Polymer, anion exchange membrane and preparation method and application thereof

Abstract

The application discloses a polymer, an anion exchange membrane and a preparation method and application thereof. The skeleton of the polymer does not contain an ether bond and has a cationic piperidinium salt, so that the polymer has good alkali resistance. The skeleton of the polymer further contains a hydrophilic side chain, so that the polymer has good solubility and film-forming performance. The skeleton of the polymer further contains a hydrophobic alkene side chain, so that the polymer has a self-crosslinking characteristic, and the film-forming quality of the polymer can be further improved. The material of the anion exchange membrane contains the polymer and / or a crosslinked compound formed by self-crosslinking reaction of the unsaturated double bond of the polymer, and has good mechanical performance, electrical conductivity, alkali stability and low swelling rate, and can be applied to preparation of an alkaline fuel cell, an alkaline water electrolysis device, a separation device, a purification device and a supercapacitor.

Description

Technical Field

[0001] This application relates to the field of compound synthesis technology, specifically to a polymer, anion exchange membrane, its preparation method and application. Background Technology

[0002] Anion exchange membranes, also known as ion-selective permeable membranes, are a type of polymer membrane containing basic active groups that selectively allow anions to pass through. Anion exchange membranes consist of a polymer backbone, positively charged basic active groups, and anions. The basic active groups are located on the polymer backbone, and the anions can move freely on these groups. Anion exchange membranes are widely used in chlor-alkali industries, water treatment industries, heavy metal recovery, hydrometallurgy, and electrochemical industries.

[0003] Currently, anion exchange membranes are mainly based on polymeric frameworks such as polysulfone, polyphenylene ether, and polyetheretherketone. However, polymeric frameworks containing ether bonds are prone to degradation under alkaline conditions, resulting in poor alkaline stability. Polyarylpiperidine is a novel ether-free framework with advantages such as high structural rigidity and ideal dimensional stability. However, existing anion exchange membranes based on polyarylpiperidine polymeric frameworks suffer from poor conductivity. Therefore, developing a novel polymer for preparing anion exchange membranes with both high conductivity and high alkaline stability is of great significance for the application and development of anion exchange membranes. Summary of the Invention

[0004] This application provides a polymer, anion exchange membrane, preparation method and application thereof, to improve the conductivity of anion exchange membrane based on polyarylpiperidine polymer backbone.

[0005] The technical solution of this application is as follows:

[0006] In a first aspect, this application provides a polymer having repeating units of the structure shown in general formula (I):

[0007]

[0008] In general formula (Ⅰ), Ar1, Ar2, and Ar3 are independently selected from divalent aryl groups, X1 - X2 - X3 - and X4 - Selected independently from Br - I - Cl - OH - or HCO3 - a, b, and c represent the molar percentage of the corresponding chain segment in the repeating unit, and the sum of a, b, and c is 100%; n is a positive integer from 1 to 5.

[0009] Optionally, Ar1, Ar2, and Ar3 are independently selected from divalent aryl groups having 12 to 24 carbon atoms;

[0010] 0% < a ≤ 100%, 0% < b ≤ 30%, 0% < c ≤ 100%;

[0011] The number-average molecular weight of the polymer is 10,000 to 20,000.

[0012] Optionally, Ar1, Ar2, and Ar3 are independently selected from:

[0013]

[0014] In this context, * represents a connector.

[0015] Optionally, the repeating unit is selected from:

[0016]

[0017] Secondly, this application also provides a method for preparing a polymer, comprising the following steps:

[0018] Using trifluoroacetic acid and trifluoromethanesulfonic acid as catalysts, aromatic compounds and N-methyl-4-piperidinone undergo a polymerization reaction to obtain polyarylpiperidine compounds;

[0019] Quaternizing the piperidine in the polyarylpiperidine compound yields a second compound; and

[0020] A mixture containing the second compound, the first base, and the ionic liquid is reacted at 60°C to 80°C to obtain an intermediate product. Then, iodomethane and the third compound are added to the intermediate product at room temperature to react and generate a polymer.

[0021] The aromatic compound has the structure shown in general formula (II) below:

[0022]

[0023] In general formula (II), A is selected from Ar4 or -R-Ar4, Ar4 is selected from aryl, and R is selected from -(CH2). s -, the value of s is 1 to 10;

[0024] The polyarylpiperidine compound has the structure shown in general formula (III) below:

[0025]

[0026] In general formula ((Ⅲ), Ar5 is the divalent aryl group obtained by losing a hydrogen atom from Ar4, m is the degree of polymerization of the polyarylpiperidine compound, and m is greater than zero;

[0027] The ionic liquid has the structure shown in the following general formula (Ⅳ):

[0028]

[0029] In general formula (Ⅳ), X5 is selected from -Cl, -Br or -I;

[0030] The third compound has the structure shown in the following general formula (V):

[0031]

[0032] In general formula (V), X6 is selected from -Cl, -Br or -I, and t is a positive integer from 1 to 5.

[0033] Optionally, the Ar4 is selected from aryl groups with a ring number of 6 to 18, and the aromatic compound has a carbon number of 12 to 24. Preferably, the aromatic compound is selected from one or more of biphenyl, o-terphenyl, p-terphenyl, diphenylmethane, diphenylethane, and p-tetraphenyl.

[0034] In the step of polymerization of the aromatic compound and N-methyl-4-piperidinone, the reaction temperature is -10℃ to 10℃, the reaction time is 7h to 24h, and the molar ratio of the aromatic compound to N-methyl-4-piperidinone is 1:(1 to 1.3).

[0035] The step of quaternizing piperidine in the polyarylpiperidine compound includes: reacting the polyarylpiperidine compound with iodomethane in a Mensougin reaction;

[0036] In the step of reacting the mixture containing the second compound, the first base, and the ionic liquid at 60°C to 80°C to obtain an intermediate product, the molar ratio of the second compound to the first base to the ionic liquid is 1:(0.5 to 0.8):(0.2 to 0.4), the first base is selected from alkali metal carbonates; and / or, the mixture is in liquid state, and the mass of the second compound accounts for 4% to 6% of the total mass of the mixture.

[0037] In the step of adding iodomethane and a third compound to the intermediate product to react and generate a polymer, the molar ratio of the intermediate product to the iodomethane to the third compound is 1:(1.5-2):(0.95-1).

[0038] Thirdly, this application also provides an anion exchange membrane, the material of which includes any of the polymers described in the first aspect, and / or cross-linked compounds formed by the self-cross-linking reaction of any of the polymers described in the first aspect through their own unsaturated double bonds.

[0039] Fourthly, this application also provides a method for preparing anion exchange membranes, comprising the following steps:

[0040] A deposition material solution, said material solution comprising a polymer as described in any of the first aspects or a polymer prepared by any of the preparation methods described in any of the second aspects; and

[0041] The deposited material solution is dried to obtain an anion exchange membrane.

[0042] Optionally, the thickness of the anion exchange membrane is 10 μm to 60 μm;

[0043] The drying process is a heat treatment and / or irradiation treatment. During the drying process, a portion of the polymer undergoes a self-crosslinking reaction through its own unsaturated double bonds to form a crosslinked compound.

[0044] Fifthly, this application also provides the application of anion exchange membranes prepared according to the third aspect or any of the preparation methods described in the fourth aspect in alkaline fuel cells, alkaline water electrolysis devices, separation devices, purification devices, and supercapacitors.

[0045] This application provides a polymer, anion exchange membrane, its preparation method, and its application, which have the following technical advantages:

[0046] In the polymer of this application, the polymer backbone is free of ether bonds and contains cationic piperidinium salts, giving the polymer good alkali resistance. The polymer backbone includes hydrophilic side chains to give the polymer good solubility and film-forming properties, and it can dissolve in polar solvents such as dimethylacetamide and dimethyl sulfoxide at room temperature. The polymer backbone also includes hydrophobic alkyl side chains to endow the polymer with self-crosslinking properties, which can further improve the film-forming quality of the polymer. Furthermore, the presence of hydrophobic alkyl side chains can promote the construction of microphase separation structures within the membrane, forming high-speed ion transport channels within the membrane and effectively improving the ionic conductivity of the membrane. The polymer of this application has the advantages of simple synthesis method, low cost, and suitability for industrial production.

[0047] In the anion exchange membrane of this application, firstly, the polymer backbone is free of ether bonds and heteroatoms and contains cationic piperidinium salts, giving the anion exchange membrane good chemical stability, especially excellent alkali stability; secondly, the polymer backbone contains long side chains, which can promote the cationic functional groups to move away from the polymer backbone, further improving the alkali resistance of the anion exchange membrane and helping to extend the service life of the ion exchange membrane; thirdly, since the polymer backbone contains hydrophobic alkyl side chains, it can promote the construction of microphase separation structure within the membrane, thereby forming a high-speed ion transport channel within the membrane, effectively improving the ionic conductivity of the anion exchange membrane. The tensile strength of the anion exchange membrane of this application can reach 20MPa to 30MPa, the swelling rate is less than 10% at 80℃, the conductivity can reach 142.6mS / cm, and the conductivity retention rate can reach 90% after soaking in 2mol / L NaOH solution for 1000h. Attached Figure Description

[0048] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0049] Figure 1 The polyarylpiperidine compound in Example 1 of this application 1 HNMR spectrum;

[0050] Figure 2 For the first polymer in Example 1 of this application 1 HNMR spectrum;

[0051] Figure 3 The ionic liquid in Example 1 of this application 1 HNMR spectrum;

[0052] Figure 4 This is a scanning electron microscope image of the surface of the anion exchange membrane in Example 2 of this application;

[0053] Figure 5 This is a cross-sectional scanning electron microscope image of the anion exchange membrane in Example 2 of this application;

[0054] Figure 6 This is a polarization curve of the alkaline fuel cell in Application Example 1 of this application;

[0055] Figure 7 This is a schematic diagram of the proton exchange membrane electrolyzer in Application Embodiment 2 of this application;

[0056] Figure 8 This is a polarization curve of the proton exchange membrane electrolyzer in Application Example 2 of this application. Detailed Implementation

[0057] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0058] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art, and the materials or reagents used in the embodiments and comparative examples of this application are commercially available. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0059] It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of embodiments. Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is indicated herein, it means including any referenced number (fraction or integer) within the indicated range.

[0060] In the description of this application, the term "comprising" means "including but not limited to".

[0061] The term "at least one" means one or more, and "multiple" means two or more. The terms "at least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can be expressed as: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0062] The term "and / or" encompasses any one of two or more of the listed items, as well as any and all combinations of the listed items. These combinations include any two listed items, any number of listed items, or a combination of all listed items. For example, "A and / or B" includes three parallel solutions: A, B, and A+B. Similarly, the technical solution "A, and / or, B, and / or, C, and / or, D" includes any one of A, B, C, and D (i.e., all connected by "logical OR"), any and all combinations of A, B, C, and D, including combinations of any two or three of A, B, C, and D, and combinations of all four of A, B, C, and D (i.e., all connected by "logical AND").

[0063] This application provides a polymer having repeating units with the structure shown in general formula (Ⅰ):

[0064]

[0065] In general formula (I), Ar1, Ar2, and Ar3 are independently selected from divalent aryl groups. A "divalent aryl" refers to a group derived from an aromatic hydrocarbon by removing two -H atoms from a carbon atom in the aromatic ring structure. In some embodiments of this application, Ar1, Ar2, and Ar3 are independently selected from divalent aryl groups having 12 to 24 carbon atoms. For example, the number of carbon atoms in a divalent aryl group can be 12, 13, 14, 18, or 24. Examples of Ar1, Ar2, and Ar3 independently selected from:

[0066]

[0067] In this context, * represents a connector.

[0068] In general formula (Ⅰ), X1 - X2 - X3 - and X4 - Selected independently from Br - I - Cl - OH - or HCO3 - a, b, and c represent the molar percentages of the corresponding chain segments in the repeating units, and the sum of a, b, and c is 100%; where 0% < a ≤ 100%, and / or 0% < b ≤ 30%, and / or 0% < c ≤ 100%. n is a positive integer from 1 to 5, with examples of n being 1, 2, 3, 4, or 5.

[0069] In some embodiments of this application, the number-average molecular weight of the polymer is 10,000 to 20,000.

[0070] In the polymers of this application embodiment, the polymer backbone does not contain ether bonds and has cationic piperidinium salts to give the polymer good alkali resistance; the polymer backbone contains hydrophilic side chains to give the polymer good solubility and film-forming properties, and can be dissolved in polar solvents such as dimethylacetamide and dimethyl sulfoxide at room temperature; the polymer backbone also contains hydrophobic alkenyl side chains to give the polymer self-crosslinking properties, which can further improve the film-forming quality of the polymer, and the presence of hydrophobic alkenyl side chains can promote the construction of microphase separation structure in the membrane, form high-speed ion transport channels in the membrane, and effectively improve the ionic conductivity of the membrane.

[0071] This application also provides a method for preparing a polymer, which can be used to prepare any of the polymers described above. The method for preparing the polymer includes the following steps:

[0072] S1. Using trifluoroacetic acid and trifluoromethanesulfonic acid as catalysts, aromatic compounds and N-methyl-4-piperidinone undergo a polymerization reaction to obtain polyarylpiperidine compounds.

[0073] S2. Quaternize the piperidine in the polyarylpiperidine compound obtained in step S1 to obtain the second compound;

[0074] S3. The mixture containing the second compound, the first base and the ionic liquid is reacted at 60°C to 80°C to obtain an intermediate product. Then, iodomethane and the third compound are added to the intermediate product at room temperature to react and generate a polymer.

[0075] In step S1, the aromatic compound has the structure shown in the following general formula (II):

[0076]

[0077] In general formula (II), A is selected from Ar4 or -R-Ar4, and Ar4 is selected from aryl groups. "Arlyl" refers to a group derived from an aromatic hydrocarbon by removing a -H atom from a carbon atom in an aromatic ring structure. Ar4 is, for example, selected from aryl groups with 6 to 18 ring atoms. Suitable Ar4 for embodiments of this application includes, but is not limited to, phenyl, biphenyl, terphenyl, naphthyl, anthraceneyl, phenanthryl, or pyrene. R is selected from -(CH2). s -, the value of s is 1 to 10, for example 1 to 3, 1 to 5, 2 to 6, 1 to 8, 3 to 5, or 2 to 8.

[0078] In some embodiments of this application, the aromatic compound has 12 to 24 carbon atoms, such as 12 to 18, 14 to 18, 12 to 20, or 18 to 24. Aromatic compounds suitable for embodiments of this application include, but are not limited to, one or more of biphenyl, o-terphenyl, p-terphenyl, diphenylmethane, diphenylethane, and p-tetraphenyl.

[0079] Polyarylpiperidine compounds have the structure shown in general formula (Ⅲ) below:

[0080]

[0081] In general formula (Ⅲ), Ar5 is the divalent aryl group obtained by losing a hydrogen atom from Ar4, and m is the degree of polymerization of the polyarylpiperidine compound, where m is greater than zero. Ar5 can be referred to in the previous descriptions of Ar1 to Ar3.

[0082] In order to balance improving the yield of polyarylpiperidine compounds and reducing production costs, in some embodiments of this application, the molar ratio of aromatic compound to N-methyl-4-piperidinone in step S1 is 1:(1 to 1.3), for example, it can be 1:(1 to 1.1), 1:(1 to 1.2), or 1:(1 to 1.3), with examples being 1:1.1, 1:1.2, or 1:1.3.

[0083] To further improve the yield of polyarylpiperidine compounds, in some embodiments of this application, the reaction temperature of the aromatic compound with N-methyl-4-piperidinone is -10°C to 10°C, and / or the reaction time is 7h to 24h.

[0084] In some embodiments of this application, step S1 includes the following steps: mixing an aromatic compound, N-methyl-4-piperidinone and a first solvent, and stirring under ice bath conditions to obtain a mixture; lowering the temperature of the mixture to -10°C to 10°C, adding trifluoroacetic acid and trifluoromethanesulfonic acid to it, and stirring at -10°C to 10°C for 7h to 24h.

[0085] The molar ratio of aromatic compound to N-methyl-4-piperidinone is 1:(1-1.3). The addition of trifluoroacetic acid and trifluoromethanesulfonic acid can be made by dropping or uniform flow, etc. The volume ratio of the first solvent to trifluoroacetic acid to trifluoromethanesulfonic acid is, for example, (8-10):1:(12-18), in order to balance the amount of catalyst used and the catalytic effect of the reaction.

[0086] It should be noted that, in addition to trifluoroacetic acid and trifluoromethanesulfonic acid as catalysts, other catalysts can also be used, such as one or more of methanesulfonic acid, pentafluoropropionic acid, and heptafluorobutyric acid. The first solvent is selected from one or more of aromatic hydrocarbons and haloalkanes, wherein the aromatic hydrocarbons include, but are not limited to, one or more of diethylbenzene, trimethylbenzene, propylbenzene, cumene, p-toluene, cumene, and 1-methylnaphthalene or indene, and the haloalkanes include, but are not limited to, one or more of chloromethane, dichloromethane, trichloromethane, chloroform, and tetrachloroethane.

[0087] To improve the purity of polyarylpiperidine compounds, the reaction product of the aromatic compound and N-methyl-4-piperidinone needs to be separated and purified. This purification is mainly achieved through solid-liquid separation, which includes, but is not limited to, precipitation, centrifugation, filtration, and drying. In some embodiments of this application, step S1 further includes the following steps: mixing the reaction product of the aromatic compound and N-methyl-4-piperidinone with deionized water to precipitate the product, neutralizing excess acid with a second base, washing repeatedly with water until neutral, and then sequentially performing filtration, chopping, and vacuum drying to obtain the polyarylpiperidine compound.

[0088] The second base includes one or more of organic and inorganic bases. The inorganic base includes, but is not limited to, one or more of alkali metal oxides, alkali metal hydroxides, alkali metal bicarbonates, alkali metal carbonates, alkaline earth metal oxides, alkaline earth metal hydroxides, alkaline earth metal bicarbonates, barium hydroxide, and ammonia water. The inorganic base is selected from, for example, one or more of lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium oxide, potassium oxide, calcium oxide, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, and calcium bicarbonate. The organic base includes, but is not limited to, one or more of amine compounds, alkanolamine compounds, and alkyl ammonium hydroxides. The alkyl group in the alkyl ammonium hydroxide contains 1 to 20 carbon atoms. The alkyl ammonium hydroxide is selected from, for example, one or more of tetramethyl ammonium hydroxide, tetraethyl ammonium hydroxide, tetrapropyl ammonium hydroxide, and tetrabutyl ammonium hydroxide. The alkanolamine compounds are selected from, for example, one or more of ethanolamine, diethanolamine, and triethanolamine. The amine compounds are selected from, for example, ethylenediamine.

[0089] In some embodiments of this application, step S2 includes the step of reacting the polyarylpiperidine compound and iodomethane with a Mensøe-Kreutz reaction. As an example, step S2 includes the step of reacting a mixture containing the polyarylpiperidine compound, a third base, and iodomethane at room temperature for 24 hours under light-protected conditions to obtain a second compound. The third base is used to provide an alkaline environment, and is described above with reference to the second base; for example, the third base is potassium carbonate. The solvent for the mixture is selected from one or more of dimethyl sulfoxide, tetrahydrofuran, acetonitrile, N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide. To balance increasing the yield of the second compound with reducing production costs, the molar ratio of the polyarylpiperidine compound: third base: iodomethane is 1:(0.5–1):(1–1.2).

[0090] To improve the purity of the second compound, after quaternizing the piperidine in the polyarylpiperidine compound, the quaternized reaction product needs to be separated and purified. This purification is mainly achieved through solid-liquid separation, which includes, but is not limited to, precipitation, centrifugation, filtration, and drying. As an example, the steps for separating and purifying the quaternized reaction product include: mixing the quaternized reaction product with a precipitating agent to precipitate, followed by washing, filtration, and drying to obtain the purified second compound. The precipitating agent, for example, is selected from R... a COOR b and one or more alkanes having 5 to 10 carbon atoms, R a and R b The alkyl groups are independently selected from alkyl groups having 1 to 6 carbon atoms, preferably R. a and R b Each is independently selected from methyl, ethyl, or propyl.

[0091] Specifically, in step S3, the first base refers to the description of the second base above; an example of the first base is potassium carbonate. The ionic liquid has the structure shown in the following general formula (Ⅳ):

[0092]

[0093] In general formula (Ⅳ), X5 is selected from -Cl, -Br or -I.

[0094] It should be noted that ionic liquids can be prepared using conventional methods in the art. As an example, when X5 is -Br, the preparation method of the ionic liquid includes the following steps: dissolving 48.8 g of 1,6-dibromohexane in 140 mL of ethyl acetate to obtain a 1,6-dibromohexane-ethyl acetate solution, and dissolving 9.92 g of N-methylpiperidine in 50 mL of ethyl acetate to obtain an N-methylpiperidine-ethyl acetate solution; then, slowly adding the N-methylpiperidine-ethyl acetate solution to the 1,6-dibromohexane-ethyl acetate solution, stirring the reaction at room temperature for 24 h, and allowing it to stand until a white precipitate forms. The supernatant is discarded and the white precipitate is collected. The white precipitate is washed several times with ethyl acetate and then dried under vacuum at room temperature for 48 h to obtain the ionic liquid.

[0095] In step S3, the third compound has the structure shown in the following general formula (V):

[0096]

[0097] In general formula (V), X6 is selected from -Cl, -Br or -I, and t is a positive integer from 1 to 5.

[0098] In some embodiments of this application, in step S3, the step of reacting the mixture containing the second compound, the first base, and the ionic liquid at 60°C to 80°C to obtain an intermediate product, the molar ratio of the second compound: the first base: the ionic liquid is 1:(0.5 to 0.8):(0.2 to 0.4); and / or, the mixture is in a liquid state, the mass of the second compound accounts for 4% to 6% of the total mass of the mixture, and the solvent of the mixture is selected, for example, from one or more of dimethyl sulfoxide, tetrahydrofuran, acetonitrile, N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0099] In order to balance improving polymer yield and reducing production costs, in some embodiments of this application, in the step of adding iodomethane and a third compound to the intermediate product to react and generate polymer, the molar ratio of the intermediate product: iodomethane: the third compound is 1:(1.5~2):(0.95~1).

[0100] To improve the purity of the polymer, after the reaction of the intermediate product, the iodomethane, and the third compound is complete, the reaction products need to be separated and purified. Purification is mainly achieved through solid-liquid separation, which includes, but is not limited to, precipitation, centrifugation, filtration, and drying. As an example, the steps for separating and purifying the reaction products of the intermediate product, the iodomethane, and the third compound include: mixing the reaction products of the intermediate product, the iodomethane, and the third compound with a precipitating agent to precipitate, followed by washing, filtration, and drying to obtain the purified polymer. The precipitating agent is as described above.

[0101] This application also provides an anion exchange membrane, the material of which includes any of the polymers described above, and / or cross-linked compounds formed by the self-cross-linking reaction of the polymers described above through their unsaturated double bonds.

[0102] In the anion exchange membrane of this application embodiment, firstly, the polymer backbone does not contain ether bonds and heteroatoms, and has a cationic piperidinium salt, giving the anion exchange membrane good chemical stability, especially excellent alkali stability; secondly, the polymer backbone contains long side chains, which can promote the cationic functional groups to move away from the polymer backbone, further improving the alkali resistance of the anion exchange membrane and helping to extend the service life of the ion exchange membrane; thirdly, since the polymer backbone contains hydrophobic alkyl side chains, it can promote the construction of the microphase separation structure inside the membrane, thereby forming a high-speed ion transport channel inside the membrane and effectively improving the ionic conductivity of the anion exchange membrane; fourthly, compared to the anion exchange membrane material being any of the polymers described above, when the anion exchange membrane material is... When the material of the ion exchange membrane is a cross-linked compound formed by the self-cross-linking reaction of any of the polymers mentioned above through their own unsaturated double bonds, it can further improve the mechanical properties and dimensional stability of the anion exchange membrane, and is more conducive to balancing swelling, thereby reducing the swelling rate; Fifth, compared with the material of the anion exchange membrane being a cross-linked compound formed by the self-cross-linking reaction of any of the polymers mentioned above through their own unsaturated double bonds, when the material of the anion exchange membrane includes both the polymers mentioned above and the cross-linked compound formed by the self-cross-linking reaction of any of the polymers mentioned above through their own unsaturated double bonds, it can better balance improving the conductivity of the anion exchange membrane and reducing the swelling rate.

[0103] This application also provides a method for preparing anion exchange membrane, comprising the following steps:

[0104] S100, a deposition material solution, wherein the material solution comprises any of the polymers described above;

[0105] S200. The deposited material solution is dried to obtain anion exchange membrane.

[0106] In step S100, the deposition method of the material solution includes, but is not limited to, one or more of the following: casting, spin coating, printing, inkjet printing, blade coating, printing, dip-coating, immersion, spraying, roller coating, casting, slot coating, and strip coating.

[0107] In step S200, "drying treatment" includes all processes that enable the deposited material solution to acquire higher energy and transform into a solidified film, including but not limited to one or more of vacuum drying treatment, heat treatment, and irradiation treatment. It should be noted that, to obtain an anion exchange membrane comprising any of the polymers described above and a cross-linked compound formed by the self-cross-linking reaction of any of the polymers described above through their unsaturated double bonds, the cross-linking reaction can be carried out in the drying treatment step. Correspondingly, the drying treatment is heat treatment and / or irradiation treatment. The heat treatment temperature is, for example, 80°C to 140°C, and the heat treatment time is, for example, 12h to 24h. The irradiation intensity is, for example, 80kGy to 120kGy, and the irradiation time is, for example, 12h to 24h. The cross-linking reaction can also be carried out after the drying treatment step, that is, an induced cross-linking reaction step is added after the drying treatment step. The induced cross-linking reaction step includes, but is not limited to, heat treatment and / or irradiation treatment.

[0108] In some embodiments of this application, the thickness of the anion exchange membrane is 10 μm to 60 μm.

[0109] It is understood that, after the step of drying the deposited material solution and before the step of obtaining the anion exchange membrane, the method for preparing the anion exchange membrane further includes the step of placing the cured membrane formed after drying and / or induced crosslinking reaction in a solution containing hydroxide or bicarbonate ions for anion replacement treatment, thereby replacing halide ions with OH-. - or HCO3 - .

[0110] This application also provides an application of an anion exchange membrane as described in any of the preceding descriptions, or an anion exchange membrane prepared by any of the preceding descriptions, in alkaline fuel cells, alkaline water electrolysis devices, separation devices, purification devices, and supercapacitors. It should be noted that the types of alkaline fuel cells, alkaline water electrolysis devices, separation devices, purification devices, and supercapacitors are not specifically limited.

[0111] The technical solutions and effects of this application will be described in detail below through specific embodiments, comparative examples and experimental examples. The following embodiments are only some embodiments of this application and are not intended to limit this application.

[0112] Example 1

[0113] This embodiment provides a first polymer and its preparation method. The number average molecular weight of the first polymer is 10,000 to 20,000, and the first polymer has repeating units with the structure shown in formula (1.1):

[0114]

[0115] The preparation method of the first polymer includes the following steps:

[0116] S1.1 Take a reaction flask, add 2.3g of p-terphenyl (CAS No.: 92-94-4), 1.4g of N-methyl-4-piperidinone, and 10mL of dichloromethane to the flask, and stir under ice bath to obtain a first mixed system; cool the first mixed system to 0℃, and then add 1.8mL of trifluoroacetic acid and 16mL of trifluoromethanesulfonic acid dropwise to the first mixed system, stir at 0℃ for 8h to obtain a first reactant, mix the first reactant with deionized water to precipitate the precipitate, and neutralize the excess acid with potassium carbonate, wash with water several times until neutral, and then perform filtration, shearing, and vacuum drying to obtain a white fibrous polyarylpiperidine compound. 1 HNMR image as follows Figure 1 (as shown);

[0117] S1.2 Take 1g of the polyarylpiperidine compound obtained in step S1.1 and dissolve it in 20mL of dimethyl sulfoxide. Then add 0.3g of potassium carbonate and 300μL of iodomethane to obtain a second mixed system. Place the second mixed system at room temperature and react for 24h to obtain a second reactant. Mix the second reactant with ethyl acetate to precipitate the precipitate. Wash the precipitate several times with ethyl acetate and filter to obtain the quaternized polyarylpiperidine compound.

[0118] S1.3. Dissolve 1g of the quaternized polyarylepiperidine compound obtained in step S1.2 in 20mL of dimethyl sulfoxide, then add 0.3g of potassium carbonate and 0.3g of ionic liquid to obtain a third mixture. Heat the third mixture to 80℃ and react for 48h to obtain a fourth mixture. After the reaction is complete, cool the fourth mixture to room temperature, then add 0.24g of 8-bromo-1-octene (CAS No. 2695-48-9) and 0.3g of iodomethane to the fourth mixture and react at room temperature for 48h to obtain a third reactant. Mix the third reactant with ethyl acetate to precipitate the precipitate. Wash the precipitate several times with deionized water and dry at 60℃ to obtain the first polymer.1 HNMR image as follows Figure 2 (As shown).

[0119] The preparation method of the ionic liquid includes the following steps: dissolving 48.8 g of 1,6-dibromohexane in 140 mL of ethyl acetate to obtain a 1,6-dibromohexane-ethyl acetate solution, and dissolving 9.92 g of N-methylpiperidine in 50 mL of ethyl acetate to obtain an N-methylpiperidine-ethyl acetate solution; then, slowly adding the N-methylpiperidine-ethyl acetate solution to the 1,6-dibromohexane-ethyl acetate solution, stirring the reaction at room temperature for 24 h, and allowing it to stand until a white precipitate forms after the reaction is complete. The supernatant is discarded and the white precipitate is collected. The white precipitate is washed several times with ethyl acetate and then vacuum dried at room temperature for 48 h to obtain the ionic liquid. 1 HNMR image as follows Figure 3 (As shown).

[0120] Example 2

[0121] This embodiment provides an anion exchange membrane and its preparation method. The material of the anion exchange membrane in this embodiment includes the first polymer in Example 1 and a cross-linked compound formed by the self-cross-linking reaction of the first polymer through its own unsaturated double bonds. The thickness of the anion exchange membrane in this embodiment is 40 μm.

[0122] The preparation method of the anion exchange membrane in this embodiment includes the following steps:

[0123] S2.1. Dissolve an appropriate amount of the first polymer in dimethyl sulfoxide to obtain a uniform and transparent solution of the first polymer.

[0124] S2.2. The first polymer solution is uniformly cast onto a flat glass plate and vacuum dried at 120°C for 24 hours to allow a portion of the first polymer to undergo a self-crosslinking reaction to form a crosslinking compound, thereby obtaining an anion exchange membrane containing the first polymer and the crosslinking compound.

[0125] The performance of the anion exchange membranes in Example 2 was tested. Performance indicators included total ion exchange capacity, water absorption rate, swelling rate, and conductivity at 80°C. The conductivity retention rate of each anion exchange membrane was also tested after immersion in a 2 mol / L sodium hydroxide aqueous solution at 80°C for 1000 hours. The results are shown in Table 1 below.

[0126] Table 1. Performance Indicators of the Anion Exchange Membrane in Example 2

[0127]

[0128] As shown in Table 1, the anion exchange membrane in Example 2 exhibits good performance, with both low swelling ratio and high conductivity, and good alkali stability.

[0129] The anion exchange membrane from Example 2 was immersed in liquid nitrogen for 30 seconds, then removed and broken with tweezers. The surface and cross-sectional morphology of the anion exchange membrane were observed using a HITACHI S-4800 scanning electron microscope. Testing revealed that, as... Figure 4 and Figure 5 As shown, the anion exchange membrane in Example 2 has the advantages of being dense, uniform, and flat.

[0130] Application Example 1

[0131] The anion exchange membrane from Example 2 was applied to an alkaline fuel cell, and the performance of the alkaline fuel cell was then tested.

[0132] First, commercially available Hispec4000 Pt / C catalyst, deionized water, and isopropanol were added to a 5 mL sample vial. Then, 5% (mass fraction) of a polymer solution (the first polymer prepared in Example 1, with dimethyl sulfoxide as the solvent) was added and mixed to obtain a slurry. The mass ratio of Pt / C catalyst to polymer solution was 1:3, and the volume ratio of deionized water to isopropanol was 1:10. The slurry was mixed evenly under magnetic stirring and ultrasonic treatment to obtain a highly uniformly dispersed catalyst slurry.

[0133] Then, the prepared catalyst slurry was sprayed onto both sides of the anion exchange membrane prepared in Example 2 to form a cathode and an anode, and then sandwiched between two carbon papers to prepare a membrane electrode (MEA).

[0134] Finally, the effective area is 1cm. 2 The membrane electrode assembly (MEA) was installed in a single-cell test system. Under fully humidified conditions without back pressure, the fuel cell's performance was tested at 80°C. After complete activation in constant-pressure mode, the fuel cell's polarization curve was also tested. The fuel cell polarization curve is shown below. Figure 6 As shown, the alkaline fuel cell using the anion exchange membrane in Example 2 demonstrates excellent performance.

[0135] Application Example 2

[0136] The anion exchange membrane from Example 2 was applied to an anion exchange membrane electrolyzer. For example... Figure 7As shown, the anion exchange membrane electrolyzer 100 includes a membrane electrode 101, an anode diffusion layer 102, an anode plate 103, a cathode diffusion layer 104, and a cathode plate 105. The membrane electrode 101 includes an anion exchange membrane 1011, and an anode catalyst layer 1012 and a cathode catalyst layer 1013 disposed opposite to each other on both sides of the anion exchange membrane 1011. The anode diffusion layer 102 is disposed on the side of the anode catalyst layer 1012 away from the anion exchange membrane 1011, the anode plate 103 is disposed on the side of the anode diffusion layer 102 away from the anode catalyst layer 1012, the cathode diffusion layer 104 is disposed on the side of the cathode catalyst layer 1013 away from the anion exchange membrane 1011, and the cathode plate 105 is disposed on the side of the cathode diffusion layer 104 away from the cathode catalyst layer 1013.

[0137] The anode catalyst layer 1012 is prepared from commercially available Sinoro IrO2 catalyst and 7.5% (by mass) of a polymer solution (the solvent being the first polymer obtained in Example 1, with dimethyl sulfoxide as the solvent). The cathode catalyst layer 1013 is prepared from 60% (by mass) of commercially available Hispec9100 Pt / C catalyst and 10% (by mass) of a polymer solution (the solvent being the first polymer obtained in Example 1, with dimethyl sulfoxide as the solvent). The anode diffusion layer 102 is made of nickel foam, the anode plate 103 is made of titanium, the cathode diffusion layer 104 is made of hydrophilic carbon paper, the cathode plate 105 is made of titanium, and the anion exchange membrane 1011 is the anion exchange membrane obtained in Example 2. It should be noted that the effective area of ​​the membrane electrode is 4 cm². 2 Before assembling the membrane electrode to form an anion exchange membrane electrolyzer, the membrane electrode is first immersed in a 1 mol / L NaOH aqueous solution for 24 hours for ion exchange, and then washed several times with deionized water to remove residual alkali solution from the surface.

[0138] Electrochemical tests were performed on the assembled anion exchange membrane electrolyzer at 80℃. Polarization curves were obtained by measuring the water splitting voltage of the anion exchange membrane electrolyzer at different current densities. The tests were conducted at 80℃ and a current density of 1 A·cm⁻¹. -2 The water decomposition voltage under constant current was used to evaluate the durability of the alkaline water electrolysis device.

[0139] Depend on Figure 8 It can be seen that the anion exchange membrane electrolyzer prepared in Example 2 exhibits good hydrogen production performance. The anion exchange membrane electrolyzer operates at 80°C and a current density of 1 A·cm⁻¹. -2 The water decomposition initiation voltage at constant current density is relatively low, specifically 1.73V.

[0140] The foregoing has provided a detailed description of a polymer, anion exchange membrane, its preparation method, and its application, as provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A polymer, characterized in that, The polymer has repeating units with the structure shown in general formula (Ⅰ): (Ⅰ) In general formula (I), Ar1, Ar2, and Ar3 are independently selected from divalent aryl groups having 12 to 24 carbon atoms, X1 - X2 - X3 - and X4 - Selected independently from Br - I - Cl - OH - or HCO3 - a, b, and c represent the molar percentages of the corresponding chain segments in the repeating units, and the sum of a, b, and c is 100%; n is a positive integer from 1 to 5. 0%<a<100%, 0%<b≤30%, 0%<c<100%; The number-average molecular weight of the polymer is 10,000 to 20,000.

2. The polymer according to claim 1, characterized in that, Ar1, Ar2, and Ar3 are independently selected from: 、 、 、 , or ; in, Represents a connection key.

3. The polymer according to claim 1, characterized in that, The repeating unit is selected from: 。 4. A method for preparing a polymer, characterized in that, The preparation of the polymer as described in any one of claims 1 to 3 comprises the following steps: Using trifluoroacetic acid and trifluoromethanesulfonic acid as catalysts, aromatic compounds and N-methyl-4-piperidinone undergo a polymerization reaction to obtain polyarylpiperidine compounds; Quaternizing the piperidine in the polyarylpiperidine compound yields a second compound; as well as A mixture containing the second compound, the first base, and the ionic liquid was reacted at 60 °C to 80 °C to obtain an intermediate product. Then, iodomethane and the third compound were added to the intermediate product at room temperature to react and generate a polymer. The aromatic compound has the structure shown in general formula (II) below: (Ⅱ) In general formula (II), A is selected from Ar4 or -R-Ar4, wherein Ar4 is selected from aryl groups with 6 to 18 ring atoms, and R is selected from -(CH2). s -, the value of s is 1 to 2; The polyarylpiperidine compound has the structure shown in general formula (Ⅲ) below: (Ⅲ) In general formula ((Ⅲ), Ar5 is the divalent aryl group obtained by losing a hydrogen atom from Ar4, m is the degree of polymerization of the polyarylpiperidine compound, and m is greater than zero; The ionic liquid has the structure shown in the following general formula (Ⅳ): (Ⅳ) In general formula (Ⅳ), X5 is selected from -Cl, -Br or -I; The third compound has the structure shown in the following general formula (V): (Ⅴ)； In general formula (V), X6 is selected from -Cl, -Br or -I, and t is a positive integer from 1 to 5.

5. The preparation method according to claim 4, characterized in that, The aromatic compound is selected from one or more of biphenyl, o-terphenyl, p-terphenyl, diphenylmethane, diphenylethane, and p-tetraphenyl; and / or In the step of polymerization of the aromatic compound and N-methyl-4-piperidinone, the reaction temperature is -10 °C to 10 °C, and / or the reaction time is 7 h to 24 h, and / or the molar ratio of the aromatic compound to N-methyl-4-piperidinone is 1:(1 to 1.3); and / or The step of quaternizing piperidine in the polyarylpiperidine compound includes: reacting the polyarylpiperidine compound with iodomethane using a Mensøein reaction; and / or In the step of reacting the mixture containing the second compound, the first base, and the ionic liquid at 60 °C to 80 °C to obtain an intermediate product, the molar ratio of the second compound to the first base to the ionic liquid is 1:(0.5–0.8):(0.2–0.4), the first base is selected from alkali metal carbonates; and / or, the mixture is in a liquid state, and the mass of the second compound accounts for 4%–6% of the total mass of the mixture; and / or In the step of adding iodomethane and a third compound to the intermediate product to react and generate a polymer, the molar ratio of the intermediate product to the iodomethane to the third compound is 1:(1.5-2):(0.95-1).

6. An anion exchange membrane, characterized in that, The material of the anion exchange membrane includes the polymer as described in any one of claims 1 to 3, and / or a cross-linked compound formed by the self-cross-linking reaction of the polymer as described in any one of claims 1 to 3 through its own unsaturated double bonds.

7. A method for preparing an anion exchange membrane, characterized in that, Includes the following steps: A deposition material solution, said material solution comprising the polymer as described in any one of claims 1 to 3 or a polymer prepared by the preparation method as described in claim 4 or 5; and The deposited material solution is dried to obtain an anion exchange membrane.

8. The preparation method according to claim 7, characterized in that, The thickness of the anion exchange membrane is 10 μm to 60 μm; and / or The drying process is a heat treatment and / or irradiation treatment. During the drying process, a portion of the polymer undergoes a self-crosslinking reaction through its own unsaturated double bonds to form a crosslinked compound.

9. The application of the anion exchange membrane according to claim 6, or the anion exchange membrane prepared by the preparation method according to claim 7 or 8, in alkaline fuel cells, alkaline water electrolysis devices, separation devices, purification devices, and supercapacitors.

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