A type of polyarylethersulfone polymer containing multiple side chain tetramethylimidazolium structures and its preparation method and application

Abstract

The present invention discloses a type of polyarylethersulfone polymer containing multiple side chain tetramethylimidazolium structures, and discloses a preparation method and application of the polymer. By simultaneously introducing dense side chain structures into the polymer molecular structural units, the aggregation of ionic functional groups is increased to promote ion aggregation, thereby improving the ionic conductivity of the polymer membrane material; at the same time, by introducing 1,2,4,5-tetramethylimidazole, the ionic conductivity and alkali resistance stability of the membrane material are effectively improved. The polyarylethersulfone polymer containing multiple side chain tetramethylimidazolium structures can be applied to dissolve in dimethyl sulfoxide and prepare an ion exchange membrane by a cast film method. It is used as an ion exchange membrane material in alkaline water electrolyzer hydrogen production and has good ionic conductivity, dimensional stability and chemical stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of ion exchange membranes, and is specifically applied to polymer anion exchange membranes for hydrogen production in alkaline electrolyzers and their preparation. More specifically, it relates to a type of polyarylethersulfone polymer containing multiple side-chain tetramethylimidazolium structures, its preparation method and application. Background Art

[0002] With the increasing use of fossil fuels and the growing severity of environmental and energy shortages, research into the production and consumption of clean energy is becoming increasingly necessary. Therefore, research into hydrogen production in water electrolyzers and hydrogen fuel cells is urgent. Polymer membrane water electrolyzers are divided into acidic proton exchange membrane electrolyzers and alkaline anion exchange membrane electrolyzers. Acidic proton exchange membrane electrolysis is a highly efficient electrolysis technology, but its application is limited by the presence of precious metals such as iridium and platinum. Alkaline environments can completely avoid the need for key raw materials, leading to recent developments in alkaline electrolyzers, which can operate dynamically and achieve excellent battery performance without compromising energy efficiency. Polymer anion exchange membranes are the core component material of alkaline electrolyzers, acting as an anion transporter and blocking fuel and electrons. Their performance directly impacts the performance of the entire system.

[0003] Currently available polymer anion exchange membranes have the following problems: (1) Low ion conductivity: Compared with the H+ conducted by proton exchange membranes, the OH - The atomic radius is large and the conductivity is low; (2) Poor alkali stability: the anion exchange membrane needs to work in an alkaline environment for a long time, and there will be OH - Attack polymers, and most functional groups such as quaternary ammonium, piperidine, pyrrole, etc. are easily attacked by OH - The attack occurs through nucleophilic substitution, Hofmann elimination, and ring-opening reactions. AEMs are the core components of water electrolyzers, and their chemical stability under high alkalinity and high temperature conditions is crucial. Therefore, a stable anion exchange membrane needs to be developed. Summary of the Invention

[0004] The purpose of the present invention is to address the above shortcomings and improve the ionic conductivity and alkali stability of anion exchange membranes used for hydrogen production in alkaline electrolyzers. A class of polyaryl ether sulfone polymers containing multiple side chain tetramethylimidazolium structures and their preparation methods and applications are provided. By simultaneously introducing dense side chain structures into the polymer molecular structural units, the aggregation of ionic functional groups is increased, thereby improving the ionic conductivity of the polymer membrane material; at the same time, the alkali stability of the polymer membrane material is further improved by introducing 1,2,4,5-tetramethylimidazole.

[0005] To achieve the above object, the present invention is implemented through the following technical solutions:

[0006] The present invention provides a poly(aryl ether sulfone) polymer containing multiple side chain tetramethylimidazolium structures. The structural formula of the poly(aryl ether sulfone) polymer containing multiple side chain tetramethylimidazolium structures is:

[0007]

[0008] In Formula 1, the content of the functionalized structural unit x=0.15-0.30, and each unit contains eight 1,2,4,5-tetramethylimidazolium rigid side chains, the content of the non-functionalized structural unit 1-x=0.70-0.85, and n=50-80.

[0009] Furthermore, the polyaryl ether sulfone polymer containing multiple side chain tetramethylimidazolium structures shown in Formula 1 is prepared by reacting the polyaryl ether sulfone containing multiple benzyl bromide structures shown in Formula 2 with 1,2,4,5-tetramethylimidazole.

[0010]

[0011] In the formula 2, the content of the benzyl bromide-containing structural unit x is 0.15 to 0.30, the content of the non-benzyl bromide-containing structural unit 1-x is 0.70 to 0.85, and n is 50 to 80.

[0012] The present invention also provides a method for preparing the polyarylethersulfone polymer containing multiple side chain tetramethylimidazolium structures, comprising:

[0013] Under nitrogen protection, the polyaryl ether sulfone polymer containing multiple benzyl bromide structures shown in Formula 2 is dissolved in a first organic solvent, and then mixed with 1,2,4,5-tetramethylimidazole and stirred for reaction. After the reaction is completed, it is filtered and dried to obtain the polyaryl ether sulfone polymer containing multiple side chain tetramethylimidazolium structures shown in Formula 1.

[0014] Preferably, the reaction temperature of the above reaction is 50-80° C., and the reaction time is 10-16 h.

[0015] Preferably, the organic solvent is N-methylpyrrolidone or dimethyl sulfoxide, and the amount thereof is 30 to 60 times the mass of the polyarylethersulfone polymer containing multiple benzyl bromide structures.

[0016] Preferably, the amount of 1,2,4,5-tetramethylimidazole used is 1 to 2 times the molar amount of benzyl bromide in the polyaryl ether sulfone polymer containing multiple benzyl bromide structures as shown in Formula 2.

[0017] Preferably, the polyarylethersulfone polymer containing multiple benzyl bromide structures shown in Formula 2 is prepared by brominating the polyarylethersulfone polymer containing multiple methyl structures shown in Formula 3.

[0018]

[0019]

[0020] In the formula 3, the content of the methyl-containing structural unit x=0.15-0.30, the content of the non-methyl-containing structural unit 1-x=0.70-0.85, and n=50-80.

[0021] The specific preparation method is as follows: under nitrogen protection, a certain amount of polyaryl ether sulfone containing a polymethyl structure shown in formula 3 is dissolved in a second organic solvent, an initiator and a brominating agent are added successively to react, and after the reaction is completed, the mixture is poured into ethanol for sedimentation, filtered and dried to obtain a polyaryl ether sulfone polymer containing multiple benzyl bromide structures shown in formula 2.

[0022] Preferably, in the above method, the second organic solvent is 1,1,2,2-tetrachloroethane, and its amount is 30 to 60 of the mass of the polyarylethersulfone polymer containing multiple methyl structures described in Formula 3; the brominating agent is N-bromosuccinimide (NBS), and its amount is 2.0 to 3.0 of the molar content of the methyl group; the initiator is benzoyl peroxide (BPO), and its amount is 5% to 9% of NBS; the reaction temperature is 60 to 85°C, and the reaction time is 6 to 8 hours.

[0023] Preferably, the polyarylethersulfone containing multiple methyl structures shown in Formula 3 is prepared by the following method: 3,3',5,5'-tetrakis(3",5"-dimethylphenyl)-4,4'-difluorodiphenylsulfone, 4,4'-difluorodiphenylsulfone and 2,2-bis-(4-hydroxyphenyl)hexafluoropropane shown in Formula 4 are subjected to a nucleophilic condensation reaction.

[0024]

[0025] The specific preparation method is as follows: under nitrogen protection, x parts of 3,3',5,5'-tetrakis(3",5"-dimethylphenyl)-4,4'-difluorodiphenyl sulfone shown in formula 4, 1-x parts of 4,4'-difluorodiphenyl sulfone and 1 part of 2,2-bis-(4-hydroxyphenyl)hexafluoropropane are added into a three-necked flask, and an appropriate amount of catalyst, a third organic solvent and a dehydrating agent are added to carry out a nucleophilic polycondensation reaction, the reaction is carried out at 130-140° C. for 1-2 hours, and then dehydration is carried out, and then the reaction is carried out at 165-175° C. for 4-8 hours to obtain a polyarylethersulfone containing multiple methyl structures shown in formula 3.

[0026] Further preferably, the third organic solvent is N-methylpyrrolidone, and its amount is 2 to 7 times the total mass of the three reaction monomers; the catalyst is potassium carbonate; its amount is 2 to 3 times the molar amount of 2,2-bis-(4-hydroxyphenyl)hexafluoropropane; the dehydrating agent is toluene, and its amount is 0.35 to 0.5 times the volume of N-methylpyrrolidone.

[0027] The present invention also provides an application of the above-mentioned polyaryl ether sulfone polymer containing multiple side chain tetramethylimidazolium structures, which is to apply the polymer to the preparation of ion exchange membranes. Specifically, the polyaryl ether sulfone polymer containing multiple side chain tetramethylimidazolium structures can be dissolved in dimethyl sulfoxide, and the ion exchange membrane can be prepared by a cast film method.

[0028] Furthermore, the ion exchange membrane prepared from the polyarylethersulfone polymer containing multiple side chain tetramethylimidazolium structures is used in hydrogen production in alkaline water electrolyzers.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) The present invention designs and synthesizes a type of polyaryl ether sulfone polymer containing multiple side chain tetramethylimidazolium structures. Eight side chain structures are simultaneously introduced into the polymer structural unit to increase the aggregation degree of ionic functional groups and further improve the ionic conductivity of the polymer membrane material; the alkali resistance stability of the polymer membrane material is further improved by introducing 1,2,4,5-tetramethylimidazolium.

[0031] (2) The polyaryl ether sulfone polymer with multiple side chain tetramethylimidazolium structures provided by the present invention is soluble in dimethyl sulfoxide and can be used to prepare ion exchange membranes by a cast film method. The prepared ion exchange membranes have good ion conductivity, dimensional stability and chemical stability, and can be used as ion exchange membrane materials in alkaline water electrolyzers for hydrogen production.

[0032] (3) The present invention provides a method for preparing a type of polyaryl ether sulfone polymer containing multiple side chain tetramethylimidazolium structures, wherein the ion exchange capacity of the polymer can be regulated according to the content of active difluorosulfone monomer containing polymethyl structure; the prepared polyaryl ether sulfone polymer ion exchange membrane containing multiple side chain tetramethylimidazolium structures contains eight rigid side chains of tetramethylimidazolium salt structures, which improves the aggregation of ion functional groups, is beneficial to the formation of ion transport channels in the ion exchange membrane, and thus improves the ion conductivity, and 1,2,4,5-tetramethylimidazole is used as the main functional group, and the alkali resistance stability is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a synthetic route for the polyarylethersulfone polymer containing multiple side chain tetramethylimidazolium structures as described in Example 1 of the present invention;

[0034] Figure 2 This is the NMR spectrum of the polyarylethersulfone polymer containing multiple methyl structures described in Example 2 of the present invention;

[0035] Figure 3 This is the NMR spectrum of the polyarylethersulfone polymer containing multiple benzyl bromide structures described in Example 2 of the present invention;

[0036] Figure 4This is the NMR spectrum of the polyarylethersulfone polymer containing multiple side chain tetramethylimidazolium structures described in Example 2 of the present invention;

[0037] Figure 5 Graphs showing the ionic conductivity of the polyarylethersulfone polymer membranes described in Examples 1, 2, 3, and 4 of the present invention;

[0038] Figure 6 This is a graph showing the alkali resistance stability of the polyarylethersulfone polymer membrane described in Example 3 of the present invention;

[0039] Figure 7 This is a performance diagram of a water electrolyzer using the polyarylethersulfone polymer membrane described in Example 3 of the present invention. DETAILED DESCRIPTION

[0040] The preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings and specific examples.

[0041] The sources of the drugs and reagents described in the examples are as follows:

[0042] N-Methylpyrrolidone: aladdin, ≥99.5%

[0043] Dimethyl sulfoxide: Shanghai Lingfeng Chemical Reagent Co., Ltd., ≥99.0%

[0044] 1,2,4,5-Tetramethylimidazole: TCI, ≥98%

[0045] Potassium carbonate: Shanghai Lingfeng Chemical Reagent Co., Ltd., ≥99.0%

[0046] 1,1',2,2'-Tetrachloroethane: Shanghai Lingfeng Chemical Reagent Co., Ltd., ≥99.0%

[0047] Benzoyl peroxide: aladdin, 90.0%

[0048] N-bromosuccinimide: Anaiji Chemical, 98%

[0049] 3,3',5,5'-Tetrakis(3",5"-dimethylphenyl)-4,4'-difluorodiphenyl sulfone: prepared according to reference (Electrochimica Acta, 2016, 190, 1057-1065), 98%

[0050] 4,4'-Difluorodiphenyl sulfone: Great Wall Reagent, 98%

[0051] 2,2-Bis-(4-hydroxyphenyl)hexafluoropropane: Anaiji Chemical, 98%

[0052] Toluene: Sinopharm Chemical Reagent Co., Ltd., ≥99.5%

[0053] Example 1

[0054] A method for preparing a polyarylethersulfone polymer containing multiple side chain tetramethylimidazolium structures comprises the following steps:

[0055] (1) Preparation of polyarylethersulfone containing multiple methyl structures

[0056] 1.0063 g (1.50 mmol) of 3,3',5,5'-tetrakis(3",5"-dimethylphenyl)-4,4'-difluorodiphenyl sulfone, 2.1611 g (8.50 mmol) of 4,4'-difluorodiphenyl sulfone, 3.3623 g (10.00 mmol) of 2,2-bis-(4-hydroxyphenyl)hexafluoropropane, 2.7642 g (20.00 mmol) of K2CO3, 12 mL of N-methylpyrrolidone, and 4 mL of toluene were added to a 100 mL three-necked flask equipped with a stirrer, a water separator, a condenser, and an N2 inlet and outlet. The reaction was first carried out at 140°C for 2 h, and then N2 was passed through to remove water and toluene. The temperature was then raised to 170°C for 5 h. The reaction solution was poured into ethanol for precipitation to obtain polyarylethersulfone containing multiple methyl structures (PAES-M-15) with a yield of 87%.

[0057] (2) Preparation of polyaryl ether sulfone containing multiple benzyl bromide structures

[0058] To a 100 mL three-necked flask equipped with a stirrer and N2 inlet and outlet, 1.2000 g (methyl content: 2.3493 mmol) of poly(aryl ether sulfone) (PAES-M-15) with a polymethyl structure and 48 mL of 1,1',2,2'-tetrachloroethane were added and stirred until completely dissolved. Subsequently, 1.0453 g (5.8731 mmol) of N-bromosuccinimide and 0.1067 g (0.4405 mmol) of benzoyl peroxide were added and reacted at 85°C for 7 h. The orange-red reaction solution was poured into hot ethanol for precipitation to obtain poly(aryl ether sulfone) containing multiple benzyl bromides (PAES-Br-15) in a 78% yield.

[0059] (3) Preparation of polyarylethersulfone polymers containing multiple side chain tetramethylimidazolium structures

[0060] 0.6000 g (benzyl bromide content of 1.0175 mmol) of a polyaryl ether sulfone polymer (PAES-Br-15) containing a polybenzyl bromide structure was dissolved in 24 mL of dimethyl sulfoxide and added to a three-necked flask equipped with a stirrer and a N2 inlet and outlet. Then, 0.1327 g (1.0683 mmol) of 1,2,4,5-tetramethylimidazole was added to the three-necked flask, and the temperature was raised to 60°C. The reaction was continued for 12 hours to obtain a polyaryl ether sulfone polymer (PAES-TMI-15) containing multiple side chain tetramethylimidazolium structures with a yield of 91%. The reaction solution was filtered with a sand core funnel and poured into a prepared mold to obtain a polyaryl ether sulfone polymer membrane (PAES-TMI-15) containing multiple side chain tetramethylimidazolium structures.

[0061] The synthetic route of the above preparation method is as follows Figure 1 shown.

[0062] Example 2

[0063] A method for preparing a polyarylethersulfone polymer containing multiple side chain tetramethylimidazolium structures, comprising the following steps

[0064] (1) Preparation of polyarylethersulfone containing multiple methyl structures

[0065] 1.3417 g (2.00 mmol) of 3,3',5,5'-tetrakis(3",5"-dimethylphenyl)-4,4'-difluorodiphenyl sulfone, 2.0340 g (8.00 mmol) of 4,4'-difluorodiphenyl sulfone, 3.3623 g (10.00 mmol) of 2,2-bis-(4-hydroxyphenyl)hexafluoropropane, 2.7642 g (20.00 mmol) of K2CO3, 12 mL of N-methylpyrrolidone, and 4 mL of toluene were added to a 100 mL three-necked flask equipped with a stirrer, a water separator, a condenser, and an N2 inlet and outlet. The mixture was first reacted at 140°C for 2 h, then N2 was passed through to remove water and toluene. The temperature was then raised to 170°C for 6 h. The reaction solution was poured into ethanol for precipitation to obtain polyarylethersulfone containing multiple methyl structures (PAES-M-20) with a yield of 84%.

[0066] (2) Preparation of polyaryl ether sulfone containing multiple benzyl bromide structures

[0067] To a 100 mL three-necked flask equipped with a stirrer and N2 inlet and outlet, 1.2000 g (3.0294 mmol) of poly(aryl ether sulfone) (PAES-M-20) with a polymethyl structure and 48 mL of 1,1',2,2'-tetrachloroethane were added and stirred until completely dissolved. Subsequently, 1.3479 g (7.5735 mmol) of N-bromosuccinimide and 0.1376 g (0.5680 mmol) of benzoyl peroxide were added and reacted at 85°C for 7 hours. The orange-red reaction solution was poured into hot ethanol for precipitation to obtain poly(aryl ether sulfone) containing multiple benzyl bromides (PAES-Br-20) in an 89% yield.

[0068] (3) Preparation of poly(aryl ether sulfone) polymer membranes containing multiple side chain tetramethylimidazolium structures

[0069] 0.6000 g (benzyl bromide content of 1.2631 mmol) of a polyaryl ether sulfone polymer (PAES-Br-20) containing a polybenzyl bromide structure was dissolved in 24 mL of N-methylpyrrolidone and added to a three-necked flask equipped with a stirrer and a N2 inlet and outlet. Then, 0.1647 g (1.2631 mmol) of 1,2,4,5-tetramethylimidazole was added to the three-necked flask, and the temperature was raised to 60°C. The reaction was continued for 12 hours to obtain a polyaryl ether sulfone polymer containing multiple side chain tetramethylimidazolium structures (PAES-TMI-20) with a yield of 89%. The reaction solution was filtered with a sand core funnel and poured into a prepared mold to obtain a polyaryl ether sulfone polymer membrane (PAES-TMI-20) containing multiple side chain tetramethylimidazolium structures.

[0070] Example 3

[0071] A method for preparing a poly(aryl ether sulfone) polymer containing multiple side chain tetramethylimidazolium structures comprises the following steps:

[0072] (1) Preparation of polyarylethersulfone containing multiple methyl structures

[0073] 1.6772 g (2.50 mmol) of 3,3',5,5'-tetrakis(3",5"-dimethylphenyl)-4,4'-difluorodiphenyl sulfone, 1.9029 g (7.50 mmol) of 4,4'-difluorodiphenyl sulfone, 3.3623 g (10.00 mmol) of 2,2-bis-(4-hydroxyphenyl)hexafluoropropane, 2.7642 g (20.00 mmol) of K2CO3, 15 mL of N-methylpyrrolidone and 5 mL of toluene were added to a 100 mL three-necked flask equipped with a stirrer, a water separator, a condenser and a N2 inlet and outlet. The mixture was first reacted at 140°C for 2 h, then N2 was passed through to remove water and toluene, and the temperature was raised to 170°C for 5 h. The reaction solution was poured into ethanol for precipitation to obtain polyarylethersulfone containing multiple methyl structures (PAES-M-25) with a yield of 87%. 1H NMR (CDCl3) as attached Figure 2 shown.

[0074] (2) Preparation of polyaryl ether sulfone containing multiple benzyl bromide structures

[0075] In a 100 mL three-necked flask equipped with a stirrer and N2 inlet and outlet, 1.2000 g (methyl content: 3.6662 mmol) of polymethyl polyethersulfone (PAES-M-25) and 48 mL of 1,1',2,2'-tetrachloroethane were added and stirred until completely dissolved. Subsequently, 1.6313 g (9.1656 mmol) of N-bromosuccinimide and 0.1665 g (0.6874 mmol) of benzoyl peroxide were added and reacted at 85°C for 7 hours. The orange-red reaction solution was poured into hot ethanol for precipitation to obtain polyethersulfone (PAES-Br-25) containing multiple benzyl bromide structures with a yield of 81%. 1 H NMR (DMSO-d6) as attached Figure 3 shown.

[0076] (3) Preparation of poly(aryl ether sulfone) polymer membranes containing multiple side chain tetramethylimidazolium structures

[0077] 0.6000 g (benzyl bromide content: 1.4771 mmol) of polyaryl ether sulfone polymer (PAES-Br-25) containing multiple benzyl bromide structures was dissolved in 24 mL of N-methylpyrrolidone and added to a three-necked flask equipped with a stirrer and a N2 inlet and outlet. 0.1926 g (1.5509 mmol) of 1,2,4,5-tetramethylimidazole was then added to the three-necked flask, and the temperature was raised to 60° C. The reaction was continued for 12 hours to obtain a polyaryl ether sulfone polymer (PAES-TMI-25) containing multiple side chain tetramethylimidazolium structures with a yield of 85%. 1 HNMR (DMSO-d6) as attached Figure 4 As shown; the reaction solution was filtered with a sand core funnel and then poured into the prepared mold to obtain a polyarylethersulfone polymer membrane (PAES-TMI-25) containing multiple side chain tetramethylimidazolium structures.

[0078] Example 4

[0079] A method for preparing a poly(aryl ether sulfone) polymer containing multiple side chain tetramethylimidazolium structures comprises the following steps:

[0080] (1) Preparation of polyarylethersulfone containing multiple methyl structures

[0081] 2.0126 g (3.00 mmol) of 3,3',5,5'-tetrakis(3",5"-dimethylphenyl)-4,4'-difluorodiphenyl sulfone, 1.7798 g (7.00 mmol) of 4,4'-difluorodiphenyl sulfone, 3.3623 g (10.00 mmol) of 2,2-bis-(4-hydroxyphenyl)hexafluoropropane, 2.7642 g (20.00 mmol) of K2CO3, 15 mL of N-methylpyrrolidone, and 5 mL of toluene were added to a 100 mL three-necked flask equipped with a stirrer, a water separator, a condenser, and an N2 inlet and outlet. The reaction was first carried out at 140°C for 2 h, and then N2 was passed through to remove water and toluene. The temperature was then raised to 170°C for 5 h. The reaction solution was poured into ethanol for precipitation to obtain polyarylethersulfone containing multiple methyl structures (PAES-M-30) with a yield of 86%.

[0082] (2) Preparation of polyaryl ether sulfone containing multiple benzyl bromide structures

[0083] To a 100 mL three-necked flask equipped with a stirrer and N2 inlet and outlet, 1.2000 g (methyl content, 4.2638 mmol) of poly(aryl ether sulfone) (PAES-M-30) with a polymethyl structure and 48 mL of 1,1',2,2'-tetrachloroethane were added and stirred until completely dissolved. Subsequently, 1.8972 g (10.6595 mmol) of N-bromosuccinimide and 0.1937 g (0.7995 mmol) of benzoyl peroxide were added and reacted at 85°C for 7 h. The orange-red reaction solution was poured into hot ethanol for precipitation to obtain poly(aryl ether sulfone) containing multiple benzyl bromides (PAES-Br-30) in an 82% yield.

[0084] (3) Preparation of poly(aryl ether sulfone) polymer membranes containing multiple side chain tetramethylimidazolium structures

[0085] 0.6000 g (benzyl bromide content of 1.6651 mmol) of a polyaryl ether sulfone polymer (PAES-Br-30) containing a polybenzyl bromide structure was dissolved in 24 mL of N-methylpyrrolidone and added to a three-necked flask equipped with a stirrer and a N2 inlet and outlet. Then, 0.2171 g (1.7484 mmol) of 1,2,4,5-tetramethylimidazole was added to the three-necked flask, and the temperature was raised to 60°C. The reaction was continued for 12 hours to obtain a polyaryl ether sulfone polymer (PAES-TMI-30) containing multiple side chain tetramethylimidazolium structures with a yield of 86%. The reaction solution was filtered with a sand core funnel and poured into a prepared mold to obtain a polyaryl ether sulfone polymer membrane (PAES-TMI-30) containing multiple side chain tetramethylimidazolium structures.

[0086] Table 1 shows a comparison of the basic properties of the ion exchange membrane prepared from the polyarylethersulfone polymer containing multiple side-chain tetramethylimidazolium structures obtained in the above examples and the existing Nafion membrane.

[0087] Table 1

[0088]

[0089] In the table: Test conditions: temperature is 30℃,

[0090] IEC t is the theoretical value;

[0091] IEC e Measured by titration;

[0092] σ was measured in pure water using an electrochemical workstation;

[0093] WU% is the mass change of the membrane before and after water absorption;

[0094] SR% is the change in membrane length before and after water absorption.

[0095] It can be seen from Table 1 that the thickness of the prepared PAES-TMI-x film is 43 About 48μm, IEC t The theoretically designed values ​​range from 1.39 to 2.06 mmol / g; IEC e The content of imidazole groups per unit mass increases with increasing IEC values, further promoting ion conduction. Consequently, the ionic conductivity σ increases with increasing IEC values, from 26.38 mS / cm to 51.03 mS / cm at 30°C. Water absorption (WU) and swelling ratio (SR) also increase with increasing IEC values, with WU increasing from 15.8% to 38.9% and SR from 6.1% to 11.1% at 30°C.

[0096] The ionic conductivity of the membrane is one of the key factors in evaluating the performance of the membrane. The ionic conductivity of the PAES-TMI-x membrane was tested in the temperature range of 20℃ to 80℃ by the four-electrode method. Figure 5 As shown in the figure, the ionic conductivity of PAES-TMI-x membrane increases with the increase of IEC, and water is the key carrier of ion conduction. The increase of water content promotes the ion diffusion rate, which leads to the increase of ionic conductivity with the increase of temperature.

[0097] When AEMs are assembled in a water electrolyzer, strong alkaline hydroxide ions are generated during the electrolysis process. Therefore, alkali resistance is one of the key properties to measure the performance of anion exchange membranes. This test takes PAES-TMI-0.25 membrane as an example and immerses it in 2 mol L -1 The membrane was immersed in a NaOH solution at 80°C for 480 hours. The membrane's alkali resistance stability was evaluated by measuring the IEC and ionic conductivity of the membrane. Figure 6 As shown in the figure, IEC decreased with time, and its retention rate was 91.5% after 480 h. The retention rate of ionic conductivity was 86.8% after 480 h of durability test.

[0098] Figure 7 The battery voltage durability curve is shown at 30°C and 500 mA cm -2 Steady-state polarization curves were recorded for 480 hours at a constant current density. Throughout the test, the voltage fluctuated between 1.76 V and 1.81 V. This overall test demonstrates the feasibility of this type of membrane operating under alkaline conditions.

[0099] While various embodiments of the present invention have been described above, the foregoing description is intended to be illustrative and non-exhaustive, and is not intended to be limiting of the disclosed embodiments. Numerous modifications and variations will be apparent to those skilled in the art without departing from the scope and technical principles of the described embodiments, and such modifications and variations should be considered within the scope of the present invention.

Claims

1. A poly(aryl ether sulfone) polymer containing multiple side chain tetramethylimidazolium structures, characterized in that: The structural formula of the polyarylethersulfone polymer containing multiple side chain tetramethylimidazolium structures is: ； Formula 1 In Formula 1, the content of the functionalized structural unit x = 0.15 to 0.30, and each unit contains eight 1,2,4,5-tetramethylimidazolium rigid side chains, the content of the non-functionalized structural unit 1-x = 0.70 to 0.85, and n = 50 to 80; The polyaryl ether sulfone polymer containing multiple side chain tetramethylimidazolium structures shown in formula 1 is prepared by reacting the polyaryl ether sulfone containing multiple benzyl bromide structures shown in formula 2 with 1,2,4,5-tetramethylimidazole. ； Formula 2 In Formula 2, the content of the benzyl bromide-containing structural unit is x=0.15-0.30, the content of the non-benzyl bromide-containing structural unit is 1-x=0.70-0.85, and n=50-80.

2. A method for preparing a polyarylethersulfone polymer containing multiple side chain tetramethylimidazolium structures according to claim 1, characterized in that: include: Under nitrogen protection, the polyaryl ether sulfone polymer containing multiple benzyl bromide structures shown in Formula 2 is dissolved in a first organic solvent, and then mixed with 1,2,4,5-tetramethylimidazole and stirred for reaction. After the reaction is completed, it is filtered and dried to obtain the polyaryl ether sulfone polymer containing multiple side chain tetramethylimidazolium structures shown in Formula 1.

3. The method for preparing a polyarylethersulfone polymer containing multiple side chain tetramethylimidazolium structures according to claim 2, wherein: The first organic solvent is N-methylpyrrolidone or dimethyl sulfoxide, and its usage is 30 to 60 times the mass of the polyaryl ether sulfone polymer containing multiple benzyl bromide structures shown in Formula 2.

4. The method for preparing a polyarylethersulfone polymer containing multiple side chain tetramethylimidazolium structures according to claim 2, wherein: The amount of 1,2,4,5-tetramethylimidazole used is 1 to 2 times the molar amount of benzyl bromide in the polyaryl ether sulfone polymer containing multiple benzyl bromide structures as shown in Formula 2.

5. The method for preparing a polyarylethersulfone polymer containing multiple side chain tetramethylimidazolium structures according to claim 2, wherein: The polyarylethersulfone polymer containing multiple benzyl bromide structures shown in Formula 2 is prepared by brominating the polyarylethersulfone polymer containing multiple methyl structures shown in Formula 3. ； Formula 3 In Formula 3, the content of the methyl-containing structural unit is x=0.15-0.30, the content of the non-methyl-containing structural unit is 1-x=0.70-0.85, and n=50-80.

6. The method for preparing a polyarylethersulfone polymer containing multiple side chain tetramethylimidazolium structures according to claim 5, characterized in that: The preparation method of the polyarylethersulfone polymer containing multiple benzyl bromide structures shown in Formula 2 comprises: The polyaryl ether sulfone polymer containing multiple methyl structures described in formula 3 is dissolved in a second organic solvent, and then an initiator and a brominating agent are added successively to react. After the reaction is completed, the polymer is poured into ethanol for sedimentation, filtered and dried to obtain the polyaryl ether sulfone polymer containing multiple benzyl bromide structures shown in formula 2.

7. The method for preparing a polyarylethersulfone polymer containing multiple side chain tetramethylimidazolium structures according to claim 6, characterized in that: The second organic solvent is 1,1,2,2-tetrachloroethane, and its usage is 30-60% of the mass of the polyarylethersulfone polymer containing multiple methyl structures described in Formula 3; the brominating agent is NBS, and its usage is 2.0-3.0% of the methyl molar content; the initiator is BPO, and its usage is 5%-9% of NBS.

8. The use of the polyarylethersulfone polymer containing multiple side chain tetramethylimidazolium structures according to claim 1, characterized in that: The polymer is used in the preparation of ion exchange membranes.

9. The use of the polyarylethersulfone polymer containing multiple side chain tetramethylimidazolium structures according to claim 8, characterized in that: The ion exchange membrane is used in hydrogen production in an alkaline water electrolyzer.

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