Large steric hindrance aryl polymer, anion exchange membrane and preparation method and application thereof

Abstract

The invention discloses a large-steric-hindrance aryl polymer, an anion exchange membrane and a preparation method and application thereof, and relates to the technical field of compound synthesis. The skeleton of the large-steric-hindrance aryl polymer does not contain ether bonds and heteroatoms, so that the anion exchange membrane is endowed with excellent chemical stability, and particularly, the stability of the anion exchange membrane in an alkaline environment is outstanding. Besides, a polymer skeleton comprises a large-steric-hindrance structural unit, a spirobifluorene rigid skeleton is introduced, a hydrophobic functional unit is embedded into a monomer, and a multi-level ion transmission channel is formed with inherent micropores through cooperative regulation and control of hydrophilic / hydrophobic microphase separation, so that the ionic conductivity of the anion exchange membrane is remarkably improved, and the ionic conductivity of the anion exchange membrane is improved. And due to the characteristics, the application requirements of alkaline fuel cells and alkaline electrolyzed water devices can be met. The preparation method is simple, low in cost and very suitable for large-scale industrial production, powerful support is provided for technical progress in related fields, and a solid foundation is laid for industrial application.

Description

Technical Field

[0001] The present invention relates to the technical field of compound synthesis, and particularly to a bulky aryl polymer, an anion exchange membrane, and a preparation method and application thereof. Background Art

[0002] An anion exchange membrane (AEM), also known as an ion-selective permeable membrane, refers to a type of polymer membrane containing basic active groups and having selective permeability to anions. The AEM is an important component in the anion exchange membrane electrolyzed water technology and the anion exchange membrane fuel cell technology system. Its function is to conduct hydroxide ions from the cathode to the anode, while blocking the direct transfer of gases and electrons between the electrodes. At the same time, the AEM is also widely used in other new energy electrochemical devices such as electrodialysis, carbon dioxide reduction, and flow batteries.

[0003] The anion exchange membrane includes a polymer backbone, quaternary ammonium active groups, and anions. Among them, the quaternary ammonium active groups are located on the polymer backbone, and the anions can move freely on the quaternary ammonium active groups. Compared with cation exchange membranes, the anion exchange membrane not only has a more complex preparation route, but also has disadvantages such as low hydroxide ion conductivity, poor mechanical stability, and poor chemical stability, which are the bottlenecks in its development. Moreover, during the operation of the AEM, the locally strong alkaline environment formed on the membrane surface will cause the AEM to degrade under the action of hydroxide ions and generate perforations, thereby triggering electrode short circuits and affecting the service life. Therefore, the development of new anion exchange membranes is expected in this field, and synergistically enhancing ionic conductivity, dimensional stability, and alkali stability is the key problem for the further development of anion exchange membrane electrolyzed water technology and anion exchange membrane fuel cell technology.

[0004] At present, anion exchange membranes are mainly based on polymer backbones such as polysulfone, polyphenylene oxide, and polyether ether ketone. However, polymer backbones containing ether bonds are prone to degradation under alkaline conditions, and there is a problem of poor alkali stability. Polyaryl 4-piperidine copolymer is a new type of anion exchange membrane with an ether bond-free backbone, which has the advantages of high structural rigidity and ideal dimensional stability. However, the existing anion exchange membranes based on polyaryl 4-piperidine polymer backbones have poor conductivity.

[0005] In summary, there are still many structural defects in the currently available anion exchange membranes on the market, resulting in relatively poor chemical stability and inability to meet the requirements of special application scenarios. Therefore, how to provide a new type of polymer for preparing an anion exchange membrane with both high conductivity and high alkali stability is of great significance for the application and development of anion exchange membranes. Summary of the Invention

[0006] The object of the present invention is to provide a bulky aryl polymer, an anion exchange membrane, and a preparation method and application thereof, so as to solve the problems existing in the above-mentioned prior art. The structural feature that the main chain of the bulky aryl polymer of the present invention does not contain an ether bond and the phenyl structural monomer with a large steric hindrance can improve the alkali resistance stability of the anion exchange membrane (AEM). Moreover, by using a copolymerization strategy with a quaternary ammonium group-containing structural monomer to modify the polymer, a hydrophobic functional unit is embedded in the monomer, and through the synergistic regulation of hydrophilic / hydrophobic microphase separation, a multi-level ion transport channel is formed with intrinsic micropores, reducing the water absorption rate and swelling rate of the AEM, further improving the dimensional stability and ionic conductivity of the AEM, and it can be used to prepare an anion exchange membrane with high stability performance.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] One of the technical solutions of the present invention: Provide a bulky aryl polymer having a general structural formula shown in formula (P):

[0009]

[0010] Among them, Ar is an aryl structural unit; M is a carbonyl structural unit; the sum of x and y is 100%.

[0011] Further, Ar is selected from one of the copolymerization units having the following structures:

[0012]

[0013] The R1 and R2 groups are independently selected from a hydrogen atom and a hydrocarbon group having 1 to 20 carbon atoms;

[0014] Among them, * represents a connecting bond.

[0015] Further, M is independently selected from one of the copolymerization units having the following structures:

[0016]

[0017] Among them, * represents a connecting bond.

[0018] Another technical solution of the present invention: Provide a preparation method of the above-mentioned bulky aryl polymer, including the following steps:

[0019] Mix the Ar group monomer, the ketone monomer corresponding to M, and the bulky aryl structural monomer in a first solvent, react in the presence of a first catalyst, add the obtained reaction solution to a second solvent, collect the precipitated solid, wash and dry it to obtain the bulky aryl polymer;

[0020] Further, the molar ratio of the bulky aryl structural monomer to the Ar structural monomer is (0 - 50):(100 - 50); and it is not 0; the molar amount ratio of the ketone monomer corresponding to M to the sum of the molar amounts of the bulky aryl structural monomer and the Ar group monomer is 1.1:1; the first catalyst includes trifluoroacetic acid (TFA) and / or trifluoromethanesulfonic acid (TFSA).

[0021] Further, the molar ratio of the trifluoroacetic acid to the ketone monomer corresponding to M is (0.5 - 2):1; the molar ratio of the trifluoromethanesulfonic acid to the ketone monomer corresponding to M is (8 - 15):1.

[0022] Further, the first solvent includes at least one of dichloromethane, chloroform, or tetrahydrofuran; the second solvent includes at least one of water, ethyl acetate, methanol, ethanol, ether, tetrahydrofuran, or acetone.

[0023] Further, the volume ratio of the first solvent to the second solvent is 1:(10 - 30).

[0024] Further, the addition amount of the ketone monomer corresponding to M based on the first solvent is: 5 - 25 mmol of the ketone monomer corresponding to M is added per 10 - 15 mL of the first solvent.

[0025] Furthermore, the reaction temperature is -5 to 15 °C, and the reaction time is 0 - 48 h.

[0026] Further, the washing step includes the step of adding the precipitated polymer to an alkali solution for washing.

[0027] Further, the alkali solution includes at least one of K2CO3, KOH, NaOH, and NaHCO3 solutions.

[0028] Further, the drying includes the step of vacuum drying at 70 - 90 °C.

[0029] Among them, the bulky aryl structural monomer is (2,7 - bis(3,5 - bis(trifluoromethyl)phenyl)-9,9'-spirobifluorene); its preparation method includes the following steps:

[0030] Mix 2,7 - dibromo - 9,9'-spirobifluorene and 3,5 - bis(trifluoromethyl)phenylboronic acid in a third solvent, and react in the presence of a second catalyst to obtain the bulky aryl structural monomer.

[0031] Further, the molar ratio of 2,7 - dibromo - 9,9'-spirobifluorene to 3,5 - bis(trifluoromethyl)phenylboronic acid is (0 - 5):1, and it is not 0.

[0032] Furthermore, the third solvent is a mixed alkaline solution of at least one aqueous solution of Cs2CO3, K2CO3, Na2CO3, Li2CO3 and at least one organic solvent of toluene, tetrahydrofuran, N,N-dimethylformamide.

[0033] Furthermore, the second catalyst includes at least one of Pd(PPh3)4, AsPh3, n-Bu3P and (MeO)3P.

[0034] Furthermore, the temperature of the reaction is 60 - 90 °C, and the reaction time is 12 - 36 hours.

[0035] Furthermore, after the reaction, it also includes the steps of adding a quenching agent to quench the reaction, extraction, drying, separation, and drying. Preferably, the quenching agent includes methanol and / or ethanol. The drying steps before and after the separation treatment include vacuum drying, and the preferred drying temperature is 50 - 90 °C.

[0036] Furthermore, the extraction includes extraction with a mixed solvent of dichloromethane and water; the preferred molar ratio of dichloromethane to water is (0 - 10):1 and not 0.

[0037] Furthermore, the separation includes the step of silica gel column chromatography separation. Preferably, the silica gel column chromatography separation reagent is n-hexane.

[0038] The third technical solution of the present invention: Provide a bulky aryl quaternary ammonium polymer having a general formula structure as shown in formula (Q):

[0039]

[0040] Ar is selected from one of the copolymerization units having the following structures:

[0041]

[0042] The R1 and R2 groups are independently selected as a hydrogen atom or an alkane having 1 - 20 carbon atoms;

[0043] QA is independently selected from one of the following structures:

[0044]

[0045] Among them, * represents a connecting bond.

[0046] The R3, R4, and R5 groups are independently selected as a hydrogen atom or an alkane having 1 - 20 carbon atoms;

[0047] The sum of x and y is 100%.

[0048] The fourth technical solution of the present invention: Provide a preparation method of a large steric hindrance aryl quaternized polymer, including the following steps:

[0049] Mix the above-mentioned large steric hindrance aryl polymer with a haloalkane or trimethylamine solution in a fourth solvent, react in the presence of a third catalyst, add the obtained reaction solution to a fifth solvent, collect the precipitated solid, and obtain the large steric hindrance aryl quaternized polymer after drying, characterized in that

[0050] Furthermore, the temperature of the quaternization reaction is 40 - 60 °C, and the reaction time is 24 - 48 hours.

[0051] Furthermore, the third catalyst includes K2CO 3、 KOH, NaOH.

[0052] Still further, the mass ratio of the large steric hindrance aryl polymer to the third catalyst is (1 - 4):1.

[0053] Furthermore, the solid-liquid ratio of the large steric hindrance aryl polymer to the haloalkane is 1 g:(2 - 6) mL.

[0054] Furthermore, the fourth solvent includes at least one of dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylformamide or N,N-dimethylacetamide; the fifth solvent includes at least one of ethyl acetate, methanol, ethanol, acetone or ether.

[0055] The solid-liquid ratio of the large steric hindrance aryl polymer to the fourth solvent is 1 g:(15 - 25) mL.

[0056] Furthermore, the volume ratio of the fourth solvent to the fifth solvent is 1:(20 - 30).

[0057] Furthermore, the drying includes a step of vacuum drying at 70 - 90 °C.

[0058] The fifth technical solution of the present invention: Provide a preparation method of an anion exchange membrane, including the following steps:

[0059] Add the above-mentioned large steric hindrance aryl quaternized polymer to a sixth solvent and mix, cast it on the surface of a substrate to obtain a polymer membrane; immerse the polymer membrane in an alkali solution to obtain an OH - type anion exchange membrane.

[0060] Furthermore, the alkali solution includes NaOH and / or KOH solution.

[0061] Furthermore, the temperature of the immersion step is 25 - 80 °C, and the immersion time is 10 - 24 h.

[0062] Further, the sixth solvent includes at least one of dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylformamide, or N,N-dimethylacetamide.

[0063] Further, the solid-liquid ratio of the sterically hindered aryl quaternized polymer to the sixth solvent is 1 g : (6 - 15) mL.

[0064] Further, the thickness of the polymer membrane is 20 - 60 μm.

[0065] Technical solution six of the present invention: Provide an anion exchange membrane prepared by the above preparation method.

[0066] Technical solution seven of the present invention: Provide the application of the above anion exchange membrane in an alkaline fuel cell and an alkaline water electrolysis device.

[0067] The present invention discloses the following technical effects:

[0068] The present invention relates to a sterically hindered aryl polymer, whose backbone contains sterically hindered structural units, which can effectively promote the formation of a microphase separation structure in the membrane. This microphase separation structure constructs a high-speed ion transport channel in the membrane, thereby significantly improving the ionic conductivity of the anion exchange membrane; meanwhile, by copolymerizing with a structural unit having a quaternary ammonium structure, the alkali resistance of the membrane material is further enhanced.

[0069] The preparation method of the present invention has a simple process and low cost, and is very suitable for large-scale industrial production. In addition, since the backbone of the sterically hindered aryl polymer does not contain ether bonds and heteroatoms, it endows the anion exchange membrane with excellent chemical stability, especially excellent stability in an alkaline environment.

[0070] The sterically hindered aryl polymer and its preparation method of the present invention not only solve the problem of insufficient performance of anion exchange membranes in the prior art, but also meet the application requirements in fields such as alkaline fuel cells and alkaline water electrolysis devices. Experimental data show that the anion exchange membrane prepared by the present invention has the following excellent properties: the tensile strength can reach 44 MPa, the conductivity can reach 170 mS / cm 2 , at a potential of 2 V, the current density can reach 2.30 A / cm 2 . BRIEF DESCRIPTION OF THE DRAWINGS

[0071] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0072] Figure 1 For the OH-type anion exchange membrane based on the bulky polyaryl 3-piperidine copolymer in Example 1 of the present invention - Spectrum diagram

[0073] Figure 2 For the OH-type anion exchange membrane based on the bulky polyaryl fluoro ketone copolymer in Example 2 of the present invention - Spectrum diagram

[0074] Figure 3 Ionic conductivity of the anion exchange membrane prepared in Example 1 of the present invention at different temperatures

[0075] Figure 4 Tensile strength and elongation at break of the anion exchange membrane prepared in Example 1 of the present invention

[0076] Figure 5 Polarization curve of the membrane electrode based on the anion exchange membrane in Example 1 of the present invention at 80 °C

[0077] Figure 6 In-situ durability curve of the anion exchange membrane based on Example 1 of the present invention at 80 °C

[0078] Figure 7 Ionic conductivity of the anion exchange membrane prepared in Example 2 of the present invention at different temperatures

[0079] Figure 8 Tensile strength and elongation at break of the anion exchange membrane prepared in Example 2 of the present invention

[0080] Figure 9 Spectrum diagram of the bulky aryl structure monomer and its reactants of the present invention Detailed implementation mode

[0081] Now, various exemplary embodiments of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention

[0082] It should be understood that the terms described in the present invention are only for describing specific implementation modes and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Among any stated value or range of values, the intermediate value, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range

[0083] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this invention pertains. Although this invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of this invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0084] Without departing from the scope or spirit of this invention, various improvements and changes can be made to the specific embodiments of the specification of this invention, which are obvious to those skilled in the art. Other embodiments obtained from the specification of this invention are obvious to those skilled in the art. The specification and examples of this invention are merely exemplary.

[0085] Regarding "comprising", "including", "having", "containing", etc. used herein, they are all open-ended terms, meaning including but not limited to.

[0086] The synthesis method of the large steric hindrance aryl polymer of this invention can synthesize a series of large steric hindrance aryl polymers with different hydrophobic segments and prepare them into polymer membranes by regulating the ratio of large steric hindrance groups and linear structure phenyl monomers Ar and performing a polycondensation reaction under the catalysis of trifluoromethanesulfonic acid, which are used in anion exchange membrane alkaline water electrolysis devices and anion exchange membrane fuel cell devices.

[0087] In the following examples of this invention, the synthesis method of the large steric hindrance aryl quaternized polymer is prepared by performing a quaternization reaction by adding a haloalkane and / or trimethylamine solution with the corresponding structure on the basis of the large steric hindrance aryl polymer.

[0088] In the following examples of this invention, the anion exchange membrane, i.e., the OH - type anion exchange membrane is synthesized by forming a film by means of solvent evaporation on the basis of the large steric hindrance aryl quaternized polymer and then impregnating the formed polymer membrane in an alkaline solvent.

[0089] It should be noted that those aspects not described in detail in this invention are all conventional operating means in the art and are not the focus of this invention.

[0090] Example 1

[0091] An OH - type anion exchange membrane based on a large steric hindrance polyaryl 3-piperidine copolymer has the following synthesis route:

[0092]

[0093] In this example, the OH- The type of anion exchange membrane is prepared by the following method:

[0094] (1) In a 100 mL three-necked flask, 2,7-dibromo-9,9'-spirobifluorene (1.90 g, 4.00 mmol), 3,5-bis(trifluoromethyl)phenylboronic acid (2.27 g, 8.80 mmol), and K2CO3 (1.11 g, 8.00 mmol) were added to a mixed solution of deionized water (10.00 mL) and toluene (40.00 mL). The mixture was stirred with a magnetic stirrer under a nitrogen atmosphere for 10 min. Subsequently, tetrakis(triphenylphosphine)palladium (0.1155 g, 0.1 mmol) was injected under a N2 atmosphere. After stirring at room temperature for 5 min, the reaction system was heated to 85 °C. During the reaction, the solution changed from yellow to grayish black. After 24 h of reaction, 1 mL of methanol solution was injected into the system for quenching, and post-treatment was carried out. After repeating extraction three times with dichloromethane and deionized water, anhydrous magnesium sulfate powder was finally added to remove the water in the obtained organic phase. After standing for 30 min, filtration was carried out, and the filtrate was rotary evaporated and dried at 50 °C for 2 h. The obtained product was vacuum dried at 60 °C for 24 h. After silica gel column chromatography separation using n-hexane as the solvent, a solution containing the coupling product was obtained, which was vacuum dried at 60 °C for 24 h, and finally a white coupling product, 2,7-bis(3,5-bis(trifluoromethyl)phenyl)-9,9'-spirobifluorene, was obtained.

[0095] (2) In a 100 mL single-necked flask, p-terphenyl (1.00 g, 4.34 mmol), 3-piperidone (0.56 g, 5.62 mmol), and 2,7-bis(3,5-bis(trifluoromethyl)phenyl)-9,9'-spirobifluorene (0.57 g, 0.77 mmol) were added to dichloromethane (6.00 mL). The mixture was stirred with a magnetic stirrer in an ice-water bath under an air atmosphere for 10 min to obtain a yellowish-white mixed solution. Then, TFSA (4.00 mL, 46.69 mmol) was added dropwise to the above yellowish-white mixed solution. After the addition, the reaction was stirred for 8 h. During the reaction, the color of the solution changed from yellowish-white to red and finally to purplish-red. The obtained viscous solution was poured into 500 mL of methanol solution to precipitate a white polymer;

[0096] (3) The above white polymer was crushed, and these fragments were collected by filtration. They were stirred and washed with a 1 M K2CO3 solution at room temperature for 12 h to neutralize the acid remaining from the reaction, and then washed three times with deionized water and dried in a vacuum oven at 80 °C for 12 h to obtain a sterically hindered polyaryl 3-piperidine copolymer (PF-SAP-15);

[0097] (4) In a flask, dissolve PF-SAP-15 (0.50 g) in DMSO (20.00 mL), stir for 30 min at room temperature, then add K2CO3 (0.60 g) and methyl iodide (1.00 mL), stir for 2 h at room temperature in the dark, and then heat to 50 °C and stir for 48 h. Add 400 mL of ethyl acetate to the resulting viscous solution, filter the yellow precipitate, wash it 3 times with deionized water, and dry it in a vacuum oven at 80 °C for 12 h to obtain the quaternized large steric polyaryl 3-piperidine copolymer (QPF-SAP-15(I - ));

[0098] (5) Dissolve QPF-SAP-15(I - )(0.32 g) in DMSO (4.00 mL), filter the solution through a polytetrafluoroethylene (PTFE) filter, cast it on a flat and clean glass plate, and then dry it in an oven at 70 °C for 24 h. After completely removing the residual solvent, a 20-μm-thick I - -type polymer membrane is obtained;

[0099] (6) Peel the I - -type polymer membrane from the glass plate, soak it in 1 M NaOH solution, and perform ion exchange at 60 °C for 12 h to obtain the OH - -type membrane (labeled QPF-SAP-15), then wash it 3 times with deionized water to obtain the OH - -type anion exchange membrane. To avoid contamination by CO2 and the formation of carbonates, soak it in deionized water purged with nitrogen for storage.

[0100] Example 2

[0101] An OH - -type anion exchange membrane based on a large steric polyaryl fluoro ketone copolymer has the following synthesis route:

[0102]

[0103] The OH - -type anion exchange membrane in this example is prepared by the following method:

[0104] (1) In a 100 mL three-necked flask, 2,7-dibromo-9,9'-spirobifluorene (1.90 g, 4.00 mmol), 3,5-bis(trifluoromethyl)phenylboronic acid (2.27 g, 8.80 mmol), and K2CO3 (1.11 g, 8.00 mmol) were added to a mixed solution of deionized water (10.00 mL) and toluene (40.00 mL). The mixture was stirred with a magnetic stirrer under a nitrogen atmosphere for 10 min. Subsequently, tetrakis(triphenylphosphine)palladium(0) (0.1155 g, 0.1 mmol) was injected under a N2 atmosphere. After stirring at room temperature for 5 min, the reaction system was heated to 85 °C. During the reaction, the solution changed from yellow to grayish black. After 24 h of reaction, 1 mL of methanol solution was injected into the system for quenching, and then post-treatment was carried out. After repeating extraction three times with dichloromethane and deionized water, anhydrous magnesium sulfate powder was finally added to remove the water in the obtained organic phase. After standing for 30 min, filtration was carried out, and the filtrate was rotary evaporated and dried at 50 °C for 2 h. The obtained product was vacuum dried at 60 °C for 24 h. After silica gel column chromatography separation using n-hexane as the solvent, a solution containing the coupling product was obtained, which was vacuum dried at 60 °C for 24 h, and finally a white coupling product 2,7-bis(3,5-bis(trifluoromethyl)phenyl)-9,9'-spirobifluorene was obtained.

[0105] (2) In a 100 mL single-necked flask, p-terphenyl (1.00 g, 4.34 mmol), 7-bromo-1,1,1-trifluoro-2-heptanone (1.31 g, 5.30 mmol), and 2,7-bis(3,5-bis(trifluoromethyl)phenyl)-9,9'-spirobifluorene (0.36 g, 0.48 mmol) were added to dichloromethane (6.00 mL). The mixture was stirred with a magnetic stirrer in an ice-water bath under an air atmosphere for 10 min to obtain a white mixed solution. Then TFSA (6.00 mL, 70.04 mmol) was added dropwise to the above white mixed solution. After the addition, the reaction was stirred for 6 h. During the reaction, the color of the solution changed from white to red and finally to purple-red. The obtained viscous solution was poured into methanol solution to precipitate a white polymer.

[0106] (3) The above white polymer was crushed, and these pieces were collected by filtration. They were stirred and washed with a 1 M K2CO3 solution at room temperature for 12 h to neutralize the residual acid in the reaction, and then washed three times with deionized water and dried in a vacuum oven at 80 °C for 12 h to obtain a sterically hindered polyaryl fluoroketone copolymer (PF-SA-10).

[0107] (4) In a flask, dissolve PF-SA-10 (0.50 g) in NMP (20.00 mL), stir for 30 min at room temperature, then add K2CO3 (0.60 g) and 30% wt trimethylamine ethanol solution (1.00 mL), stir for 2 h at room temperature in the dark, and then heat to 50 °C and stir for 48 h. Add 400 mL of ethyl acetate to the resulting viscous solution, filter the yellow precipitate, wash it 3 times with deionized water, and dry it in a vacuum oven at 80 °C for 12 h to obtain the quaternized sterically hindered polyarylfluoroketone copolymer (QPF-SA-10(Br - ));

[0108] (5) Dissolve QPF-SA-10(Br - )(0.32 g) in DMSO (4.00 mL), filter the solution through a polytetrafluoroethylene (PTFE) filter, cast it on a flat and clean glass plate, and then dry it in an oven at 70 °C for 24 h. After completely removing the residual solvent, a 20-μm-thick Br - -type polymer membrane is obtained;

[0109] (6) Peel the Br - -type polymer membrane from the glass plate, soak it in 1 M NaOH solution, and perform ion exchange at 60 °C for 12 h to obtain the OH - -type membrane (labeled as QPF-SA-10), then wash it 3 times with deionized water. To avoid contamination by CO2 and the formation of carbonates, soak the membrane in deionized water purged with nitrogen for storage.

[0110] Effect verification example:

[0111] 1. Conductivity test

[0112] The ionic conductivity (σ, mS·cm -1 ) of the membrane is calculated by measuring the alternating current impedance (R, kΩ) of the anion exchange membrane (AEMs) using a Shanghai Chenhua CHI 760E electrochemical workstation. The frequency range is 1 MHz to 1 Hz, and the potential amplitude is 10 mA.

[0113] The test process is as follows: Immerse the membrane sample in deionized water for 24 h under a N2 atmosphere to achieve water absorption equilibrium. Cut a strip of membrane with a length greater than 1 cm, clamp it between two pairs of copper electrode plates with a spacing of 1 cm, and place it in a wide-mouth bottle filled with deionized water. Nitrogen is introduced into the container for protection to avoid interference of AEMs by CO2 in the air because the ionic conductivities of HCO3 - and CO3 2- are lower than that of OH -. Heat the water bath to 30°C, 40°C, 50°C, 60°C, 70°C and 80°C respectively. After balancing for 2 h at each specific temperature, the measurement of the AC impedance of the membrane can be started.

[0114] The ionic conductivity of AEMs can be calculated by the formula;

[0115]

[0116] In the formula, L is the distance between two electrode plates, A is the effective cross-sectional area of the membrane, and R is the AC impedance of the membrane.

[0117] Figure 3 are the ionic conductivities of the anion exchange membranes prepared in Example 1 at different temperatures. It can be seen that the conductivity of the QPF-SAP-15 membrane at 80°C is 170 mS / cm 2 , reaching a relatively high level among the known structures, indicating that the anion exchange membrane has good conductivity.

[0118] Figure 7 are the ionic conductivities of the anion exchange membranes prepared in Example 2 at different temperatures. It can be seen that the conductivity of the QPF-SA-10 membrane at 80°C is 130.48 mS / cm 2 , reaching a relatively high level among the known structures, indicating that the anion exchange membrane has good conductivity.

[0119] 2. Mechanical property test

[0120] At room temperature, use the MODEL universal testing machine of Shenzhen Sansi Zongheng Science Co., Ltd., with a relative humidity of 55% and a tensile rate of 10 mm / min to conduct a tensile test on AEMs; obtain the tensile strength and elongation at break of the membrane sample.

[0121] Figure 4 are the tensile strength and elongation at break of the anion exchange membrane prepared in Example 1 of the present invention. It can be seen that the elongation at break reaches about 10.5%, and the tensile strength exceeds 44 MPa, indicating that the anion exchange membrane has excellent mechanical properties.

[0122] Figure 8 are the tensile strength and elongation at break of the anion exchange membrane prepared in Example 2 of the present invention. It can be seen that the elongation at break reaches about 10.7%, and the tensile strength exceeds 46 MPa, indicating that the anion exchange membrane has excellent mechanical properties.

[0123] 3. Alkaline water electrolysis performance test

[0124] Perform a single cell test of alkaline water electrolysis on the performance of the membrane electrode assembled with the OH - type anion exchange membrane prepared in Example 1.

[0125] Take the OH prepared in Example 1 - type anion exchange membrane, anode catalyst nickel-iron catalyst, and cathode catalyst platinum-carbon catalyst to assemble a membrane electrode, which is installed in an AEM electrolytic cell and undergoes electrochemical testing on an Autolab electrochemical workstation.

[0126] The sizes of the anode and cathode catalysts are 2 cm × 2 cm, and the electrolyte solution of the AEM electrolytic cell is 1 M KOH solution. Before the electrochemical testing, cycle for two hours to ensure the test temperature is constant and the voltage is stable, then replace the alkali solution with a new one, and record the current-voltage (I-V) polarization curve with a DC regulated power supply after stabilizing for another half hour. For the durability experiment, perform water electrolysis testing at a current density of 1 A / cm 2 of the current density.

[0127] Figure 5 is the polarization curve of the membrane electrode based on the anion exchange membrane in Example 1 at 80 °C. It can be seen that under the condition of 80 °C: at a potential of 2 V, the current density can reach 2.3 A / cm 2 .

[0128] Figure 6 is the in-situ durability curve of the anion exchange membrane in Example 1 at 80 °C. It can be seen that under the condition of 80 °C: at a current density of 1 A / cm 2 of the current density, in the test of nearly 1000 hours, the total voltage loss rate of the QPF-SAP-15 AEMWE single cell is less than 2%.

[0129] In summary, based on the OH of the sterically hindered aryl polymer provided by the present invention - type anion exchange membrane has good mechanical stability and excellent conductivity, and has excellent durability in the testing of water electrolysis devices; by adding sterically hindered groups, it promotes the formation of the microphase separation structure of the anion exchange membrane, which helps to establish ion channels with lower transport resistance; and by applying it to alkaline water electrolysis, it proves that this type of polymer has very excellent performance.

[0130] The above-described embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention should fall within the protection scope determined by the claims of the present invention.

Claims

1. A large steric hindrance aryl polymer, characterized in that, It has a general formula structure shown in formula (P): Wherein, Ar is an aryl structural unit; M is a carbonyl structural unit; the sum of x and y is 100%.

2. The sterically hindered aryl polymer according to claim 1, wherein Ar is selected from one of the copolymerization units having the following structures: The R1 and R2 groups are independently selected as a hydrogen atom or an alkane having 1 to 20 carbon atoms; Wherein, * represents a connecting bond.

3. The sterically hindered aryl polymer according to claim 1, wherein, M is independently selected from one of the copolymerization units having the following structures: Wherein, * represents a connecting bond.

4. The preparation method of the bulky aryl polymer according to any one of claims 1-3, characterized in that, It includes the following steps: Mix an Ar group monomer, a ketone monomer corresponding to M and a sterically hindered aryl structural monomer in a first solvent, react in the presence of a first catalyst, add the obtained reaction solution to a second solvent, collect the precipitated solid, and obtain a sterically hindered aryl polymer after drying; The structure of the bulky aryl structural monomer is The preparation method of the sterically hindered aryl structural monomer includes the following steps: Mix 2,7-dibromo-9,9'-spirobifluorene and 3,5-bis(trifluoromethyl)phenylboronic acid in a third solvent, and react in the presence of a second catalyst to obtain the sterically hindered aryl structural monomer.

5. The preparation method of the large steric hindrance aryl polymer according to claim 4, wherein: The temperature for the reaction in the presence of the first catalyst is -5 to 15 °C, the time is 0 - 48 h and not 0; the first catalyst includes trifluoroacetic acid and / or trifluoromethanesulfonic acid; The temperature for the reaction in the presence of the second catalyst is 60 - 90 °C, the time is 12 - 36 h; the second catalyst includes at least one of Pd(PPh3)4, AsPh3, n-Bu3P and (MeO)3P.

6. A bulky aryl quaternized polymer, characterized in that, It has a general formula structure shown in formula (Q): Ar is selected from one of the copolymerization units having the following structures: The R1 and R2 groups are independently selected as a hydrogen atom or an alkane having 1 to 20 carbon atoms; QA is independently selected from one of the copolymerization units having the following structures: The R3, R4 and R5 groups are independently selected as a hydrogen atom or an alkane having 1 to 20 carbon atoms; The sum of x and y is 100%.

7. The preparation method of the bulky aryl quaternized polymer according to claim 6, characterized in that, It includes the following steps: Mix the sterically hindered aryl polymer according to any one of claims 1 - 3 with a haloalkane or trimethylamine solution in a fourth solvent, react in the presence of a third catalyst, add the obtained reaction solution to a fifth solvent, collect the precipitated solid, and obtain a sterically hindered aryl quaternized polymer after drying.

8. A method for preparing an anion exchange membrane, characterized in that, It includes the following steps: The bulky aryl quaternized polymer described in claim 6 is added to a sixth solvent, and the resulting mixture is cast on the surface of a substrate to obtain a polymer membrane; the polymer membrane is immersed in an alkaline solution to obtain an OH - type anion exchange membrane.

9. A sterically hindered aryl anion exchange membrane prepared by the preparation method according to claim 8.

10. Use of the anion exchange membrane according to claim 9 in an alkaline fuel cell or an alkaline water electrolysis device.

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