WO2023052226A1 - Membranes - Google Patents

Membranes Download PDF

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Publication number
WO2023052226A1
WO2023052226A1 PCT/EP2022/076334 EP2022076334W WO2023052226A1 WO 2023052226 A1 WO2023052226 A1 WO 2023052226A1 EP 2022076334 W EP2022076334 W EP 2022076334W WO 2023052226 A1 WO2023052226 A1 WO 2023052226A1
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Prior art keywords
layer
polymer
curable composition
membrane according
curable
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PCT/EP2022/076334
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English (en)
Inventor
Renée Maria RIPKEN
Elisa Huerta Martinez
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Fujifilm Manufacturing Europe Bv
Fujifilm Corporation
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Publication of WO2023052226A1 publication Critical patent/WO2023052226A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/20—Manufacture of shaped structures of ion-exchange resins
    • C08J5/22—Films, membranes or diaphragms
    • C08J5/2206—Films, membranes or diaphragms based on organic and/or inorganic macromolecular compounds
    • C08J5/2275—Heterogeneous membranes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/10—Supported membranes; Membrane supports
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/42—Electrodialysis; Electro-osmosis ; Electro-ultrafiltration; Membrane capacitive deionization
    • B01D61/44—Ion-selective electrodialysis
    • B01D61/445—Ion-selective electrodialysis with bipolar membranes; Water splitting
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
    • B01D67/0002—Organic membrane manufacture
    • B01D67/0006—Organic membrane manufacture by chemical reactions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/10—Supported membranes; Membrane supports
    • B01D69/106—Membranes in the pores of a support, e.g. polymerized in the pores or voids
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/12—Composite membranes; Ultra-thin membranes
    • B01D69/1216—Three or more layers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/12—Composite membranes; Ultra-thin membranes
    • B01D69/125—In situ manufacturing by polymerisation, polycondensation, cross-linking or chemical reaction
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/14—Dynamic membranes
    • B01D69/141—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/14—Dynamic membranes
    • B01D69/141—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes
    • B01D69/145—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes containing embedded catalysts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/76—Macromolecular material not specifically provided for in a single one of groups B01D71/08 - B01D71/74
    • B01D71/82—Macromolecular material not specifically provided for in a single one of groups B01D71/08 - B01D71/74 characterised by the presence of specified groups, e.g. introduced by chemical after-treatment
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/20—Manufacture of shaped structures of ion-exchange resins
    • C08J5/22—Films, membranes or diaphragms
    • C08J5/2206—Films, membranes or diaphragms based on organic and/or inorganic macromolecular compounds
    • C08J5/2218—Synthetic macromolecular compounds
    • C08J5/2231—Synthetic macromolecular compounds based on macromolecular compounds obtained by reactions involving unsaturated carbon-to-carbon bonds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2323/00—Details relating to membrane preparation
    • B01D2323/46—Impregnation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2325/00—Details relating to properties of membranes
    • B01D2325/42—Ion-exchange membranes

Definitions

  • This invention relates to bipolar membranes, their preparation processes and their use.
  • Ion exchange membranes are used in electrodialysis, electrolysis, production of acids and bases and a number of other processes.
  • the transport of ions through the membranes occurs under the influence of a driving force such as an ion concentration gradient or, alternatively, an electrical potential gradient.
  • Ion exchange membranes are generally categorized as bipolar membranes, cation exchange membranes or anion exchange membranes, depending on the charge of their ionic groups.
  • Cation exchange membranes comprise negatively charged groups that allow the passage of cations but reject anions
  • anion exchange membranes comprise positively charged groups that allow the passage of anions but reject cations.
  • a bipolar membrane (BPM) has both a cationic layer or anion exchange layer (AEL) and an anionic layer or cation exchange layer (CEL) and thus have both a negatively charged layer and a positively charged layer.
  • Some ion exchange membranes and bipolar membranes comprise a porous support, which provides mechanical strength.
  • Such membranes are often called “composite membranes” due to the presence of both an ionically-charged polymer which discriminates between oppositely charged ions and the porous support which provides mechanical strength.
  • Composite membranes are known from, for example, US 4,253,900, which describes a bipolar membrane containing a monobead layer of ion exchange resin.
  • WO2017/205458 and the article by McClure in ECS Transactions, 2015 69 (18) pages 35-44 describe a bipolar membrane containing a junction layer of interpenetrating polymer nanofibers or microfibers of anion exchange polymers and cation exchange polymers.
  • Other examples of composite membranes are described in e.g. EP3604404, wherein one of the layers comprise an ion exchange resin powder, and US 4,673,454 disclosing the use of an ion exchange resin in an interfacial layer.
  • bipolar membranes having improved properties, e.g. high permselectivity, low electrical resistance, good mechanical strength, low swelling under aqueous conditions, stability at extremes of pH and ability to provide acids and bases in high purity. Ideally such bipolar membranes may be produced quickly, efficiently and cheaply.
  • a bipolar membrane comprising: a) a first layer comprising a first polymer having ionic groups; b) a second layer comprising a second polymer having ionic groups of charge opposite to the charge of the ionic groups of the first polymer; and c) a third layer comprising a third polymer; wherein:
  • the ratio of the average thickness of the first layer a) to the average thickness of the second layer b) is from 0.25 to 0.8 or from 1 .2 to 4;
  • third layer c) is interposed between first layer a) and second layer b).
  • the first polymer having ionic groups is sometimes abbreviated to “the first polymer”
  • the second polymer having ionic groups of the charge opposite to the charge of the ionic groups of the first polymer is sometimes abbreviated to “the second polymer”
  • the third polymer preferably having ionic groups is sometimes abbreviated to “the third polymer”
  • fourth polymer (referred to below) having ionic groups of charge opposite to the charge of the ionic groups of the third polymer is sometimes abbreviated to “the fourth polymer”.
  • the term “bipolar membrane” is often abbreviated to just “membrane” when used in relation to the present invention. “First layer a)” is sometimes abbreviated to “layer a)”, “second layer b)” is sometimes abbreviated to “layer b)” and ’’third layer c)” is sometimes abbreviated to “layer c)”.
  • first polymer is anionic and the second polymer is cationic. In another embodiment the first polymer is cationic and the second polymer is anionic. In one embodiment the first layer a) is thicker than the second layer b). In another embodiment the first layer a) is thinner than the second layer b).
  • one of the second polymer and the first polymers is a cationic polymer (i.e. carries positively charged groups) and the other is an anionic polymer (i.e. carries negatively charged groups).
  • the third polymer comprises ionic groups, i.e. anionic or cationic groups.
  • the third layer c) comprises a co-continuous polymeric network of (i) the third polymer having ionic groups and a network of pores; and (ii) a fourth polymer having ionic groups of charge opposite to the charge of the ionic groups of the third polymer.
  • one of the third and fourth polymers is a cationic polymer (i.e. carries positively charged groups) and the other is an anionic polymer (i.e. carries negatively charged groups).
  • the third polymer is anionic and the fourth polymer is cationic.
  • the third polymer is cationic and the fourth polymer is anionic.
  • the third polymer is obtainable by phase-separation of the third polymer from a composition used to prepare the third polymer.
  • the third polymer in a form which comprises a network of pores and the pores may be used to receive the fourth polymer (or a curable composition used to prepare the fourth polymer) in order to make the third layer c) and provide a co-continuous polymeric network of (i) the third polymer having ionic groups; and (ii) the fourth polymer having ionic groups of charge opposite to the charge of the ionic groups of the third polymer and being present within the network of pores of the third polymer.
  • the curable composition used to prepare the fourth polymer is identical to the curable composition used to prepare the first polymer.
  • the co- continuous polymeric network comprises the third polymer and the fourth polymer, wherein the third polymer provides a network of pores and the fourth polymer is present within that network of pores.
  • the third polymer comprises a porous first polymeric domain comprising ionic groups and a network of pores.
  • the fourth polymer comprises a second polymeric domain comprising ionic groups having a charge opposite to the charge of the ionic groups of the first polymeric domain.
  • the second polymeric domain is located in the pores of the first polymeric domain (i.e. in the network of pores of the third polymer).
  • the co-continuous polymeric network preferably comprises two individual, continuous, polymeric domains, one bearing anionic charges and the other bearing cationic charges.
  • one of the polymeric domains is phase-separated, e.g. one of the third and fourth polymers, especially the third polymer, is obtained by phase separation from a composition used to prepare that polymer in porous form and the other polymer, i.e. the fourth polymer, fills the pores of that polymer.
  • the third and fourth polymers in the third layer (c) are non-mixed, non-encapsulated and preferably they are non-fibrillar.
  • the third layer contains one or more than one further polymeric domains each bearing an anionic charge or a cationic charge.
  • the fourth polymer is present in the network of pores of the third polymer and in the first layer a).
  • the third polymer has the same charge as and/or is chemically identical to the second polymer in the second layer b).
  • the chemical composition of the first polymer is the same as or substantially the same as the chemical composition of the fourth polymer.
  • the chemical composition of the second polymer is the same as or substantially the same as the chemical composition of the third polymer.
  • the third layer c) preferably comprises at least two continuous intermingled polymeric domains (one domain derived from the third polymer and the other domain derived from the fourth polymer) having a large contact area with each other.
  • This may be achieved by the third polymer comprising a network of pores and the fourth polymer being different to the third polymer (e.g. one is cationic and the other is anionic) and being present within the network of pores of the third polymer.
  • the third polymer comprising a network of pores and the fourth polymer being different to the third polymer (e.g. one is cationic and the other is anionic) and being present within the network of pores of the third polymer.
  • the large contact area between the third and fourth polymers present in the third layer is preferably provided by the co-continuous network wherein the two (or more) polymeric domains derived from the third and fourth polymers bear opposite charges (i.e. one domain has anionic charges and the other has cationic charges).
  • An advantage of the co-continuous network is that newly produced anions (e.g. OH') and cations (e.g. H + ) created at the interface between the third and fourth polymers (i.e. the interface of the two polymeric domains) are separated into the individual polymeric domains immediately after their formation, preventing ion recombination.
  • the adhesion between the third and fourth polymers i.e.
  • adhesion between the first and second polymeric domains) in the third layer c) is extremely strong as a result of the entanglement of the third and fourth polymers, and the large contact area between the third and fourth polymers.
  • the strong adhesion between the third and fourth polymers prevents/reduces the so-called ballooning effect in which large water-filled blisters can be formed at the interface between positively and the negatively charged polymers of a bipolar membrane, where OH' and H + might recombine (undesirably) to form water.
  • the membrane of the present invention preferably comprises an interface between the first layer a) and the third layer c) (a first interface) and an interface between the third layer c) and the second layer b) (a second interface) and preferably both the first interface and the second interface are uninterrupted, without any gaps and/or spaces between the first layer a) and the third layer c) and without any gaps and/or spaces between the third layer c) and the second layer b).
  • the third layer c) comprises a blend morphology of two continuous polymeric domains derived from the third and fourth polymers respectively, of which one domain (derived from the fourth polymer) is located within the other domain (derived from the third polymer), forming the abovementioned co-continuous polymeric network (of the fourth polymer within the network of pores of the third polymer).
  • each of the first and second polymeric domains is continuous, and at least one of the first and second polymeric domains substantially comprises a single covalently linked carbon backbone such that it is interconnected to itself.
  • polymeric domains are not encapsulated, not isolated, not discontinued and are non-fibrillar (e.g. not made by electrospinning).
  • the third layer c) preferably comprises a porous support and the third polymer is present within the porous structure of this support.
  • the third polymer comprises a network of pores and the fourth polymer present within those pores (thereby providing the co-continuous polymeric network, e.g. two polymeric domains of which one bears anionic charges and the other cationic charges).
  • the two (or more) polymeric domains (one from the third polymer and another from the fourth polymer present within the network of pores of the third polymer) occupy the pores of the porous support and preferably comprise a seamless (third) interface (the first and second interfaces being at the junction of the third layer c) and the first and second layers a) and b) respectively).
  • the membrane preferably comprises an interface at the junction of the third layer c) and the first layer a), an interface at the junction of the third layer c) and the second layer b), and a third interface within the third layer c) at the junction of the third polymer and the fourth polymer.
  • this third interface is uninterrupted, without any gaps and/or spaces between the third polymer and the fourth polymer.
  • this third interface is not an interface between a polymer and fused/com pressed fibers, beads, or particles.
  • the third layer c) comprises the third polymer and the fourth polymer and the volume fraction of the third polymer or the fourth polymer is defined as the fraction of the volume of the third polymer or the fourth polymer as part of the total volume of the third layer c) itself.
  • the volume fraction of the third polymer in the third layer c) is preferably from 0.1 to 0.9, more preferably from 0.2 to 0.8, especially 0.3 to 0.7, e.g. about 0.4, about 0.5 or about 0.6.
  • the third polymer is obtained by a process comprising polymerisation- induced phase separation, more preferably photopolymerization-induced phase separation, e.g. of the third polymer from a composition used to prepare that polymer.
  • a process comprising polymerisation- induced phase separation, more preferably photopolymerization-induced phase separation, e.g. of the third polymer from a composition used to prepare that polymer.
  • the third polymer is particularly good at providing a third polymer which comprises a network of pores capable of receiving the fourth (oppositely charged) polymer or a curable composition for preparing the fourth (oppositely charged) polymer.
  • the third polymer is formed by a (photo-)polymerization reaction.
  • the third polymer comprises a network of pores which has an average pore diameter of less than 5 ⁇ m, more preferably less than 2 ⁇ m, especially less than 1 ⁇ m.
  • the pores within the third polymer may then be filled with a (fourth) curable composition and that curable composition may then be cured in order to provide the fourth polymer within the third polymer’s network of pores.
  • the third polymer comprises a network of pores and the network of pores is substantially or completely filled with the fourth polymer.
  • a third layer c) results in which the third polymer comprises a network of pores which are filled with the (oppositely charged) fourth polymer.
  • the third and fourth polymers may therefore provide a co-continuous polymeric network comprising two polymeric domains: one from the third polymer and another from the fourth polymer.
  • this co- continuous polymeric network is free from other polymers (except for any polymer present in the porous support).
  • the pores present in the third polymer may comprise more than one polymer, e.g. the fourth polymer (derived from a fourth curable composition) and optionally a second polymer (derived from a second curable composition) such that the fourth polymer partly fills the pores of the third polymer and the second polymer is filling the remaining pores.
  • the pores in the third polymer when present, may comprise one or more further polymers if desired.
  • Fig 1 shows a 6-chamber testing cell.
  • Fig 1 shows a 6-chamber testing cell (10) comprising an electrodialysis tank (12), an anode (14) is provided at inside the electrodialysis tank (12) and a cathode (15) provided on the side opposite to the anode (14).
  • the device comprises five cation exchange membranes (C) and five anion exchange membranes (A) (only 2 are shown) and six bipolar membranes (BP) according to the present invention (only 4 are shown) provided alternately between the anode (14) and the cathode (15).
  • a feed tank (17) is connected to the channels (27) between (A) and (C).
  • An acid tank (18) is connected to the channels (28) between (BP) and (A).
  • a base tank (19) is connected to the channels (29) between (BP) and (C).
  • An electrolyte tank (16) is connected to the channels (26) between (BP)s and electrodes (14, 15).
  • the cell is powered by a power supply connected to the anode and the cathode.
  • the porous supports may be physically and chemically identical to each other or they may be different from one or more of the other porous supports present in the membrane (if any), depending on the properties desired for and intended use of the membrane.
  • the membrane of the present invention is preferably a composite membrane.
  • a porous support is useful to provide mechanical strength and typically one or more of the layers a), b) and c) comprise a porous support.
  • Each porous support may be positioned wholly within a layer or, if desired, at the interface of third layer c) and first layer a) and/or the interface of third layer c) and second layer b).
  • all three layers a), b) and c) comprise a porous support.
  • a single porous support is present in and common to both the first layer a) and the third layer c).
  • second layer b) optionally comprises a second porous support.
  • the polymer of the relevant layer is preferably present within the pores of the relevant porous support.
  • first layer a) optionally comprises a second porous support.
  • the polymer of the relevant layer is preferably present within the pores of the relevant porous support.
  • layers a), b) and c) comprise a porous support.
  • layers a) and c) comprise a porous support and layer b) is free from porous supports, or layers b) and c) comprise a porous support and layer a) is free from porous supports, or layers a) and b) comprise a porous support and layer c) is free from porous supports.
  • the two layers optionally each comprise a separate support or the two layers comprise the same single support.
  • At least layer c) comprises a porous support.
  • one of the first layer a) and the second layer b) comprises a porous support.
  • layer c) is partly supported by a first porous support and partly unsupported.
  • the membrane comprises a porous support which fully supports layer a) or layer b) and partly supports layer c).
  • the remaining layer (layer b) or layer a) as the case may be) is preferably free from porous supports or comprises a second porous support.
  • porous supports which may be included in the layers a), b) and/or c) there may be mentioned woven and non-woven synthetic fabrics and extruded films.
  • examples include wetlaid and drylaid non-woven material, spunbond and meltblown fabrics and nanofiber webs made from, e.g. polyethylene, polypropylene, polyacrylonitrile, polyvinyl chloride, polyphenylenesulfide, polyester, polyamide, polyaryletherketones such as polyether ether ketone and copolymers thereof.
  • Porous supports may also be porous membranes, e.g.
  • the porous support(s), when present, each independently have an average thickness of between 20 and 180 ⁇ m, more preferably between 20 and 150 ⁇ m and especially between 25 and 130 ⁇ m.
  • the porous support(s), when present, have a porosity of between 30 and 95%.
  • the porosity of a support may be determined by a porometer, e.g. a PoroluxTM 1000 from IB-FT GmbH, Germany.
  • One or more of the porous supports may be treated to modify its surface energy, e.g. to values above 45 mN/m, preferably above 55mN/m. Suitable treatments include corona discharge treatment, plasma glow discharge treatment, flame treatment, ultraviolet light irradiation treatment, chemical treatment or the like, e.g. for the purpose of improving the wettability of and the adhesiveness to the porous support.
  • porous supports are available from a number of sources, e.g. from Freudenberg Filtration Technologies (Novatexx materials), Lydall Performance Materials, Celgard LLC, APorous Inc., SWM (Conwed Plastics, DelStar Technologies), Teijin, Hirose, Mitsubishi Paper Mills Ltd and Sefar AG.
  • each porous support independently is a polymeric support.
  • Preferred supports comprise a woven or non-woven synthetic fabric or an extruded film without covalently bound ionic groups.
  • first layer a) is thicker than the second layer b). In another embodiment the first layer a) is thinner than the second layer b).
  • the first layer a) is thicker than the second layer b). In another embodiment the first layer a) is thinner than the second layer b). As the thickness of layer a) or b) increases, the permselectivity of that layer increases and as a consequence the ability of the bipolar membrane to provide purer acids and bases in use is increased. A higher selectivity also makes it possible to reach higher concentrations of base and acid.
  • the first layer a) and the second layer b) of the membrane each independently has an average thickness of between 20 ⁇ m and 180 ⁇ m, more preferably of between 20 ⁇ m and 150 ⁇ m and especially between 25 and 130 ⁇ m.
  • the third layer c) of the membrane has an average thickness of between 1 ⁇ m and 180 ⁇ m, more preferably of between 2.5 ⁇ m and 100 ⁇ m and especially between 5 and 80 ⁇ m.
  • the membrane of the present invention has an average thickness of between 41 ⁇ m and 540 ⁇ m, more preferably of between 60 ⁇ m and 450 ⁇ m and especially between 90 and 300 ⁇ m.
  • the thickness ratio of layer a) to layer b) is from 0.4 to 0.8 or from 1 .2 to 2.2, more preferably 0.5 to 0.8 or 1.2 to 2.
  • the thickness ratio of layer c) to the thinnest of layer a) and layer b) is from 0.05 to 1.1 , more preferably from 0.1 to 1.0, especially 0.1 to 0.8.
  • the thickness ratio of layer c) to the thickest of layer a) and layer b) is from 0.02 to 1.0, more preferably from 0.04 to 0.9, especially 0.1 to 0.7.
  • At least two porous supports are present in the bipolar membrane. This helps to compensate differences in swelling of specially the layer a) with respect to the layer b) due to thickness and composition difference and to prevent (excessive) curling of the final membrane assembly when wet. While membrane curling does not affect the bipolar membrane performance, it is not desired for stack assembly.
  • the first, second, third and fourth polymers are preferably each independently obtained by a process comprising curing a curable composition comprising a curable compound having an ionic group, e.g. an anionic group or a cationic group.
  • the first polymer may be obtained from a first curable composition
  • the second polymer may be obtained from a second curable composition
  • the third polymer may be obtained from a third curable composition
  • the fourth polymer may be obtained from a fourth curable composition.
  • the ionic groups may be partially or wholly in salt form.
  • the curable compound having an ionic group may be rendered curable by the presence of one or more ethylenically unsaturated groups.
  • the curable compound having an ionic group preferably comprises an ethylenically unsaturated group and a cationic group or an anionic group.
  • Anionic groups have a charge opposite to cationic groups.
  • aromatic vinyl groups e.g. styrenic groups
  • Preferred anionic groups are acidic groups, for example a sulpho, carboxy and/or phosphato groups, especially sulpho groups.
  • the preferred salts are lithium, ammonium, sodium and potassium salts and mixtures comprising two or more thereof.
  • Preferred cationic groups are quaternary ammonium groups.
  • curable compounds having an anionic group or a quaternary ammonium group are provided below.
  • the curable compositions which may be used to prepare the first, second third and fourth polymers preferably further comprise a crosslinking agent, e.g. curable compound comprising at least two ethylenically unsaturated groups and optionally an ionic group, in an amount of 1 to 88 wt% (or 1 to 70wt%).
  • a crosslinking agent e.g. curable compound comprising at least two ethylenically unsaturated groups and optionally an ionic group
  • examples of curable compound comprising at least two ethylenically unsaturated groups and optionally an ionic group are provided below.
  • the curable compositions which may be used to prepare the first, second third and fourth polymers preferably further comprise a radical initiator, e.g. 0 to 10 wt% of radical initiator.
  • a radical initiator e.g. 0 to 10 wt% of radical initiator.
  • suitable radical initiators are provided below.
  • the curable compositions which may be used to prepare the first, second third and fourth polymers preferably further comprise a solvent, e.g. 0 to 55wt% or 20 to 98 wt% of solvent. Examples of suitable solvents are provided below.
  • the first polymer is obtainable by a process comprising curing a first curable composition comprising:
  • the second polymer is obtainable by a process comprising curing a second curable composition comprising:
  • the third polymer is preferably obtained from a process comprising polymerisation-induced phase separation of the third polymer from a third curable composition used to prepare the third polymer.
  • This process is particularly useful for providing the third polymer in a form which comprises a network of pores capable of receiving a fourth curable composition (which may be identical to the first curable composition or different to the first curable composition) for preparation of the fourth polymer within the network of pores (and optionally on the surface of the third polymer too, if desired, in order to provide the first layer a) in a very efficient manner).
  • the third polymer comprising ionic groups and the network of pores is obtainable by a process comprising curing a third curable composition comprising:
  • the charge of the ionic group of components (a3/b3) is the same as the charge of the ionic group of components (a2/b2) and opposite to the charge of the ionic group of components (a1/b1).
  • the fourth polymer (when present) is obtainable by a process comprising curing a fourth curable composition which falls within the definition provided above for the first curable composition.
  • the fourth curable composition may be the same as or different to the first curable composition.
  • the fourth curable composition comprises a curable compound having one ethylenically unsaturated group and an ionic group of charge opposite to the curable compound present in the third curable composition.
  • the fourth polymer is obtainable by a process comprising curing a fourth curable composition comprising:
  • the amount of each of component (a1), (a2) and (a4) independently is preferably 0 to
  • the amount of component (a3) is preferably 0 to 30wt%, especially 0 to 20wt%.
  • the amount of each of components (b1), (b2) and (b4) independently is preferably 5 to 80wt%, especially 10 to 70wt%.
  • the amount of component (b3) is preferably 9 to 65wt%, especially 14 to 59wt%, more especially 19 to 49wt%.
  • the curable compositions which may be used to make the first, second, third and fourth polymers preferably comprise a radical initiator (component (c1), (c2), (c3) and (c4)) when it is intended to cure the composition by UV, visible light or thermally.
  • a radical initiator component (c1), (c2), (c3) and (c4)
  • Alternative methods for curing include electron beam and gamma irradiation. Those methods do not require a radical initiator.
  • the amount of component (c1), (c2), (c3) and (c4) present in the relevant compositions is preferably 0 to 2wt%, more preferably (for curing by UV, visible light or thermally) 0.001 to 2wt%, especially 0.005 to 0.9wt%.
  • the amount of component (d1), (d2) and (d4) present in the relevant compositions is preferably 20 to 45wt%.
  • the amount of component (d3) is preferably 30 to 90wt%, especially 40 to 85wt%, more especially 49 to 78wt%.
  • the solvent(s) used as component (d1), (d2), (d3) and (d4) are inert, i.e. they do not react with any of the other components of the curable composition.
  • Component (d3) is preferably a single solvent.
  • Preferably component (d3) is water.
  • Component (d3) optionally comprises two or more inert solvents, at least one of which is a solvent for the other components of the curable composition and at least one of which is a nonsolvent for the third polymer formed from curing the composition, e.g. by phase separation, thereby forming the third polymer comprising a network of pores capable of receiving the fourth curable composition.
  • inert solvents which may be present in the curable compositions include water, alcohol-based solvents, ether-based solvents, amide-based solvents, ketone-based solvents, sulfoxide-based solvents, sulfone-based solvents, nitrile-based solvents and organic phosphorus-based solvents.
  • examples of alcohol-based solvents which may be used as or in component (d3) (especially in combination with water) include methanol, ethanol, isopropanol, n- propanol, n-butanol, 1-methoxy-2-propanol, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol and mixtures comprising two or more thereof.
  • organic solvents which may be used in component (d 1 ), (d2), (d3) and (d4) include dimethyl sulfoxide, dimethyl imidazolidinone, sulfolane, N-methyl pyrrolidone, dimethyl formamide, acetonitrile, acetone, 1 ,4-dioxane, 1 ,3-dioxolane, tetramethyl urea, hexamethyl phosphoramide, hexamethyl phosphorotriamide, pyridine, propionitrile, butanone, cyclohexanone, tetra hydrofuran, tetrahydropyran, 2-methyltetrahydrofuran, ethylene glycol diacetate, cyclopentylmethylether, methylethylketone, ethyl acetate, y-butyrolactone and mixtures comprising two or more thereof.
  • component (d3) comprises at least one of the solvents from list (i) below and at least one of the solvents from list (ii) below wherein the at least two solvents are different: list (i): iso-propanol, methanol, ethanol, acetone, tetramethyl urea, hexamethyl phosphoramide, hexamethyl phosphorotriamide, butanone, cyclohexanone, methylethylketone, tetra hydrofuran, tetrahydropyran, 2-methyltetrahydrofuran, cyclopentylmethylether, propionitrile, acetonitrile, 1 ,4-dioxane, 1 ,3-dioxolane, ethyl acetate, y-butyrolactone; and list (ii): water, glycerol, ethylene glycol, dimethyl sulfoxide, sulpholane, dimethyl imidazolidinone
  • component (d1), (d2), (d3) and/or (d4) comprises water and one or more other solvents from list (i).
  • one of the first curable composition and the second curable composition comprises a curable compound having an ethylenically unsaturated group and an anionic group and the other comprises a curable compound having an ethylenically unsaturated group and a cationic group.
  • one of the third curable composition and the fourth curable composition comprises a curable compound having an ethylenically unsaturated group and an anionic group and the other comprises a curable compound having an ethylenically unsaturated group and a cationic group.
  • curable compounds having an ethylenically unsaturated group and an anionic group or cationic group include the following compounds of Formula (A), (B), (CL), (SM), (MA), (MB-a), (C), (ACL-A), (ACL-B), (ACL-C), and/or (AM-B): wherein in Formulae (A) and (B),
  • R A1 to R A3 each independently represent a hydrogen atom or an alkyl group
  • R B1 to R B7 each independently represent an alkyl group or an aryl group
  • Z A1 to Z A3 each independently represent -O- or -NRa-, wherein Ra represents a hydrogen atom or an alkyl group;
  • L A1 to L A3 each independently represent an alkylene group, an arylene group or a divalent linking group of a combination thereof;
  • R x represents an alkylene group, an alkenylene group, an alkynylene group, an arylene group, or a divalent linking group of a combination thereof;
  • X A1 to X A3 each independently represent an organic or inorganic anion, preferably a halogen ion or an aliphatic or aromatic carboxylic acid ion.
  • Examples of compounds of Formula (A) or (B) include:
  • L 1 represents an alkylene group or an alkenylene group
  • R a , R b , R c , and R d each independently represent a linear or branched alkyl group or an aryl group, R a and R b , and/or R c and R d may form a ring by being bonded to each other;
  • R 1 , R 2 , and R 3 each independently represent a linear or branched alkyl group or an aryl group, R 1 and R 2 , or R 1 , R 2 and R 3 may form an aliphatic heterocycle by being bonded to each other; n1 , n2 and n3 each independently represent an integer of 1 to 10; and
  • X1-, X2- and X3- each independently represent an organic or inorganic anion.
  • R A1 represents a hydrogen atom or an alkyl group
  • Z 1 represents -O- or -NRa-, wherein Ra represents a hydrogen atom or an alkyl group
  • M + represents an organic or inorganic cation, preferably a hydrogen ion or an alkali metal ion;
  • R A2 represents a hydrogen atom or an alkyl group
  • R A4 represents an organic group comprising a sulphonic acid group and having no ethylenically unsaturated group
  • Z 2 represents -NRa-, wherein Ra represents a hydrogen atom or an alkyl group preferably a hydrogen atom.
  • formula (MA) and (MB-a) include:
  • L 1 represents an alkylene group
  • n represents an integer of 1 to 3, preferably 1 or 2
  • m represents an integer of 1 or 2;
  • L 2 represents an n-valent linking group
  • R 1 represents a hydrogen atom or an alkyl group
  • R 2 represents -SO3-M + or-SO 3 R 3 ; in case of plural R 2 ‘s, each R 2 independently represents -SO3-M + or -SO 3 R 3 ; M + represents a hydrogen ion, an inorganic ion, or an organic ion; and
  • R 3 represents an alkyl group or an aryl group.
  • each of R and R' independently represents a hydrogen atom or an alkyl group
  • LL represents a single bond or a bivalent linking group
  • each of LL 1 , LL 1 ', LL 2 , and LL 2 ' independently represents a single bond or a bivalent linking group
  • each of A and A' independently represents a sulpho group in free acid or salt form
  • m represents 1 or 2.
  • formula (ACL-A), (ACL-B), (ACL-C) and (AM-B) include:
  • the curable compositions may be cured by any suitable process, including thermal curing, photocuring, electron beam (EB) radiation, gamma radiation, and combinations of the foregoing.
  • the curable compositions are preferably cured by photocuring, e.g. by irradiating the curable compositions by ultraviolet of visible light and thereby causing the curable components present in the compositions to polymerise.
  • thermal initiators examples include 2,2’-azobis(2-methylpropionitrile) (Al BN), 4,4’-azobis(4-cyanovaleric acid), 2,2’- azobis(2,4-dimethyl valeronitrile), 2,2’-azobis(2-methylbutyronitrile), 1 ,1’-azobis(cyclohexane-1- carbonitrile), 2,2’-azobis(4-methoxy-2,4-dimethyl valeronitrile), dimethyl 2,2’-azobis(2- methylpropionate), 2,2’-azobis[N-(2-propenyl)-2-methylpropionamide, 1-[(1-cyano-1- methylethyl)azo] formamide, 2,2'-Azobis(N-butyl-2-methylpropionamide), 2,2'-Azobis(N- cyclohexyl-2-methylpropionamide), 2,2'-Azobis(2-methylpropionamidine)
  • Suitable photoinitiators which may be included in the curable compositions include aromatic ketones, acylphosphine compounds, aromatic onium salt compounds, organic peroxides, thio compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon halogen bond, and an alkyl amine compounds.
  • Preferred examples of the aromatic ketones, the acylphosphine oxide compound, and the thio-compound include compounds having a benzophenone skeleton or a thioxanthone skeleton described in "RADIATION CURING IN POLYMER SCIENCE AND TECHNOLOGY", pp.77-117 (1993).
  • More preferred examples thereof include an alpha-thiobenzophenone compound described in JP1972- 6416B (JP-S47-6416B), a benzoin ether compound described in JP1972-3981 B (JP-S47-3981 B), an alpha-substituted benzoin compound described in JP1972-22326B (JP-S47-22326B), a benzoin derivative described in JP1972-23664B (JP-S47-23664B), an aroylphosphonic acid ester described in JP1982-30704A (JP-S57-30704A), dialkoxybenzophenone described in JP1985- 26483B (JP-S60-26483B), benzoin ethers described in JP1985-26403B (JP-S60-26403B) and JP1987-81345A (JPS62-81345A), alpha-amino benzophenones described in JP1989-34242B (JP H01-342
  • JP1990-211452A JP-H02- 211452A
  • a thio- substituted aromatic ketone described in JP1986-194062A
  • an acylphosphine sulfide described in JP1990-9597B
  • an acylphosphine described in JP1990- 9596B
  • thioxanthones described in JP1988-61950B
  • JP-S63-61950B coumarins described in JP1984-42864B
  • photoinitiators described in JP2008-105379A and JP2009-114290A are also preferable.
  • photoinitiators described in pp. 65 to 148 of "Ultraviolet Curing System” written by Kato Kiyomi may be used.
  • Especially preferred photoinitiators include Norrish Type II photoinitiators having an absorption maximum at a wavelength longer than 380nm, when measured in one or more of the following solvents at a temperature of 23°C: water, ethanol and toluene.
  • Examples include a xanthene, flavin, curcumin, porphyrin, anthraquinone, phenoxazine, camphorquinone, phenazine, acridine, phenothiazine, xanthone, thioxanthone, thioxanthene, acridone, flavone, coumarin, fluorenone, quinoline, quinolone, naphtaquinone, quinolinone, arylmethane, azo, benzophenone, carotenoid, cyanine, phtalocyanine, dipyrrin, squarine, stilbene, styryl, triazine or anthocyanin- derived photoinitiator.
  • the curable compositions may be applied continuously to moving supports, preferably by means of a manufacturing unit comprising curable composition application stations, one or more curing stations comprising irradiation source(s) for curing the compositions, a membrane collecting station and a means for moving the supports from the curable composition application stations to the curing station(s) and to the membrane collecting station.
  • a manufacturing unit comprising curable composition application stations, one or more curing stations comprising irradiation source(s) for curing the compositions, a membrane collecting station and a means for moving the supports from the curable composition application stations to the curing station(s) and to the membrane collecting station.
  • the curable composition application stations may be located at an upstream position relative to the curing station(s) and the curing station(s) is/are located at an upstream position relative to the membrane collecting station.
  • Examples of application techniques include slot die coating, slide coating, air knife coating, roller coating, screen-printing, and dipping.
  • it might be necessary to remove excess coating from the substrate by, for example, roll-to-roll squeeze, roll-to-blade or blade-to-roll squeeze, blade-to-blade squeeze or removal using coating bars.
  • Curing by ultraviolet of visible light can occur at wavelengths between 100 nm and 800 nm using doses between 40 and 20000 mJ/cm 2 .
  • Thermal curing preferably takes place in the range between 20°C and 100°C for 0 to 20 h.
  • the membrane comprises a catalyst.
  • the catalyst or a precursor thereof may be included in one or more of the first curable composition, the second curable composition, the third curable composition and the fourth composition.
  • Also possible is to apply the catalyst or a precursor thereof (e.g. as a post-treatment step) to the third polymer i.e. after curing the third curable composition) using for example (but not limited to), dipping, air knife coating, microroller coating, spraying, chemical (vapour) deposition or physical (vapour) deposition.
  • the catalyst is present at the (third) interface between the third and the fourth polymer.
  • the third layer comprises a catalyst.
  • At least one of the layers a), b) and c) and/or interfaces comprises a catalyst.
  • Suitable catalysts include metal salts, metal oxides, organometallic compounds, monomers, polymers or co-polymers. Examples include, but are not limited to, FeCI3, FeCI 2 , AlCI 3 , MgCI 2 , RuCI 3 , CrCI 3 , Fe(OH) 3 , Sn(OH) 2 , Sn(OH) 4 , SnCI 2 , SnCI 4 , SnO, SnO 2 , AI 2 O 3 , NiO, Zr(HPO 4 ) 2 , MoS 2 , graphene oxide, Fe-polyvinyl alcohol complexes, polyvinyl alcohol (PVA), polyethylene glycol (PEG), polyethyleneimine (PEI), polyacrylic acid (PAA), co-polymer of acrylic acid and maleic anhydride (PAAMA) and hyperbranched aliphatic polyester. Any of these catalysts may be present in a range up to 5wt%, e.g. 0.001 wt% or 1 wt%
  • a first layer a) comprising a first polymer having ionic groups of charge opposite to the charge of the ionic groups of the third polymer
  • a second layer b) comprising a second polymer having ionic groups of charge opposite to the charge of the ionic groups of the first polymer
  • a third layer c) comprising a third polymer; wherein third layer c) is interposed between first layer a) and second layer b) and the ratio of the average thickness of the first layer a) to the average thickness of the second layer b) is from 0.25 to 0.8 or from 1 .2 to 4.
  • the third polymer comprises ionic groups and a network of pores.
  • the layer of first curable composition and the layer of second curable composition each comprise a porous support when they are cured.
  • a porous support is present in the first layer a) and in the second layer b).
  • the process further comprises the steps of providing a fourth curable composition comprising a curable compound having an ionic group, prior to step (iv) impregnating the pores of the third polymer with the fourth curable composition, wherein in step (iv) the first curable composition does not impregnate the pores of the third polymer but only provides a layer of the first curable composition on the first side of the base layer, and curing the fourth curable composition within the pores of the third polymer.
  • the process of the second aspect of the present invention preferably provides a membrane according to the first aspect of the present invention.
  • first curable composition and the fourth curable composition each comprise a curable compound having an anionic group and both the second curable composition and the third curable composition comprise a curable compound having a cationic group.
  • step (ii) of the process further comprises placing the porous support impregnated with the third curable composition between transparent foils to give a sandwich of the impregnated porous support and two foils and then squeezing the sandwich, e.g. between rollers or blades, to remove any excess of third curable composition.
  • the transparent foils may be removed before performing step (iv).
  • curing of the third curable composition in step (iii) is performed under an inert atmosphere, e.g. under nitrogen, carbon dioxide or argon gas.
  • the bipolar membranes of the present invention may be used in various applications, including recovery and production of organic and inorganic acids and bases (e.g. ammonia, ethanolamine, lithium hydroxide, gluconic acid, formic acid, amino acids, sulphuric acid), production of oligosaccharides and proteins, and capture of CO2 and SO2 from flue gases. They have good durability in acidic and basic media, low swelling, and may be produced cheaply, quickly and efficiently.
  • organic and inorganic acids and bases e.g. ammonia, ethanolamine, lithium hydroxide, gluconic acid, formic acid, amino acids, sulphuric acid
  • production of oligosaccharides and proteins e.g. CO2 and SO2 from flue gases. They have good durability in acidic and basic media, low swelling, and may be produced cheaply, quickly and efficiently.
  • XL-2 and MM-M may be synthesized as described below.
  • PP means polypropylene and PE means polyethylene.
  • styrene sulfonamide (NH2-SS) was dried in a vacuum oven overnight (30°C, vac).
  • a solution of the dried styrene sulfonamide (16.90 g, 0.092 mol, 2.05 moleq) and 4OH-TEMPO (30 mg, 500 p ⁇ m) in tetra hydrofuran (THF) (100 mL) was added lithium hydride (LiH) (1.50 g, 0.189 mol, 4.2 moleq) as a solid at once.
  • the reaction mixture was stirred for 30 minutes at room temperature.
  • methane sulfonamide was dried in a vacuum oven overnight at 30°C.
  • a solution of the dried methane sulfonamide (0.100 mol, 1 moleq) and 4OH-TEMPO (30 mg, 500 p ⁇ m) in THF (100 mL) was added LiH (0.300 mol, 3 moleq) as a solid at once.
  • the reaction mixture was stirred for 30 minutes at room temperature.
  • a solution of vinyl benzyl sulphonyl chloride (CI-SS) (0.100 mol, 1 moleq) in THF (50 mL) was added and the reaction mixture was heated to 60°C (water bath temperature) for 16h.
  • Second and third curable compositions were prepared by mixing the components indicated in Table 2.
  • the first curable composition was also used as fourth curable composition.
  • a 60 ⁇ m thick layer of the third curable composition was applied to a transparent PET foil sheet using a Meyer bar.
  • a porous support (Test support 2) was applied to the layer of the third curable composition, thereby becoming impregnated with the third curable composition.
  • a second transparent PET foil sheet was applied to the impregnated porous support to provide a sandwich of the impregnated porous support between the two transparent foils. Gently all air was squeezed out of the porous support using a roller.
  • the sandwich of the impregnated porous support between the two transparent foils was irradiated using a Light Hammer LH10 from Fusion UV Systems fitted with a D-bulb working at 60% intensity at a speed of 5 m/min in order to cure the third curable composition present in the porous support.
  • the transparent PET foils were removed and the cured product was allowed to dry in the air at room temperature to give a base layer (i.e. a porous support comprising a third polymer comprising ionic groups and a network of pores) having a first side and a second side.
  • the base layer was dipped in a catalyst solution comprising 1.35wt% of tin(ll)chloride in a slightly acidic aqueous solution, and allowed to dry at room temperature. Subsequently the base layer was dipped in a 0.12N NaOH solution to precipitate the catalyst and was allowed to dry at room temperature.
  • the first curable composition was applied to a transparent PET foil using a 80 ⁇ m Meyer bar.
  • a porous support (Test support 2) was applied to the layer of the fist curable composition, thereby becoming impregnated with the third curable composition.
  • the base layer comprising a catalyst, prepared as described above, was placed on top of the layer of first curable composition with the first side of the base layer contacting the first curable composition whereupon a part of the first composition (which in this case doubles-up as fourth composition) entered into the pores of the third polymer. This gave a base layer impregnated with the first curable composition and provided a layer of the first curable composition on the first side of the base layer.
  • the base layer impregnated with the first curable composition and having a layer of the first composition on its first side and a porous support was irradiated on the second side of the base layer (i.e. the side without the first curable composition) using a Light Hammer LH10 from Fusion UV Systems fitted with a D-bulb working at 50% intensity at a speed of 5 m/min.
  • the resulting cured film was a laminate of layer a) and layer c) in which the pores of the third polymer were filled with cured first curable composition.
  • a 60 ⁇ m layer of the second curable composition was applied to the second side of the laminate of layer a) and layer c) which was free from layer a) using a Meyer bar and a second porous support (Test support 2) was applied to the layer of the second curable composition. After 5 seconds excess second curable composition was removed using a 4 ⁇ m Meyer bar.
  • the resulting product was irradiated on both sides using a Light Hammer LH10 from Fusion UV Systems fitted with a D-bulb working at 50% intensity at a speed of 5 m/min in order to cure the second curable composition.
  • the PET foil was removed to give a bipolar, composite membrane according to the first aspect of the present invention comprising the first layer a), the second layer b) and the third layer c) interposed between the first layer a) and the second layer b).
  • the average thickness of layers a), b) and c) and the thickness ratio a):b) are shown in Table 4 below.
  • the first curable composition was applied to a transparent PET foil using a 120 ⁇ m Meyer bar.
  • a porous support (Test support 1) was applied to the layer of the fist curable composition, thereby becoming impregnated with the first curable composition.
  • the base layer comprising a catalyst, prepared as described above, was placed on top of the layer of first curable composition with the first side of the base layer contacting the first curable composition whereupon a part of the first composition (which in this case doubles-up as fourth composition) entered into the pores of the third polymer. This gave a base layer impregnated with the first curable composition and provided a layer of the first curable composition on the first side of the base layer.
  • the base layer impregnated with the first curable composition and having a layer of the first composition comprising the porous support on its first side was irradiated on the second side of the base layer (i.e. the side without the first curable composition) using a Light Hammer LH10 from Fusion UV Systems fitted with a D-bulb working at 50% intensity at a speed of 5 m/min.
  • the resulting cured film was a laminate of layer a) and layer c) in which the pores of the third polymer were filled with cured first curable composition.
  • a 60 ⁇ m layer of the second curable composition was applied to the second side of the laminate of layer a) and layer c) which was free from layer a) using a Meyer bar and a second porous support (Test support 2) was applied to the layer of the second curable composition. After 5 seconds excess second curable composition was removed using a 4 ⁇ m Meyer bar.
  • the resulting product was irradiated on both sides using a Light Hammer LH10 from Fusion UV Systems fitted with a D-bulb working at 50% intensity at a speed of 5 m/min in order to cure the second curable composition.
  • the PET foil was removed to give a bipolar, composite membrane according to the first aspect of the present invention comprising the first layer a), the second layer b) and the third layer c) interposed between the first layer a) and the second layer b).
  • the average thickness of layers a), b) and c) and the thickness ratio a):b) are shown in Table 4 below.
  • the first curable composition was applied to a transparent PET foil using a 80 ⁇ m Meyer bar.
  • a porous support (Test support 2) was applied to the layer of the fist curable composition, thereby becoming impregnated with the first curable composition.
  • the base layer comprising a catalyst, prepared as described above, was placed on top of the layer of first curable composition with the first side of the base layer contacting the first curable composition whereupon a part of the first composition (which in this case doubles-up as fourth composition) entered into the pores of the third polymer. This gave a base layer impregnated with the first curable composition and provided a layer of the first curable composition on the first side of the base layer.
  • the base layer impregnated with the first curable composition and having a layer of the first composition on its first side and a porous support was irradiated on the second side of the base layer (i.e. the side without the first curable composition) using a Light Hammer LH10 from Fusion UV Systems fitted with a D-bulb working at 50% intensity at a speed of 5 m/min.
  • the resulting cured film was a laminate of layer a) and layer c) in which the pores of the third polymer were filled with cured first curable composition.
  • a 100 ⁇ m layer of the second curable composition was applied to the second side of the laminate of layer a) and layer c) which was free from layer a) using a Meyer bar and a second porous support (Test support 1) was applied to the layer of the second curable composition. After 5 seconds excess second curable composition was removed using a 4 ⁇ m Meyer bar.
  • the resulting product was irradiated on both sides using a Light Hammer LH10 from Fusion UV Systems fitted with a D-bulb working at 50% intensity at a speed of 5 m/min in order to cure the second curable composition.
  • the PET foil was removed to give a bipolar, composite membrane according to the first aspect of the present invention comprising the first layer a), the second layer b) and the third layer c) interposed between the first layer a) and the second layer b).
  • the average thickness of layers a), b) and c) and the thickness ratio a):b) are shown in Table 4 below.
  • the average thickness of layers a), b) and c) was determined by optical microscopy of a membrane cross-section. The results are shown in Table 4 below.
  • a device comprising a 6-chamber cell was constructed (as shown in Fig 1) for measuring the leak current and testing the performance of the bipolar membranes (BPMs) according to the present invention and a commercial reference BPM.
  • the results are expressed in terms of the purity of the generated acid and base solutions.
  • Feed solution, acid solution and base solution were supplied at a flow rate of 35L/min respectively.
  • a current of 12A was applied across the electrodes for 2 hours and during this period the voltage was recorded. The average value was taken as operating voltage.
  • the acid and base concentration of the acid and base tank respectively was quantified by titration, and the anionic impurities were quantified by ion chromatography, cationic impurities by Inductively Coupled Plasma (ICP) analysis.
  • ICP Inductively Coupled Plasma
  • Acid purity (%) (1- ( ⁇ [Na + ] I [H + ])) x 100%; wherein ⁇ [Na + ] is the increase in the concentration of sodium ions in the acid tank during the test in mol/L and [H + ] is the hydrogen ion concentration in the acid tank after the test in mol/L.
  • Base purity (%) (1 - (( ⁇ [CI- ] + ⁇ [SO 4 2- ]) I [OH ])) x 100%; wherein ⁇ [CI'] is the increase in concentration of chloride ions in the base tank during the test in mol/L, ⁇ [SO 4 2 '] is the increase in concentration of sulfate ions in the base tank during the test in mol/L and [OH-] is the hydroxide ion concentration in the base tank after the test in mol/L.
  • the leak currents of the bipolar membrane samples were determined form the intensity vs. voltage (V-l) curves obtained using a 6-chamber cell equipped with a 1 st electrode compartment containing a platinum plate as cathode and separated from the 2 nd compartment by a standard CEM (CMX from Astom). The electrode compartment was filled with 0.5 M Na2SO 4 . Between the 2 nd and the 3 rd compartment a standard bipolar membrane (from Fumatech) was present. Both the 2 nd and the 3 rd compartment contained a 0.5M NaCI solution. Between the 3 rd and 4 th compartment the BPM to be analyzed was placed.
  • V-l intensity vs. voltage
  • the same standard bipolar membrane as between the 2 nd and the 3 rd compartment was placed and between the 5 th and the 6 th compartment a standard CEM (CMX from Astom).
  • the 4 th and 5 th compartments were also filled with a 0.5M NaCI solution.
  • the 6 th compartment containing a platinum plate as anode formed an electrode compartment and contained 0.5 M Na2SO 4 .
  • the solutions were pumped through the compartments at a temperature of 25°C while a constant voltage of 0.4 V was applied.
  • the bipolar membranes were placed with the AEL side towards the anode and with the CEL side towards the cathode.
  • the current was measured by using a Luggin capillary placed at each side of the BPM to be analyzed at a distance of 4.5 mm. The data were acquired for a period of 600 seconds to ensure that the current had stabilized. The current leak value obtained was the average of the last 5 data points of the current (after it had stabilized). Prior to the measurement, all samples were conditioned in 0.5 M NaCI solution. Preferably the leak current is as low as possible.

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Abstract

Membrane bipolaire comprenant : a) une première couche comprenant un premier polymère possédant des groupes ioniques ; b) une deuxième couche comprenant un deuxième polymère possédant des groupes ioniques de charge opposée à la charge des groupes ioniques du premier polymère ; et c) une troisième couche comprenant un troisième polymère ; i) le rapport entre l'épaisseur moyenne de la première couche a) et l'épaisseur moyenne de la deuxième couche b) étant de 0,25 à 0,8 ou de 1,2 à 4 ; et (ii) la troisième couche c) étant intercalée entre la première couche a) et la deuxième couche b).
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Citations (33)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS473981B1 (fr) 1968-06-11 1972-02-03
JPS476416B1 (fr) 1968-04-16 1972-02-23
JPS4722326B1 (fr) 1968-07-26 1972-06-22
JPS4723664B1 (fr) 1968-07-26 1972-07-01
US4253900A (en) 1977-02-28 1981-03-03 Allied Chemical Corporation Method of making novel two component bipolar ion exchange membranes
JPS5730704A (en) 1980-06-24 1982-02-19 Bayer Ag Photopolymerizable mixture containing aroylphosphoric acid ester as photoinitiator
US4318791A (en) 1977-12-22 1982-03-09 Ciba-Geigy Corporation Use of aromatic-aliphatic ketones as photo sensitizers
JPS5942864B2 (ja) 1979-04-13 1984-10-18 京セラミタ株式会社 投影用原稿の作成方法及びそれに用いる静電写真用転写フイルム
JPS6026403B2 (ja) 1977-05-17 1985-06-24 メルク・パテント・ゲゼルシヤフト・ミツト・ベシユレンクテル・ハフツング 不飽和化合物の光重合用光増感剤
JPS6026483B2 (ja) 1972-07-28 1985-06-24 チバ・ガイギ−・アクチエンゲゼルシヤフト 不飽和化合物を含む重合系の光重合反応用増感剤
JPS61194062A (ja) 1985-02-21 1986-08-28 メルク・パテント・ゲゼルシヤフト・ミツト・ベシユレンクテル・ハフツング チオ置換ケトン化合物を用いる光重合開始剤
JPS6281345A (ja) 1985-09-28 1987-04-14 チバ―ガイギー　アクチェンゲゼルシャフト 共重合性光開始剤
US4673454A (en) 1983-11-23 1987-06-16 Chinese Petroleum Corp. Process for preparing bipolar membranes
EP0284561A2 (fr) 1987-03-26 1988-09-28 Ciba-Geigy Ag Alpha-aminoacétophénones comme photo-initiateurs
JPS6361950B2 (fr) 1981-03-16 1988-11-30
JPH029596B2 (fr) 1980-05-27 1990-03-02 Basf Ag
JPH029597B2 (fr) 1980-09-15 1990-03-02 Basf Ag
JPH02211452A (ja) 1988-12-01 1990-08-22 Polychrome Corp 光開始剤
JP2008105379A (ja) 2006-09-29 2008-05-08 Fujifilm Corp インクジェット記録方法及びインクジェット記録装置
JP2009114290A (ja) 2007-11-05 2009-05-28 Fujifilm Corp 光硬化性組成物、インクジェット記録用インク組成物、および、インクジェット記録方法
US20140378561A1 (en) 2011-07-19 2014-12-25 Fujifilm Manufacturing Europe Bv Curable Compositions and Membranes
CN104593819A (zh) * 2015-01-06 2015-05-06 山东天维膜技术有限公司 双极膜及其制备方法
US20150353696A1 (en) 2013-03-07 2015-12-10 Fujifilm Corporation Functional polymer membrane, manufacturing method therefor, ion exchange membrane and proton conductive membrane equipped with functional polymer membrane, and ion exchange device
US20150353721A1 (en) 2013-02-15 2015-12-10 Fujifilm Corporation Polymer functional film and method for producing same
US20160001238A1 (en) 2013-03-26 2016-01-07 Fujifilm Corporation Polymer functional film and method for producing same
US20160362526A1 (en) 2014-02-28 2016-12-15 Fujifilm Corporation Ion exchange membrane and method for manufacturing the same
US20160367980A1 (en) 2014-03-07 2016-12-22 Fujifilm Corporation Ion-exchange polymer and production method therefor, electrolyte membrane and production method therefor, and composition for producing ion-exchange polymer
US20160369017A1 (en) 2014-03-12 2016-12-22 Fujifilm Corporation Curable composition, polymer functional cured product, water-soluble acrylamide compound, and method for manufacturing same
EP3184558A1 (fr) 2014-08-19 2017-06-28 Fujifilm Corporation Composition pour la formation d'une membrane polymère, son procédé de production, membrane polymère, module de membrane de séparation et dispositif d'échange d'ions
EP3187516A1 (fr) 2014-08-28 2017-07-05 Fujifilm Corporation Composition durcissable, produit durci de polymère fonctionnel, empilement ou dispositif doté de film de polymère fonctionnel, composé amide et son procédé de production
WO2017205458A1 (fr) 2016-05-24 2017-11-30 Vanderbilt University Membranes bipolaires à base de nanofibres, procédés pour leur fabrication et applications correspondantes
EP3604404A1 (fr) 2017-03-28 2020-02-05 Coway Co., Ltd. Membrane échangeuse d'ions bipolaire utilisant une membrane échangeuse d'ions hétérogènes comme support et procédé de production associé
JP2020097648A (ja) * 2018-12-17 2020-06-25 株式会社アストム バイポーラ膜

Patent Citations (35)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS476416B1 (fr) 1968-04-16 1972-02-23
JPS473981B1 (fr) 1968-06-11 1972-02-03
JPS4722326B1 (fr) 1968-07-26 1972-06-22
JPS4723664B1 (fr) 1968-07-26 1972-07-01
JPS6026483B2 (ja) 1972-07-28 1985-06-24 チバ・ガイギ−・アクチエンゲゼルシヤフト 不飽和化合物を含む重合系の光重合反応用増感剤
US4253900A (en) 1977-02-28 1981-03-03 Allied Chemical Corporation Method of making novel two component bipolar ion exchange membranes
JPS6026403B2 (ja) 1977-05-17 1985-06-24 メルク・パテント・ゲゼルシヤフト・ミツト・ベシユレンクテル・ハフツング 不飽和化合物の光重合用光増感剤
JPH0134242B2 (fr) 1977-12-22 1989-07-18 Ciba Geigy
US4318791A (en) 1977-12-22 1982-03-09 Ciba-Geigy Corporation Use of aromatic-aliphatic ketones as photo sensitizers
JPS5942864B2 (ja) 1979-04-13 1984-10-18 京セラミタ株式会社 投影用原稿の作成方法及びそれに用いる静電写真用転写フイルム
JPH029596B2 (fr) 1980-05-27 1990-03-02 Basf Ag
JPS5730704A (en) 1980-06-24 1982-02-19 Bayer Ag Photopolymerizable mixture containing aroylphosphoric acid ester as photoinitiator
JPH029597B2 (fr) 1980-09-15 1990-03-02 Basf Ag
JPS6361950B2 (fr) 1981-03-16 1988-11-30
US4673454A (en) 1983-11-23 1987-06-16 Chinese Petroleum Corp. Process for preparing bipolar membranes
JPS61194062A (ja) 1985-02-21 1986-08-28 メルク・パテント・ゲゼルシヤフト・ミツト・ベシユレンクテル・ハフツング チオ置換ケトン化合物を用いる光重合開始剤
JPS6281345A (ja) 1985-09-28 1987-04-14 チバ―ガイギー　アクチェンゲゼルシャフト 共重合性光開始剤
EP0284561A2 (fr) 1987-03-26 1988-09-28 Ciba-Geigy Ag Alpha-aminoacétophénones comme photo-initiateurs
JPH02211452A (ja) 1988-12-01 1990-08-22 Polychrome Corp 光開始剤
JP2008105379A (ja) 2006-09-29 2008-05-08 Fujifilm Corp インクジェット記録方法及びインクジェット記録装置
JP2009114290A (ja) 2007-11-05 2009-05-28 Fujifilm Corp 光硬化性組成物、インクジェット記録用インク組成物、および、インクジェット記録方法
US20140378561A1 (en) 2011-07-19 2014-12-25 Fujifilm Manufacturing Europe Bv Curable Compositions and Membranes
US20150353721A1 (en) 2013-02-15 2015-12-10 Fujifilm Corporation Polymer functional film and method for producing same
US20150353696A1 (en) 2013-03-07 2015-12-10 Fujifilm Corporation Functional polymer membrane, manufacturing method therefor, ion exchange membrane and proton conductive membrane equipped with functional polymer membrane, and ion exchange device
US20160001238A1 (en) 2013-03-26 2016-01-07 Fujifilm Corporation Polymer functional film and method for producing same
EP2979748A1 (fr) 2013-03-26 2016-02-03 Fujifilm Corporation Film fonctionnel de polymère et son procédé de production
US20160362526A1 (en) 2014-02-28 2016-12-15 Fujifilm Corporation Ion exchange membrane and method for manufacturing the same
US20160367980A1 (en) 2014-03-07 2016-12-22 Fujifilm Corporation Ion-exchange polymer and production method therefor, electrolyte membrane and production method therefor, and composition for producing ion-exchange polymer
US20160369017A1 (en) 2014-03-12 2016-12-22 Fujifilm Corporation Curable composition, polymer functional cured product, water-soluble acrylamide compound, and method for manufacturing same
EP3184558A1 (fr) 2014-08-19 2017-06-28 Fujifilm Corporation Composition pour la formation d'une membrane polymère, son procédé de production, membrane polymère, module de membrane de séparation et dispositif d'échange d'ions
EP3187516A1 (fr) 2014-08-28 2017-07-05 Fujifilm Corporation Composition durcissable, produit durci de polymère fonctionnel, empilement ou dispositif doté de film de polymère fonctionnel, composé amide et son procédé de production
CN104593819A (zh) * 2015-01-06 2015-05-06 山东天维膜技术有限公司 双极膜及其制备方法
WO2017205458A1 (fr) 2016-05-24 2017-11-30 Vanderbilt University Membranes bipolaires à base de nanofibres, procédés pour leur fabrication et applications correspondantes
EP3604404A1 (fr) 2017-03-28 2020-02-05 Coway Co., Ltd. Membrane échangeuse d'ions bipolaire utilisant une membrane échangeuse d'ions hétérogènes comme support et procédé de production associé
JP2020097648A (ja) * 2018-12-17 2020-06-25 株式会社アストム バイポーラ膜

Non-Patent Citations (5)

* Cited by examiner, † Cited by third party
Title
"RADIATION CURING IN POLYMER SCIENCE AND TECHNOLOGY", 1993, pages: 77 - 117
DATABASE WPI Week 201551, 6 May 2015 Derwent World Patents Index; AN 2015-41486E, XP002808426 *
DATABASE WPI Week 2020005, 25 June 2020 Derwent World Patents Index; AN 2020-573304, XP002808425 *
KATO KIYOMI: "Ultraviolet Curing System", 1989, RESEARCH CENTER CO., LTD., pages: 65 - 148
MCCLURE, ECS TRANSACTIONS, vol. 69, no. 18, 2015, pages 35 - 44

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