High-branching-degree polymer based on tetraphenylmethane, anion exchange membrane and preparation method of anion exchange membrane

Abstract

The invention relates to a high-branching-degree polymer based on tetraphenylmethane, an anion exchange membrane and a preparation method of the high-branching-degree polymer. The polymer has a repeating unit shown as a formula 1, wherein Ar1, Ar2, Ar3 and Ar4 are respectively and independently selected from biaryl compound monomers with linear structures; r is a nitrogen-containing heterocyclic group; x is the molar ratio of the three-dimensional tetraphenylmethane branched structural unit in the polymer; y = y1 + y2 + y3 + y4 which is the molar ratio of a linear structure repeating unit in the polymer; x + y = 100%, and x = 2.5%-10%; according to the anion exchange membrane, the swelling property of the anion exchange membrane is greatly reduced, and the ionic conductivity and the mechanical property of the anion exchange membrane are improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of anion exchange membrane materials, and particularly relates to a high-branched degree polymer based on tetraphenylmethane, an anion exchange membrane and a preparation method thereof. BACKGROUND

[0002] With the continuous growth of global energy demand and the non-renewable problem of traditional fossil energy, developing efficient and clean energy technology has become the core proposition of energy revolution. As the key component of fuel cells, water electrolysis hydrogen production and other electrochemical devices, anion exchange membranes (AEMs) exhibit significant technical advantages due to their alkaline operating environment: on the one hand, it can break through the dependence on platinum group noble metal catalysts, and use non-precious metals such as nickel and cobalt to achieve efficient oxygen evolution reaction; on the other hand, by using industrial-grade chemicals to prepare membrane materials and nickel-plated stainless steel bipolar plates and other components, the system cost is greatly reduced; at the same time, the alkaline medium endows the catalyst with higher stability, effectively prolonging the service life of the equipment. However, the existing perfluoro / hydrocarbon polymer-based electrolyte membrane relies on microphase separation to form disordered ion conduction zones, and the size distribution of the ion channels is uncontrollable, resulting in an inherent contradiction between ion conductivity and selective permeability, which seriously restricts the energy efficiency and cycle stability of the battery. Especially under high-concentration alkaline conditions, the chemical degradation (such as the rupture of the aromatic skeleton, the degradation of quaternary ammonium salt, etc.) and mechanical degradation of traditional materials further limit the durability of AEMs.

[0003] Therefore, it is of great importance to develop a high-branched degree polymer based on tetraphenylmethane with high ion conductivity, low swelling rate and water absorption rate, and good mechanical properties, an anion exchange membrane and a preparation method thereof, for improving the long-term stability and efficiency of electrochemical devices. SUMMARY

[0004] The present application aims to overcome the defects in the prior art and provides a high-branched degree polymer based on tetraphenylmethane, an anion exchange membrane and a preparation method thereof, which greatly reduces the swelling of the anion exchange membrane and improves its ion conductivity and mechanical properties.

[0005] To achieve the above-mentioned purpose, the technical solutions adopted by the present application are as follows: A high-branched degree polymer based on tetraphenylmethane has a repeating unit as shown in formula 1: Formula 1; Wherein, Ar1, Ar2, Ar3, Ar4 are independently selected from linear structure biaryl compound monomers; R is a nitrogen-containing heterocyclic group; x represents the molar percentage of the three-dimensional tetraphenylmethane branched structural unit in the polymer; y = y1 + y2 + y3 + y4 represents the molar percentage of the linear repeating structural unit in the polymer; x + y = 100%, x = 2.5-10%; y = 90-97.5%.

[0006] As a further technical solution, Ar1, Ar2, Ar3, and Ar4 are each independently selected from... , , , .

[0007] As a further technical solution, R is selected from... , , Any one of them.

[0008] As a further technical solution, in the three-dimensional tetraphenylmethane branched structural unit, the structure of the three-dimensional tetraphenylmethane is shown in Formula 2. Formula 2.

[0009] A method for preparing the highly branched polymer based on tetraphenylmethane includes the following steps: Under ice-water bath conditions, tetraphenylmethane, biaryl compound monomers, and ketone monomers were dissolved in a first solvent. Then, trifluoroacetic acid (TFA) and trifluoromethanesulfonic acid (TFSA) were added dropwise while stirring. After stirring for 2-72 hours, the reaction was stopped, and the reaction solution was poured into a second solvent. The solid, i.e., the polymer, was collected. Excess acid in the solid polymer was washed away with a first alkaline solution, and the polymer was washed with deionized water until neutral. The polymer was then dried in a vacuum oven to obtain a highly branched polymer with a tetraphenylmethane central molecule.

[0010] As a further technical solution, the biaryl compound monomer is selected from one or more of biphenyl, p-terphenyl, m-terphenyl, and tetraphenyl; The molar ratio of tetraphenylmethane to biaryl compound monomers is (1-20):(99-80); The molar ratio of biaryl compound monomers to ketone monomers is 1:(1-2); The molar ratio of ketone monomers, trifluoroacetic acid, and trifluoromethanesulfonic acid is 1:(0.8–2):(8–1.2). The first solvent is one or more of dichloromethane solution, trichloromethane, and 1,2-dichloroethane; The second solvent is one or more of water, ethyl acetate, methanol, ethanol, diethyl ether, tetrahydrofuran, or acetone; The concentration of the first alkaline solution is 0.5–2.0 M, and the first alkaline solution is a K2CO3 solution, KOH solution, NaOH solution, or NaHCO3 solution.

[0011] An anion exchange membrane is prepared using the highly branched polymer based on tetraphenylmethane or the highly branched polymer based on tetraphenylmethane prepared by the method described above as raw materials.

[0012] A method for preparing the anion exchange membrane includes the following steps: Step 1, Quaternization: Dissolve the highly branched polymer based on tetraphenylmethane or the highly branched polymer based on tetraphenylmethane prepared by any one of the preparation methods described in claims 5-7 in a third solvent, add K2CO3 and iodomethane, stir at 25-40°C for 12-48 h, then stop the reaction, pour the reaction solution into a fourth solvent, filter to collect the precipitate, wash with deionized water, and dry in a vacuum oven to obtain the quaternized highly branched polymer based on tetraphenylmethane; Step 2: Dissolve the quaternized, highly branched polymer based on tetraphenylmethane in a fifth solvent, stir at 50–60 °C, and then filter through a microfiltration membrane to obtain a polymer solution; then cast the polymer solution onto a glass plate and dry it in an oven at 80–120 °C to obtain I. - Type I film; the obtained I - The membrane is peeled off and immersed in anion exchange solution for ion exchange to obtain anion exchange membrane.

[0013] As a further technical solution, the mass-volume ratio of the highly branched polymer based on tetraphenylmethane to the third solvent is 1 g:(6~40) mL.

[0014] As a further technical solution, the third solvent and the fifth solvent are each independently selected from one or more of N,N-dimethylformamide, N,N-diethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone.

[0015] As a further technical solution, the fourth solvent is one or more of ethyl acetate, methanol, ethanol, acetone or diethyl ether.

[0016] As a further technical solution, the mass-volume ratio of the quaternized tetraphenylmethane-based highly branched polymer and the fifth solvent is 1 g:(6-30) mL.

[0017] As a further technical solution, the anion exchange solution includes one or more of NaOH, KOH, NaCl, KCl, NaBr, KBr, NaSO4, and NaCO3; the concentration of the anion exchange solution is 0.5–2.0 M.

[0018] The application of the anion exchange membrane in alkaline batteries or water electrolysis.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention innovatively designs a novel polymer system based on a rigid tetraphenylmethane backbone with extended benzene rings for anion exchange membranes (AEMs). By introducing additional benzene rings onto each benzene ring of the tetraphenylmethane to construct a biphenyl structure, a comprehensive improvement in membrane material performance is achieved. This structural design significantly enhances the separation of hydrophilic and hydrophobic microphases by increasing the rigidity and steric hindrance of the hydrophobic backbone, forming a more continuous and stable ion transport channel. Simultaneously, it effectively suppresses excessive swelling of the membrane material, improving dimensional stability and mechanical strength. The extended benzene ring structure not only provides more functionalizable sites for precise control of ion exchange capacity (IEC), but also disperses the charge density of anion attack through conjugation, significantly improving the material's alkali resistance. From a molecular scale perspective, the tetraphenylmethane units with non-coplanar twisted structures in the polymer act as rigid network nodes, forcing molecular chain segments to extend in different directions. The introduction of benzene rings extends the monomer in three dimensions, significantly expanding the spatial configuration of the backbone and resulting in a three-dimensional network structure with a larger free volume and micropores. The free volume distribution was optimized, creating favorable conditions for the efficient transport of OH⁻.

[0020] This invention combines three major advantages: enhanced microphase separation, optimized structural stability, and tunable functionalization. It promotes nanoscale phase separation to improve ionic conductivity, suppresses swelling and improves chemical stability by expanding the conjugated system, and allows for precise modification of quaternary ammonium groups to optimize the balance between IEC and membrane performance. This provides new research ideas and technical paths for the development of high-performance anion exchange membranes.

[0021] In summary, the anion exchange membrane prepared by this invention improves its conductivity and mechanical properties, making it a membrane with good mechanical properties and excellent OH- ion exchange capacity. - Anion exchange membranes with high conductivity and alkali resistance. Attached Figure Description

[0022] Figure 1 The image shows the proton NMR spectrum of the anion exchange membrane shown in formula C1.

[0023] Figure 2 The image shows the proton NMR spectrum of the anion exchange membrane shown in formula C2.

[0024] Figure 3 The nuclear magnetic resonance hydrogen spectrum of the anion exchange membrane shown in formula C3 is shown below.

[0025] Figure 4The graph shows the conductivity of the anion exchange membrane shown in Equation C1 at different temperatures.

[0026] Figure 5 The tensile strength diagram is shown for the anion exchange membrane as indicated by formula C1. Detailed Implementation

[0027] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Unless otherwise specified, all raw materials used in this invention are commercially available.

[0029] Example 1 Taking the arylpiperidine-tetraphenylmethane homopolymer (with the same aryl group) shown in A1 as an example, the preparation method of highly branched polymers and anion exchange membranes based on tetraphenylmethane is introduced. The reaction route is as follows: ; Where x + y = 100%.

[0030] 1. A method for preparing arylpiperidine-tetraphenylmethane homopolymer, specifically including the following steps: In a three-necked flask, 7.6 mmol (1.750 g) of terphenyl, 0.4 mmol (0.250 g) of tetraphenylmethane, and 10.08 mmol (1.16 ml) of N-methyl-4-piperidinone were dissolved in 7 mL of dichloromethane. The system was slowly stirred using a two-bladed polytetrafluoroethylene stirrer and a mechanical stirrer to ensure uniform mixing of the reactants and solvent. Subsequently, trifluoroacetic acid (10.08 mmol, 0.74 ml) was added dropwise under ice-water bath conditions while maintaining a stirring speed of less than 100 rpm. After the trifluoroacetic acid was added, trifluoromethanesulfonic acid (100.08 mmol, 8.06 ml) was slowly added to the system using a constant-pressure dropping funnel over 15–20 min, while maintaining a stirring speed of 180 rpm. The mixture was stirred at 0 °C for 12 minutes. After 12 hours, the reaction was stopped, and the resulting viscous, deep purple solution was slowly poured into a 50% (v / v) aqueous ethanol solution. The polymer (PTTBP-5%) was then cut into small pieces and washed with 1M K₂CO₃ solution at 50°C with stirring for 12 hours. Finally, the polymer was washed repeatedly with deionized water until neutral and dried in an oven at 80°C to obtain an arylpiperidine-tetraphenylmethane homopolymer; the structure is shown in formula A1, where x = 5% and y = 95%.

[0031] 2. The preparation method of anion exchange membrane includes the following steps: 1) Quaternization: In a round-bottom flask, 2 g of arylpiperidine-tetraphenylmethane homopolymer and 1.68 g of potassium carbonate were dissolved in 60 mL of dimethyl sulfoxide. Then, 2 mL of iodomethane was added, and the mixture was stirred in the dark for 24 h. The resulting solution was poured into ethyl acetate solution, and the white precipitate was collected. The precipitate was washed several times with deionized water until it was neutral. The precipitate was then dried in a vacuum oven at 60–80 °C to obtain quaternized arylpiperidine-tetraphenylmethane homopolymer (QPTTBP-5%). The structure is shown in Formula B1, where x = 5% and y = 95%. 2) Film Formation: Dissolve 1g of the solution in 20mL of dimethyl sulfoxide and stir at 50-60℃ until clear and transparent. Filter the solution through a 0.45μm polytetrafluoroethylene (PTFE) filter to obtain a polymer solution. Cast the polymer solution onto a clean glass plate and dry it in an oven at 80℃ to obtain I. - The membrane was then peeled off and immersed in a 1M NaOH solution for ion exchange to obtain OH-. - Anion exchange membrane in the form of a compound structure as shown in formula C1, where x = 5% and y = 95%.

[0032] The obtained OH - The anion exchange membrane material was subjected to proton NMR spectroscopy, and the results are shown in [Figure 1]. Figure 1 The specific parameters are as follows: the chemical shift between 7.59ppm and 7.72ppm is the absorption peak of aryl compounds (terphenyl and tetraphenylmethane), 3.34ppm is the water peak in the deuterated reagent, 3.15ppm is the methyl peak on piperidine, and 2.54ppm and 1.23ppm are the methylene peaks on piperidine.

[0033] 3. The anion exchange membrane of this embodiment can be used to prepare alkaline batteries or water electrolysis equipment.

[0034] Example 2 Taking the arylpiperidine-tetraphenylmethane homopolymer (with different aryl groups) shown in Formula A2 as an example, the preparation method of highly branched polymers and anion exchange membranes based on tetraphenylmethane is introduced. The reaction route is as follows: .

[0035] 1. A method for preparing arylpiperidine-tetraphenylmethane homopolymers (with different aryl groups), specifically including the following steps: In a three-necked flask, terphenyl (5.56 mmol, 1.327 g), biphenyl (1.44 mmol, 0.222 g), tetraphenylmethane (0.8 mmol, 0.499 g), and N-methyl-4-piperidinone (10.56 mmol, 1.22 ml) were dissolved in 8 mL of dichloromethane. The system was slowly stirred using a two-bladed polytetrafluoroethylene stirrer and a mechanical stirrer to ensure uniform mixing of the reactants and solvent. Subsequently, trifluoroacetic acid (10.56 mmol, 0.78 ml) was added dropwise under ice-water bath conditions while maintaining a stirring speed of less than 100 rpm. After the trifluoroacetic acid was added, trifluoromethanesulfonic acid (105.6 mmol, 8.44 ml) was slowly added to the system using a constant-pressure dropping funnel over 15–20 min, while maintaining a stirring speed of 180 rpm. The mixture was stirred at 0 °C for 12 minutes. After 12 hours, the reaction was stopped, and the resulting viscous, dark purple solution was slowly poured into an ethanol-water solution. The polymer (PTTBP-10%) was then cut into small pieces and washed with 1M K₂CO₃ solution at 50°C with stirring for 12 hours. Finally, the polymer was washed repeatedly with deionized water until neutral and dried in an oven at 80°C to obtain an arylpiperidine-tetraphenylmethane homopolymer; the structure is shown in formula A2, where x=10%, y=90% (where biphenyl: p-terphenyl = 18%: 72%).

[0036] 2. The preparation method of anion exchange membrane includes the following steps: 1) Quaternization: In a round-bottom flask, arylpiperidine-tetraphenylmethane homopolymer (2g) and potassium carbonate (1.68g) were dissolved in 60mL of dimethyl sulfoxide, and then 2mL of iodomethane was added. The mixture was stirred in the dark for 24h. The resulting solution was poured into ethyl acetate solution, and the white precipitate was collected. It was washed several times with deionized water until it was neutral. The precipitate was then dried in a vacuum oven at 60-80℃ to obtain quaternized arylpiperidine-tetraphenylmethane homopolymer (QPTTBP-10%). The structure is shown in formula B2, where x=10% and y=90% (where biphenyl: p-terphenyl = 18%: 72%). 2) Film Formation: Dissolve 1g of the solution in 20mL of dimethyl sulfoxide and stir at 50-60℃ until clear and transparent. Filter the solution through a 0.45μm polytetrafluoroethylene (PTFE) filter to obtain a polymer solution. Cast the polymer solution onto a clean glass plate and dry it in an oven at 80℃ to obtain I. - The membrane was then peeled off and immersed in a 1M NaOH solution for ion exchange to obtain OH-. - An anion exchange membrane in the form of a compound structure as shown in formula C2, where x = 10% and y = 90% (where biphenyl: p-terphenyl = 18%: 72%). The obtained OH - The anion exchange membrane material was subjected to proton NMR spectroscopy, and the results are shown in [Figure 1]. Figure 2 .

[0037] 3. The anion exchange membrane of this embodiment can be used to prepare alkaline batteries or water electrolysis equipment.

[0038] Example 3 Taking the arylquinine-tetraphenylmethane homopolymer shown in A3 as an example, this paper introduces the preparation method of highly branched polymers based on tetraphenylmethane and anion exchange membranes. The reaction route is as follows: .

[0039] 1. A method for preparing arylquinine-tetraphenylmethane homopolymer, specifically including the following steps: In a three-necked flask, p-terphenyl (7.92 mmol, 1.658 g), tetraphenylmethane (0.8 mmol, 0.499 g), and 3-quinine cyclohexane hydrochloride (10.56 mmol, 1.63 g) were dissolved in 8 mL of dichloromethane. The system was slowly stirred using a two-bladed polytetrafluoroethylene stirrer and a mechanical stirrer to ensure uniform mixing of the reactants and solvent. Subsequently, under ice-water bath conditions (0 °C), trifluoroacetic acid (10.08 mmol, 0.74 mL) was added dropwise using a constant-pressure dropping funnel while maintaining a stirring speed of less than 100 rpm. After the trifluoroacetic acid was added, the solution changed from white to light pink. Trifluoromethanesulfonic acid (100.08 mmol, 8.06 mL) was then slowly added to the system using a constant-pressure dropping funnel over 15–20 min, while maintaining a stirring speed of 180 rpm. The reaction was stopped by stirring at ℃ for 12 hours. The resulting viscous, dark purple solution was slowly poured into a 50% (v / v) aqueous ethanol solution. The polymer (PTTBP-10%) was then cut into small pieces and washed with 1 M K2CO3 solution at 50℃ with stirring for 12 hours. Finally, the polymer was washed repeatedly with deionized water until neutral and dried in an oven at 80℃ to obtain an arylquinine-tetraphenylmethane homopolymer; the structure is shown in formula A3, where x = 10% and y = 90%.

[0040] 2. The preparation method of anion exchange membrane includes the following steps: 1) Quaternization: In a round-bottom flask, 2 g of arylquinine-tetraphenylmethane homopolymer and 1.68 g of potassium carbonate were dissolved in 60 mL of dimethyl sulfoxide. Then, 3 mL of iodomethane was added, and the mixture was stirred under light at 40 °C for 24 h. The resulting solution was poured into ethyl acetate solution, and the white precipitate was collected. The precipitate was washed several times with deionized water until it was neutral. The precipitate was then dried in a vacuum oven at 60–80 °C to obtain quaternized arylquinine-tetraphenylmethane homopolymer (QPTTBP-10%). The structure is shown in Formula B3, where x = 10% and y = 90%. 2) Film Formation: Dissolve 1g of quaternized arylquinine-tetraphenylmethane in 20mL of dimethyl sulfoxide and stir at 50-60℃ until clear and transparent; filter the solution through a 0.45μm polytetrafluoroethylene (PTFE) filter to obtain a polymer solution. Cast the polymer solution onto a clean glass plate and dry it in an oven at 80℃ to obtain I. - The membrane was then peeled off and immersed in a 1M NaOH solution for ion exchange to obtain OH-. - An anion exchange membrane in the form of a compound structure as shown in formula C3, where x = 10% and y = 90%.

[0041] The obtained OH - The anion exchange membrane material was subjected to proton NMR spectroscopy, and the results are shown in [Figure 1]. Figure 3 .

[0042] 3. The anion exchange membrane of this embodiment can be used to prepare alkaline batteries or water electrolysis equipment.

[0043] Example of effect 1 The anion exchange membranes prepared in Examples 1-3 were tested for ion conductivity and tensile strength. The results are shown in the figure. Figures 4-5 and Table 1; The conductivity of the branched anion exchange membrane was tested using electrochemical impedance spectroscopy (EIS). The membrane was cut into 4cm × 1cm pieces and placed in a polytetrafluoroethylene (PTFE) fixture. Testing was conducted at 30℃–80℃. Finally, the ionic conductivity σ of the sample was calculated using the formula: ; In the formula, L is the length of the interelectrode membrane (cm), w is the width of the membrane (cm), d is the thickness of the membrane (cm), and R is the measured resistance of the membrane (Ω). Tensile strength: The laboratory used a WDW-05 microcomputer-controlled electronic universal testing machine. APE was cut into rectangular strips of 2cm*5cm. Before the tensile test, the width and thickness of the membrane at the middle position were measured. During the tensile test, the two ends of the rectangular strip membrane were clamped and the membrane was pulled outward at a fixed speed. The stress-strain curve of the membrane was recorded.

[0044] Water absorption rate: The dry membrane material was soaked in 1 M KOH solution for 24 h to exchange iodide ions for hydroxide ions, resulting in an alkaline membrane with hydroxide anions. The free alkali on the alkaline membrane was washed away with deionized water, and then the membrane was soaked in deionized water and placed in a water bath at different temperatures (from low to high) for half an hour to allow it to fully absorb water at the specified temperature. Afterward, the membrane was removed, the surface moisture was blotted dry with lint-free paper, and the wet mass (W) of the membrane was measured using an electronic balance with an accuracy of 0.1 mg. hyd Finally, the film was thoroughly dried in an oven and weighed in its dry state (W). dry The method for calculating the water absorption rate of an alkaline membrane is as follows: ; Swelling rate: Dry membrane material was cut into 2.00 cm x 2.00 cm pieces, and the thickness of the dry membrane was measured using a micrometer. The membrane was then soaked in 1 M KOH solution for 24 h to exchange iodide ions for hydroxide ions, resulting in an alkaline membrane with hydroxide anions. The free alkali on the alkaline membrane was washed away with deionized water, and the membrane was then soaked in deionized water and placed in water baths at varying temperatures (from low to high) for half an hour to allow it to fully swell at the specified temperature. The membrane was then removed, and its length, width, and thickness were measured after swelling. The changes in length and width of the alkaline membrane represent the transverse swelling (in-plane SD), and the changes in membrane thickness represent the longitudinal swelling (through-plane SD). The calculation methods for both are as follows: .

[0045] Table 1

[0046] The embodiments described above are merely preferred embodiments of the present invention, and not an exhaustive list of all possible implementations of the present invention. Any obvious modifications made by those skilled in the art without departing from the principles and spirit of the present invention should be considered to be included within the scope of protection of the claims of the present invention.

Claims

1. A highly branched polymer based on tetraphenylmethane, characterized in that, It has repeating units as shown in Equation 1: Formula 1; Ar1, Ar2, Ar3, and Ar4 are each independently selected from linear biaryl compound monomers; R is a nitrogen-containing heterocyclic group; x represents the molar percentage of the three-dimensional tetraphenylmethane branched structural unit in the polymer; y = y1 + y2 + y3 + y4 represents the molar percentage of the linear repeating structural unit in the polymer; x + y = 100%, x = 2.5-10%; y = 90-97.5%.

2. The highly branched polymer based on tetraphenylmethane according to claim 1, characterized in that, Ar1, Ar2, Ar3, and Ar4 are each independently selected from , , , .

3. The highly branched polymer based on tetraphenylmethane according to claim 1, characterized in that, The R is selected from , , Any one of them.

4. The highly branched polymer based on tetraphenylmethane according to claim 1, characterized in that, In the three-dimensional tetraphenylmethane branched structural unit, the structure of the three-dimensional tetraphenylmethane is shown in Formula 2. Formula 2.

5. A method for preparing a highly branched polymer based on tetraphenylmethane as described in any one of claims 1-4, characterized in that, Includes the following steps: Under ice-water bath conditions, tetraphenylmethane, biaryl compound monomers, and ketone monomers were dissolved in a first solvent. Then, trifluoroacetic acid and trifluoromethanesulfonic acid were added dropwise while stirring. After stirring for 2-72 hours, the reaction was stopped, and the reaction solution was poured into a second solvent. The solid, i.e., the polymer, was collected. Excess acid in the solid polymer was washed away with a first alkaline solution, and the polymer was washed with deionized water until neutral. The polymer was then dried in a vacuum oven to obtain a highly branched polymer with a tetraphenylmethane central molecule.

6. The method for preparing a highly branched polymer based on tetraphenylmethane according to claim 5, characterized in that, The biaryl compound monomer is selected from one or more of biphenyl, para-terphenyl, meta-terphenyl and tetraphenyl; The molar ratio of tetraphenylmethane to biaryl compound monomers is (1-20):(99-80); The molar ratio of biaryl compound monomers to ketone monomers is 1:(1-2); The molar ratio of ketone monomers, trifluoroacetic acid, and trifluoromethanesulfonic acid is 1:(0.8-2):(8-12); The first solvent is one or more of dichloromethane solution, trichloromethane, and 1,2-dichloroethane; The second solvent is one or more of water, ethyl acetate, methanol, ethanol, diethyl ether, tetrahydrofuran, or acetone; The concentration of the first alkaline solution is 0.5–2.0 M, and the first alkaline solution is a K2CO3 solution, KOH solution, NaOH solution, or NaHCO3 solution.

7. An anion exchange membrane, characterized in that, It is prepared using the highly branched polymer based on tetraphenylmethane as described in any one of claims 1-4 or the highly branched polymer based on tetraphenylmethane prepared by the preparation method as described in any one of claims 5-7 as raw materials.

8. A method for preparing an anion exchange membrane as described in claim 7, characterized in that, Includes the following steps: Step 1, Quaternization: Dissolve the highly branched polymer based on tetraphenylmethane as described in any one of claims 1-4 or the highly branched polymer based on tetraphenylmethane prepared by the preparation method as described in any one of claims 5-7 in a third solvent, add K2CO3 and iodomethane, stir at 25-40°C for 12-48 h, stop the reaction, pour the reaction solution into a fourth solvent, filter to collect the precipitate, wash with deionized water, and dry in a vacuum oven to obtain the quaternized highly branched polymer based on tetraphenylmethane; Step 2: Dissolve the quaternized, highly branched polymer based on tetraphenylmethane in a fifth solvent, stir at 50–60°C, and then filter through a microfiltration membrane to obtain a polymer solution; then cast the polymer solution onto a glass plate and dry it in an oven at 80–120°C to obtain I. - Type I film; the obtained I - The membrane is peeled off and immersed in anion exchange solution for ion exchange to obtain anion exchange membrane.

9. The method for preparing an anion exchange membrane according to claim 8, characterized in that, The mass-volume ratio of the highly branched polymer based on tetraphenylmethane to the third solvent is 1 g:(6-40) mL; The third solvent and the fifth solvent are each independently selected from one or more of N,N-dimethylformamide, N,N-diethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone; The fourth solvent is one or more of ethyl acetate, methanol, ethanol, acetone, or diethyl ether; The mass-volume ratio of the quaternized tetraphenylmethane-based highly branched polymer and the fifth solvent is 1 g: (6–30) mL; The anion exchange solution includes one or more of NaHCO3, KHCO3, NaOH, KOH, NaCl, KCl, NaBr, KBr, NaSO4, and NaCO3; the concentration of the anion exchange solution is 0.5–2.0 M.

10. The application of the anion exchange membrane as described in claim 8 in alkaline batteries or water electrolysis.

Images