOH / g of sulfonated poly(arylene ethersulfone) polymer, as determined by titration with a 0.1 mol / l tetrabutylammonium hydroxide solution (TBAH, methanol / toluene) against a Sorbotrode electrode (Metrohm).

[0057] Sulfonated poly(arylene ethersulfone) polymers can be prepared by any method known to those skilled in the art.

[0058] Preferably, sulfonated poly(arylene ethersulfone) polymers are produced by treating each unsulfonated poly(arylene ethersulfone) polymer with at least one sulfonating agent. The at least one sulfonating agent is preferably one cation equivalent (the cation equivalent is H) on the aromatic ring of the unsulfonated poly(arylene ethersulfone) polymer. + Li + kaNa + , K + Mg 2+ Ca 2+ or NH4 + (where X is Cl or O) combined with at least one SO2X group (where X is Cl or O) - The SO2X group is any compound known to those skilled in the art that can be introduced. The SO2X group is preferably a sulfonic acid group (-SO3H) or a group that can react with water to form a sulfonic acid group. Groups of this type are known to those skilled in the art and include, for example, a chlorosulfonyl group (-SO2Cl). Therefore, the SO2X group is, more preferably, a sulfonic acid group (-SO3H) or a chlorosulfonyl group (-SO2Cl), and most preferably, the SO2X group is a sulfonic acid group (-SO3H).

[0059] The reaction between a non-sulfonated poly(arylene ethersulfone) polymer and at least one sulfonating agent preferably involves at least partially sulfonating at least one of the aromatic rings of the non-sulfonated poly(arylene ethersulfone) polymer.

[0060] The mechanism of the sulfonation reaction is known to those skilled in the art. In this case, it is particularly preferable that the sulfonation reaction replaces the hydrogen atoms of the aromatic ring with sulfonic acid groups (-SO3H).

[0061] Typically, 0.001 to 1 SO2X group, preferably 0.005 to 0.1, and more preferably 0.01 to 0.08 SO2X groups are introduced per aromatic ring in a non-sulfonated poly(arylene ethersulfone) polymer. Therefore, sulfonated poly(arylene ethersulfone) polymers typically have 0.001 to 1, preferably 0.005 to 0.1, and more preferably 0.01 to 0.08 sulfonic acid groups per aromatic ring.

[0062] The number of SO2X groups per aromatic ring is determined by averaging across all aromatic rings in the sulfonated poly(arylene ethersulfone) polymer. For this purpose, the number of SO2X groups in the sulfonated poly(arylene ethersulfone) polymer is divided by the number of aromatic rings in the sulfonated poly(arylene ethersulfone) polymer. Methods for determining the number of SO2X groups and the number of aromatic rings, respectively, in the sulfonated poly(arylene ethersulfone) polymer are known to those skilled in the art. The number of SO2X groups can be determined, for example, by acid-base titration or H 1 This can be determined by spectroscopic methods such as NMR spectroscopy or IR spectroscopy (infrared spectroscopy). Sulfonated aromatic polymers having SO2X groups on the aromatic rings exhibit characteristic peaks and bands, making it possible to determine the number of SO2X groups per aromatic ring in sulfonated poly(arylene ethersulfone) polymers. The ratio of sulfonated aromatic rings to unsulfonated aromatic rings can also be determined by these methods, especially H 1 This can be determined by NMR spectroscopy.

[0063] (Non-sulfonated) poly(arylene ethersulfone) polymers are of general formula (I) [ka] It may be preferable that the units consist of the following: In the formula, the symbols t, q, Q, T, Y, Ar and Ar 1 The definition is as follows: t and q are independent of each other and can be 0, 1, 2, or 3. Q, T, and Y are, independently of each other, a chemical bond, or a group selected from -O-, -S-, -SO2-, S=O, C=O, -N=N- and -CR a R b -, where R a O and R b are, independently of each other, a hydrogen atom, (C1-C 12 )alkyl, (C1-C 12 )alkoxy, (C3-C 12 )cycloalkyl or (C6-C 18 )aryl group, where at least one of Q, T, and Y is present and is -SO2-, Ar and Ar 1 are, independently of each other, (C6-C 18 )arylene.

[0064] When Q, T, or Y is a chemical bond within the above premises, this means that the adjacent group on the left and the adjacent group on the right are directly linked to each other via a chemical bond.

[0065] According to a preferred embodiment, t and q are independently 0 or 1.

[0066] According to a preferred embodiment, Q, T, and Y in formula II are independently selected from a chemical bond, -O-, -SO2-, and -CR a R b -, provided that at least one of Q, T, and Y is present and is -SO2-. Further, R a O and R b are preferably, independently of each other, hydrogen or (C1-C4)alkyl.

[0067] -CR a R b - in, R a O and R b are preferably, independently of each other, selected from hydrogen, (C1-C 12 )alkyl, (C1-C 12 )alkoxy and (C6-C 18 )aryl.

[0068] (C1~C 12 ) alkyl, C1~C 12 -alkoxy", (C3~C 12 ) The term cycloalkyl, Ar and Ar 1 It is defined, preferably as defined above.

[0069] A poly(arylene ether sulfone) polymer containing at least one of the units Ia to Io defined above as a repeating structural unit may be preferred.

[0070] In addition to the units Ia to Io which may preferably be present, other repeating units are those in which one or more 1,4-phenylene units derived from hydroquinone are replaced by 1,3-phenylene units derived from resorcinol or naphthylene units derived from dihydroxynaphthalene.

[0071] Particularly preferred units of general formula (I) are units Ia, Ig and / or Ik. According to certain embodiments, it is particularly preferable that the poly(arylene ethersulfone) polymer is essentially composed of one type of units of general formula (I), the one type of which can be particularly selected from Ia, Ig and Ik.

[0072] According to a preferred embodiment, the poly(arylene ethersulfone) polymer is composed of repeating units in which Ar is 1,4-phenylene, t is 1, q is 0, T is a chemical bond, and Y is SO2. This poly(arylene ethersulfone) is also called polyphenylene sulfone (PPSU) (formula Ig).

[0073] In a more preferred embodiment, the poly(arylene ethersulfone) polymer is composed of repeating units in which Ar is 1,4-phenylene, t is 1, q is 0, T is C(CH3)2, and Y is SO2. This poly(arylene ethersulfone) is also called polysulfone (PSU) (formula Ia).

[0074] In a more preferred embodiment, the poly(arylene ethersulfone) polymer (P) is composed of repeating units in which Ar is 1,4-phenylene, t is 1, q is 0, and T and Y are SO2. This poly(arylene ethersulfone) is also called polyethersulfone (PESU) (formula Ik).

[0075] For the purposes of this disclosure, abbreviations such as PPSU, PESU, and PSU are used in accordance with DIN EN ISO 1043-1:2001.

[0076] The weight-average molar mass M of the poly(arylene ethersulfone) polymer (P) of the present invention w This is determined by gel permeation chromatography in dimethylacetamide as a solvent against a narrowly distributed polymethyl methacrylate as a standard, and is preferably 10,000 to 40,000 g / mol, more specifically 10,000 to 37,000 g / mol, particularly 12,000 to 35,000 g / mol, and especially preferably 14,000 to 33,000 g / mol.

[0077] The methods for producing the above-mentioned poly(arylene ethersulfone) polymers are known to those skilled in the art, for example, in Herman F. Mark, "Encyclopedia of Polymer Science and Technology," third edition, volume 4, 2003, chapter "Polsulfones," pages 2 to 8, and also in Hans R. Kricheldorf, "Aromatic Polyethers" in Handbook of Polymer Synthesis, second edition, 2005, pages 427 to 443.

[0078] The synthesis of poly(arylene ethersulfone) polymers can generally be carried out by polycondensation of suitable monomers in a dipolar aprotic solvent at high temperatures (RN. Johnson et.al., J. Polym. Sci. A-1 5(1967)2375, J. E. McGrath et.al., Polymer 25(1984)1827).

[0079] Known poly(arylene ethersulfone) polymers typically have halogen-terminated groups, particularly -F or -Cl, or phenolic OH-terminated groups or phenolate-terminated groups, the latter of which may exist as is or in a reacted form, particularly in the form of -OCH3-terminated groups.

[0080] The reaction between at least one aromatic compound having two halogen substituents and at least one aromatic compound having two functional groups reactive to the halogen substituents is particularly preferred in an aprotic polar solvent and in the presence of an anhydrous alkali metal carbonate, particularly sodium carbonate, potassium carbonate, calcium carbonate, or a mixture thereof, very preferably potassium carbonate. One particularly preferred combination is N-methyl-2-pyrrolidone as the solvent and potassium carbonate as the base.

[0081] The poly(arylene ether sulfone) polymer preferably has either a halogen-terminated group, particularly a chlorine-terminated group, or an etherified-terminated group, particularly an alkyl-ether-terminated group, the etherified-terminated group can be obtained by the reaction of an OH-terminated group or a phenolate-terminated group, respectively, with a suitable etherifying agent. Examples of suitable etherifying agents are monofunctional alkyl halides or aryl halides, such as C1-C6 alkyl chloride, C1-C6 alkyl bromide, or C1-C6 alkyl iodide, preferably methyl chloride, or benzyl chloride, benzyl bromide, or benzyl iodide, or mixtures thereof. For the purposes of the polyarylene (ether) sulfone of component A), preferred terminal groups are halogens, particularly chlorine, alkoxys, particularly methoxy, aryloxys, particularly phenoxy, or benzyloxy.

[0082] According to the present invention, the hollow fiber membrane further comprises a water-soluble polymer additive (A), wherein the additive (A) comprises polyvinylpyrrolidone (PVP).

[0083] Polyvinylpyrrolidone is commercially available, for example, Luvitec® from BASF SE. In one embodiment, the PVP has a solution viscosity characterized by a K value of at least 12 (PVP K12), at least 17 (PVP K17), at least 30 (PVP K30), at least 80 (PVP K80), at least 85 (PVP K85), or at least 90 (PVP K90). Preferably, the PVP has a solution viscosity characterized by a K value of at least 80 (PVP K80), such as Luvitec® K80. In a more preferred embodiment, the PVP has a solution viscosity characterized by a K value of at least 85 (PVP K85), such as Luvitec® K85. A PVP having a solution viscosity characterized by a K value of at least 90 (PVP K90), such as Luvitec® K90, is particularly preferred.

[0084] The viscosity of the solution is determined according to Fikentscher's method (Fikentscher, Cellulosechemie 13, 1932(58)).

[0085] The water-soluble additive (A) may further contain components selected from poly(alkylene oxides) and alcohols. Suitable examples of poly(alkylene oxides) are poly(ethylene oxide), poly(propylene oxide), and poly(ethylene oxide)-poly(propylene oxide) copolymers. Suitable examples of alcohols are dihydric alcohols or trihydric alcohols such as glycerol.

[0086] Preferably, the water-soluble polymer additive (A) contains at least 50% by weight, preferably at least 60% by weight, and particularly at least 70% by weight of PVP relative to the amount of additive (A) in the film.

[0087] In a preferred embodiment, the water-soluble polymer additive (A) consists of a defined, preferably a defined, polyvinylpyrrolidone.

[0088] In further embodiments, the water-soluble polymer additive (A) comprises a defined, preferably as defined herein, PVP and at least one alcohol, preferably glycerol. In particular, the water-soluble polymer additive (A) comprises 30 to 90% by weight of polyvinylpyrrolidone and 10 to 70% by weight of at least one alcohol, preferably glycerol.

[0089] The amount of PVP in the hollow fiber membrane is, preferably, at least 10% by weight, more specifically at least 11% by weight, and even more specifically at least 12% by weight, based on the total weight of the membrane. In further embodiments, the amount of PVP in the hollow fiber membrane is at least 13% by weight, more specifically at least 14% by weight, and even more specifically at least 15% by weight. In further embodiments, the amount of PVP in the hollow fiber membrane is at least 16% by weight. In particular, PVP is present in an amount of 10-30% by weight, more specifically 10-20% by weight. This content is PVP total It is also called [another name].

[0090] According to one aspect, the present invention relates to a porous support structure and an inner membrane surface layer (SL) in a humidifier, more specifically in a fuel cell membrane humidifier. in ) and the outer film surface layer (SL out The present invention relates to a hollow fiber membrane comprising a polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone), and a water-soluble polymer additive (A) containing polyvinylpyrrolidone (PVP).

[0091] In another aspect, the present invention provides a porous support structure and an inner membrane surface layer (SL in ) and the outer film surface layer (SL outThe present invention relates to a hollow fiber membrane comprising a polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone), and a water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP), for selectively suppressing nitrogen gas and selectively allowing water vapor to pass through a gaseous mixture containing water vapor and nitrogen.

[0092] In particular, the hollow fiber membrane described is especially useful for humidifiers in polymer electrolyte membrane fuel cells.

[0093] In yet another aspect, the present invention provides a porous support structure and an inner membrane surface layer (SL in ) and the outer film surface layer (SL out The present invention relates to a hollow fiber membrane comprising a polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone), and a water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP) having a solution viscosity characterized by a K value of at least 80, in an amount of at least 10% by weight based on the total weight of the membrane.

[0094] In the film of the present invention, PVP is present in an amount of at least 10% by weight based on the total weight of the film. total It is also called [another name]. More specifically, the amount of PVP in the membrane of the present invention is at least 11% by weight, and more specifically at least 12% by weight. In a further embodiment, the amount of PVP in the membrane is at least 13% by weight, more specifically at least 14% by weight, and more specifically at least 15% by weight. In a further embodiment, the amount of PVP in the membrane is at least 16% by weight. In particular, PVP is present in an amount of 10-30% by weight, more specifically 10-20% by weight.

[0095] The hollow fiber membrane of the present invention and the hollow fiber membrane used in accordance with the present invention have a porous support structure and an inner membrane surface layer (SL in ) and the outer film surface layer (SL out ) and include.

[0096] Those skilled in the art will know the inner lining surface layer (SL in ) and / or outer film surface layer (SL out It is known that the ) functions as an active separation layer. The support structure typically contains pores. The minimum pore diameter of the hollow fiber membrane and the support structure of the hollow fiber membrane used according to the present invention may be less than 10 nm, and the support structure may have pore diameters up to 10 μm.

[0097] Preferably, the polyvinylpyrrolidone content in the inner or outer surface layer is at least 10% by weight based on the total weight of the membrane. In a further embodiment, the polyvinylpyrrolidone content in the inner and outer surface layers is at least 10% by weight based on the total weight of the membrane.

[0098] Preferably, the inner surface layer (SL in The PVP content in the film is at least 10% by weight based on the total weight of the film. in It is also called PVP. More specifically, PVP in This is at least 11% by weight, and more specifically at least 12% by weight. In further embodiments, PVP in This is at least 13% by weight, more specifically at least 14% by weight, and even more specifically at least 15% by weight. In further embodiments, PVP in It is at least 16% by weight. In particular, PVP in This can be 10-30% by weight, or more specifically, 10-20% by weight.

[0099] Preferably, the outer film surface layer (SL out The PVP content in the film is at least 10% by weight based on the total weight of the film. out It is also called PVP. More specifically, PVP out This is at least 11% by weight, and more specifically at least 12% by weight. In further embodiments, PVP outThis is at least 13% by weight, more specifically at least 14% by weight, and even more specifically at least 15% by weight. In further embodiments, PVP out It is at least 16% by weight. In particular, PVP out This can be 10-30% by weight, or more specifically, 10-20% by weight.

[0100] The hollow fiber membrane of the present invention is characterized by exhibiting a high water transport rate while selectively suppressing gases such as nitrogen. This combination of properties makes the membrane of the present invention particularly useful for use in humidifiers, especially fuel cell membrane humidifiers, where water vapor needs to selectively pass through the membrane. In particular, in fuel cell humidifier assemblies, a gaseous exhaust composition is supplied to the fuel cell, and it is necessary to suppress undesirable gases contained in the gaseous exhaust composition, especially nitrogen.

[0101] Further gases that may be included in the gaseous composition supplied to the fuel cell include, for example, nitrogen, oxygen, carbon dioxide, carbon monoxide, noble gases, and / or ambient air.

[0102] According to the present invention, the hollow fiber membrane has a water flux (WET-IN) of 10 g / sm 2 Preferably, at 80°C, at least 3.5 kg / h·m 2 More specifically, at least 3.6 kg / h·m at 80°C. 2 More specifically, at 80°C, at least 3.7 kg / h·m 2 It has a water vapor permeability of 10 g / sm³. In particular, the hollow fiber membrane has a water flux (WET-IN) of 10 g / sm³. 2 Preferably, at 80°C, at least 3.8 kg / h·m 2 More specifically, at least 3.9 kg / h·m at 80°C. 2 More specifically, at 80°C, at least 4.0 kg / h·m 2 It has a water vapor transmission rate of [value].

[0103] According to the present invention, when measured before contact with water vapor, the hollow fiber membrane preferably has a nitrogen gas permeability of 3 L / m³ at 2 bar. 2Below h·bar, more specifically 2 bar, which is 2.9 L / m³. 2 Below h·bar, and more specifically at 2 bar, 2.8 L / m³ 2 The pressure is less than or equal to 1 / h·bar. In particular, when measured before contact with water vapor, the nitrogen gas permeability of the hollow fiber membrane is preferably 2.7 L / m³ at 2 bar. 2 Below h·bar, more specifically 2 bar, which is 2.6 L / m³. 2 Below h·bar, and more specifically at 2 bar, 2.5 L / m³ 2 The pressure is less than or equal to 1 / h·bar. According to a very specific embodiment, the hollow fiber membrane, when measured before contact with water vapor, has a nitrogen gas permeability of preferably 2.4 L / m³ at 2 bar. 2 Below h·bar, more specifically 2 bar, which is 2.3 L / m³. 2 Below h·bar, and more specifically at 2 bar, 2.2 L / m³ 2 The value is less than or equal to 1 / h·bar. According to a more specific embodiment, the hollow fiber membrane, when measured before contact with water vapor, has a nitrogen gas permeability of preferably 2.1 L / m³ at 2 bar. 2 Below h·bar, more specifically 2 bar and 2.0 L / m³ 2 Below h·bar, and more specifically at 2 bar, 1.9 L / m³ 2 It is less than or equal to h·bar.

[0104] According to the present invention, the hollow fiber membrane preferably has a Brunauer-Emmett Teller (BET) value of 35m on its surface (=the entire surface of the measured membrane). 2 / g or less, especially 34m 2 / g or less, more specifically 33m 2 The value is less than or equal to / g. More specifically, the hollow fiber membrane preferably has a surface BET value of 32m 2 / g or less, especially 31m 2 / g or less, more specifically 30m 2 The value is less than / g. The surface BET value is 29m 2 / g or less, especially 28m 2It is preferable that the concentration be less than or equal to / g. The BET surface is determined by a five-point gas adsorption-desorption (GAD) experiment using nitrogen with ASAP 2420 (Fa. Micromeritics, Norcross, USA). The sample is activated at 130°C for 15 minutes before measurement.

[0105] A further aspect of the present invention is a method for preparing a hollow fiber membrane, a) A step of providing a solution (S) comprising at least one polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone), a water-soluble polymer additive (A) having a solution viscosity characterized by a K value of at least 80 with polyvinylpyrrolidone (PVP), and at least one solvent (D), b) A step of passing the solution (S) through a spinneret and bringing the formed hollow fiber into contact with at least one protic polar solvent to form a hollow fiber membrane, c) A step of isolating the hollow fiber membrane without performing a step of removing additive (A) from the membrane. This is a preparation method that includes [the following].

[0106] In step a), a solution (S) is provided comprising at least one polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone) as defined, preferably as defined herein, a water-soluble polymer additive (A), and at least one solvent (D), wherein the water-soluble polymer additive (A) comprises polyvinylpyrrolidone (PVP) having a solution viscosity characterized by a K value of at least 80 as defined, preferably as defined herein.

[0107] The solution (S) in step a) can be provided by any method known to those skilled in the art. For example, the solution (S) can be provided in step a) in a conventional container which may include a stirring device, preferably a temperature control device. Preferably, the solution (S) is provided by dissolving the polymer (P) and the water-soluble polymer additive (A) in at least one solvent (D).

[0108] The dissolution of the polymer (P) and the water-soluble polymer additive (A) in at least one solvent (D) to provide a solution (S) is preferably carried out under stirring.

[0109] Step a) is preferably carried out at a high temperature, particularly in the range of 20 to 100°C, more preferably in the range of 40 to 80°C. Those skilled in the art will select the temperature according to at least one solvent (D).

[0110] The solution (S) preferably comprises a polymer (P) and a water-soluble polymer additive (A) completely dissolved in at least one solvent (D). This means that the solution (S) preferably does not contain solid particles of the polymer (P) and the water-soluble polymer additive (A).

[0111] At least one polymer (P) used in the method of the present invention is selected from and defined, preferably as defined above, from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone).

[0112] The solution (S) may contain at least one polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone) in any case, based on the total weight of the solution (S), in an amount of 1 to 50% by weight, particularly 1 to 45% by weight, more specifically 5 to 40% by weight, and more specifically 8 to 35% by weight.

[0113] A water-soluble polymer additive (A) containing polyvinylpyrrolidone (PVP) having a solution viscosity characterized by a K value of at least 80 is as defined, and preferably as defined above.

[0114] Preferably, the water-soluble polymer additive (A) contains at least 50% by weight, preferably at least 60% by weight, and particularly at least 70% by weight of PVP based on the total weight of additive (A) in the solution (S). In a preferred embodiment, the water-soluble polymer additive (A) consists of the defined, preferably the above-defined, polyvinylpyrrolidone.

[0115] Preferably, the solution (S) comprises, in any case, at least 3% by weight, more specifically at least 4% by weight, and more specifically at least 4.5% by weight of polyvinylpyrrolidone (PVP) having a solution viscosity characterized by a K value of at least 80, based on the total weight of the solution (S). In particular, the solution (S) may comprise, in any case, 3 to 30% by weight, more specifically 3 to 25% by weight, and more specifically 3 to 20% by weight of a water-soluble polymer additive (A), based on the total weight of the solution (S). According to a further embodiment, the solution (S) comprises, in any case, at least 4% by weight, more specifically 4 to 30% by weight, and more specifically 5 to 30% by weight of polyvinylpyrrolidone (PVP) having a solution viscosity characterized by a K value of at least 80, based on the total weight of the solution (S).

[0116] As described above, the water-soluble polymer additive (A) used in the method of the present invention contains polyvinylpyrrolidone, but may further contain other suitable water-soluble additives selected from, for example, poly(alkylene oxide) and alcohol.

[0117] Suitable poly(alkylene oxides) that may be included in the water-soluble polymer additive (A) are poly(ethylene oxide), poly(propylene oxide), and poly(ethylene oxide)-poly(propylene oxide) copolymers. Suitable alcohols that may be included in the water-soluble polymer additive (A) are dihydric alcohols or trihydric alcohols such as glycerol.

[0118] According to one embodiment, the water-soluble polymer additive (A) comprises 60 to 90% by weight of polyvinylpyrrolidone and 10 to 40% by weight of at least one alcohol, preferably glycerol.

[0119] According to one embodiment, the solution (S) comprises, in any case, 1 to 50% by weight of at least one polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone), 3 to 30% by weight of a defined, preferably PVP-based, water-soluble polymer additive (A), and 20 to 96% by weight of at least one solvent (D), based on the total weight of the solution (S).

[0120] In a further embodiment, the solution (S) comprises, in any case, 1 to 40% by weight of at least one polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone), 3 to 20% by weight of a defined, preferably PVP-based, water-soluble polymer additive (A), and 40 to 96% by weight of at least one solvent (D), based on the total weight of the solution (S).

[0121] In the context of this invention, "at least one solvent" means exactly one solvent, and also a mixture of two or more solvents. The at least one solvent (D) may be any solvent known to those skilled in the art that is suitable for at least one polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone), as well as a water-soluble polymer additive (A). Preferably, the at least one solvent (D) is soluble in water.

[0122] Therefore, at least one solvent (D) is selected from the group consisting of N-alkyl-2-pyrrolidone, preferably N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-butyl-2-pyrrolidone and N-tert.-butyl-2-pyrrolidone, 2-pyrrolidone, N-dimethylacetamide, dimethyl sulfoxide, dimethylformamide, N,N-dimethyl-2-hydroxypropanamide, N,N-diethyl-2-hydroxypropanamide, γ-valerolactone, dihydrolevoglucocenone, methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate and sulfolane. N-alkyl-2-pyrrolidone, γ-valerolactone and N,N-dimethyl-2-hydroxypropanamide are particularly preferred. N-methylpyrrolidone is most preferred as at least one solvent (D).

[0123] The solution (S) may contain, based on the total weight of the solution (S), at least one solvent (D) in the range of 20 to 96% by weight, preferably at least one solvent (D) in the range of 40 to 96% by weight, and more preferably at least one solvent (D) in the range of 50 to 70% by weight.

[0124] It will be obvious to those skilled in the art that the weight percentages of at least one polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone), a water-soluble polymer additive (A), and at least one solvent (D) typically total 100% by weight.

[0125] The duration of step a) may vary across a wide range of limits, preferably in the range of 10 minutes to 48 hours, particularly in the range of 10 minutes to 24 hours, and more preferably in the range of 15 minutes to 12 hours. Those skilled in the art will select the duration of step a) such that a homogeneous solution of at least one polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone) and a water-soluble polymer additive (A) is obtained in at least one solvent (D).

[0126] In step b), the solution (S) is passed through a spinneret, and the resulting hollow fibers are brought into contact with at least one protic polar solvent to form a hollow fiber membrane. To produce multi-bore hollow fibers, step b) can be carried out by extruding the solution (S) through an extrusion nozzle (also called a spinneret) equipped with the required number of hollow needles. In particular, the hollow fibers are preferably introduced into a liquid containing at least one protic polar solvent.

[0127] Before performing step b), it is possible to filter the solution (S) to obtain a filtered solution (S). Furthermore, before performing step b), it is possible to degas the solution (S). Degassing of the solution (S) can be done by any method known to those skilled in the art, for example, by vacuum, or by allowing the solution (S) to stand.

[0128] Preferably, a single-bore hollow fiber membrane or a multi-bore hollow fiber membrane is obtained by following the phase inversion method, which means that a composition in which at least one polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone) and a water-soluble polymer additive (A) is dissolved is converted into a solid phase.

[0129] The method of phase inversion is generally known to those skilled in the art.

[0130] The phase inversion method can be carried out, for example, by cooling the solution, causing at least one polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone) contained in the solution to precipitate. Another possibility for carrying out the phase inversion method is to bring the solution into contact with a gaseous liquid that is the nonsolvent of at least one polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone). Then, at least one polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone) precipitates in the same manner.

[0131] A preferred gaseous liquid that is a nonsolvent for at least one polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone) is, for example, a protic polar solvent as described below in their gaseous state. Another preferred phase inversion method in the context of the present invention is phase inversion by immersing the solution in at least one protic polar solvent.

[0132] Therefore, according to step b) of the method of the present invention, the hollow fibers formed from the solution (S) are brought into contact with at least one protic solvent. This results in the formation of a hollow fiber membrane.

[0133] In particular, according to one embodiment of step b), the hollow fiber is brought into contact with the at least one protic polar solvent by introducing the hollow fiber into a liquid containing at least one protic polar solvent. The liquid may be a bath such as a solidification bath.

[0134] At least one suitable protic polar solvent is known to those skilled in the art. The at least one protic polar solvent is preferably a non-solvent of at least one polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone). Preferred at least one protic polar solvents are water, methanol, ethanol, n-propanol, isopropanol, glycerol, ethylene glycol, and mixtures thereof.

[0135] Preferably, at least one protic polar solvent is an aqueous coagulation solution. Therefore, another object of the present invention is a method for preparing a hollow fiber membrane, wherein at least one protic polar solvent in step c) is an aqueous coagulation solution.

[0136] The aqueous coagulation solution may contain further components other than water, such as the same solvent (D) present in the solution (S), or an alcohol, such as glycerol.

[0137] At least one polar solvent used as a coagulation solution may also be injected into the extruded polymer solution (S) through a hollow needle during the process of passing the solution through the spinneret. This creates a continuous parallel channel extending in the extrusion direction.

[0138] The step of contacting with at least one protic solvent is preferably carried out at a temperature in the range of 20 to 80°C, more preferably in the range of 20 to 60°C. In particular, at least one protic polar solvent, especially an aqueous coagulation solution, is maintained at a temperature in the range of 20 to 80°C, more preferably in the range of 20 to 60°C.

[0139] In particular, according to certain preferred embodiments, for the formation of the hollow fiber membrane by step b), the coagulation solution defined above is injected into the extruded polymer through a hollow needle during extrusion. This setting causes the extruded polymer membrane to acquire a hollow cylindrical shape, and parallel continuous channels extending in the extrusion direction are formed in the extruded polymer. The formed hollow fibers are then preferably brought into contact with water as a coagulant. Method parameters such as extrusion speed, temperature, nozzle shape, type and concentration of coagulant may affect parameters such as the shape and thickness of the membrane and therefore the performance of the membrane, and thus these parameters can be controlled using method parameters. The hollow fiber membrane may optionally be wound onto a roll and / or bundled into a bundle of hollow fibers.

[0140] Subsequently, without performing the step of removing additive (A) from the membrane, the hollow fiber membrane is isolated according to step c).

[0141] Furthermore, "without performing a step to remove additive (A) from the membrane" means that the hollow fiber membrane formed by the method of the present invention is not subjected to a specific cleaning step aimed at removing the water-soluble polymer additive (A) from the membrane. In particular, oxidative post-treatment with, for example, sodium hypochlorite is not performed.

[0142] According to a preferred embodiment, the method of the present invention also, d) A rinsing step with a liquid containing water, preferably at a high temperature such as 60°C. Includes.

[0143] Preferably, the liquid is water.

[0144] Step d) may be desired and optionally performed to remove residual components, such as residual amounts of solvent D), from the film. Under the conditions of the rinse step with water, additive (A), particularly polyvinylpyrrolidone (PVP) having a K value of at least 80, is not substantially washed away.

[0145] According to a more preferred embodiment, the method of the present invention also, e) Drying the hollow fiber membrane Includes.

[0146] The drying process can be carried out by any means known to those skilled in the art of filmmaking.

[0147] In a further aspect, the present invention relates to a hollow fiber membrane that can be obtained by the method of the present invention described herein.

[0148] The resulting hollow fiber membrane of the present invention is essentially free of at least one solvent (D). In the context of the present invention, "essentially free" means that the membrane contains at least one solvent in an amount of up to 1% by weight, preferably up to 0.5% by weight, and particularly preferably up to 0.1% by weight, based on the total weight of the hollow fiber membrane.

[0149] In fuel cell humidifiers, water vapor from the exhaust gases of the fuel cell reaction is typically used to supply water to the fuel cell membrane. The water vapor is supplied to the polymer electrolyte membrane by permeating the membrane as selectively as possible.

[0150] The present invention has shown that the hollow fiber membrane described herein, in particular the membrane according to the present invention, can be successfully used as a membrane for a fuel cell humidifier because it can allow water vapor to pass through the humidifier membrane while suppressing gases contained in a gaseous mixture. In particular, the hollow fiber membrane has been shown to be selectively gas-tight with respect to undesirable gases such as nitrogen, and that the membrane is effective at the operating temperature of fuel cells, which is typically 80-90°C. The hollow fiber membrane described herein has been shown to function particularly well and selectively in this temperature range.

[0151] Accordingly, according to further embodiments, the present invention relates to a separation element, membrane module, membrane cartridge, or separation system comprising the hollow fiber membrane of the present invention as described herein.

[0152] A further object of the present invention is a humidifier comprising the hollow fiber membrane of the present invention as described herein, in particular a fuel cell membrane humidifier.

[0153] A further object of the present invention is a humidifier comprising a hollow fiber membrane, wherein the membrane comprises a porous support structure and an inner membrane surface layer (SL in ) and the outer film surface layer (SL out The humidifier comprises a membrane containing at least one polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone), and a water-soluble polymer additive (A) containing polyvinylpyrrolidone (PVP). In particular, the humidifier is a fuel cell membrane humidifier.

[0154] In a further embodiment, the present invention relates to a fuel cell comprising a hollow fiber membrane, wherein the membrane comprises a porous support structure and an inner membrane surface layer (SL in ) and the outer film surface layer (SL out The present invention relates to a fuel cell comprising a membrane comprising at least one polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone), and a water-soluble polymer additive (A) containing polyvinylpyrrolidone (PVP).

[0155] In further embodiments, the present invention relates to a fuel cell comprising the hollow membrane of the present invention as described herein.

[0156] In further embodiments, the present invention relates to a fuel cell comprising a separation element, membrane module, membrane cartridge, or separation system including the hollow fiber membrane of the present invention as described herein.

[0157] In a further embodiment, the present invention relates to a humidifier, more particularly a fuel cell including a fuel cell membrane humidifier, wherein the humidifier includes a hollow fiber membrane, and the membrane comprises a porous support structure and an inner membrane surface layer (SL in ) and the outer film surface layer (SL out The present invention relates to a fuel cell comprising a membrane comprising at least one poly(arylene ethersulfone) polymer (P) and a water-soluble polymer additive (A) containing polyvinylpyrrolidone (PVP).

[0158] In further embodiments, the present invention relates to a humidifier, and more particularly to a fuel cell, including the fuel cell membrane humidifier described herein.

[0159] Examples Abbreviations and compounds used in the examples: NTU (Turbidity Unit) WTR water permeability NMP N-methyl-2-pyrrolidone [CAS 872-50-4] PVP (Polyvinylpyrrolidone) BET Brunauer-Emmett Teller Surface Evaluation PAES poly(arylene ether sulfone) used in the examples: Ultrason® E 6020 P: Viscosity number of 81 ml / g (measured according to ISO 1628-5 (1998) in a 1 wt% polymer solution in N-methylpyrrolidone); glass transition temperature of 225°C (DSC, 10 K / min; compliant with ISO 11357-1 (2017) and 11357-2 (2020)); molecular weight of 75000 g / mol M w (THF GPC, PS standard), and M w / M nPolyethersulfone having =3.4 Luvitec® K90 polyvinylpyrrolidone, which has a solution viscosity characterized by a K value of 90, as determined according to Fikentscher's method (Fikentscher, Cellulosechemie 13, 1932(58)).

[0160] Turbidity The turbidity of the polymer solution was measured at 60°C using a turbidimeter 2100AN (Hach Lange GmbH, Dusseldorf, Germany) with an 860 nm filter, and expressed in turbidimetric units (NTU). An NTU value of less than 1 is preferred.

[0161] WTR rate, nitrogen transmission rate Water vapor transmission rate (WTR, g / sm) 2 The nitrogen permeability (L / m³) was tested using minimodules containing 8-10 hollow fibers, each 10 cm long. The nitrogen permeability (L / m³) at a pressure of 2 bar was also measured before and after WTR measurements at 80 and 90°C. 2 We evaluated the (h bar) level. High WTR combined with low nitrogen leakage is desirable.

[0162] viscosity Polymer solution viscosity was measured at 60°C and 20 rpm using a Brookfield Viscometer DV-I Prime (Brookfield Engineering Laboratories, Inc., Middleboro, USA) equipped with an RV 6 spindle.

[0163] PVP content Polyvinylpyrrolidone (PVP) content of the membrane (PVP totalThe polyvinylpyrrolidone content was determined by dissolving the film sample in N,N-dimethylformamide (DMF) and casting the solution as a film onto a thallium bromiodide KRS-5 window. The film was dried at 160°C and analyzed using a Nicolet 6700 FT-IR spectrometer (Thermo Fischer Scientific, Waltham, Massachusetts, USA). Along with calibration samples of known polyvinylpyrrolidone content, the analysis was performed at 1680 cm⁻¹. -1 The overall polyvinylpyrrolidone content of the membrane samples was determined using adsorption bands. (Inner and outer membrane surface layers (PVP)) in PVP out The polyvinylpyrrolidone content of the sample was estimated using attenuated infrared spectroscopy (ATR) and a reference sample, based on the same adsorption band.

[0164] BET surface evaluation The solvent was changed, and the dried film samples were used for Brunauer-Emmett Teller (BET) surface evaluation. Subsequently, the wet film samples were stored for 12 hours in water / ethanol (1:1 wt / wt), water / ethanol (1:2 wt / wt), ethanol / n-hexane (1:1 wt / wt), and finally in n-hexane, and then dried under vacuum at 60°C. The BET surface was determined by a five-point gas adsorption-desorption (GAD) experiment using nitrogen with ASAP 2420 (Fa. Micromeritics, Norcross, USA). Before measurement, the samples were activated at 130°C for 15 minutes.

[0165] Preparation of hollow fiber membranes General procedure The amounts given in this general procedure are general ranges, and the exact amounts for each experiment can be found in Table 1. Clear viscous solutions containing 19 wt% membrane polymer and 5 wt% polyvinylpyrrolidone in 76 wt% NMP were prepared within 30 minutes of mixing using a SpeedMixer® DAC 600.1 Vac-P (Hauschild & Co. KG, Hamm, Germany) at speeds of 200, 800, and 1200 rpm. The solutions were degassed overnight at room temperature. The central fluid was prepared by mixing distilled water with N-methylpyrrolidone (NMP). The weight fractions of the two components in the central fluid were water:NMP = 60 wt%:40 wt%.

[0166] A polymer solution was reheated at 60°C for 2 hours, and hollow fiber membranes were formed by passing this solution and the central fluid through a spinning die. The diameter of the spinning die ranged from 0.33 mm to 0.62 mm to 1.3 mm. The die temperature was 60°C. Hollow fibers were formed at a spinning rate of 13 cm / min. The polymer solution exited the die at a rate of 3.0 ml / min, while the central fluid exited at a rate of 3.3 ml / min. A liquid capillary tube was passed through a water bath at 24°C. The distance between the die and the sedimentation bath was 13 cm. The formed hollow fiber membranes were guided into a water bath and then wound onto a winding reel. The membranes were then either dried directly (treatment A) or treated with a 2000 ppm sodium hypochlorite aqueous solution (NaOCl), pH 9.5, for 3 hours, followed by water extraction at 80°C for 20 hours, and then dried (post-treatment B).

[0167] [Table 1]

[0168] [Table 2]

[0169] [Table 3]

[0170] [Table 4]

[0171] [Table 5]

[0172] The hollow fiber membrane according to the present invention has a density of 10 L / m 2 It exhibits particularly low gas leakage below h bar (Table 3) and simultaneously has high water permeability (WTR) at temperatures of 80 and 90°C at all relevant water flux values ​​(Tables 4 and 5). In contrast, post-treated open porous hollow fiber M-2B shows a higher WTR but exhibits significantly high nitrogen leakage and is unsuitable for fuel cell membrane humidifiers. [Brief explanation of the drawing]

[0173] [Figure 1] Secondary electron microscopy of M-2A (magnification 150x and 1500x).

Claims

1. In a fuel cell membrane humidifier, a porous support structure and an inner membrane surface layer (SL ｉｎ ) and the outer film surface layer (SL ｏｕｔ The use of a hollow fiber membrane comprising a hollow fiber membrane comprising at least one polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone), and a water-soluble polymer additive (A) containing polyvinylpyrrolidone (PVP).

2. A porous support structure and an inner film surface layer (SL) for selectively suppressing nitrogen gas and selectively allowing water vapor to pass through a gaseous mixture containing water vapor and nitrogen. ｉｎ ) and the outer film surface layer (SL ｏｕｔ The use of a hollow fiber membrane comprising a hollow fiber membrane comprising at least one polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone), and a water-soluble polymer additive (A) containing polyvinylpyrrolidone (PVP).

3. Porous support structure and inner membrane surface layer (SL ｉｎ ) and the outer film surface layer (SL ｏｕｔ A hollow fiber membrane comprising a polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone), and a water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP) having a solution viscosity characterized by a K value of at least 80, in an amount of at least 10% by weight based on the total weight of the membrane.

4. The membrane according to claim 3, wherein the polyvinylpyrrolidone content in the inner membrane surface layer and / or the outer membrane surface layer is at least 10% by weight based on the total weight of the membrane.

5. At least one of the inner film surface layer and the outer film surface layer is 10 g / s m ２ The water flow flux at 80°C is at least 3.5 kg / h·m ２ The film according to claim 3 or 4, having a water vapor permeability.

6. At least one of the inner membrane surface layer and the outer membrane surface layer has a nitrogen gas permeability of 3 L / m ２ ·h·bar or less at 2 bar, the membrane according to any one of claims 3 to 5.

7. The BET (Brunauer-Emmett Teller) value of the hollow fiber membrane is 30m ２ A membrane according to any one of claims 3 to 6, wherein the amount is less than or equal to / g.

8. The film according to any one of claims 3 to 7, wherein the at least one polymer (P) does not contain any sulfonated poly(arylene ethersulfone).

9. A method for preparing a hollow fiber membrane according to any one of claims 3 to 8, a) A step of providing a solution (S) comprising at least one polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone), a water-soluble polymer additive (A) having a solution viscosity characterized by a K value of at least 80 with polyvinylpyrrolidone (PVP), and at least one solvent (D), b) A step of passing the solution (S) through a spinneret and bringing the formed hollow fiber into contact with at least one protic polar solvent to form the hollow fiber membrane, c) A step of isolating the hollow fiber membrane without performing the step of removing the additive (A) from the hollow fiber membrane. A preparation method including the following.

10. The method according to claim 9, wherein the solution (S) comprises at least 3% by weight of the polyvinylpyrrolidone (PVP) having a solution viscosity characterized by a K value of at least 80.

11. A hollow fiber membrane obtained by the method described in claim 9 or 10.

12. A separation element, membrane module, membrane cartridge, or separation system comprising a hollow fiber membrane according to any one of claims 3 to 8 or 11.

13. Porous support structure and inner membrane surface layer (SL ｉｎ ) and the outer film surface layer (SL ｏｕｔ A hollow fiber membrane comprising a polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone), and a water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP), or a humidifier comprising a hollow fiber membrane according to any one of claims 3 to 8 or 11.

14. The humidifier according to claim 13, which is a fuel cell membrane humidifier.

15. Porous support structure and inner membrane surface layer (SL ｉｎ ) and the outer film surface layer (SL ｏｕｔ A hollow fiber membrane comprising a hollow fiber membrane comprising at least one polymer (P) selected from sulfonated poly(arylene ethersulfone) and poly(arylene ethersulfone) and a water-soluble polymer additive (A) comprising polyvinylpyrrolidone (PVP), the hollow fiber membrane according to any one of claims 3 to 8 or 11, the separation element, membrane module, membrane cartridge or separation system according to claim 12, or the humidifier according to claim 13 or 14, a fuel cell.

16. Use of the hollow fiber membrane in a fuel cell membrane humidifier according to any one of claims 3 to 8 or 11.

17. Use of a hollow fiber membrane according to any one of claims 3 to 8 or 11 for selectively suppressing nitrogen gas and selectively allowing water vapor to pass through a gaseous mixture containing water vapor and nitrogen.

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