Copolymer for anion exchange membrane and anion exchange membrane comprising the same

Abstract

The present application provides a copolymer for an anion exchange membrane comprising a repeating unit represented by the following Chemical Formula 1, and an anion exchange membrane comprising the copolymer. [Chemical Formula 1] With respect to M1, M2, L1, L2, x, and y in the Chemical Formula 1, refer to the content described in the specification.

Description

Technical Field

[0001] This invention relates to a copolymer for anion exchange membranes and anion exchange membranes comprising the copolymer. Background Technology

[0002] An electrolyte membrane is a membrane that possesses ionic conductivity and selectively transfers ions during electrochemical reactions. Electrolyte membranes are used in fuel cells, water electrolysis devices, and other fields.

[0003] Anion exchange membranes, as one type of electrolyte membrane, are membranes that selectively transfer anions and are used in fields such as fuel cells.

[0004] Regarding anion exchange membranes, research and development are underway to improve their physical properties, such as stability, durability, and ionic conductivity. Summary of the Invention

[0005] (a) Technical problems to be solved One technical problem of the present invention is to provide a copolymer for anion exchange membranes with improved chemical stability and ionic conductivity.

[0006] One technical problem of the present invention is to provide an anion exchange membrane with improved ionic conductivity, mechanical and physical properties and reliability.

[0007] (II) Technical Solution The copolymer for anion exchange membranes according to embodiments of the present invention comprises repeating units represented by the following chemical formula 1: [Chemical Formula 1] In the chemical formula 1, M1 is selected from any of the arylene groups represented by chemical formulas 2-1 and 2-2 below, M2 is an arylene group represented by chemical formula 3 below, x and y are each independently 0.1 to 0.9, and x+y=1, L1 and L2 are each independently selected from the arylene groups represented by chemical formulas 4-1 and 4-2 below.

[0008] [Chemical Formula 2-1] [Chemical Formula 2-2] [Chemical Formula 3] [Chemical Formula 4-1] [Chemical Formula 4-2] In chemical formulas 2-1, 2-2, 3, 4-1, and 4-2, a is an integer from 2 to 6, b is an integer from 0 to 4, and R1 and R2 are each independently C1 to C2. 10 The alkyl group, R3 and R4 are each independently C3 to C4 with a quaternary ammonium salt at the end. 10 The alkyl group, R5 and R6 are each independently selected from -H and C1 to C3 alkyl groups, - and- ' indicates the binding site of the cross-linking.

[0009] In some implementations, a in chemical formula 2-1 can be an integer from 2 to 5, and b in chemical formula 2-2 can be an integer from 0 to 3.

[0010] In some embodiments, the divalent phenylene groups in Formula 2-1 and Formula 2-2 can each be independently linked at the meta or para position.

[0011] In some embodiments, the counter ion of the quaternary ammonium salt can be a halide anion, OH- - or HCO3 - .

[0012] In some embodiments, M1 may be selected from any of the arylene groups represented by the following chemical formulas 2-1A to 2-1E: [Chemical Formula 2-1A] [Chemical Formula 2-1B] [Chemical Formula 2-1C] [Chemical Formula 2-1D] [Chemical Formula 2-1E] In chemical formulas 2-1A to 2-1E, R1 and R2 are each independently C1 to C2. 10 alkyl, - and- ' indicates the binding site of the cross-linking.

[0013] In some embodiments, the fluorene-derived aryl groups in Formulas 2-1C to 2-1E can be meta-linked to adjacent phenylene groups.

[0014] In some implementations, R1 and R2 can each be independently C1 to C5 alkyl groups.

[0015] In some embodiments, R3 and R4 can each be independently C4 to C7 alkyl groups with a terminal quaternary ammonium halide.

[0016] In some embodiments, the quaternary ammonium salt may be selected from groups represented by the following chemical formulas 5-1 to 5-3: [Chemical Formula 5-1] [Chemical Formula 5-2] [Chemical Formula 5-3] In chemical formulas 5-1 to 5-3, R7 to R 11 Each is an alkyl group from C1 to C5, and X is OH, F, Cl, Br or I, each independently. This indicates the binding position at the end of R3 or R4.

[0017] In some embodiments, the copolymer for anion exchange membranes may further comprise crosslinking units represented by any one of the following chemical formulas 6-1 and 6-2: [Chemical Formula 6-1] [Chemical Formula 6-2] In chemical formulas 6-1 and 6-2, - - '、- "Indicates the binding site where the repeating unit is crosslinked, R" 12 and R 13 Each is an alkyl group from C1 to C5, and Y is O or S.

[0018] In some embodiments, the repeating unit and the crosslinking unit may be directly crosslinked or linked by an arylene crosslinking represented by any one of the following chemical formulas 7-1 and 7-2: [Chemical Formula 7-1] [Chemical Formula 7-2] In chemical formulas 7-1 and 7-2, R 14 and R 15 Each is independently selected from -H and C1 to C3 alkyl groups, - and- ' indicates the binding site of the cross-linking.

[0019] In some embodiments, the content of the repeating unit represented by Formula 1 may be from 90.0 mol% to 100 mol% relative to all repeating units contained in the copolymer.

[0020] In some embodiments, in the copolymer for anion exchange membranes, the content of repeating units represented by Formula 1 may be from 80.0 mol% to 99.0 mol% relative to all repeating units contained in the copolymer, and the content of crosslinking units represented by any one of Formula 6-1 and Formula 6-2 may be from 1.0 mol% to 20.0 mol%.

[0021] In some embodiments, the weight-average molecular weight of the copolymer used for the anion exchange membrane can be from 30,000 g / mol to 2,000,000 g / mol.

[0022] In some embodiments, the reduction rate (R) of the ionic conductivity of the copolymer used for the anion exchange membrane, calculated by Formula 1 below, can be less than 15%. [Formula 1] The rate of decrease in ionic conductivity (R, %) = {(C1-C2) / C1} × 100 In Formula 1, C1 refers to the preparation of an anion exchange membrane comprising the copolymer used for anion exchange membranes, which converts counterions into OH-. - Then, at room temperature, OH - The ionic conductivity of anion exchange membranes is evaluated based on their morphology; C2 refers to the conductivity of the membrane with OH groups. - The anion exchange membrane was immersed in a 1M alkaline solution and placed at 80°C for 28 days. After cooling to room temperature, the ionic conductivity was evaluated at room temperature.

[0023] The anion exchange membrane according to an embodiment of the present invention comprises the above-described copolymer.

[0024] In some embodiments, the thickness of the anion exchange membrane can be from 10 μm to 80 μm.

[0025] In some embodiments, the OH content of the copolymer used for the anion exchange membrane is measured at room temperature. - The ionic conductivity can be above 30 mS / cm.

[0026] (III) Beneficial Effects The copolymers according to embodiments of the present invention can achieve improved chemical stability, physical stability, and ionic conductivity.

[0027] The anion exchange membrane according to embodiments of the present invention can achieve improved ion exchange characteristics, high-temperature stability, and operational stability.

[0028] The copolymer and anion exchange membrane of the present invention can be applied to technical fields such as membrane electrode assemblies, fuel cells such as alkaline fuel cells, water electrolysis devices, carbon dioxide conversion devices, and electrochemical hydrogen condensation systems. Detailed Implementation

[0029] The following detailed description of exemplary embodiments of the present invention enables those skilled in the art to readily implement it. However, this is merely exemplary, and the present invention is not limited to the exemplary embodiments described.

[0030] Copolymers for Anion Exchange Membranes The copolymer for anion exchange membranes according to embodiments of the present invention comprises repeating units represented by the following chemical formula 1: [Chemical Formula 1] In the chemical formula 1, M1 is selected from any of the arylene groups represented by chemical formulas 2-1 and 2-2 below, M2 is an arylene group represented by chemical formula 3 below, x and y are each independently 0.1 to 0.9, and x+y=1, L1 and L2 are each independently selected from the arylene groups represented by chemical formulas 4-1 and 4-2 below.

[0031] [Chemical Formula 2-1] [Chemical Formula 2-2] [Chemical Formula 3] [Chemical Formula 4-1] [Chemical Formula 4-2] In chemical formulas 2-1, 2-2, 3, 4-1, and 4-2, a is an integer from 2 to 6, b is an integer from 0 to 4, and R1 and R2 are each independently C1 to C2. 10 The alkyl group may be, for example, a straight-chain alkyl group.

[0032] R3 and R4 are each independently C3 to C4 terminals with quaternary ammonium salts at the end. 10 The alkyl group may be, for example, a straight-chain alkyl group.

[0033] R5 and R6 are each independently selected from -H and C1 to C3 alkyl groups.

[0034] - and- ' indicates the binding site of the cross-linking.

[0035] The ionic conductivity, chemical stability, and physical stability of the copolymer used in the anion exchange membrane can be improved. Anion exchange membranes containing the copolymer can achieve improved ion exchange characteristics, high-temperature stability, and operational stability.

[0036] In some embodiments, the copolymer may be a random copolymer or a block copolymer; for example, it may be a random copolymer.

[0037] In some embodiments, 'a' in chemical formula 2-1 can be an integer from 2 to 5, and 'b' in chemical formula 2-2 can be an integer from 0 to 3. For example, 'a' can be 2 or 3, and 'b' can be 0 or 1.

[0038] In some embodiments, the divalent phenylene groups in Formula 2-1 and Formula 2-2 can each be independently linked at the meta or para position.

[0039] In some embodiments, the counter ion of the quaternary ammonium salt can be a halide anion, OH- - or HCO3 - The halide anion can be selected from F. - Cl - ,Br - and I - .

[0040] In some embodiments, M1 may be selected from any of the arylene groups represented by the following chemical formulas 2-1A to 2-1E: [Chemical Formula 2-1A] [Chemical Formula 2-1B] [Chemical Formula 2-1C] [Chemical Formula 2-1D] [Chemical Formula 2-1E] In chemical formulas 2-1A to 2-1E, R1 and R2 are each independently C1 to C2. 10 alkyl, - and- ' indicates the bonding position of the cross-linking. The alkyl group can be, for example, a straight-chain alkyl group.

[0041] In some implementations, R1 and R2 can be the same as each other.

[0042] R1 and R2 can be, for example, straight-chain alkyl groups from C1 to C7.

[0043] In some embodiments, the fluorene-derived aryl groups in Formulas 2-1C to 2-1E can be meta-linked to adjacent phenylene groups.

[0044] For example, the fluorene-derived arylene group can be bonded to the adjacent phenylene group at position 4, as shown below. For example, the adjacent phenylene group can be bonded to position 1, 2, or 3 of the fluorene-derived arylene group.

[0045] [Chemical Formula 2-1C] [Chemical Formula 2-1D] [Chemical Formula 2-1E] In some embodiments, R1 and R2 can each be independently C1 to C5 alkyl groups, for example, C1 to C3 alkyl groups.

[0046] In some embodiments, R3 and R4 can each be independently C4 to C7 alkyl groups with a terminal quaternary ammonium halide.

[0047] In some embodiments, the quaternary ammonium salt may be an alkyl ammonium salt, an alicyclic or aromatic ammonium salt containing one or two nitrogen atoms.

[0048] The alicyclic or aromatic ammonium salt may be, for example, an ammonium salt of pyrrolidine, piperidine, pyrrole, pyridine, or imidazole.

[0049] In some embodiments, the quaternary ammonium salt may be selected from groups represented by the following chemical formulas 5-1 to 5-3.

[0050] [Chemical Formula 5-1] [Chemical Formula 5-2] [Chemical Formula 5-3] In chemical formulas 5-1 to 5-3, R7 to R 11Each is an alkyl group from C1 to C5, and X is OH, F, Cl, Br or I, each independently. This indicates the binding position at the end of R3 or R4. The alkyl group may be, for example, a straight-chain alkyl group.

[0051] In some embodiments, the copolymer for anion exchange membranes may further comprise crosslinking units represented by any one of the following chemical formulas 6-1 and 6-2: [Chemical Formula 6-1] [Chemical Formula 6-2] In chemical formulas 6-1 and 6-2, - - '、- "Indicates the binding site where the repeating unit is crosslinked, R" 12 and R 13 Each is an alkyl group, C1 to C5, and Y is O or S. The alkyl group may, for example, be a straight-chain alkyl group.

[0052] The copolymer can be a random copolymer or a block copolymer, for example, a random copolymer.

[0053] In some embodiments, the repeating unit and the crosslinking unit may be directly crosslinked or crosslinked by an arylene group represented by any one of the following chemical formulas 7-1 and 7-2.

[0054] [Chemical Formula 7-1] [Chemical Formula 7-2] In chemical formulas 7-1 and 7-2, R 14 and R 15 Each is independently selected from -H and C1 to C3 alkyl groups, - and- ' indicates the binding site of the cross-linking.

[0055] In some embodiments, the copolymer for anion exchange membranes may comprise repeating units represented by Chemical Formula 1. For example, the content of repeating units represented by Chemical Formula 1 in the copolymer for anion exchange membranes may be from 90.0 mol% to 100 mol% or from 90.0 mol% to 99.9 mol% relative to all repeating units contained in the copolymer.

[0056] In some embodiments, the copolymer for anion exchange membranes may comprise repeating units represented by Formula 1 and crosslinking units represented by any one of Formulas 6-1 and 6-2. For example, in the copolymer for anion exchange membranes, the content of repeating units represented by Formula 1 may be 80.0 mol% to 99.0 mol%, 90.0 mol% to 99.0 mol%, or 90.0 mol% to 95.0 mol%, relative to all repeating units contained in the copolymer; and the content of crosslinking units represented by any one of Formulas 6-1 and 6-2 may be 1.0 mol% to 20.0 mol%, 1.0 mol% to 10.0 mol%, or 5.0 mol% to 10.0 mol%.

[0057] Therefore, the high-temperature stability of anion exchange membranes can be further improved. Furthermore, the processability during membrane manufacturing or casting can be improved.

[0058] In some embodiments, the weight-average molecular weight of the copolymer used for the anion exchange membrane can be from 30,000 g / mol to 2,000,000 g / mol. For example, the weight-average molecular weight (Mw) can be measured using gel permeation chromatography (GPC) according to ISO 16014 or ASTM D5296.

[0059] In some embodiments, the reduction rate (R) of the ionic conductivity of the copolymer for anion exchange membranes, calculated by Formula 1 below, can be 15% or less. Therefore, the high-temperature stability of the copolymer for anion exchange membranes can be further improved.

[0060] [Formula 1] The rate of decrease in ionic conductivity (R, %) = {(C1-C2) / C1} × 100 In Formula 1, C1 refers to the preparation of an anion exchange membrane comprising the copolymer used for anion exchange membranes, which converts counterions into OH-. - Then, at room temperature, OH - The ionic conductivity of anion exchange membranes is evaluated based on their morphology; C2 refers to the conductivity of the membrane with OH groups. - The anion exchange membrane was immersed in a 1M alkaline solution and placed at 80°C for 28 days. After cooling to room temperature, the ionic conductivity was evaluated at room temperature.

[0061] The ionic conductivity can be achieved, for example, by placing the OH groups between the Pt electrodes. - The membrane resistance (Ω) of the anion exchange membrane in the morphology was measured using an impedance analysis device (VSP-3e, Biologics) in the frequency range of 0.1 kHz to 1 MHz using the 4-point probe method, and calculations were made based on the membrane resistance.

[0062] The alkaline solution can be, for example, KOH or NaOH solution.

[0063] In some embodiments, the reduction rate (R) of the ionic conductivity of the copolymer used for the anion exchange membrane can be, for example, less than 10%, less than 7%, less than 5%, or less than 4%.

[0064] This can further improve the high-temperature stability of the copolymer used in the anion exchange membrane.

[0065] As a non-limiting example, the copolymer for anion exchange membranes can be synthesized, for example, by a manufacturing method comprising mixing and stirring at least one of the following first monomers with at least one of the following second monomers, and mixing and stirring the following third monomer. The mixing and stirring can be carried out at a temperature of 0°C and in an inert gas atmosphere such as nitrogen, but is not limited thereto. The solution from which the polymerization reaction of the above monomers has been completed is added to, for example, methanol, to allow the solid to precipitate, followed by filtration, washing, and drying, thereby obtaining a precursor of the solid copolymer. For example, when mixing the third monomer, an acid such as trifluoromethanesulfonic acid can be mixed in.

[0066] The first monomer may, for example, include monomer a and / or monomer b.

[0067] <Single a> <Single b> The second monomer may, for example, include the following monomer c.

[0068] <Single c> The third monomer may, for example, include monomer d and / or monomer e.

[0069] <Single d> <monomer e> In the first to the third monomers, a, b, and R1 to R6 refer to the contents defined in the above chemical formula 1.

[0070] The third monomer may be included as a linking group in the copolymer for anion exchange membranes, connecting the first monomer and the second monomer.

[0071] For example, the copolymer precursor can be dissolved in a solvent, and an aqueous tertiary amine solution can be slowly added while stirring to synthesize a copolymer for anion exchange membranes.

[0072] For example, by adding a solvent such as diethyl ether to a solution containing the copolymer for anion exchange membranes, allowing the solid to precipitate, filtering, washing, and drying, a precursor of the solid copolymer can be obtained.

[0073] <Anion exchange membrane> An anion exchange membrane according to an exemplary embodiment of the present invention comprises the above-described copolymer for anion exchange membranes. Therefore, the anion exchange membrane can achieve improved ionic conductivity, mechanical and physical properties, high-temperature stability, and reliability.

[0074] As a non-limiting example, the anion exchange membrane can be prepared by dissolving the anion exchange membrane in an organic solvent to obtain a first solution, filtering the first solution to remove impurities to obtain a second solution, casting the second solution onto a substrate such as a glass substrate, and then drying and separating it.

[0075] The first solution may be formed, for example, at a concentration of 15% to 35% by weight. The drying may be carried out, for example, in a vacuum oven at a temperature of 80°C to 100°C.

[0076] In some embodiments, the anion exchange membrane may have an OH content measured at room temperature. - The ionic conductivity is 30 mS / cm or higher and / or contains copolymers comprising 80% by weight or more, 90% by weight or more, 95% by weight or more, or 99% by weight or more relative to the total polymer content of the anion exchange membrane.

[0077] In some embodiments, the thickness of the anion exchange membrane may be, for example, 10 μm to 80 μm, 25 μm to 80 μm, or 40 μm to 80 μm. The thickness may refer to the thickness under dry conditions at ambient temperature and pressure (i.e., 25°C and 1 bar).

[0078] In some embodiments, the OH content of the anion exchange membrane is measured at room temperature. - The ionic conductivity can be above 30 mS / cm. Therefore, the anion exchange membrane can achieve sufficient ionic conductivity.

[0079] For example, the OH content measured at room temperature by the anion exchange membrane. - The ionic conductivity can be above 40 mS / cm or above 50 mS / cm, and can be below 100 mS / cm.

[0080] In some embodiments, the reduction rate (R) of the ionic conductivity of the anion exchange membrane calculated using the following formula 1 can be less than 15%.

[0081] [Formula 1] The rate of decrease in ionic conductivity (R, %) = {(C1-C2) / C1} × 100 In Formula 1, C1 is the conversion of the counter ion of the copolymer contained in the anion exchange membrane into OH-. - Then, at room temperature, OH - The ionic conductivity of the anion exchange membrane was evaluated based on its morphology. C2 is the OH group. - The anion exchange membrane in this form was immersed in a 1M alkaline solution and placed at 80°C for 28 days. After cooling to room temperature, the ionic conductivity was evaluated at room temperature. For a more detailed explanation of Formula 1, please refer to the above content in this specification.

[0082] The fuel cell according to an embodiment of the present invention includes the above-described anion exchange membrane.

[0083] The fuel cell may include: a positive electrode; a negative electrode disposed opposite to the positive electrode; and an anion exchange membrane disposed between the positive electrode and the negative electrode.

[0084] The fuel cell can be, for example, a solid alkaline fuel cell (SAFC).

[0085] The water electrolysis device according to an embodiment of the present invention includes the above-described anion exchange membrane. The water electrolysis device may, for example, include the anion exchange membrane and electrode material on the anion exchange membrane, the electrode material may include, for example, a transition metal, a binder, a porous material, etc.

[0086] A carbon dioxide conversion device according to an embodiment of the present invention includes the above-described anion exchange membrane. The carbon dioxide conversion device may, for example, include: a positive electrode; a negative electrode disposed opposite to the positive electrode; and the anion exchange membrane disposed between the positive and negative electrodes. When carbon dioxide is supplied to the positive electrode and a voltage is applied to the carbon dioxide conversion device, the reaction proceeds as follows: 3CO₂ + H₂ + 2e⁻ - →CO + 2HCO3 - The reaction can reduce carbon dioxide. In the case of the anion exchange membrane, in order to prevent hydrogen ions (H+) from forming on the surface of the cation exchange membrane... +The accumulation of ions hinders the carbon dioxide conversion performance of the positive electrode. The anion exchange membrane can be inserted into the membrane electrode assembly (MEA).

[0087] The embodiments of the present invention will be further described below with reference to specific experimental examples. The embodiments and comparative examples included in the experimental examples are for illustrative purposes only and are not intended to limit the scope of the claims.

[0088] Synthesis example Monomers 1 to 5 were synthesized and used in the preparation of copolymers in the examples and comparative examples.

[0089] <Single 1> <Single 2> <Single 3> <Single 4> <Single 5> Synthesis Example 1: Synthesis of Monomer 1 In a 250 mL double-necked round-bottom flask, 3-bromo-1,1':4',1''-terphenyl (5.0 g, 16.2 mmol), phenylboronic acid (2.4 g, 19.4 mmol), and tetrahydrofuran (80 mL) were added and stirred to prepare a mixed solution. An aqueous solution (13.4 mL) containing tetrakis(triphenylphosphine)palladium(0) (0.4 g, 0.3 mmol) and potassium carbonate (6.7 g, 48.5 mmol) was added to the prepared mixed solution, and the mixture was stirred at 65 °C for 8 hours. After stirring, the mixture was cooled to room temperature, and ethyl acetate (100 mL) and water (50 mL) were added for extraction. The aqueous layer was removed using a separatory funnel. The organic solvent layer was further washed with water (50 mL) and then separated to remove the aqueous layer. The organic solvent layer was dried and filtered with anhydrous magnesium sulfate and concentrated under reduced pressure. The product was purified by silica gel column chromatography using dichloromethane / n-hexane (v / v ratio 5:95) to obtain 3.0 g of the final monomer 1 as a white solid.

[0090] Perform on the monomer 1 1 H-Nuclear magnetic resonance spectroscopy analysis ( 1 H-Nuclear Magnetic Resonance, 1 The results of H-NMR are as follows.

[0091] 1 H-NMR(CDCl3, ppm): 7.88-7.87(t,1H), 7.77-7.72(m, 4H), 7.70-7.68(m,4H), 7.67-7.61(m, 2H), 7.58-7.55(t, 1H), 7.52-7.48(td, 4H), 7.42-7.38(q, 2H) Synthesis Example 2: Synthesis of Monomer 2 In a 100 mL double-necked round-bottom flask, 2-(3-bromophenyl)-9,9-dimethyl-9H-fluorene (3.0 g, 8.6 mmol), phenylboronic acid (1.3 g, 10.3 mmol), and tetrahydrofuran (43 mL) were added and stirred to prepare a mixed solution. An aqueous solution (7.1 mL) containing tetra(triphenylphosphine)palladium(0) (0.2 g, 0.2 mmol) and potassium carbonate (3.6 g, 25.8 mmol) was added to the prepared mixed solution, and the mixture was stirred at 65 °C for 8 hours. After stirring, the mixture was cooled to room temperature, and ethyl acetate (80 mL) and water (40 mL) were added for extraction. The aqueous layer was removed using a separatory funnel, and the organic solvent layer was further washed with water (40 mL) and then separated. The organic solvent layer was dried with anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The product was purified by silica gel column chromatography with ethyl acetate / n-hexane (volume ratio 5:95) to obtain 2.4 g of final monomer 2 as a white solid.

[0092] Perform on the monomer 2 1 H-Nuclear magnetic resonance spectroscopy analysis ( 1 The results of H-NMR are as follows.

[0093] 1 H-NMR(CDCl3, ppm): 7.91-7.90(t, 1H), 7.85-7.84(d, 1H), 7.81-7.79(dd,1H), 7.73(m, 2H), 7.71(s, 1H), 7.70-7.66(td, 2H), 7.63-7.61(m, 1H), 7.59-7.56(t, 1H), 7.54-7.49(q, 3H), 7.44-7.36(m, 3H), 1.59(s, 6H) Synthesis Example 3: Synthesis of Monomer 3 In a 100 mL double-necked round-bottom flask, 2-(3-bromophenyl)-9,9-dimethyl-9H-fluorene (3.1 g, 8.6 mmol), 4-biphenylboronic acid (2.1 g, 10.3 mmol), and tetrahydrofuran (43 mL) were added and stirred to prepare a mixed solution. An aqueous solution (7.1 mL) containing tetra(triphenylphosphine)palladium(0) (0.2 g, 0.2 mmol) and potassium carbonate (3.6 g, 25.8 mmol) was added to the prepared mixed solution, and the mixture was stirred at 65 °C for 8 hours. After stirring, the mixture was cooled to room temperature, and ethyl acetate (80 mL) and water (40 mL) were added for extraction. The aqueous layer was removed using a separatory funnel, and the organic solvent layer was further washed with water (40 mL) and then separated. The organic solvent layer was dried with anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The product was purified by silica gel column chromatography using dichloromethane / n-hexane (volume ratio 5:95) to obtain 2.6 g of the final monomer 3 as a white solid.

[0094] Perform on the monomer 3 1 H-Nuclear magnetic resonance spectroscopy analysis ( 1 The results of H-NMR are as follows.

[0095] 1 H-NMR(CDCl3, ppm): 7.94-7.93(t, 1H), 7.85-7.83(d, 1H), 7.80-7.78(d,3H), 7.75-7.73(m, 3H), 7.71-7.65(m, 5H), 7.60-7.57(t, 1H), 7.52-7.47(m, 3H),7.42-7.35(m, 3H), 1.58(s, 6H) Synthesis Example 4: Synthesis of Monomer 4 In a 100 mL double-necked round-bottom flask, 2-(3-bromophenyl)-9,9-dimethyl-9H-fluorene (3.1 g, 8.6 mmol), 3-biphenylboronic acid (1.4 g, 6.9 mmol), and tetrahydrofuran (30 mL) were added and stirred to prepare a mixed solution. An aqueous solution (4.8 mL) containing tetra(triphenylphosphine)palladium(0) (0.1 g, 0.1 mmol) and potassium carbonate (2.4 g, 17.2 mmol) was added to the prepared mixed solution, and the mixture was stirred at 65 °C for 8 hours. After stirring, the mixture was cooled to room temperature, and ethyl acetate (70 mL) and water (35 mL) were added for extraction. The aqueous layer was removed using a separatory funnel, and the organic solvent layer was further washed with water (35 mL) and then separated. The organic solvent layer was dried with anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The product was purified by silica gel column chromatography using dichloromethane / n-hexane (volume ratio 5:95) to obtain 1.3 g of the final monomer 4 as a white solid.

[0096] Perform on the monomer 4 1 H-Nuclear magnetic resonance spectroscopy analysis ( 1 The results of H-NMR are as follows.

[0097] 1 H-NMR(CDCl3, ppm): 7.95-7.91(d, 2H), 7.88-7.78(dd, 2H), 7.67-6.64(m,8H), 7.61-7.57(m, 2H), 7.52-7.49(m, 3H), 7.43-7.36(m, 3H), 1.58(s, 6H) Synthesis Example 5: Synthesis of Monomer 5 (1) Synthesis of intermediate compound 5-1 <Intermediate Compound 5-1> In a 500 mL double-necked round-bottom flask, dibenzofuran-4-boronicacid (5.0 g, 23.6 mmol), methyl 2-bromobenzoate (6.1 g, 28.3 mmol), and tetrahydrofuran (120 mL) were added and stirred to prepare a mixed solution. An aqueous solution (19.6 mL) containing tetra(triphenylphosphine)palladium(0) (0.5 g, 0.5 mmol) and potassium carbonate (9.8 g, 70.8 mmol) was added to the prepared mixed solution, and the mixture was stirred at 65 °C for 8 hours. After stirring, the mixture was cooled to room temperature, and ethyl acetate (100 mL) and water (50 mL) were added for extraction. The aqueous layer was removed using a separatory funnel, and the organic solvent layer was further washed with water (50 mL) and then separated. The organic solvent layer was dried with anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The product was purified by silica gel column chromatography using n-hexane / ethyl acetate (volume ratio 5:95) to obtain 6.0 g of colorless liquid intermediate compound 5-1.

[0098] The intermediate compound 5-1 was subjected to 1 H-Nuclear magnetic resonance spectroscopy analysis ( 1 The results of H-NMR are as follows.

[0099] 1 H-NMR(CDCl3, ppm): 8.09-8.03(d, 1H), 8.01-7.98(m, 2H) 7.69-7.67(m,1H), 7.66(d, 1H), 7.61-7.52(m, 2H), 7.48-7.44(m, 3H), 7.39-7.37(t, 1H), 3.52(s, 3H) (2) Synthesis of intermediate compound 5-2 <Intermediate Compound 5-2> In a 250 mL double-necked round-bottom flask, intermediate compound 5-1 (5.7 g, 18.9 mmol) and tetrahydrofuran (75 mL) were added and stirred to prepare a solution. The stirring temperature was lowered to 0 °C using a cooling water bath, and stirring was carried out under a nitrogen atmosphere. 19 mL (56.6 mmol) of a solution of 3 Methylmagnesium bromide in tetrahydrofuran was slowly added, and the mixture was stirred at room temperature for 8 hours. After stirring, the mixture was cooled to 0 °C again, and the reaction was terminated by adding water (10 mL). Subsequently, 20 mL of saturated ammonium chloride aqueous solution and 50 mL of ethyl acetate were added. The aqueous layer was removed using a separatory funnel, and the organic solvent layer was further washed with water (50 mL) and then separated and removed. The organic solvent layer was dried with anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The product was not purified separately, yielding 5.7 g of intermediate compound 5-2 as a white solid.

[0100] The intermediate compound 5-2 was subjected to 1 H-Nuclear magnetic resonance spectroscopy analysis ( 1 The results of H-NMR are as follows.

[0101] 1 H-NMR(CDCl3, ppm): 8.03-7.99(m, 2H), 7.83-7.81(m, 1H), 7.53-7.37(m,7H), 7.26-7.24(m, 1H), 1.89(br, 1H), 1.53(s, 3H), 1.43(s, 3H) (3) Synthesis of monomer 5 In a 250 mL double-necked round-bottom flask, intermediate compound 5-2 (5.5 g, 18.2 mmol) and dichloromethane (60 mL) were added, and the mixture was stirred to prepare a solution. The stirring temperature was lowered to 0 °C using a cooling water bath, and stirring was continued under a nitrogen atmosphere. Boron trifluoride ether (2.6 g, 18.2 mmol) was slowly added, and the mixture was stirred at room temperature for 8 hours. After stirring, the mixture was cooled back to 0 °C, and water (10 mL) was added to terminate the reaction. Subsequently, saturated sodium bicarbonate aqueous solution (20 mL) and dichloromethane (50 mL) were added. The aqueous layer was removed using a separatory funnel, and the organic solvent layer was further washed with water (50 mL) and then separated and removed. The organic solvent layer was dried with anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. The product was purified by silica gel column chromatography using dichloromethane / n-hexane (volume ratio 5:95) to obtain 4.5 g of the final monomer 5.

[0102] Perform on the monomer 5 1 H-Nuclear magnetic resonance spectroscopy analysis ( 1 The results of H-NMR are as follows.

[0103] 1 H-NMR(CDCl3, ppm): 8.82-8.80(d, 1H), 8.01-8.03(d, 1H), 7.96-7.94(d,1H), 7.71-7.73(d, 1H), 7.54-7.47(m, 4H), 7.46-7.39(m, 2H), 1.61(s, 6H) Example 1 (Copolymer 1A) (1) Preparation of the precursor of copolymer 1A In a 25 mL round-bottom flask, monomer 1 (0.20 g, 0.65 mmol), 9,9-bis(6-bromohexyl)-9H-fluorene (0.32 g, 0.65 mmol), and dichloromethane (3.5 mL) were added, and the mixture was stirred to prepare a solution. The stirring temperature was lowered to 0 °C using a cooling water bath, and stirring was carried out under a nitrogen atmosphere. 1,1,1-trifluoroacetone (0.18 mL, 1.96 mmol) and trifluoromethanesulfonic acid (1.6 mL, 17.70 mmol) were then added. The mixture was stirred at 0 °C for 2 hours, and the increased viscosity of the solution was added to methanol (100 mL) to precipitate the solid. The precipitated solid was filtered, washed twice with 50 mL of methanol, and then dried in an oven to obtain 0.67 g of the precursor of copolymer 1A.

[0104] The results of gel permeation chromatography (GPC) of the precursor of copolymer 1A are as follows. GPC analysis was performed using a Shodex KF-805L column and an Agilent 1260 HPLC system. Tetrahydrofuran (THF) was used as the mobile phase, the flow rate was set to 0.5 mL / min, and the analysis was performed at a column temperature of 40 °C.

[0105] Mn 1.99×10 4 g / mol, Mw 2.32×10 5 g / mol <Precursor of copolymer 1A> (2) Preparation of copolymer 1A In a 25 mL round-bottom flask, 0.67 g of the precursor of copolymer 1A and 6.5 mL of N-methyl-2-pyrrolidone were added and stirred to prepare a solution. After the precursor of copolymer 1A was completely dissolved, 1.1 mL of a 43% trimethylamine aqueous solution was slowly added. The mixture was stirred at room temperature for 24 hours, and then the solution was added to 100 mL of diethyl ether to precipitate the solid. The precipitated solid was filtered, washed twice with 50 mL of diethyl ether, and dried in an oven to obtain 0.76 g of copolymer 1A.

[0106] The copolymer 1A comprises repeating units represented by the following chemical formula 1A.

[0107] [Chemical Formula 1A] Example 2 (Copolymer 1B) (1) Preparation of precursor of copolymer 1B Monomer 1 (0.16 g, 0.52 mmol), 9,9-bis(6-bromohexyl)-9H-fluorene (0.39 g, 0.78 mmol), and dichloromethane (4.0 mL) were added to a 25 mL round-bottom flask, and the mixture was stirred to prepare a solution. The stirring temperature was lowered to 0 °C using a cooling water bath, and stirring was carried out under a nitrogen atmosphere. 1,1,1-trifluoroacetone (0.18 mL, 1.96 mmol) and trifluoromethanesulfonic acid (1.3 mL, 14.75 mmol) were added to the solution. The mixture was then stirred at 0 °C for 1 hour, and the increased viscosity of the solution was added to methanol (100 mL) to precipitate a solid. The precipitated solid was filtered, washed twice with 50 mL of methanol, and dried in an oven to obtain 0.65 g of the precursor of copolymer 1B.

[0108] The results of gel permeation chromatography (GPC) of the precursor of the copolymer 1B are as follows.

[0109] Mn 1.78×10 4 g / mol, Mw 1.94×10 5 g / mol <Precursor of copolymer 1B> (2) Preparation of copolymer 1B In a 25 mL round-bottom flask, 0.65 g of the copolymer 1B precursor and 6.5 mL of N-methyl-2-pyrrolidone were added and stirred to prepare a solution. After the copolymer 1B precursor was completely dissolved, 1.3 mL of a 43% trimethylamine aqueous solution was slowly added. The mixture was stirred at room temperature for 24 hours, and then the solution was added to 100 mL of diethyl ether to precipitate the solid. The precipitated solid was filtered, washed twice with 50 mL of diethyl ether, and then dried in an oven to obtain 0.70 g of copolymer 1B.

[0110] Copolymer 1B comprises repeating units represented by the following chemical formula 1B.

[0111] [Chemical Formula 1B] Example 3 (Copolymer 1C) (1) Preparation of precursor of copolymer 1C Monomer 2 (0.17 g, 0.49 mmol), 9,9-bis(6-bromohexyl)-9H-fluorene (0.36 g, 0.74 mmol), and dichloromethane (3.0 mL) were added to a 25 mL round-bottom flask, and the mixture was stirred to prepare a solution. The stirring temperature was lowered to 0 °C using a cooling water bath, and stirring was continued under a nitrogen atmosphere. 1,1,1-trifluoroacetone (0.16 mL, 1.84 mmol) and trifluoromethanesulfonic acid (1.5 mL, 16.63 mmol) were added to the solution. The mixture was then stirred at 0 °C for 2 hours, and the increased viscosity of the solution was added to methanol (100 mL) to precipitate a solid. The precipitated solid was filtered, washed twice with 50 mL of methanol, and dried in an oven to obtain 0.65 g of the precursor of copolymer 1C.

[0112] The results of gel permeation chromatography (GPC) of the precursor of the copolymer 1C are as follows.

[0113] Mn 1.93×10 4 g / mol, Mw 1.84×10 6 g / mol <Precursor of copolymer 1C> (2) Preparation of copolymer 1C In a 25 mL round-bottom flask, 0.65 g of the precursor of copolymer 1C and 16.4 mL of N-methyl-2-pyrrolidone were added and stirred to prepare a solution. After the precursor of copolymer 1C was completely dissolved, 1.2 mL of a 43% trimethylamine aqueous solution was slowly added. The solution was stirred at room temperature for 48 hours, and then added to 100 mL of diethyl ether to precipitate the solid. The precipitated solid was filtered, washed twice with 50 mL of diethyl ether, and dried in an oven to obtain 0.63 g of copolymer 1C.

[0114] The copolymer 1C contains repeating units represented by the following chemical formula 1C.

[0115] [Chemical Formula 1C] Example 4 (Copolymer 1D) (1) Preparation of precursors of copolymer 1D Monomer 3 (0.20 g, 0.47 mmol), 9,9-bis(6-bromohexyl)-9H-fluorene (0.54 g, 1.10 mmol), and dichloromethane (9.5 mL) were added to a 25 mL round-bottom flask, and the mixture was stirred to prepare a solution. The stirring temperature was lowered to 0 °C using a cooling water bath, and stirring was carried out under a nitrogen atmosphere. 1,1,1-trifluoroacetone (0.21 mL, 2.37 mmol) and trifluoromethanesulfonic acid (0.4 mL, 4.46 mmol) were added to the solution. The mixture was then stirred at 0 °C for 2 hours, and the increased viscosity of the solution was added to methanol (100 mL) to precipitate a solid. The precipitated solid was filtered, washed twice with 50 mL of methanol, and dried in an oven to obtain 0.89 g of the precursor of copolymer 1D.

[0116] The results of gel permeation chromatography (GPC) of the precursor of the copolymer 1D are as follows.

[0117] Mn 2.01×10 4 g / mol, Mw 9.20×10 4 g / mol <Precursor of copolymer 1D> (2) Preparation of copolymer 1D In a 25 mL round-bottom flask, 0.89 g of the copolymer 1D precursor and 8.0 mL of dimethylformamide were added and stirred to prepare a solution. After the copolymer 1D precursor was completely dissolved, 1.5 mL of a 43% trimethylamine aqueous solution was slowly added. The mixture was stirred at room temperature for 48 hours, and then the solution was added to 100 mL of diethyl ether to precipitate the solid. The precipitated solid was filtered, washed twice with 50 mL of diethyl ether, and then dried in an oven to obtain 1.04 g of copolymer 1D.

[0118] The copolymer 1D comprises repeating units represented by the following chemical formula 1D.

[0119] [Chemical Formula 1D] Example 5 (1) Preparation of precursor of copolymer 1E Monomer 3 (0.15 g, 0.35 mmol), 9,9-bis(6-bromohexyl)-9H-fluorene (0.41 g, 0.83 mmol), monomer 5 (0.03 g, 0.09 mmol), and dichloromethane (7.1 mL) were added to a 25 mL round-bottom flask, and the mixture was stirred to prepare a solution. The stirring temperature was lowered to 0 °C using a cooling water bath, and stirring was carried out under a nitrogen atmosphere. 1,1,1-trifluoroacetone (0.16 mL, 1.77 mmol) and trifluoromethanesulfonic acid (0.3 mL, 2.67 mmol) were added. The mixture was then stirred at 0 °C for 7 hours, and the increased viscosity of the solution was added to methanol (100 mL) to precipitate a solid. The precipitated solid was filtered, washed twice with 50 mL of methanol, and dried in an oven to obtain 0.70 g of the precursor of copolymer 1E.

[0120] The results of gel permeation chromatography (GPC) of the precursor of the copolymer 1E are as follows.

[0121] Mn 2.12×10 4 g / mol, Mw 2.68×10 5 g / mol The precursor of copolymer 1E comprises a crosslinking unit represented by the following chemical formula 1E and a repeating unit represented by the following chemical formula 1E-1, and x=0.28, y=0.65, z=0.07.

[0122] [Chemical Formula 1E] [Chemical Formula 1E-1] (2) Preparation of copolymer 1E In a 25 mL round-bottom flask, 0.70 g of the copolymer 1E precursor, 6.0 mL of dimethylformamide, and 6.0 mL of N-methyl-2-pyrrolidone were added and stirred to prepare a solution. After the copolymer 1E precursor was completely dissolved, 1.1 mL of a 43% trimethylamine aqueous solution was slowly added. The mixture was stirred at room temperature for 48 hours, and then the solution was added to 100 mL of diethyl ether to precipitate the solid. The precipitated solid was filtered, washed twice with 50 mL of diethyl ether, and then dried in an oven to obtain 0.78 g of copolymer 1E.

[0123] Copolymer 1E comprises a crosslinking unit represented by the following chemical formula 1E and a repeating unit represented by the following chemical formula 1E-2, where x = 0.28, y = 0.65, and z = 0.07. The crosslinking unit of chemical formula 1E and the repeating unit of chemical formula 1E-2 can be directly crosslinked or crosslinked via a methylene group derived from 1,1,1-trifluoroacetone.

[0124] [Chemical Formula 1E] [Chemical Formula 1E-2] Example 6 (Copolymer 1F) (1) Preparation of precursor of copolymer 1F Monomer 3 (0.15 g, 0.35 mmol), 9,9-bis(6-bromohexyl)-9H-fluorene (0.41 g, 0.83 mmol), 1,3,5-triphenylbenzene (0.02 g, 0.06 mmol), and dichloromethane (7.1 mL) were added to a 25 mL round-bottom flask, and the mixture was stirred to prepare a solution. The stirring temperature was lowered to 0 °C using a cooling water bath, and stirring was carried out under a nitrogen atmosphere. 1,1,1-trifluoroacetone (0.16 mL, 1.77 mmol) and trifluoromethanesulfonic acid (0.3 mL, 2.67 mmol) were added to the solution. The mixture was then stirred at 0 °C for 6 hours, and the increased viscosity of the solution was added to methanol (100 mL) to precipitate a solid. The precipitated solid was filtered, washed twice with 50 mL of methanol, and dried in an oven to obtain 0.64 g of the precursor of copolymer 1F.

[0125] The results of gel permeation chromatography (GPC) of the precursor of the copolymer 1F are as follows.

[0126] Mn 2.58×10 4 g / mol, Mw 1.10×10 6 g / mol The precursor of copolymer 1F comprises a crosslinking unit represented by the following chemical formula 1F and a repeating unit represented by the following chemical formula 1F-1, and x=0.29, y=0.67, z=0.05.

[0127] [Chemical Formula 1F] [Chemical formula 1F-1] (2) Preparation of copolymer 1F In a 25 mL round-bottom flask, 0.64 g of the copolymer 1F precursor, 3.0 mL of dimethylformamide, and 7.0 mL of N-methyl-2-pyrrolidone were added and stirred to prepare a solution. After the copolymer 1F precursor was completely dissolved, 1.1 mL of a 43% trimethylamine aqueous solution was slowly added. The mixture was stirred at room temperature for 48 hours, and then the solution was added to 100 mL of diethyl ether to precipitate the solid. The precipitated solid was filtered, washed twice with 50 mL of diethyl ether, and then dried in an oven to obtain 0.77 g of copolymer 1F.

[0128] Copolymer 1F comprises a crosslinking unit represented by the following chemical formula 1F and a repeating unit represented by the following chemical formula 1F-2, where x = 0.29, y = 0.67, and z = 0.05. The crosslinking unit of chemical formula 1F and the repeating unit of chemical formula 1F-2 can be directly crosslinked or crosslinked via a methylene group derived from 1,1,1-trifluoroacetone.

[0129] [Chemical Formula 1F] [Chemical formula 1F-2] Example 7 (Copolymer 1G) (1) Preparation of precursor of copolymer 1G Monomer 4 (0.25 g, 0.59 mmol), 9,9-bis(6-bromohexyl)-9H-fluorene (0.68 g, 1.38 mmol), and dichloromethane (9.9 mL) were added to a 25 mL round-bottom flask, and the mixture was stirred to prepare a solution. The stirring temperature was lowered to 0 °C using a cooling water bath, and stirring was carried out under a nitrogen atmosphere. 1,1,1-trifluoroacetone (0.26 mL, 2.96 mmol) and trifluoromethanesulfonic acid (0.5 mL, 5.57 mmol) were added to the solution. The mixture was then stirred at 0 °C for 7 hours, and the increased viscosity of the solution was added to methanol (100 mL) to precipitate a solid. The precipitated solid was filtered, washed twice with 50 mL of methanol, and dried in an oven to obtain 1.19 g of the precursor of copolymer 1G.

[0130] The results of gel permeation chromatography (GPC) of the precursor of the copolymer 1G are as follows.

[0131] Mn 1.86×10 4 g / mol, Mw 1.26×10 5 g / mol <Precursor of copolymer 1G> (2) Preparation of copolymer 1G In a 25 mL round-bottom flask, 1.14 g of the precursor of copolymer 1G and 9.9 mL of dimethylformamide were added and stirred to prepare a solution. After the precursor of copolymer 1G was completely dissolved, 1.8 mL of a 43% trimethylamine aqueous solution was slowly added. The mixture was stirred at room temperature for 48 hours, and then the solution was added to 120 mL of diethyl ether to precipitate the solid. The precipitated solid was filtered, washed twice with 70 mL of diethyl ether, and then dried in an oven to obtain 1.18 g of copolymer 1G.

[0132] The copolymer 1G comprises repeating units represented by the following chemical formula 1G.

[0133] [Chemical Formula 1G] Comparative Example 1 (Copolymer H) In a 100 mL round-bottom flask, 9,9-dimethylfluorene (0.24 g, 1.24 mmol), 9,9-bis(6-bromohexyl)-9H-fluorene (0.79 g, 1.60 mmol), and dichloromethane (17.0 mL) were added and stirred to prepare a solution. The stirring temperature was lowered to 0 °C using a cooling water bath, and stirring was carried out under a nitrogen atmosphere. 1,1,1-trifluoroacetone (0.38 mL, 4.26 mmol) and trifluoromethanesulfonic acid (0.71 mL, 8.02 mmol) were added. The mixture was then stirred at 0 °C for 2 hours. The increased viscosity of the solution was added to methanol (200 mL) to precipitate a solid. The precipitated solid was filtered, washed twice with 50 mL of methanol, and dried in an oven to obtain 1.20 g of the precursor of copolymer H.

[0134] In a 50 mL round-bottom flask, 1.20 g of the precursor of copolymer H and 13.3 mL of N-methyl-2-pyrrolidone were added, and the mixture was stirred to prepare a solution. After the precursor of copolymer H was completely dissolved, 2.49 mL of a 43% trimethylamine aqueous solution was slowly added. The mixture was stirred at room temperature for 48 hours, and then the solution was added to 200 mL of ethyl acetate to precipitate a solid. The precipitated solid was filtered, washed twice with 50 mL of ethyl acetate, and dried in an oven to obtain 1.18 g of copolymer H.

[0135] The copolymer H contains repeating units represented by the following chemical formula H.

[0136] [Chemical formula H] Comparative Example 2 Sustainion® X37-50 Grade RT from Dioxide Materials was used as the anion exchange membrane.

[0137] Comparative Example 3 Sustainion® X37-50 Grade T from Dioxide Materials was used as the anion exchange membrane.

[0138] Experimental Example <Preparation of Ion Exchange Membranes> (1) Using the copolymers synthesized in the above examples and comparative examples, anion exchange membranes were prepared as follows.

[0139] The prepared copolymer was dissolved in N-methylpyrrolidone, and impurities were filtered out using a 5 μm syringe filter. The mixture was then cast onto a glass substrate using a blade. The solvent was removed and the substrate was dried in an oven at 80 °C. Distilled water was added to separate the membrane from the glass substrate, thus obtaining the anion exchange membrane.

[0140] (2) The obtained anion exchange membrane can be immersed in a 1M potassium hydroxide aqueous solution to convert anions into OH-. - Then use. The membrane prepared in (1) is immersed in a 1M KOH aqueous solution (room temperature, 24 hours) to convert the anions to OH. - .

[0141] Experimental Example 1: Ionic Conductivity at Room Temperature The ionic conductivity (σ) of anion exchange membranes is measured under conditions of room temperature (25℃) and triple-distilled water, with respect to OH-. - The morphology of the membrane was evaluated.

[0142] The anion exchange membrane was cut into 1cm × 3cm pieces to prepare the sample, which was then fixed between the Pt electrodes of the conductivity clamp (BT-110, Scribner).

[0143] The resistivity (R) of the membrane samples was measured using an impedance analysis apparatus (VSP-3e, Biologics) with a four-point probe method in the frequency range of 0.1 kHz to 1 MHz at room temperature. The thickness (T) of the membrane samples was measured using a micrometer. The membrane thickness (T) was measured under wet conditions using an outer micrometer with a minimum measuring unit of 1 μm.

[0144] The ionic conductivity (σ)(C1) is calculated using Equation 2 below.

[0145] [Formula 2] In the said Formula 2, R is the membrane resistance (Ω), A is the cross-sectional area of the membrane (cm 2 ), L is the distance between the electrodes (cm), W is the width of the membrane sample (cm), and T is the thickness of the membrane (cm).

[0146] For reference, the ion exchange capacity (IEC, mmol / g, based on OH - ) of the anion exchange membrane is determined by converting the membrane into the OH - type, cutting it into a predetermined size, reacting it with a standard acid solution of known concentration (e.g., 0.01 M HCl), and then back-titrating the remaining acid with a standard base solution (e.g., 0.01 M NaOH). The IEC (mmol / g) is calculated by dividing the number of moles of acid consumed by the membrane by the dry mass of the membrane. The method for manufacturing the membrane converted into the OH - type is as follows: First, cut the X-type (mainly halide type) membrane into a predetermined size and measure its mass, and then immerse it in 1 M KOH aqueous solution for more than 24 hours for anion exchange (X - OH - ). Here, the dry mass refers to the mass of the membrane measured before immersion in the 1 M KOH solution.

[0147] The results are shown in Table 1 below.

[0148] [Table 1] The room temperature ionic conductivities of the anion exchange membranes according to the examples and comparative examples are all 30 mS / cm or more, achieving sufficient ionic conductivity. In the repeating unit represented by the said Chemical Formula 1, when x < y is satisfied and there are 3 phenylene groups, the room temperature ionic conductivities of Examples 2, Examples 4 to 7 are further improved.

[0149] Experimental Example 2: High-temperature stability For Examples 4, Example 6 and Comparative Example 1 above, the high-temperature stability was evaluated as follows.

[0150] As in Experimental Example 1 above, prepare a membrane sample of the anion exchange membrane, immerse it in 1 M KOH solution, and store it in an oven at 80°C.

[0151] Take out the membrane sample after storing the said membrane sample in the oven at 80°C for 7 days and / or 28 days, cool it to room temperature, and wash it with triple-distilled water.

[0152] Then, the ionic conductivity (C2) was calculated using the same conditions and methods as in Experimental Example 1.

[0153] Substitute the ionic conductivity (C1) calculated in Experimental Example 1 and the ionic conductivity (C2) calculated in Experimental Example 2 into Equation 1 below to calculate the rate of decrease (R) of ionic conductivity.

[0154] [Formula 1] The rate of decrease in ionic conductivity (%) = {(C1-C2) / C1} × 100 In Formula 1, C1 refers to the preparation of an anion exchange membrane comprising the copolymer used for anion exchange membranes, which converts counterions into OH-. - Then, at room temperature, OH - The ionic conductivity of anion exchange membranes is evaluated based on their morphology; C2 refers to the conductivity of the membrane with OH groups. - The anion exchange membrane was immersed in a 1M alkaline solution and placed at 80°C for 28 days. After cooling to room temperature, the ionic conductivity was evaluated at room temperature.

[0155] The results are shown in Table 2 below.

[0156] [Table 2] The anion exchange membrane prepared in Example 4 showed a decrease in ionic conductivity of -1.7% after being placed at high temperature for 28 days, which is equivalent to or more stable. Therefore, it can be confirmed that the operation stability and reliability can be ensured.

[0157] The anion exchange membrane prepared in Example 6 showed a reduction rate of only 2.4% in ionic conductivity after being placed at high temperature for 28 days, achieving improved chemical and physical stability. Therefore, it can be confirmed that operational stability and reliability can be ensured.

[0158] The anion exchange membrane prepared in Comparative Example 1 was originally evaluated after 28 days of storage. However, before reaching 28 days, i.e. after 7 and 14 days of storage at high temperature, the reduction rate of ionic conductivity had already exceeded 15%. This indicates that the anion exchange membrane of Comparative Example 1 has low chemical and physical stability, and its operational stability and reliability cannot be guaranteed.

Claims

1. A copolymer for use in anion exchange membranes, wherein, The copolymer for the anion exchange membrane comprises repeating units represented by the following chemical formula 1: [Chemical Formula 1] In the aforementioned chemical formula 1, M1 is selected from any of the arylene groups represented by chemical formulas 2-1 and 2-2 below, M2 is an arylene group represented by chemical formula 3 below, x and y are each independently between 0.1 and 0.9, and x + y = 1. L1 and L2 are each independently selected from the arylene groups represented by the following chemical formulas 4-1 and 4-2. [Chemical Formula 2-1] [Chemical Formula 2-2] [Chemical Formula 3] [Chemical Formula 4-1] [Chemical Formula 4-2] In chemical formulas 2-1, 2-2, 3, 4-1, and 4-2, a is an integer from 2 to 6, and b is an integer from 0 to 4. R1 and R2 are each independently C1 to C 10 alkyl groups, R3 and R4 are each independently C3 to C4 terminals with quaternary ammonium salts at the end. 10 alkyl groups, R5 and R6 are each independently selected from -H and C1 to C3 alkyl groups. - and- ' indicates the binding site of the cross-linking.

2. The copolymer for anion exchange membranes according to claim 1, wherein, In chemical formula 2-1, 'a' is an integer from 2 to 5, and in chemical formula 2-2, 'b' is an integer from 0 to 3.

3. The copolymer for anion exchange membranes according to claim 1, wherein, The divalent phenylene groups in chemical formula 2-1 and chemical formula 2-2 are each independently linked at the meta or para position.

4. The copolymer for anion exchange membranes according to claim 1, wherein, The counter ions of the quaternary ammonium salt are halide anions and OH-. - or HCO3 - .

5. The copolymer for anion exchange membranes according to claim 1, wherein, M1 is selected from any of the following aryl groups represented by chemical formulas 2-1A to 2-1E: [Chemical Formula 2-1A] [Chemical Formula 2-1B] [Chemical Formula 2-1C] [Chemical Formula 2-1D] [Chemical Formula 2-1E] In chemical formulas 2-1A to 2-1E, R1 and R2 are each independently C1 to C2. 10 alkyl, - and- ' indicates the binding site of the cross-linking.

6. The copolymer for anion exchange membranes according to claim 5, wherein, In the chemical formulas 2-1C to 2-1E, the fluorene-derived arylene groups are meta-linked to adjacent phenylene groups.

7. The copolymer for anion exchange membranes according to claim 1, wherein, R1 and R2 are each independently C1 to C5 alkyl groups.

8. The copolymer for anion exchange membranes according to claim 1, wherein, R3 and R4 are each independently C4 to C7 alkyl groups with a terminal quaternary ammonium halide.

9. The copolymer for anion exchange membranes according to claim 1, wherein, The quaternary ammonium salt is selected from the groups represented by the following chemical formulas 5-1 to 5-3: [Chemical Formula 5-1] [Chemical Formula 5-2] [Chemical Formula 5-3] In chemical formulas 5-1 to 5-3, R7 to R 11 Each is an alkyl group from C1 to C5, and X is OH, F, Cl, Br or I, each independently. This indicates the binding position at the end of R3 or R4.

10. The copolymer for anion exchange membranes according to claim 1, wherein, The copolymer for the anion exchange membrane further comprises crosslinking units represented by any one of the following chemical formulas 6-1 and 6-2: [Chemical Formula 6-1] [Chemical Formula 6-2] In chemical formulas 6-1 and 6-2, - - '、- "Indicates the binding site where the repeating unit is crosslinked, R" 12 and R 13 Each is an alkyl group from C1 to C5, and Y is O or S.

11. The copolymer for anion exchange membranes according to claim 10, wherein, The repeating unit is directly crosslinked with the crosslinking unit, or is crosslinked via an arylene group represented by any one of the following chemical formulas 7-1 and 7-2: [Chemical Formula 7-1] [Chemical Formula 7-2] In chemical formulas 7-1 and 7-2, R 14 and R 15 Each is independently selected from -H and C1 to C3 alkyl groups, - and- ' indicates the binding site of the cross-linking.

12. The copolymer for anion exchange membranes according to claim 1, wherein, The content of the repeating unit represented by the chemical formula 1 is 90.0 mol% to 100 mol% relative to all repeating units contained in the copolymer for the anion exchange membrane.

13. The copolymer for anion exchange membranes according to claim 10, wherein, The content of repeating units represented by Formula 1 is from 80.0 mol% to 99.0 mol% relative to all repeating units contained in the copolymer for anion exchange membranes, and the content of crosslinking units represented by either Formula 6-1 or Formula 6-2 is from 1.0 mol% to 20.0 mol%.

14. The copolymer for anion exchange membranes according to claim 1, wherein, The reduction rate R of ionic conductivity calculated by Equation 1 below is less than 15%. [Formula 1] The rate of decrease in ionic conductivity (R, %) = {(C1-C2) / C1} × 100 In Formula 1, C1 refers to the preparation of an anion exchange membrane comprising the copolymer used for anion exchange membranes, which converts counterions into OH-. - Then, at room temperature, OH - The ionic conductivity of anion exchange membranes is evaluated based on their morphology; C2 refers to the conductivity of the membrane with OH groups. - The anion exchange membrane was immersed in a 1M alkaline solution and placed at 80°C for 28 days. After cooling to room temperature, the ionic conductivity was evaluated at room temperature.

15. An anion exchange membrane, wherein, The anion exchange membrane comprises the copolymer for anion exchange membrane as described in claim 1.

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