Branched block type polyaryl piperidine polymer, anion exchange membrane and preparation method and application thereof

Abstract

The invention provides a branched block type polyaryl piperidine polymer, an anion exchange membrane as well as a preparation method and application of the branched block type polyaryl piperidine polymer and the anion exchange membrane. The polymer comprises a branched structure unit and a block linear structure unit, the branched structural unit is a branched phenyl monomer Ar1, and the block linear structural unit comprises a linear phenyl monomer Ar2 and a linear phenyl monomer Ar3, and is prepared by condensation polymerization of the branched phenyl monomer, the linear phenyl monomer and N-methyl-4-piperidone under catalysis of trifluoroacetic acid and trifluoromethanesulfonic acid. The polymer is subjected to further membrane treatment and alkali treatment processes to obtain the anionic polymer membrane. The process for preparing the anion exchange membrane is simple, not only is the yield high, but also good balance of ionic conductivity, dimensional stability and alkali stability of the membrane is realized.

Description

Technical Field

[0001] The invention relates to the field of water electrolyzer membrane materials, and in particular to a branched block polyaryl piperidine polymer, an anion exchange membrane, and a preparation method and application thereof. Background Art

[0002] With the rapid development of society and the acceleration of industrialization, the energy crisis and resource shortage of conventional fossil fuels such as coal, natural gas, and oil are becoming increasingly serious. Hydrogen (H2), as a potential energy carrier, plays a vital role in the field of zero carbon emissions due to its many advantages such as high energy content, sustainability, and non-toxicity. Among them, anion exchange membrane water electrolyzer (AEMWE) is considered to be one of the most promising sustainable hydrogen production technologies. This technology can not only use platinum group metal-free catalysts, but also adopt low-cost anode flow fields and bipolar plates to achieve water separation. Therefore, AEMWE technology is highly cost-effective.

[0003] Anion exchange membrane (AEM) is a key component of AEMWE, and its performance directly affects the effectiveness of the entire system. AEM is usually made of polymers containing cationic groups that can transport OH - ions and water molecules. However, most existing polymers, such as polyetheretherketone (PEEK), polysulfone (PSF), poly(phenylene ether) (PPO), polybenzimidazole (PBI), etc. and their cationic groups (such as ammonium, imidazole, molybdenum, phosphine and organometallic cations, etc.) tend to degrade under alkaline conditions. In addition, under similar ion exchange capacity (IEC), the OH of AEM - The conductivity is much lower than that of the proton exchange membrane (PEM) + conductivity, which is due to OH - Lower mobility and incomplete dissociation of quaternary ammonium hydroxide. Therefore, in order to achieve ionic conductivity equivalent to PEM, AEM needs to have a higher IEC. However, too high IEC will lead to high water absorption and swelling, which in turn damages the mechanical stability of AEM. Therefore, the development of anion exchange membranes with both high conductivity and excellent stability has become a hot topic and focus of current research. Summary of the invention

[0004] In view of this, the present invention proposes a branched block polyaryl piperidine polymer, anion exchange membrane and its preparation method and application to obtain anion exchange membrane with high conductivity and excellent stability, so that it can be suitable for energy conversion and storage devices such as alkaline water electrolysis and fuel cells.

[0005] In a first aspect, the present invention provides a branched block polyaryl piperidine polymer, wherein the polymer comprises a branched structural unit and a block linear structural unit; the branched structural unit is a branched phenyl monomer Ar1, and the block linear structural unit comprises a linear structure phenyl monomer Ar2 and a linear structure phenyl monomer Ar3;

[0006] The Ar1 is selected from one or more of triphenylbenzene, triptycene or triindene; the Ar2 is selected from biphenyl, p-terphenyl, fluorene or 1,2-diphenylethane; the Ar3 is selected from 5,5'-dimethoxy-1,1,1',1'-tetramethyl-3,3'-spirobiindene or its derivatives.

[0007] Among them, the preferred structural formula of the branched phenyl monomer Ar1 of the present invention is as shown in formula (II) to (IV):

[0008]

[0009] Formula (II) is triphenylbenzene, formula (III) is triptycene, and formula (IV) is trimerized indene.

[0010] The preferred linear phenyl monomer Ar2 of the present invention has a structural formula as shown in formulas (V) to (VIII):

[0011]

[0012] Formula (V) is biphenyl, formula (VI) is p-terphenyl, formula (VII) is fluorene, and formula (VIII) is 1,2-diphenylethane.

[0013] The preferred linear phenyl monomer Ar3 of the present invention has a structural formula as shown in formulas (IX) to (XI):

[0014]

[0015] Formula (IX) is 5,5'-dimethoxy-1,1,1',1'-tetramethyl-3,3'-spirobiindene, and formulas (X) and (XI) are both derivatives of formula (IX).

[0016] Furthermore, the branched block polyaryl piperidine polymer of the present invention uses the branched phenyl monomer Ar1 as the basic skeleton, and the linear structure phenyl monomer Ar2 and the linear structure phenyl monomer Ar3 are embedded in the branch chain. The embedding method is not limited in any way. The structural formula of the preferred polymer of the present invention is shown in formula (I):

[0017]

[0018] In formula (I), m is the molar proportion of the branched structural unit in the polymer, x and y are the molar proportions of the block linear structural unit in the polymer, respectively, and the ratio of m to (x+y) is 1-10:99-90; the values ​​of x and y are independently selected from 1 to 99.

[0019] On the basis of the above technical solution, preferably, the degree of polymerization of the branched phenyl monomer Ar1 is 1 to 100, the degree of polymerization of the linear structure phenyl monomer Ar2 is 9 to 9900, and the degree of polymerization of the linear structure phenyl monomer Ar3 is 9 to 9900.

[0020] In a second aspect, the present invention provides a method for preparing the above-mentioned branched block polyaryl piperidine polymer, wherein the polymer is prepared by polycondensation reaction of branched phenyl monomers, linear phenyl monomers and N-methyl-4-piperidone under the catalysis of trifluoroacetic acid and trifluoromethanesulfonic acid. The method specifically comprises the following steps:

[0021] S1. Mix bisphenol A and methanesulfonic acid under stirring to prepare the product 5,5-dihydroxy-1,1,1,1-tetramethyl-3,3-spirobiaindene (TTSBD), dissolve it in N,N-dimethylformamide, add K2CO3 and alkyl halide to obtain a mixed solution, crystallize, wash, and vacuum dry to obtain a linear structure phenyl monomer Ar3;

[0022] S2, mix branched phenyl monomer Ar1, linear phenyl monomers Ar2, Ar3 and N-methyl-4-piperidone, stir, add trifluoroacetic acid (TFA) and trifluoromethanesulfonic acid (TFSA) dropwise, pour the obtained solution into organic solvent 2, and obtain a branched block polyaryl piperidine polymer.

[0023] On the basis of the above technical scheme, preferably, in step S1, the mixing temperature of bisphenol A and methanesulfonic acid is 135°C, and the mixing time is 4 to 6 hours. In the present invention, 1 ml of methanesulfonic acid corresponds to 10 g of bisphenol A; when the temperature of the mixed solution gradually changes from wine red to dark red, a solvent, such as deionized water, can be used to precipitate the powder. In addition, the present invention requires purification of the powder, and the purification method can be various. The present invention preferably uses a mixed solvent of ethanol and water in any mass ratio to recrystallize and purify the powder. It is further preferred that the mass ratio of ethanol and water is set to 40:60. After purification, a white needle-shaped product TTSBD is obtained.

[0024] Based on the above steps, the present invention further needs to process the white needle-shaped product TTSBD. During the processing, the operation sequence is not in particular order, and the operations include but are not limited to: drying, modification, crystallization, washing and vacuum drying. The preferred operation steps of the present invention are specifically manifested as:

[0025] After drying the white needle-like product TTSBD at 80°C for 24 hours, dissolve it in N,N-dimethylformamide, add K2CO3 and alkyl halide, store it in the dark at room temperature for 24 hours, and then slowly pour the mixed solution into ice water under vigorous stirring to precipitate solids. The solids are filtered and washed with deionized water several times. Finally, vacuum dry it at 80°C for 24 hours.

[0026] Based on the above steps, in the present invention, every 40 to 50 ml of N,N-dimethylformamide corresponds to 4 to 5 g of TTSBD, and the molar ratio of the K2CO3 to the TTSBD is 1:1 to 1.5, and the molar ratio of the TTSBD to the alkyl halide is 1:2.5-3; the alkyl halide is preferably one or more of iodomethane, iodoethane, iodobutane, 2,2,2-trifluoro-1-iodoethane, 2,2,3,3,3-pentafluoro-1-iodopropane or 2,2,3,3,4,4,4-heptafluoro-1-iodobutane.

[0027] On the basis of the above technical scheme, preferably, in step S2, branched phenyl monomer Ar1, linear phenyl monomer Ar2, Ar3 and N-methyl-4-piperidone need to be mixed in organic solvent 1. In the present invention, the mixing temperature is 0-25°C, the mixing time is 30-60min, and it is completed under stirring conditions. Wherein, organic solvent 1 is selected from dichloromethane and / or chloroform, and every 10-15ml of organic solvent 1 corresponds to 5-15mmol of N-methyl-4-piperidone.

[0028] More preferably, in step S2, the molar ratio of the branched phenyl monomer to the linear phenyl monomer is (1-10):(99-90); the molar ratio of the linear phenyl monomer to the N-methyl-4-piperidone is 1:(1-1.5); the molar ratio of the trifluoroacetic acid to the N-methyl-4-piperidone is (1-2):1; the molar ratio of the trifluoromethanesulfonic acid to the N-methyl-4-piperidone is (8-12):1.

[0029] On the basis of the above technical scheme, preferably, in step S2, after dripping trifluoroacetic acid and trifluoromethanesulfonic acid, mix for 2 to 24 hours to obtain a viscous solution, which is added to an organic solvent 2 to obtain a branched block polyaryl piperidine polymer. Wherein, the organic solvent 2 is selected from one or more of methanol, ethanol, water or acetone, and the volume ratio of the organic solvent 1 to the organic solvent 2 is 1: (10 to 30).

[0030] Furthermore, the present invention also relates to the use of the branched block polyaryl piperidine polymer in the preparation of anion exchange membranes.

[0031] In a third aspect, the present invention relates to a method for preparing an anion exchange membrane, wherein the anion exchange membrane is obtained by subjecting the branched block polyaryl piperidine polymer prepared by the above method to membrane treatment and alkali treatment processes.

[0032] The method comprises the following steps:

[0033] A1, quaternizing the branched block polyaryl piperidine polymer to obtain a quaternized polyaryl piperidine polymer;

[0034] A2, dissolving the quaternized polyaryl piperidine polymer of step A1, filtering, spreading, and drying to obtain I - Type film;

[0035] A3, alkali solution soaking step A2 I - The membrane is formed into a thin film and washed to obtain an anion exchange membrane.

[0036] Furthermore, in step A1, the branched block polyaryl piperidine polymer is subjected to quaternization treatment to obtain a quaternized polyaryl piperidine polymer, which specifically comprises the following steps:

[0037] The branched block polyaryl piperidine polymer is crushed, washed, dried at 80°C for 24 hours, added to organic solvent 3, and potassium carbonate is added, stirred for 30 to 60 minutes, and then iodomethane is added dropwise, and stored in the dark for 24 to 48 hours. The obtained clear solution is added dropwise to organic solvent 4 to obtain a light yellow precipitate, which is filtered and dried in vacuum at 60 to 80°C for 12 to 24 hours to obtain a quaternized polyaryl piperidine polymer.

[0038] On the basis of the above technical scheme, preferably, when the polymer is quaternized, the monomer should be excessive and it should be carried out under light-proof conditions. Further preferably, the monomer can be any monomer with the highest activity (such as methyl iodide, methyl bromide, etc.), and the present invention recommends the use of methyl iodide.

[0039] On the basis of the above technical scheme, preferably, the mass ratio of the branched block polyaryl piperidine polymer to the organic solvent 3 is (1-10):100, the molar ratio of the branched block polyaryl piperidine polymer to the potassium carbonate is 1:(1-2), the molar ratio of the branched block polyaryl piperidine polymer to the methyl iodide is 1:(1.5-3), and the volume ratio of the organic solvent 3 to the organic solvent 4 is 1:(2-5); the organic solvent 3 is selected from one or more of dimethyl sulfoxide (DMSO), N,N-dimethylformamide, N-methylpyrrolidone or N or N-dimethylacetamide; the organic solvent 4 is selected from one or more of methanol, ethanol, water, ethyl acetate or diethyl ether.

[0040] Further, the step A2 specifically comprises: dissolving the quaternized polyaryl piperidine polymer in an organic solvent 5 to obtain a polymer solution; filtering with a 0.25-1 μm polytetrafluoroethylene (PTFE) filter, casting the filtered polymer solution on a glass plate to spread it, drying at 50-80° C. for 8-12 h, and vacuum drying at 120-140° C. for 12-36 h to completely remove the residual solvent to obtain I - Type membrane.

[0041] On the basis of the above technical scheme, preferably, the mass ratio of the quaternized polyaryl piperidine polymer to the organic solvent 5 is (1-10):100; the organic solvent 5 is selected from one or more of dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylformamide or N,N-dimethylacetamide.

[0042] Further, the step A3 specifically comprises: - The film was peeled off from the glass plate, immersed in alkaline solution at 60-80°C for 8-12 hours, and washed several times to obtain OH - Type anion exchange membrane.

[0043] On the basis of the above technical solution, preferably, the alkali solution is NaOH or KOH solution with a concentration of 0.5-2.0M.

[0044] In the present invention, the purpose of the multiple washings is to remove residual salts; in order to avoid CO2 pollution and the formation of carbonates, the OH - The anion exchange membrane needs to be stored in deionized water with nitrogen.

[0045] In a fourth aspect, the present invention relates to an anion exchange membrane, which is prepared by steps A1 to A3 and has a thickness of 20 to 50 μm.

[0046] Furthermore, it also includes: application of the anion exchange membrane of the present invention in an alkaline water electrolyzer.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] (1) The branched block polyaryl piperidine polymer of the present invention adopts a one-pot method to polymerize the polymer monomer under superacid conditions, and by introducing branched structural units, the interconnection between the linear main chains is enhanced, thereby improving the dimensional stability of the anion exchange membrane. At the same time, by introducing block linear structural units, the formation of a microphase separation structure inside the polymer is promoted.

[0049] (2) The branched block polyaryl piperidine polymer of the present invention introduces 5,5'-dimethoxy-1,1,1',1'-tetramethyl-3,3'-spirobiindene and its derivatives through the linear structure phenyl monomer Ar3. Since such monomers have the characteristics of large spatial structure and rigid hydrophobicity, the polymer structure has a larger free volume and steric hindrance, thereby significantly improving the ion conductivity and alkaline stability of the anion exchange membrane.

[0050] (3) The process for preparing anion exchange membranes according to the present invention is simple and has high yield and also achieves a good balance among the ion conductivity, dimensional stability and alkaline stability of the membranes. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0052] Figure 1 The hydrogen nuclear magnetic resonance spectrum of the quaternized polyaryl piperidine polymer prepared in Example 1 of the present invention;

[0053] Figure 2 The hydrogen nuclear magnetic resonance spectrum of the quaternized polyaryl piperidine polymer prepared in Example 2 of the present invention;

[0054] Figure 3 The figure is a comparison chart of the ion conductivity of the anion exchange membranes prepared in the embodiment of the present invention and the comparative example. DETAILED DESCRIPTION

[0055] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] The present invention is further described below in conjunction with specific examples, and the protection scope of the present invention is not limited by the following examples. The sources of materials mainly involved in the examples are all conventional commercial products.

[0057] Example 1

[0058] This embodiment provides a branched block anion exchange membrane containing characteristic groups, and the anion exchange membrane is prepared by the following method:

[0059] (1) Mix 10g of bisphenol A and 1ml of methanesulfonic acid under stirring, keep at 135℃ for 4h, until the color of the mixed solution changes from wine red to dark red, pour it into 50ml of deionized water to precipitate solid. Recrystallize and purify the solid in a mixed solvent of ethanol and water with a mass ratio of 40:60 to obtain a white needle-shaped product TTSBD; dry it at 80℃ for 24h, then dissolve TTSBD (4.63g, 15mmol) in 50ml of N,N-dimethylformamide, add K2CO3 (8.32g, 65mmol) and iodomethane (12.5g, 90mmol), and store it at room temperature (25-40℃, the same below) in the dark for 24h. The mixture solution was slowly poured into vigorously stirred ice water to precipitate a solid, namely 5,5'-dimethoxy-1,1,1',1'-tetramethyl-3,3'-spirobiindene (DM-TTSBD), which was washed several times with deionized water and finally dried under vacuum at 80°C for 24h;

[0060] (2) Add p-terphenyl (5.745 g, 24.948 mmol), triphenylbenzene (0.0858 g, 0.28 mmol), DM-TTSBD (0.9327 g, 2.772 mmol) and N-methyl-4-piperidone (3.87 g, 34.2 mmol) to dichloromethane (24 ml), stir at -1°C for 30 min to obtain a light reddish brown mixed solution, add TFA (3.66 ml) and TFSA (30 ml) dropwise thereto, stir for 2-3 h, until the color of the mixed solution changes from light reddish brown to dark brown; pour the mixed solution into 300 ml of ethanol to precipitate a light brown polymer. Then wash with deionized water three times, and vacuum dry at 80°C for 24 h to obtain a branched block polyaryl piperidine polymer;

[0061] (3) suspending the branched block polyaryl piperidine polymer (1 g) in DMSO (30 ml), adding K2CO3 (1 g), stirring at room temperature for 30 min, adding iodomethane (1 ml), stirring at room temperature in the dark for 24 h, and adding 60 ml of ethyl acetate to the obtained clear viscous solution to obtain a light yellow precipitate, filtering, washing with deionized water three times, and vacuum drying at 80°C for 24 h to obtain a quaternized polyaryl piperidine polymer;

[0062] (4) The quaternized polyaryl piperidine polymer (0.3 g) was dissolved in DMSO (10 ml), and the polymer solution was filtered using a 1 μm polytetrafluoroethylene (PTFE) filter, cast on a clean glass plate, and spread, dried at 80° C. for 24 h, and vacuum dried at 140° C. for 12 h to completely remove the residual solvent, thereby obtaining a 50 μm thick I - Type film;

[0063] (5) Will I- The film was peeled off from the glass plate and immersed in 1M KOH solution at 80℃ for 12h to obtain OH - The membrane was washed three times with deionized water to avoid CO2 contamination and carbonate formation. - The membrane was stored in deionized water with nitrogen.

[0064] The anion exchange membrane prepared in this example was tested by Bruker AVANCE III 500MHz, and the following results were obtained: Figure 1 The H NMR spectrum shown is 1 H-NMR).

[0065] Example 2

[0066] This embodiment provides a branched block anion exchange membrane, which is different from the embodiment 1 in that a derivative of a specific group is added, and the anion exchange membrane is prepared by the following method:

[0067] (1) Under stirring conditions, 10 g of bisphenol A and 1 ml of methanesulfonic acid were mixed and kept at 135°C for 4 h until the color of the mixed solution changed from wine red to dark red, and then poured into 50 ml of deionized water to precipitate a solid. The solid was recrystallized and purified in a mixed solvent of ethanol and water in a mass ratio of 40:60 to obtain a white needle-shaped product TTSBD; it was placed at 80°C and dried for 24 h, and then TTSBD (4.63 g, 15 mmol) was dissolved in 50 ml of N, N-dimethylformamide, K2CO3 (8.32 g, 65 mmol) and 2,2,3,3,4,4,4-heptafluoro-1-iodobutane (27.9 g, 90 mmol) were added, and stored at room temperature in the dark for 24 h. The mixture solution was slowly poured into vigorously stirred ice water to precipitate a solid, namely, HF-TTSBD (5,5'-heptafluorobutoxy-1,1,1',1'-tetramethyl-3,3'-spirobiindene), which was washed several times with deionized water and finally dried under vacuum at 80°C for 24 h;

[0068] The DM-TTSBD in step (2) was replaced by HF-TTSBD, and the other steps were the same as those in Example 1.

[0069] The anion exchange membrane prepared in this example was tested by Bruker AVANCE III 500MHz, and the following results were obtained: Figure 2 The H NMR spectrum shown is 1 H-NMR).

[0070] Comparative Example 1

[0071] This comparative example provides a branched block anion exchange membrane without a characteristic group, which differs from Example 1 in that step (1) is not included and an equimolar amount of biphenyl is used to replace the specific group. The anion exchange membrane is prepared by the following method:

[0072] (2) Add terphenyl (5.745 g, 24.948 mmol), triphenylbenzene (0.0858 g, 0.28 mmol), biphenyl (0.427 g, 2.772 mmol) and N-methyl-4-piperidone (3.87 g, 34.2 mmol) to dichloromethane (24 ml), stir at 0°C for 30 min to obtain a yellow mixed solution, add TFA (3.66 ml) and TFSA (30 ml) dropwise thereto, stir for 2 to 3 h, until the color of the mixed solution changes from yellow to dark brown; pour the obtained solution into 300 ml of ethanol to precipitate a light yellow polymer. Then wash three times with deionized water, dry in a vacuum oven at 80°C for 24 h, and vacuum dry at 80°C for 24 h to obtain a branched block polyaryl piperidine polymer;

[0073] The other steps are the same as in Example 1.

[0074] The branched block polyaryl piperidine polymer prepared in this comparative example has the following formula:

[0075]

[0076] Comparative Example 2

[0077] This comparative example provides a branched anion exchange membrane with characteristic groups, which is different from Example 1 in that it does not contain a linear phenyl monomer Ar2. The anion exchange membrane is prepared by the following method:

[0078] (2) Add DM-TTSBD (9.314 g, 27.72 mmol), triphenylbenzene (0.0858 g, 0.28 mmol) and N-methyl-4-piperidone (3.87 g, 34.2 mmol) to dichloromethane (24 ml), stir at 0°C for 30 min to obtain a yellow mixed solution, add TFA (3.66 ml) and TFSA (30 ml) dropwise thereto, stir for 2 to 6 h, until the color of the mixed solution changes from yellow to dark brown; pour the obtained solution into 300 ml of ethanol to precipitate a light yellow polymer. Then wash with deionized water three times, and vacuum dry at 80°C for 24 h to obtain a branched block polyaryl piperidine polymer;

[0079] The other steps are the same as in Example 1.

[0080] The branched block polyaryl piperidine polymer prepared in this comparative example has the following formula:

[0081]

[0082] Comparative Example 3

[0083] This comparative example provides a branched anion exchange membrane with characteristic groups, which is different from Example 1 in that it does not contain a linear phenyl monomer Ar1. The anion exchange membrane is prepared by the following method:

[0084] (2) Add DM-TTSBD (2.016 g, 6 mmol), p-terphenyl (5.52 g, 24 mmol) and N-methyl-4-piperidone (4.073 g, 36 mmol) to dichloromethane (24 ml), stir at 0°C for 30 min to obtain a yellow mixed solution, add TFA (3.66 ml) and TFSA (30 ml) dropwise thereto, stir for 8 to 10 h, until the color of the mixed solution changes from yellow to dark brown; pour the obtained viscous solution into 300 ml of deionized water to precipitate a light yellow polymer. Then wash with ethanol three times and vacuum dry at 80°C for 24 h to obtain a block-type polyaryl piperidine polymer;

[0085] The other steps are the same as in Example 1.

[0086] The branched block polyaryl piperidine polymer prepared in this comparative example has the following formula:

[0087]

[0088] The anion exchange membranes prepared in Examples 1 to 2 and Comparative Examples 1 to 3 were tested for ionic conductivity, which was measured by Autolab PGSTAT302N equipped with Scribner 740MTS. Membrane samples with a size of 10 mm × 30 mm were assembled in a four-electrode cell and tested using an AC impedance with a frequency range of 1 Hz to 0.1 MHz. The measurements were performed at different temperatures and 100% relative humidity (RH). The ionic conductivity σ (mS cm-1) of the membrane sample can be calculated by the following formula:

[0089]

[0090] Where L (cm) is the distance between the working electrode and the counter electrode, A (cm 2 ) is the cross-sectional area calculated by the thickness (cm) and width (cm) of the membrane sample, and R (kΩ) is the ohmic impedance obtained from the electrochemical impedance spectroscopy. Figure 3 shown.

[0091] Depend on Figure 3It can be seen that the ionic conductivity of Examples 1 and 2 is greater than that of the comparative example and the commercial membrane (FAA-3-50, purchased from the Science Materials Station, developed by FuMa-Tech, Germany). The introduction of the fluorinated monomer in Example 2 promotes the microphase separation structure of the polymer, and its conductivity is the highest. Compared with Comparative Example 1, the monomers introduced in Examples 1 and 2 have the characteristics of large spatial structure and rigid hydrophobicity, so that the polymer structure has a larger free volume and steric hindrance; compared with Comparative Example 2, the introduction of the second type of block monomer promotes the microphase separation structure of the polymer; compared with Comparative Example 3, the introduction of branched structural units enhances the interconnection between the linear main chains, thereby significantly improving the ionic conductivity of the anion exchange membrane.

[0092] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A branched block polyaryl piperidine polymer, characterized in that: The polymer comprises a branched structural unit and a block linear structural unit; the branched structural unit is a branched phenyl monomer Ar1, and the block linear structural unit comprises a linear phenyl monomer Ar2 and a linear phenyl monomer Ar3; The Ar1 is selected from one or more of triphenylbenzene, triptycene or triindene; the Ar2 is selected from biphenyl, p-terphenyl, fluorene or 1,2-diphenylethane; the Ar3 is selected from 5,5'-dimethoxy-1,1,1',1'-tetramethyl-3,3'-spirobiindene or its derivatives.

2. The branched block polyarylpiperidine polymer according to claim 1, characterized in that: The structural formula of the polymer is shown in formula (I): In formula (I), m is the molar proportion of the branched structural unit in the polymer, x and y are the molar proportions of the block linear structural unit in the polymer, respectively, and the ratio of m to (x+y) is 1-10:99-90; the values ​​of x and y are independently selected from 1 to 99.

3. A method for preparing the branched block polyaryl piperidine polymer according to claim 1 or 2, characterized in that: The polymer is prepared by polycondensation reaction of branched phenyl monomers, linear phenyl monomers and N-methyl-4-piperidone under the catalysis of trifluoroacetic acid and trifluoromethanesulfonic acid.

4. The method according to claim 3, characterized in that The method comprises the following steps: S1. Mix bisphenol A and methanesulfonic acid under stirring to obtain a product TTSBD, dissolve it in N,N-dimethylformamide, add K2CO3 and an alkyl halide to obtain a mixed solution, crystallize, wash, and vacuum dry to obtain a linear structure phenyl monomer Ar3; S2, mixing branched phenyl monomer Ar1, linear phenyl monomer Ar2, linear phenyl monomer Ar3 obtained in step S1 and N-methyl-4-piperidone, stirring, adding trifluoroacetic acid and trifluoromethanesulfonic acid dropwise, pouring the obtained solution into organic solvent 2, and obtaining a branched block polyaryl piperidine polymer.

5. The method according to claim 4, characterized in that In step S2, the molar ratio of the branched phenyl monomer to the linear phenyl monomer is (1-10): (99-90); the molar ratio of the linear phenyl monomer to the N-methyl-4-piperidone is 1: (1-1.5); the molar ratio of the trifluoroacetic acid to the N-methyl-4-piperidone is (1-2): 1; the molar ratio of the trifluoromethanesulfonic acid to the N-methyl-4-piperidone is (8-12):

1.

6. Use of the branched block polyaryl piperidine polymer prepared by the method according to any one of claims 3 to 5 in the preparation of anion exchange membranes.

7. A method for preparing an anion exchange membrane, characterized in that: The anion exchange membrane is obtained by subjecting the branched block polyaryl piperidine polymer prepared by the method according to any one of claims 3 to 5 to membrane treatment and alkali treatment processes.

8. The preparation method according to claim 7, characterized in that: The method comprises the following steps: A1, quaternizing the branched block polyaryl piperidine polymer to obtain a quaternized polyaryl piperidine polymer; A2, dissolving the quaternized polyaryl piperidine polymer of step A1, filtering, spreading, and drying to obtain I - Type film; A3, alkali solution soaking step A2 I - The membrane is formed into a thin film and washed to obtain an anion exchange membrane.

9. An anion exchange membrane prepared by the preparation method according to claim 7 or 8, characterized in that: The thickness of the anion exchange membrane is 20-50 μm.

10. Use of the anion exchange membrane as claimed in claim 9 in an alkaline water electrolyzer.

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