Anion exchange polymers, anion exchange membranes, and methods of making and using the same

Abstract

The application discloses an anion exchange polymer, an anion exchange membrane and a preparation method and application thereof. The main chain of the anion exchange polymer contains aryl and piperidine cation structures, and a side chain with a cationic group is grafted on the nitrogen of the piperidine cation structure in the main chain. The side chain contains an unsaturated carbon-carbon double bond structure. The unsaturated carbon-carbon double bond can be in-situ crosslinked to form a crosslinked network structure through thermal polymerization in a film forming process, so that the ion exchange capacity and ion conductivity of the anion exchange membrane are improved, and the mechanical strength and dimensional stability of the anion exchange membrane are improved.

Description

Technical Field

[0001] This invention belongs to the field of ion exchange polymer technology, and particularly relates to an anion exchange polymer, an anion exchange membrane, its preparation method and application. Background Technology

[0002] Anion exchange membranes (ACEs) can conduct anions and are used in devices such as alkaline fuel cells and water electrolyzers. Ion conductivity, chemical stability, and mechanical properties are important properties of ACEs. Currently, ACEs with both high ion conductivity and excellent chemical stability and mechanical properties are still relatively rare, limiting their practical application. In recent years, anion exchange polymers containing biphenyl and piperidine quaternary ammonium cation structural units have attracted attention due to their excellent chemical stability; however, their ion conductivity is relatively low, and their mechanical strength and dimensional stability need improvement. Therefore, there is a need to develop anion exchange polymers with excellent ion exchange capacity, ion conductivity, mechanical strength, and dimensional stability to meet the material requirements under different application conditions. Summary of the Invention

[0003] This invention is based on the inventor's discovery and understanding of the following facts and problems: the ion exchange capacity, ion conductivity, mechanical strength, dimensional stability and other properties of current anion exchange polymers need to be improved.

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose an anion exchange polymer, an anion exchange membrane, its preparation method, and its applications. The main chain of the anion exchange polymer contains aryl and piperidine cationic structures. Side chains with cationic groups are grafted onto the nitrogen atoms of the piperidine cationic structures in the main chain. These side chains simultaneously contain unsaturated carbon-carbon double bonds, forming a cross-linked network structure during membrane formation. This improves the ion exchange capacity and ion conductivity of the anion exchange membrane, while also enhancing its mechanical strength and dimensional stability.

[0005] An anion exchange polymer according to an embodiment of the present invention has the structure shown in formula (1):

[0006]

[0007] Ar1 and Ar2 are each independently selected from substituted or unsubstituted aryl groups;

[0008] R1 is selected from one of the C4-C100 hydrocarbon groups containing a carbon-carbon double bond;

[0009] R2 is selected from any of the following structural formulas:

[0010]

[0011] R3, R4, and R5 are each independently selected from any one of linear alkyl groups having 1 to 10 carbon atoms or cycloalkyl groups having 3 to 10 carbon atoms;

[0012] X is an anion;

[0013] 0 < p < 1; n is an integer between 20 and 20000.

[0014] The advantages and technical effects brought by the anion exchange polymer of the embodiment of the present invention are that the main chain of the anion exchange polymer contains an aryl group and a piperidine cation structure, and a side chain having a cationic group is grafted onto the nitrogen of the piperidine cation structure in the main chain, which increases the proportion of cationic groups in the anion exchange polymer. The side chain also contains a carbon-carbon double bond structure, and the carbon-carbon double bond structure can form a crosslinked network structure during the film-forming process, which increases the ion exchange capacity and ion conductivity of the anion exchange membrane, and at the same time improves its mechanical strength and dimensional stability.

[0015] In some embodiments, Ar1 and Ar2 are each independently selected from one of the following structural formulas:

[0016]

[0017] R1 is selected from one of the following structural formulas:

[0018]

[0019] In some embodiments, 0.4 ≤ p < 1.

[0020] In some embodiments, the anion exchange polymer includes at least one of formulas (2)-(5):

[0021]

[0022]

[0023] The preparation method of the anion exchange polymer of the embodiment of the present invention includes the following steps:

[0024] (1) A compound containing a carbon-carbon double bond with halogens at both ends and an amine compound are reacted in a first solvent to obtain a side chain compound;

[0025] (2) An aryl monomer and a piperidone monomer are subjected to a polymerization reaction under the action of a second solvent and a catalyst to obtain a first polymer;

[0026] (3) The first polymer and the side chain compound are subjected to a grafting reaction in a third solvent to obtain a second polymer with a grafted side chain compound;

[0027] (4) The second polymer reacts with a quaternizing agent to obtain an anion exchange polymer.

[0028] The method for preparing the anion exchange polymer according to the present invention involves polymerizing aryl monomers and piperidinone monomers to obtain a main chain containing aryl and piperidinine cationic structures, and then grafting side chains with cationic groups. These side chains also contain unsaturated double bond structures, which can form a cross-linked network structure through cross-linking during the film formation process. The second polymer undergoes a quaternization reaction with a quaternizing agent to obtain the anion exchange polymer, thereby improving the ion exchange capacity and ion conductivity of the anion exchange membrane, while also improving its mechanical strength and dimensional stability.

[0029] In some embodiments, the compound with halogenated carbon-carbon double bonds at both ends includes at least one of 1,2-di(p-chloromethylphenyl)ethylene, 1,4-di(p-chloromethylphenyl)-2-butene, 1,4-di(p-chloroethylphenyl)-2-butene, and 1,10-dichloro-5-decene.

[0030] The amine compounds include at least one of trimethylamine, N-methylpiperidine, 4-azadamane, N-methylimidazole, and N,2,4,5-tetramethylimidazole;

[0031] The aryl monomer includes at least one of biphenyl, p-terphenyl, m-terphenyl, p-tetraphenyl, diphenylmethane, 1,2-diphenylethane, and 9,9'-dimethylfluorene;

[0032] The piperidone monomers include at least one of N-methyl-4-piperidinone, N-ethyl-4-piperidinone, and N-propyl-4-piperidinone;

[0033] The quaternizing agent includes at least one of iodomethane, iodoethane, iodopropane, iodobutane, iodopentane, iodohexane, bromoethane, bromopropane, bromobutane, bromopentane, bromohexane, bromocyclopropane, bromocyclobutane, bromocyclopentane, or bromocyclohexane.

[0034] The molar ratio of the compound containing carbon-carbon double bonds with halogens at both ends to the amine compound is 1 to 100:1;

[0035] The molar ratio of the aryl monomer to the piperidinone monomer is 1:1 to 10;

[0036] The molar ratio of the first polymer to the side-chain compound is 1:0 to 1;

[0037] The molar ratio of the second polymer to the quaternizing agent is 1:1 to 50.

[0038] In some embodiments, in step (1), the reaction temperature is 10-40°C; the reaction time is 3-24 h; and the first solvent includes at least one of dichloromethane, trichloromethane, tetrachloroethane, and toluene.

[0039] In step (2), the polymerization reaction temperature is -5 to 5°C; the polymerization reaction time is 6 to 72 hours; the second solvent includes at least one of dichloromethane, trichloromethane, tetrachloroethane, and toluene; the catalyst includes at least one of trifluoromethanesulfonic acid, trifluoroacetic acid, and methanesulfonic acid; after the polymerization reaction, the product is added to an alkaline solution for soaking and washing; the alkaline solution includes at least one of sodium carbonate solution, potassium carbonate solution, potassium bicarbonate solution, sodium bicarbonate solution, sodium hydroxide solution, or potassium hydroxide solution; the concentration of the alkaline solution is 0.1 to 10 mol / L; the soaking time is 1 to 48 hours.

[0040] In step (3), the temperature of the grafting reaction is 40-80°C; the time of the grafting reaction is 10-60 h; and the third solvent includes at least one of dimethyl sulfoxide, 1-methyl-2-pyrrolidone, dimethylformamide, or dimethylacetamide.

[0041] In step (3), the first polymer is added to the third solvent, trifluoroacetic acid is added, potassium carbonate and the side chain compound are added after the first polymer is dissolved, and then a grafting reaction is carried out.

[0042] In step (4), the reaction temperature is 10-40℃; the reaction time is 6-72h; after the reaction, the product is added to a poor solvent to precipitate the polymer, and then washed and dried to obtain anion exchange polymer; the poor solvent includes at least one of ethyl formate, ethyl acetate, propyl acetate, butyl acetate, ethyl propionate, ethyl butyrate, propyl propionate, butyl propionate, and propyl butyrate.

[0043] The anion exchange membrane of this invention is prepared using the anion exchange polymer described in this invention or the anion exchange polymer prepared by the preparation method described in this invention. The anion exchange membrane of this invention is prepared using an anion exchange polymer whose main chain contains aryl and piperidine cationic structures. Side chains with cationic groups are grafted onto the nitrogen atoms of the piperidine cationic structures in the main chain. These side chains can form a cross-linked network structure through cross-linking, thereby improving the ion exchange capacity and ion conductivity of the anion exchange membrane, while also improving its mechanical strength and dimensional stability.

[0044] The method for preparing anion exchange membrane according to an embodiment of the present invention includes: dissolving the anion exchange polymer in a solvent to obtain a solution; spreading the solution flat on a plane and heating it to form a membrane; immersing the obtained membrane in an alkaline solution to perform ion exchange and obtain anion exchange membrane.

[0045] The method for preparing anion exchange membrane according to embodiments of the present invention involves dissolving anion exchange polymer in a solvent to form a solution. The side chains of the anion exchange polymer contain unsaturated double bond structures. During the heating and film-forming process, a cross-linked network structure is formed through thermal polymerization to obtain anion exchange membrane. This method improves the ion exchange capacity and ion conductivity of the anion exchange membrane, as well as its mechanical strength and dimensional stability, thus meeting the needs of actual production.

[0046] In some embodiments, the solvent is at least one selected from dimethyl sulfoxide, 1-methyl-2-pyrrolidone, dimethylformamide, or dimethylacetamide; the mass ratio of the anion exchange polymer to the solvent is 1–20:100; the heating temperature is 70–120°C; the heating time is 12–72 h; the alkaline solution includes at least one selected from 0.1–10 M KOH solution and 0.1–10 M NaOH solution; and the ion exchange time is 12–72 h.

[0047] The anion exchange membrane or the anion exchange membrane prepared by the method described in this invention is used in alkaline fuel cells or water electrolyzers. The application of the anion exchange membrane in this invention possesses all the advantages and technical effects brought by the anion exchange membrane of this invention, and will not be elaborated further here. Attached Figure Description

[0048] Figure 1 This refers to the ion exchange capacity of the anion exchange membranes in the embodiments and comparative examples of this invention.

[0049] Figure 2 The OH content of the anion exchange membranes in the embodiments and comparative examples of this invention at 80°C - Ionic conductivity.

[0050] Figure 3 This refers to the tensile strength of the anion exchange membranes in the embodiments and comparative examples of this invention.

[0051] Figure 4 It is the swelling rate of the anion exchange membrane in the embodiments and comparative examples of the present invention at 80°C. Detailed Implementation

[0052] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0053] An anion exchange polymer according to an embodiment of the present invention, the polymer having a structure shown in formula (1):

[0054]

[0055] Wherein, Ar1 and Ar2 are each independently selected from substituted or unsubstituted aryl groups;

[0056] R1 is selected from one of C4-C100 hydrocarbon groups containing a carbon-carbon double bond; preferably, selected from one of C8-C25 hydrocarbon groups containing a carbon-carbon double bond;

[0057] R2 is selected from any one of the following structural formulas:

[0058]

[0059] R3, R4, and R5 are each independently selected from any one of C1-C10 linear alkyl groups or C3-C10 cycloalkyl groups;

[0060] X is an anion; preferably, X is selected from OH - , Cl - , Br - , I - , CO3 2- , HCO3 - and at least one of them;

[0061] 0 < p < 1, optionally, for example, 0.1, 0.2, 0.4, 0.5, 0.6, 0.7, 0.9; n is an integer between 20 and 20000, optionally, for example, 20, 100, 500, 1000, 2000, 10000, 20000.

[0062] The anion exchange polymer according to an embodiment of the present invention, the main chain of the anion exchange polymer contains an aryl group and a piperidine cation structure, and a side chain with a cationic group is grafted onto the nitrogen of the piperidine cation structure in the main chain, increasing the proportion of cationic groups in the anion exchange polymer. The side chain simultaneously contains a carbon-carbon double bond structure, and the carbon-carbon double bond structure can form a crosslinked network structure during the film-forming process, increasing the ion exchange capacity and ionic conductivity of the anion exchange membrane, and simultaneously increasing its mechanical strength and dimensional stability.

[0063] In some embodiments, Ar1 and Ar2 are each independently selected from one of the following structural formulas:

[0064]

[0065] In this embodiment of the invention, the aryl group in the main chain of the anion exchange polymer can be selected from biphenyl, terphenyl, etc. The resulting anion exchange polymer can improve the ion exchange capacity and ion conductivity of the anion exchange membrane, while also improving the mechanical strength and dimensional stability.

[0066] R1 is selected from one of the following structural formulas:

[0067]

[0068] In this embodiment of the invention, R1 in the side chain of the anion exchange polymer preferably has the structural formula shown above. The resulting anion exchange polymers are all beneficial to further improve the ion exchange capacity and ion conductivity of the anion exchange membrane, while also improving mechanical strength and dimensional stability.

[0069] In some embodiments, 0.4 ≤ p < 1, specifically, for example, 0.4, 0.5, 0.6, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95. In these embodiments of the invention, the preferred value of p in the anion exchange polymer ensures the construction of the cross-linked network structure and the subsequent preparation of the anion exchange membrane, while also improving the ion exchange capacity, ion conductivity, mechanical strength, and dimensional stability of the anion exchange membrane.

[0070] In some embodiments, the anion exchange polymer comprises at least one of formulas (2)-(5):

[0071]

[0072]

[0073] In this embodiment of the invention, the type of anion exchange polymer is further optimized, which is beneficial to further improve the ion exchange capacity and ion conductivity of the anion exchange membrane, while also improving mechanical strength and dimensional stability.

[0074] The preparation method of the anion exchange polymer according to embodiments of the present invention includes the following steps:

[0075] (1) Compounds containing carbon-carbon double bonds with halogens at both ends and amine compounds are reacted in the first solvent to obtain side-chain compounds;

[0076] (2) Aryl monomers and piperidinone monomers undergo polymerization under the action of a second solvent and a catalyst to obtain the first polymer;

[0077] (3) The first polymer and the side chain compound are grafted together in a third solvent to obtain a second polymer with grafted side chain compound.

[0078] (4) The second polymer reacts with a quaternizing agent to obtain an anion exchange polymer.

[0079] The method for preparing the anion exchange polymer according to the present invention involves polymerizing aryl monomers and piperidinone monomers to obtain a main chain containing aryl and piperidinine cationic structures, and then grafting side chains with cationic groups. These side chains also contain unsaturated double bond structures, which can form a cross-linked network structure through cross-linking during the film formation process. The second polymer undergoes a quaternization reaction with a quaternizing agent to obtain the anion exchange polymer, thereby improving the ion exchange capacity and ion conductivity of the anion exchange membrane, while also improving its mechanical strength and dimensional stability.

[0080] In some embodiments, the compound with halogenated carbon-carbon double bonds at both ends includes at least one of 1,2-di(p-chloromethylphenyl)ethylene, 1,4-di(p-chloromethylphenyl)-2-butene, 1,4-di(p-chloroethylphenyl)-2-butene, and 1,10-dichloro-5-decene.

[0081] The amine compounds include at least one of trimethylamine, N-methylpiperidine, 4-azadamane, N-methylimidazole, and N,2,4,5-tetramethylimidazole;

[0082] The aryl monomer includes at least one of biphenyl, p-terphenyl, m-terphenyl, p-tetraphenyl, diphenylmethane, 1,2-diphenylethane, and 9,9'-dimethylfluorene;

[0083] The piperidone monomers include at least one of N-methyl-4-piperidinone, N-ethyl-4-piperidinone, and N-propyl-4-piperidinone;

[0084] The quaternizing agent includes at least one of iodomethane, iodoethane, iodopropane, iodobutane, iodopentane, iodohexane, bromoethane, bromopropane, bromobutane, bromopentane, bromohexane, bromocyclopropane, bromocyclobutane, bromocyclopentane, or bromocyclohexane.

[0085] The molar ratio of the compound containing carbon-carbon double bonds with halogens at both ends to the amine compound is 1 to 100:1, specifically, for example, 1:1, 5:1, 10:1, 20:1, 50:1, 100:1.

[0086] The molar ratio of the aryl monomer to the piperidinone monomer is 1:1 to 10, specifically, for example, 1:1, 1:3, 1:5, 1:7, 1:10;

[0087] The molar ratio of the first polymer to the side chain compound is 1:0 to 1, specifically, for example, 1:0.01, 1:0.1, 1:0.3, 1:0.5, 1:0.7, 1:1;

[0088] The molar ratio of the second polymer to the quaternizing agent is 1:1 to 50, specifically, for example, 1:1, 1:5, 1:10, 1:20, 1:30, 1:40, 1:50.

[0089] In some embodiments, in step (1), the reaction temperature is 10-40°C, specifically, for example, 10°C, 20°C, 25°C, 30°C, 40°C; the reaction time is 3-24 hours, specifically, for example, 3 hours, 6 hours, 9 hours, 12 hours, 24 hours; the first solvent includes at least one of dichloromethane, trichloromethane, tetrachloroethane, and toluene.

[0090] In step (2), the polymerization reaction temperature is -5 to 5°C, optionally 0°C; the polymerization reaction time is 6 to 72 hours, specifically, for example, 6 hours, 12 hours, 24 hours, 36 hours, 48 ​​hours, or 72 hours; the second solvent includes at least one of dichloromethane, trichloromethane, tetrachloroethane, and toluene; the catalyst includes at least one of trifluoromethanesulfonic acid, trifluoroacetic acid, and methanesulfonic acid, preferably trifluoromethanesulfonic acid and trifluoroacetic acid, with a volume ratio of trifluoromethanesulfonic acid to trifluoroacetic acid of 12:1; After the polymerization reaction, the product is added to an alkaline solution for soaking and washing; the alkaline solution includes at least one of sodium carbonate solution, potassium carbonate solution, potassium bicarbonate solution, sodium bicarbonate solution, sodium hydroxide solution, or potassium hydroxide solution; the concentration of the alkaline solution is 0.1–10 mol / L, specifically, for example, 0.1 mol / L, 1 mol / L, 5 mol / L, or 10 mol / L; the soaking time is 1–48 h, specifically, for example, 1 h, 12 h, 24 h, 36 h, or 48 h.

[0091] In step (3), the grafting reaction temperature is 40–80°C, specifically, for example, 40°C, 50°C, 60°C, 70°C, 80°C; the grafting reaction time is 10–60 h, specifically, for example, 10 h, 16 h, 20 h, 40 h, 60 h; the third solvent includes at least one of dimethyl sulfoxide, 1-methyl-2-pyrrolidone, dimethylformamide, or dimethylacetamide.

[0092] In step (3), the first polymer is added to the third solvent, trifluoroacetic acid is added, potassium carbonate and the side chain compound are added after the first polymer is dissolved, and then a grafting reaction is carried out.

[0093] In step (4), the reaction temperature is 10-40℃, specifically, for example, 10℃, 20℃, 25℃, 30℃, 40℃; the reaction time is 6-72h, specifically, for example, 6h, 12h, 24h, 36h, 48h, 72h; after the reaction, the product is added to a poor solvent to precipitate the polymer, and then washed and dried to obtain anion exchange polymer; the poor solvent includes at least one of ethyl formate, ethyl acetate, propyl acetate, butyl acetate, ethyl propionate, ethyl butyrate, propyl propionate, butyl propionate, and propyl butyrate.

[0094] In a preferred technical solution, a method for preparing anion exchange polymers of formulas (2)-(5) includes the following steps:

[0095] (1) 1,2-Di(p-chloromethylphenyl)ethylene and trimethylamine or N-methylpiperidine were dissolved in chloroform at a molar ratio of 10:1 and stirred at room temperature for 3-12 h to obtain an intermediate;

[0096] (2) Biphenyl or p-terphenyl and N-methyl-4-piperidinone are in a molar ratio of 10:12. Dichloromethane is added to dissolve the reactants. Trifluoromethanesulfonic acid and trifluoroacetic acid are added at -5 to 5°C, with a volume ratio of 12:1. The mixture is mechanically stirred for 6-24 hours. The product is poured into 0.5-3M K2CO3 solution and soaked at room temperature for 1-24 hours. The product is filtered to obtain a white solid product. After washing with water, it is dried to obtain an intermediate polymer containing piperidine tertiary amine groups.

[0097] (3) Add dimethyl sulfoxide to the intermediate polymer and add trifluoroacetic acid to promote polymer dissolution. After dissolution, add potassium carbonate and the intermediate obtained in step (1). The mass ratio of intermediate polymer to intermediate is 1.2:0.32. React at 20-80℃ for 10-72 hours.

[0098] (4) Then add iodomethane and react at 20-60℃ for 12-72h; pour the reaction product into ethyl acetate to obtain a precipitate, wash with ethyl acetate and then with water, and dry to obtain anion exchange polymer.

[0099] An anion exchange polymer according to an embodiment of the present invention has the structure shown in formula (6):

[0100]

[0101] Ar1 and Ar2 are each independently selected from substituted or unsubstituted aryl groups;

[0102] R6 is selected from a hydrocarbon group of C4-C100; preferably, it is selected from a hydrocarbon group of C8-C25.

[0103] R2 is selected from any one of the following structural formulas:

[0104]

[0105] Each of R3, R4, and R5 is independently selected from any one of linear alkyl groups having 1 to 10 carbon atoms or cycloalkyl groups having 3 to 10 carbon atoms;

[0106] X is an anion; preferably, X is selected from OH - , Cl - , Br - , I - , CO3 2- , HCO3 - and at least one of them;

[0107] 0 < p < 1, optionally, for example, 0.1, 0.2, 0.4, 0.5, 0.7, 0.9; n is an integer between 20 and 20000, optionally, for example, 20, 50, 100, 500, 1000, 2000, 10000, 20000; m is an integer between 5 and 500, optionally, for example, 5, 10, 50, 100, 200, 500.

[0108] The anion exchange polymer of the embodiment of the present invention, the polymer is a cross-linked polymer, the main chain contains an aryl group and a piperidine cation structure, and a side chain with a cation group is grafted onto the nitrogen of the piperidine cation structure in the main chain, which increases the proportion of cation groups in the anion exchange polymer. The side chain forms a cross-linked network structure through cross-linking, which increases the ion exchange capacity and ion conductivity of the anion exchange membrane, and at the same time improves its mechanical strength and dimensional stability.

[0109] In some embodiments, each of Ar1 and Ar2 is independently selected from one of the following structural formulas:

[0110]

[0111] R6 is selected from one of the following structural formulas:

[0112]

[0113] In some embodiments, 0.4 ≤ p < 1. Specifically, for example, 0.4, 0.6, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95. In the embodiments of the present invention, the value of p in the anion exchange polymer is preferably selected, which can not only ensure the construction of the cross-linked network structure and the subsequent preparation of the anion exchange membrane, but also be beneficial to improving the ion exchange capacity, ion conductivity, mechanical strength and dimensional stability of the anion exchange membrane.

[0114] In some embodiments, the anion exchange polymer comprises at least one of formulas (7)-(10):

[0115]

[0116]

[0117] The preparation method of the anion exchange polymer according to embodiments of the present invention includes the following steps:

[0118] (1) Compounds containing carbon-carbon double bonds with halogens at both ends and amine compounds are reacted in the first solvent to obtain side-chain compounds;

[0119] (2) Aryl monomers and piperidinone monomers undergo polymerization under the action of a second solvent and a catalyst to obtain the first polymer;

[0120] (3) The first polymer and the side chain compound are grafted together in a third solvent to obtain a second polymer with grafted side chain compound.

[0121] (4) The second polymer reacts with a quaternizing agent to obtain a third polymer;

[0122] (5) The third polymer is dissolved in the fourth solvent to obtain a polymer solution, and a cross-linking reaction is carried out to obtain an anion exchange polymer.

[0123] The method for preparing the anion exchange polymer according to the present invention involves polymerizing an aryl monomer with a piperidinone monomer to obtain a main chain containing an aryl and piperidinine cationic structures, then grafting side chains with cationic groups to obtain a second polymer, and then reacting the second polymer with a quaternizing agent to obtain a third polymer. The side chains of the third polymer contain unsaturated carbon-carbon double bond structures, and the side chains form a cross-linked network through cross-linking. This improves the ion exchange capacity and ion conductivity of the anion exchange membrane, while also enhancing its mechanical strength and dimensional stability, thus meeting the needs of actual production.

[0124] The anion exchange membrane of this invention is prepared using the anion exchange polymer described in this invention or the anion exchange polymer prepared by the preparation method described in this invention. The anion exchange membrane of this invention is prepared using an anion exchange polymer whose main chain contains aryl and piperidine cationic structures. Side chains with cationic groups are grafted onto the nitrogen atoms of the piperidine cationic structures in the main chain. These side chains can form a cross-linked network structure through cross-linking, thereby improving the ion exchange capacity and ion conductivity of the anion exchange membrane, while also improving its mechanical strength and dimensional stability.

[0125] The method for preparing anion exchange membrane according to an embodiment of the present invention includes: dissolving the anion exchange polymer in a solvent to obtain a solution; spreading the solution evenly on a flat surface and heating to form a membrane; immersing the obtained membrane in an alkaline solution to perform ion exchange, thereby obtaining an anion exchange membrane. Optionally, spreading the solution evenly in a groove in a flat glass plate.

[0126] The method for preparing anion exchange membrane according to embodiments of the present invention involves dissolving anion exchange polymer in a solvent to form a solution. The side chains of the anion exchange polymer contain unsaturated double bond structures. During the heating and film-forming process, a cross-linked network structure is formed through thermal polymerization to obtain anion exchange membrane. This method improves the ion exchange capacity and ion conductivity of the anion exchange membrane, as well as its mechanical strength and dimensional stability, thus meeting the needs of actual production.

[0127] In this embodiment of the invention, thermally initiated crosslinking polymerization allows the crosslinking network structure to be formed in situ during the membrane heating process. The uncrosslinked anion exchange polymer solution is thermally initiated to obtain a crosslinked membrane, which can achieve a greater degree of crosslinking. The thermally initiated in situ polymerization in this invention allows the use of anion exchange polymers with a higher degree of grafting to prepare anion exchange membranes with a higher degree of grafting, resulting in a greater improvement in the performance of the anion exchange membrane in all aspects, and further enhancing the performance of the membrane material.

[0128] In some embodiments, the solvent is at least one selected from dimethyl sulfoxide, 1-methyl-2-pyrrolidone, dimethylformamide, or dimethylacetamide; the mass ratio of the anion exchange polymer to the solvent is 1–20:100, specifically, for example, 1:100, 5:100, 10:100, or 20:100; the heating temperature is 70–120°C, specifically, for example, 70°C, 80°C, 100°C, or 120°C; the heating time is 12–72 h, specifically, for example, 12 h, 24 h, 36 h, 48 h, or 72 h; the alkaline solution includes at least one selected from 0.1–10 M KOH solution or 0.1–10 M NaOH solution, specifically, for example, 0.1 M, 1 M, 5 M, or 10 M; the ion exchange time is 12–72 h, specifically, for example, 12 h, 24 h, 36 h, 48 h, or 72 h.

[0129] The anion exchange membrane or the anion exchange membrane prepared by the method described in this invention is used in alkaline fuel cells or water electrolyzers. The application of the anion exchange membrane in this invention possesses all the advantages and technical effects brought by the anion exchange membrane of this invention, and will not be elaborated further here.

[0130] The present invention will now be described with reference to specific embodiments. It should be noted that these embodiments are merely descriptive and do not limit the present invention in any way.

[0131] Example 1:

[0132] Anion exchange membranes (p = 0.80) were prepared by grafting poly(biphenylpiperidine) with R1-TMA (quaternary ammonium cation) and crosslinking, including:

[0133]

[0134]

[0135] (1) Weigh 2.77 g (10.0 mmol) of 1,2-bis(p-chloromethylphenyl)ethylene and 0.06 g (1 mmol) of trimethylamine and dissolve them in 10 mL of chloroform. Stir at room temperature for 6 h to obtain intermediate 1.

[0136] (2) Weigh 1.54 g (10.0 mmol) of biphenyl into a 100 mL three-necked flask, add 1.36 g (12.0 mmol) of N-methyl-4-piperidinone, and add 10 mL of dichloromethane to dissolve the reactants. Add 12 mL of trifluoromethanesulfonic acid and 1 mL of trifluoroacetic acid at 0 °C, and react with mechanical stirring for 6 hours. Pour the viscous purple product into 1 M K2CO3 solution, soak at room temperature for 24 hours, filter to obtain a white solid product, wash thoroughly with deionized water and dry to obtain an intermediate polymer containing piperidine tertiary amine groups.

[0137] (3) Weigh 1.2g of the above intermediate polymer into a 100mL single-necked flask, add 15mL of dimethyl sulfoxide and 150μL of trifluoroacetic acid to promote polymer dissolution. After complete dissolution, add 0.36g of potassium carbonate and 0.32g of intermediate 1, and react at 60℃ for 16 hours.

[0138] (4) Then add 300 μL of iodomethane and react at room temperature for 24 h. The reaction product is poured into ethyl acetate to precipitate a yellow precipitate. After washing several times with ethyl acetate, the precipitate is washed with water and dried to obtain an anion of I. - Piperidinium-functionalized anion exchange polymers.

[0139] (5) Weigh 1g of the above anion exchange polymer, add 50mL of dimethyl sulfoxide, and dissolve it completely to obtain a polymer solution. Then pour the polymer solution into the groove of a flat glass plate and dry it at 80℃ for 48 hours to form a film, while simultaneously forming a cross-linked network structure in situ. After peeling the film off the glass plate, immerse it in 1M KOH solution and perform ion exchange at room temperature for 48 hours to obtain an anion of OH. - Anion exchange membrane.

[0140] The ion exchange capacity of anion exchange membranes was determined by titration; the OH- ions in pure water from a fully wet anion exchange membrane were measured using a four-electrode AC impedance method. - Ionic conductivity. The anion exchange membrane obtained in this example has an ion exchange capacity of 3.28 mmol / g and an ionic conductivity of 147 mS / cm at 80℃.

[0141] The swelling and tensile strength of the anion exchange membrane described in this embodiment were tested. OH groups were then subjected to swelling and tensile strength tests. - After washing the anion exchange membrane with ultrapure water, its swelling relative to the dry state membrane was tested. The anion exchange membrane obtained in this embodiment swelled by 20% at 80°C. The tensile strength of the anion exchange membrane at room temperature was measured using a tensile testing machine. The tensile strength of the anion exchange membrane obtained in this embodiment at room temperature was 74.6 MPa.

[0142] Example 2:

[0143] Anion exchange membrane prepared by grafting and crosslinking poly(p-terphenylpiperidine) with R1-TMA (p = 0.80):

[0144] The preparation method is the same as that in Example 1, except that in step (2), biphenyl is replaced with para-terphenyl.

[0145] The obtained anion exchange polymer has the following structure:

[0146]

[0147] The cross-linked anion exchange polymer contained in the obtained anion exchange membrane has the structure shown below:

[0148]

[0149] Example 3:

[0150] Anion exchange membrane prepared by grafting -R1-DMP (piperidine cation) onto poly(biphenylpiperidine) and crosslinking (p = 0.80):

[0151] The preparation method is the same as in Example 1, except that in step (1), trimethylamine is replaced with N-methylpiperidine, and the reaction formula of step (1) is as follows:

[0152]

[0153] The obtained anion exchange polymer has the following structure:

[0154]

[0155] The cross-linked anion exchange polymer contained in the obtained anion exchange membrane has the structure shown below:

[0156]

[0157] Example 4:

[0158] Anion exchange membrane prepared by grafting -R1-DMP onto poly(p-terphenylpiperidine) and crosslinking it (p = 0.80):

[0159] The preparation method is the same as in Example 2, except that in step (1), trimethylamine is replaced with N-methylpiperidine, and the reaction formula of step (1) is as follows:

[0160]

[0161] The obtained anion exchange polymer has the following structure:

[0162]

[0163] The cross-linked anion exchange polymer contained in the obtained anion exchange membrane has the structure shown below:

[0164]

[0165] Comparative Example 1:

[0166] Poly(biphenylpiperidine) anion exchange membrane

[0167]

[0168] (1) Weigh 1.54 g (10.0 mmol) of biphenyl into a 100 mL three-necked flask, add 1.36 g (12.0 mmol) of N-methyl-4-piperidinone, and add 10 mL of dichloromethane to dissolve the reactants. Add 12 mL of trifluoromethanesulfonic acid and 1 mL of trifluoroacetic acid at 0 °C, and react with mechanical stirring for 6 hours. Pour the viscous purple product into 1 M K2CO3 solution, soak at room temperature for 24 hours, filter to obtain a white solid product, wash thoroughly with deionized water and dry to obtain an intermediate polymer containing piperidine tertiary amine groups.

[0169] (2) Weigh 1.2 g of the above intermediate polymer into a 100 mL single-necked flask, add 15 mL of dimethyl sulfoxide, and then add 150 μL of trifluoroacetic acid to promote polymer dissolution. After complete dissolution, add 0.36 g of potassium carbonate and 300 μL of iodomethane, and react at room temperature for 24 h. Pour the reaction product into ethyl acetate to precipitate a yellow precipitate. Wash several times with ethyl acetate, then wash with water and dry to obtain an anion of I. - Piperidinium-functionalized anion exchange polymers.

[0170] (3) Weigh 1g of the above anion exchange polymer, add 50mL of dimethyl sulfoxide, and dissolve thoroughly to obtain a polymer solution. Then pour the polymer solution into the groove of a flat glass plate and dry it at 80℃ for 48 hours to form a film. After peeling the film off the glass plate, immerse it in 1M KOH solution and perform ion exchange at room temperature for 48 hours to obtain an anion of OH. - Anion exchange membrane.

[0171] Comparative Example 2:

[0172] Poly(p-terphenylpiperidine) anion exchange membrane

[0173]

[0174] The preparation method is the same as that of Comparative Example 1, except that in step (1), biphenyl is replaced with para-terphenyl.

[0175] The performance of the anion exchange membranes prepared in Examples 2-4 and Comparative Examples 1-2 was tested, and the test results are shown in the figure. Figure 1-4 .Depend on Figure 1-4 It is known that by grafting side chains with cationic groups onto the piperidine nitrogen of polyarylepiperidine polymers, and these side chains containing unsaturated double bonds, a cross-linked network can be formed in situ through thermal polymerization during the heating film formation process, resulting in a greater degree of cross-linking. This leads to the preparation of anion exchange membranes with a higher degree of grafting, thereby improving the ion exchange capacity and ion conductivity of the anion exchange membrane, as well as enhancing its mechanical strength and dimensional stability.

[0176] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0177] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. An anion exchange polymer, characterized in that, The polymer has the structure shown in formula (1): Equation (1) Ar1 and Ar2 are each independently selected from substituted or unsubstituted aryl groups; R1 is selected from one of the following structural formulas: ； R2 is selected from any of the following structural formulas: ； R3, R4, and R5 are each independently selected from any one of C1-C10 chain alkyl groups or C3-C10 cycloalkyl groups; X is an anion; 0.1 ≤ p < 1; n is an integer between 20 and 20000.

2. The anion exchange polymer according to claim 1, characterized in that, Ar1 and Ar2 are each independently selected from one of the following structural formulas: 。 3. The anion exchange polymer according to claim 1, characterized in that, 0.4≤p<1。 4. The anion exchange polymer according to claim 1, characterized in that, The anion exchange polymer comprises at least one of formulas (2)-(5): ； Equation (2) ； Equation (3) ； Equation (4) ； Equation (5).

5. A method for preparing anion exchange polymer according to any one of claims 1-4, characterized in that, Includes the following steps: (1) Compounds containing carbon-carbon double bonds with halogens at both ends and amine compounds are reacted in the first solvent to obtain side-chain compounds; (2) Aryl monomers and piperidinone monomers undergo polymerization under the action of a second solvent and a catalyst to obtain the first polymer; (3) The first polymer and the side chain compound are grafted in a third solvent to obtain a second polymer with grafted side chain compound; (4) The second polymer reacts with a quaternizing agent to obtain an anion exchange polymer.

6. The method for preparing the anion exchange polymer according to claim 5, characterized in that, The compounds containing carbon-carbon double bonds with halogens at both ends include at least one of 1,2-di(p-chloromethylphenyl)ethylene, 1,4-di(p-chloromethylphenyl)-2-butene, 1,4-di(p-chloroethylphenyl)-2-butene, and 1,10-dichloro-5-decene. The amine compounds include at least one of trimethylamine, N-methylpiperidine, 4-azadamane, N-methylimidazole, and N,2,4,5-tetramethylimidazole; The aryl monomer includes at least one of biphenyl, p-terphenyl, m-terphenyl, p-tetraphenyl, diphenylmethane, 1,2-diphenylethane, and 9,9'-dimethylfluorene; The piperidone monomers include at least one of N-methyl-4-piperidinone, N-ethyl-4-piperidinone, and N-propyl-4-piperidinone; The quaternizing agent includes at least one of iodomethane, iodoethane, iodopropane, iodobutane, iodopentane, iodohexane, bromoethane, bromopropane, bromobutane, bromopentane, bromohexane, bromocyclopropane, bromocyclobutane, bromocyclopentane, or bromocyclohexane. The molar ratio of the compound containing carbon-carbon double bonds with halogens at both ends to the amine compound is 1~100:1; The molar ratio of the aryl monomer to the piperidinone monomer is 1:1 to 10; The molar ratio of the first polymer to the side-chain compound is 1:0~1; The molar ratio of the second polymer to the quaternizing agent is 1:1 to 50.

7. The method for preparing the anion exchange polymer according to claim 5, characterized in that, In step (1), the reaction temperature is 10-40℃; the reaction time is 3-24h; the first solvent includes at least one of dichloromethane, trichloromethane, tetrachloroethane, and toluene. In step (2), the polymerization reaction temperature is -5 to 5°C; the polymerization reaction time is 6 to 72 hours; the second solvent includes at least one of dichloromethane, trichloromethane, tetrachloroethane, and toluene; the catalyst includes at least one of trifluoromethanesulfonic acid, trifluoroacetic acid, and methanesulfonic acid; after the polymerization reaction, the product is added to an alkaline solution for soaking and washing; the alkaline solution includes at least one of sodium carbonate solution, potassium carbonate solution, potassium bicarbonate solution, sodium bicarbonate solution, sodium hydroxide solution, or potassium hydroxide solution; the concentration of the alkaline solution is 0.1 to 10 mol / L; the soaking time is 1 to 48 hours. In step (3), the temperature of the grafting reaction is 40~80℃; the time of the grafting reaction is 10~60h; the third solvent includes at least one of dimethyl sulfoxide, 1-methyl-2-pyrrolidone, dimethylformamide or dimethylacetamide; In step (3), the first polymer is added to the third solvent, trifluoroacetic acid is added, potassium carbonate and the side chain compound are added after the first polymer is dissolved, and then a grafting reaction is carried out. In step (4), the reaction temperature is 10-40℃; the reaction time is 6-72h; after the reaction, the product is added to a poor solvent to precipitate the polymer, and then washed and dried to obtain anion exchange polymer; the poor solvent includes at least one of ethyl formate, ethyl acetate, propyl acetate, butyl acetate, ethyl propionate, ethyl butyrate, propyl propionate, butyl propionate, and propyl butyrate.

8. An anion exchange membrane, characterized in that, The anion exchange polymer prepared by any one of claims 1-4 or by any one of claims 5-7 is prepared.

9. A method for preparing the anion exchange membrane according to claim 8, characterized in that, include: The anion exchange polymer is dissolved in a solvent to obtain a solution, which is then spread evenly on a plane and heated to form a film. The obtained membrane is immersed in an alkaline solution for ion exchange to obtain an anion exchange membrane.

10. The method for preparing the anion exchange membrane according to claim 9, characterized in that, The solvent is at least one of dimethyl sulfoxide, 1-methyl-2-pyrrolidone, dimethylformamide, or dimethylacetamide; the mass ratio of the anion exchange polymer to the solvent is 1~20:100; the heating temperature is 70~120℃; the heating time is 12~72h; the alkaline solution includes at least one of 0.1~10M KOH solution and 0.1~10M NaOH solution; the ion exchange time is 12~72h.

11. The application of an anion exchange membrane according to claim 8 or an anion exchange membrane prepared by the preparation method according to claim 9 or 10, characterized in that, The anion exchange membrane is used in alkaline fuel cells or water electrolyzers.

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