Double quaternized QPVBC / QBPEI anion exchange membrane as well as preparation method and application thereof

Abstract

The invention relates to the technical field of high polymer materials, and discloses a double quaternized QPVBC / QBPEI anion exchange membrane and a preparation method and application thereof.The preparation method comprises the steps that 4-vinyl benzyl chloride, an azo initiator and a free radical polymerization reaction solvent are subjected to free radical polymerization, then quenching, sedimentation and drying are conducted, and poly 4-vinyl benzyl chloride is obtained; the preparation method comprises the following steps: carrying out quaternization on poly (4-vinylbenzyl chloride), a first quaternization reagent and a first organic solvent, and then curing to obtain quaternized poly (4-vinylbenzyl chloride); carrying out condensation reflux on the branched polyethyleneimine, a second quaternization reagent and a second organic solvent, and then carrying out rotary evaporation and drying to obtain quaternized branched polyethyleneimine; and carrying out stirring and cross-linking reaction on the quaternized poly (4-vinyl benzyl chloride), the quaternized branched polyethyleneimine and a third organic solvent to obtain the double quaternized QPVBC / QBPEI anion exchange membrane. The double quaternized QPVBC / QBPEI anion exchange membrane disclosed by the invention has excellent anion transmission capacity and has potential application value in the field of fuel cells.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a diquaternized QPVBC / QBPEI anion exchange membrane and a preparation method and application thereof. Background Art

[0002] Fuel cells have received widespread attention from all walks of life due to their advantages such as rapid startup, high energy conversion efficiency, water as the main emission, no harmful gases such as nitrogen oxides and sulfur oxides, and environmental friendliness. Among them, the ion exchange membrane material in the fuel cell is crucial. Common ion exchange membrane materials are proton exchange membrane (PEM) and anion exchange membrane (AEM). Compared with ordinary proton exchange membrane fuel cells (PEMFC), anion exchange membrane fuel cells (AEMFC) operate in an alkaline environment and can use non-precious metal catalysts, which greatly reduces production costs. At the same time, AEM has low fuel permeability and rapid electrochemical reactions. Therefore, AEMFC has quickly become a research hotspot at home and abroad. The anion exchange membrane is responsible for conducting anions to maintain the electrochemical reaction of the battery, and also acts as a barrier to isolate the fuel and oxidant. AMFC operates under alkaline conditions, and the ion conductor transported inside the electrolyte is OH. - The O2 and H2O at the cathode undergo a reduction reaction under the action of the catalyst to generate OH - , OH - The hydrogen peroxide passes through the AEM and reaches the anode, where it undergoes an oxidation reaction with H2 to produce H2O and electrons. The electrons then travel through an external circuit to the cathode, generating electricity. As a key component, the performance of the AEM directly impacts the overall performance of the AEMFC. Therefore, optimizing the performance of the AEM is crucial for improving the energy efficiency and extending the life of the AEMFC. Currently, research into the preparation of high-performance AEMs is of great significance to the development of fuel cells. Summary of the Invention

[0003] The purpose of the present invention is to overcome the above-mentioned problems existing in the prior art and provide a diquaternized QPVBC / QBPEI anion exchange membrane and its preparation method and application. This diquaternized QPVBC / QBPEI anion exchange membrane has excellent anion transport capacity and has potential application value in the field of fuel cells.

[0004] In order to achieve the above object, the present invention provides a method for preparing a diquaternized QPVBC / QBPEI anion exchange membrane, comprising the following steps: 4-vinylbenzyl chloride, an azo initiator, and a free radical polymerization solvent are mixed to perform a free radical polymerization reaction, followed by quenching, and the quenched material is precipitated and dried to obtain poly-4-vinylbenzyl chloride; The poly (4-vinylbenzyl chloride), a first quaternizing agent, and a first organic solvent are mixed to carry out a quaternization reaction, and then solidified to obtain quaternized poly (4-vinylbenzyl chloride); The branched polyethyleneimine, the second quaternizing agent and the second organic solvent are mixed to carry out condensation reflux reaction, followed by rotary evaporation and drying to obtain the quaternized branched polyethyleneimine; The quaternized poly (4-vinylbenzyl chloride), the quaternized branched polyethyleneimine and the third organic solvent are mixed, and then stirred and cross-linked to obtain a diquaternized QPVBC / QBPEI anion exchange membrane.

[0005] Preferably, the azo initiator is selected from one or more of azobisisobutyronitrile (AIBN), azobisisoheptanenitrile and dimethyl azobisisobutyrate; more preferably, it is azobisisobutyronitrile and / or azobisisoheptanenitrile.

[0006] The molar ratio of the azo initiator to 4-vinylbenzyl chloride is 1:50-1000, preferably 1:150-900. Controlling the ratio within this range can obtain poly-4-vinylbenzyl chloride with certain film-forming properties, making it easier to form a continuous film.

[0007] In the present invention, 4-vinylbenzyl chloride (CAS No. 1592-20-7) is used as a monomer to undergo a free radical polymerization reaction to obtain poly (4-vinylbenzyl chloride). While commercially available poly (4-vinylbenzyl chloride) is difficult to obtain with a desired number of repeating units, the preparation method of the present invention allows for precise control of the number of repeating units by controlling the ratio of monomer to azo initiator (the greater the amount of monomer used, the greater the number of repeating units). This allows for obtaining poly (4-vinylbenzyl chloride) (PVBC) with a target number of units, thereby producing a PVBC film with desired mechanical strength.

[0008] In the present invention, the free radical polymerization reaction solvent is selected from one or more of tetrahydrofuran (THF), isobutanol and toluene; further, the free radical polymerization reaction solvent is tetrahydrofuran and / or toluene.

[0009] In the present invention, the amount of the free radical polymerization solvent used is sufficient to dissolve the raw materials.

[0010] In the present invention, since the free radical polymerization reaction needs to be strictly controlled to be carried out under anhydrous and oxygen-free conditions, in order to ensure that the free radical polymerization reaction proceeds smoothly, in a specific embodiment of the present invention, after 4-vinylbenzyl chloride, an azo initiator and a free radical polymerization reaction solvent are added to a Shrek bottle and mixed, the mixed system needs to be cycled three times to freeze to a solid state - vacuumize in a frozen state - thaw with nitrogen until the system becomes a uniform solution (stirring is required during the thawing process), then freeze to a solid state again and vacuumize in a frozen state for three minutes, then tighten the high vacuum shut-off valve of the Shrek bottle, and then thaw the system in the Shrek bottle until it becomes a uniform solution before the free radical polymerization reaction is carried out; the thawing operation can be left to thaw naturally at room temperature or placed in a water bath to thaw at room temperature.

[0011] The room temperature described in the present invention refers to 20~30℃.

[0012] In a preferred embodiment of the present invention, the conditions for the free radical polymerization reaction include: a temperature of 50-90° C. and a time of 2-48 hours; further preferably, the conditions for the free radical polymerization reaction include: a temperature of 60-80° C. and a time of 24-36 hours.

[0013] In the present invention, after the free radical polymerization reaction is completed, the reaction system needs to be quickly placed in liquid nitrogen for quenching to stop the reaction, and then slowly heated at room temperature until the material obtained after quenching is completely dissolved, and then a small amount of dichloromethane is added dropwise thereto (because the polymer obtained after the free radical polymerization reaction has a high viscosity, a small amount of dichloromethane is used to dilute it to facilitate the washing away of impurities during subsequent sedimentation) to obtain a diluted material, which is then precipitated using a precipitant.

[0014] In a preferred embodiment of the present invention, 2 to 3 mL of dichloromethane is generally used for dilution.

[0015] The purpose of the above-mentioned sedimentation operation is to remove unreacted monomers, initiators, etc. embedded in the high-viscosity polymer. In order to ensure sufficient removal of unreacted substances, the number of sedimentation is preferably three times, wherein the specific operation of each sedimentation is to add a sedimentation agent under stirring conditions, let it stand, and then centrifuge, retain the precipitate after centrifugation, and discard the supernatant; wherein after the sedimentation operation is completed, the solid material obtained after sedimentation needs to be dried to obtain poly (4-vinylbenzyl chloride).

[0016] In a specific embodiment, the rotation speed of each centrifugation is 6000 rpm and the time is 5 minutes.

[0017] Furthermore, the sedimentation agent used in the present invention is selected from one or more of methanol, ether and petroleum ether; preferably, the sedimentation agent used in the present invention is ether and / or petroleum ether.

[0018] In a specific embodiment of the present invention, the amount of sedimentation agent used for each sedimentation is only required to completely immerse the solids.

[0019] In a preferred embodiment of the present invention, the drying conditions include: a temperature of 20-40° C. and a drying time of 24-48 hours.

[0020] In a preferred embodiment of the present invention, the first quaternizing agent is selected from one or more of trimethylamine aqueous solution, triethylamine and tripropylamine; more preferably trimethylamine aqueous solution and / or triethylamine.

[0021] The trimethylamine aqueous solution can be purchased commercially. In a specific embodiment, the concentration of the trimethylamine aqueous solution is 4.3 mol / L.

[0022] Preferably, the first organic solvent is selected from one or more of dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP) and N,N-dimethylformamide (DMF); further preferably, the first organic solvent is DMSO and / or DMF.

[0023] In the present invention, the solid-liquid ratio of the poly (4-vinylbenzyl chloride) to the first organic solvent is 1 g: 5 to 500 mL; more preferably, the solid-liquid ratio of the poly (4-vinylbenzyl chloride) to the first organic solvent is 1 g: 20 to 250 mL.

[0024] In a preferred embodiment, the solid-liquid ratio of the poly (4-vinylbenzyl chloride) to the first quaternary ammonium reagent is 1 g: 50-5000 μL; further, the solid-liquid ratio of the poly (4-vinylbenzyl chloride) to the first quaternary ammonium reagent is 1 g: 125-2000 μL.

[0025] In the present invention, by adjusting the dosage ratio of poly (4-vinylbenzyl chloride) and the first quaternizing agent, poly (4-vinylbenzyl chloride) (QPVBC) with different and higher degrees of quaternization can be obtained. In a specific embodiment, in order to ensure that the raw materials are fully mixed, it is preferred that the poly (4-vinylbenzyl chloride) and the first organic solvent are mixed and fully dissolved before being mixed with the first quaternary ammonium agent.

[0026] In a preferred embodiment, the conditions for the quaternization reaction include: a temperature of 0-30° C. and a time of 20-60 minutes; more preferably, the conditions for the quaternization reaction include: a temperature of 0-20° C. and a time of 30-50 minutes; wherein the temperature can ensure solubility and the time can ensure complete reaction, and therefore it is more appropriate to control the conditions for the quaternization reaction within the above range.

[0027] In the present invention, in order to ensure complete curing, the curing conditions include: a temperature of 60-90° C. and a time of 10-15 hours.

[0028] In a specific embodiment, the curing conditions include: a temperature of 80° C. and a time of 15 hours.

[0029] In the present invention, the second quaternizing agent is selected from ethyl bromide and / or 1-propane bromide.

[0030] Wherein, the second organic solvent is selected from one or more of methanol, ethanol and isobutanol; further, the second organic solvent is methanol and / or ethanol.

[0031] Preferably, the solid-liquid ratio of the branched polyethyleneimine to the second organic solvent is 1 g:5-500 mL; further preferably, the solid-liquid ratio of the branched polyethyleneimine to the second organic solvent is 1 g:20-250 mL.

[0032] In the present invention, the molar ratio of the second quaternizing agent to the total number of amine groups of the branched polyethyleneimine is 0.2-1:1, preferably 0.2-0.8:1.

[0033] The total number of amine groups in the branched polyethyleneimine in the present invention refers to the number of amine groups in one repeating unit of the branched polyethyleneimine multiplied by the number of repeating units, that is, the total number of amine groups in the branched polyethyleneimine.

[0034] Similarly, in order to ensure that all materials are fully mixed, it is preferred that the branched polyethyleneimine and the second organic solvent are fully stirred and dissolved before being uniformly mixed with the second quaternary ammonium agent.

[0035] The average weight-average molecular weight of the branched polyethyleneimine in the present invention is 20,000-30,000.

[0036] In the process of quaternizing branched polyethyleneimine (BPEI) to obtain quaternized branched polyethyleneimine (QBPEI), the present invention uses branched polyethyleneimine as a monomer and adjusts the dosage ratio of the second quaternizing agent to the total number of amine groups of the branched polyethyleneimine to obtain branched polyethyleneimine (QBPEI) with different and higher degrees of quaternization. Furthermore, the conditions for the condensation reflux include: a temperature of 30-80° C. and a time of 0.2-6 hours; further, the conditions for the condensation reflux include: a temperature of 40-60° C. and a time of 0.5-2 hours.

[0037] The purpose of the rotary evaporation in the present invention is to dry out the solvent and unreacted raw materials. Controlling the rotary evaporation temperature within the range of 60-75° C. is beneficial for removing the solvent and unreacted raw materials.

[0038] The drying conditions include: a temperature of 70-90° C. and a drying time of 6-48 hours.

[0039] In a specific embodiment, the drying conditions include: a temperature of 80° C. and a time of 24 hours.

[0040] In the present invention, the third organic solvent is dimethyl sulfoxide.

[0041] The ratio of the quaternized poly (4-vinylbenzyl chloride), the quaternized branched polyethyleneimine, and the third organic solvent is 1 g: 0.1 to 1 g: 5 to 50 mL. In the present invention, controlling the ratio of the quaternized poly (4-vinylbenzyl chloride) to the quaternized branched polyethyleneimine within this range can produce a better composite material.

[0042] In the present invention, stirring is preferably performed at room temperature, wherein the stirring time is 5 to 60 minutes.

[0043] After the stirring is completed, the stirred material can be poured into a suitable polytetrafluoroethylene mold according to the required membrane size, and then a cross-linking reaction is carried out to obtain a diquaternized QPVBC / QBPEI anion exchange membrane of the required size.

[0044] Furthermore, the conditions of the cross-linking reaction include: temperature of 50-90° C. and time of 0.5-5 hours.

[0045] Furthermore, the cross-linking reaction time is 0.5 to 2 hours.

[0046] A second aspect of the present invention provides a diquaternized QPVBC / QBPEI anion exchange membrane prepared by the above-mentioned method for preparing a diquaternized QPVBC / QBPEI anion exchange membrane.

[0047] The surface of the double-quaternized QPVBC / QBPEI anion exchange membrane prepared by the present invention is dense and non-porous, and the cross section is uniform and dense.

[0048] The third aspect of the present invention provides the use of the above-mentioned diquaternized QPVBC / QBPEI anion exchange membrane in a fuel cell membrane.

[0049] In the present invention, poly (4-vinylbenzyl chloride) (PVBC) homopolymer is first prepared via conventional free radical polymerization. Next, PVBC undergoes quaternization to produce a QPVBC raw material. Finally, quaternized branched polyethyleneimine (QBPEI) is added and blended for crosslinking to produce a cross-linked, diquaternized PVBC anion exchange membrane, namely, a QPVBC / QBPEI anion exchange membrane.

[0050] The double-quaternized QPVBC / QBPEI anion exchange membrane described in the present invention has a main structure of PVBC membrane, which is easy to synthesize, rich in benzyl chloride functional groups, and has excellent quaternization ability. After quaternization and cross-linking, it is easy to prepare a membrane with high ion transport capacity and excellent mechanical properties, providing a potential polymer material for fuel cell membranes. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is the QPVBC prepared in Example 1 800 and PVBC 800 of 1 H NMR spectrum; Figure 2 The PVBC prepared in Example 1 800 , QBPEI and QPVBC 800 / Thermogravimetric curve of QBPEI; Figure 3 It is the QPVBC prepared in Example 2 150 / QBPEI and PVBC 150 FTIR spectrum of Figure 4 The QPVBC prepared in Example 1 800 / SEM cross-sectional image of QBPEI film; Figure 5 The QPVBC prepared in Example 2 150 / SEM cross-sectional image of QBPEI film; Figure 6 The QPVBC prepared in Example 3 300 / SEM cross-sectional image of QBPEI film; Figure 7 It is QPVBC prepared in Example 1-3 150 / QBPEI film, QPVBC 300 / QBPEI film and QPVBC 800 / Mechanical properties of QBPEI film; Figure 8 It is QPVBC prepared in Example 1-3 150 / QBPEI film, QPVBC 300 / QBPEI film and QPVBC 800 / Conductivity performance diagram of QBPEI film. DETAILED DESCRIPTION

[0052] The following describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0053] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0054] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments provided by the present invention can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0055] The present invention will be described in detail below by way of examples. In the following examples, the experimental methods in the following examples, unless otherwise specified, are conventional methods in the art. The 4-vinylbenzyl chloride used in the following examples was purchased from Aladdin with the designation V592268, and the branched polyethyleneimine was purchased from Aladdin with an average weight-average molecular weight of 25,000 and the designation P434400.

[0056] The room temperature below refers to 25°C.

[0057] Example 1 Use a syringe to measure 17.2 mL of 4-vinylbenzyl chloride and 50 mL of free radical polymerization solvent (THF), weigh 0.025 g of azo initiator (AIBN) (the molar ratio of azo initiator to 4-vinylbenzyl chloride is 1:820), and add them to the Shrek bottle in sequence. At the same time, add a clean magnetic particle and seal the bottle mouth with a rubber stopper, and stir evenly with a magnetic stirrer. The mixed system is cycled three times to freeze to a solid state - vacuum in a frozen state - thaw with nitrogen until the system becomes a uniform solution (stirring is required during the thawing process), then freeze to a solid state again and vacuum in a frozen state for three minutes, then tighten the high vacuum shut-off valve of the Shrek bottle, and then place the Shrek bottle in a water bath to thaw. Wait until the system in the Shrek bottle is completely thawed and becomes a uniform solution After the solution is homogenized, a free radical polymerization reaction is carried out in a constant temperature oil bath at 60°C. The conditions for the free radical polymerization reaction include: temperature of 60°C and time for 24 hours. After the free radical polymerization reaction is completed, the Shrek bottle is quickly placed in liquid nitrogen for quenching to stop the reaction in the bottle, and then the temperature is slowly raised at room temperature until the material obtained after quenching is completely dissolved. Then, 2 mL of dichloromethane is added dropwise to dilute it, and then a precipitant (anhydrous ether) is added for precipitation. The number of precipitations is 3 times. The specific operation of each precipitation is to slowly add 500 mL of precipitant with a dropper under stirring conditions (using a magnetic stirrer), then stand, and then centrifuge (each centrifugation speed is 6000 rpm, time is 5 minutes), retain the precipitate after centrifugation, and pour off the supernatant. After the precipitation is completed, the solid material obtained after precipitation is placed in a vacuum oven at 40°C and dried for 24 hours to obtain pure, dry white powder poly (4-vinylbenzyl chloride) PVBC, recorded as PVBC 800 ; (2) 0.9 g of PVBC obtained in step (1) 800 Add to the single-necked bottle, then add 20 mL of the first organic solvent (DMSO) and mix (PVBC 800 The solid-liquid ratio of the first organic solvent is 1g:22.2mL), and the PVBC 800 Completely dissolve, then add the first quaternary ammonium reagent (trimethylamine aqueous solution with a concentration of 4.3 mol / L) 500 μL (PVBC 800 The solid-liquid ratio of the first quaternizing agent is 1g:555.6μL), the bottle mouth is quickly sealed with a rubber stopper, and after mixing, the single-mouth bottle is placed in a constant temperature water bath at 20℃ for quaternization reaction. The quaternization reaction conditions include: temperature of 20℃, time of 30 minutes; then the material obtained after the quaternization reaction is poured into a clean and flat glass plate, and then cured on a hot plate at 80℃ for 15 hours to obtain quaternized poly 4-vinylbenzyl chloride, denoted as QPVBC 800 ; Detection of PVBC 800 and QPVBC 800 of1 H NMR spectrum, such as Figure 1 As shown, according to Figure 1 It can be seen that QPVBC 800 The newly appeared peak at chemical shift δ = 3.1 ppm, namely the peak of three methyl H connected to N after quaternization, proved that quaternized poly (4-vinylbenzyl chloride) was obtained; (3) Add 0.8 g of branched polyethyleneimine to a clean beaker, then add 20 mL of the second organic solvent (anhydrous ethanol) and a magnet (the solid-liquid ratio of branched polyethyleneimine to the second organic solvent is 1 g: 25 mL). After sufficient stirring and dissolution, transfer all of the mixture to a single-necked bottle. Use a pipette to transfer 295.6 μL of the second quaternary ammonium reagent (1-bromopropane) to the single-necked bottle (the molar ratio of the second quaternary ammonium reagent to the total number of amino groups of the branched polyethyleneimine is 0.6:1). Continue stirring for 10 minutes to mix evenly. Then place the single-necked bottle in a 60°C constant temperature oil bath for condensation and reflux reaction for 2 hours. After the condensation and reflux reaction is completed, use a rotary evaporator to evaporate the solvent and unreacted 1-bromopropane at a rotary evaporation temperature of 60°C. Then, dry the mixture in a vacuum oven at 80°C for 24 hours to obtain the quaternized branched polyethyleneimine QBPEI. (4) 0.9 g of QPVBC obtained in step (2) was added 800 and 0.4 g of QBPEI obtained in step (3) were placed in a beaker, and 20 mL of the third organic solvent (DMSO) was added to mix (QPVBC 800 , QBPEI and the third organic solvent in a ratio of 1 g: 0.44 g: 22.2 mL), and then magnetically stirred at room temperature for 20 min. After the stirring was completed, the solution obtained after stirring was poured into a 9 cm × 9 cm polytetrafluoroethylene plate, which was placed in an 80 ° C oven for cross-linking reaction for 2 h, and the membrane was removed to obtain a diquaternized QPVBC / QBPEI anion exchange membrane, which was recorded as QPVBC 800 / QBPEI; PVBC was detected by thermogravimetric analysis. 800 , QBPEI and QPVBC 800 / Thermogravimetric curve of QBPEI, such as Figure 2 As shown, according to Figure 2 It can be seen that the mass of the three substances decreases at around 100℃, which is the evaporation of water; QBPEI loses weight again at 260℃, which means it starts to thermally decompose; PVBC 800 Thermal decomposition begins at around 220°C; QPVBC 800 / QBPEI begins to thermally decompose at around 240℃; this indicates that after compounding with QBPEI, QPVBC 800 / QBPEI film has improved thermal stability.

[0058] Example 2 The diquaternized QPVBC / QBPEI anion exchange membrane was prepared according to the method of Example 1, except that in step (1), the amount of 4-vinylbenzyl chloride was 3.2 mL, and the molar ratio of the azo initiator to 4-vinylbenzyl chloride was 1:160 to obtain PVBC. 150 ; In step (2), 0.8 g PVBC 150 Add to the single-mouth bottle, the amount of trimethylamine aqueous solution is 400μL, PVBC 150 The solid-liquid ratio of the first quaternary ammonium reagent is 1g:500μL to obtain QPVBC 150 ; In step (4), 0.2 g of QBPEI obtained in step (3) and 0.4 g of QPVBC obtained in step (2) were used. 150 (QPVBC 150 , QBPEI and the third organic solvent in a ratio of 1 g: 0.5 g: 50 mL), to obtain QPVBC 150 / QBPEI; PVBC 150 and QPVBC 150 / FTIR spectrum of QBPEI, such as Figure 3 As shown, according to Figure 3 It can be seen that PVBC 150 The characteristic peak of CH-Cl is 1264 cm -1 This characteristic peak is at QPVBC 150 / QBPEI composite film obviously disappeared, indicating that the quaternary ammonium substitution was successful.

[0059] Example 3 The diquaternized QPVBC / QBPEI anion exchange membrane was prepared according to the method of Example 1, except that in step (1), the amount of 4-vinylbenzyl chloride was 6.4 mL, and the molar ratio of the azo initiator to 4-vinylbenzyl chloride was 1:320 to obtain PVBC. 300 ; In step (2), 0.9 g PVBC 300 Add to the single-mouth bottle, the amount of trimethylamine aqueous solution is 500μL, PVBC 300 The solid-liquid ratio of the first quaternary ammonium reagent is 1g:555.6μL to obtain QPVBC 300 ; In step (4), 0.4 g of QBPEI obtained in step (3) and 0.4 g of QPVBC obtained in step (2) were used. 300 (QPVBC 300, QBPEI and the third organic solvent in a ratio of 1 g: 1 g: 50 mL) to obtain QPVBC 300 / QBPEI.

[0060] Test Example 1 The QPVBC prepared in Example 1 800 / QBPEI, QPVBC prepared in Example 2 150 / QBPEI and QPVBC prepared in Example 3 300 The cross section of / QBPEI was observed by scanning electron microscopy. Figures 4-6 As shown, Figure 4 It is QPVBC 800 / SEM cross-section of QBPEI, Figure 5 It is QPVBC 150 / SEM cross-section of QBPEI, Figure 6 It is QPVBC 300 / SEM cross-sectional view of the cross section of QBPEI, according to Figures 4-6 It can be seen that the diquaternized QPVBC / QBPEI anion exchange membrane prepared by the present invention is dense and uniform, and is suitable for the field of fuel cell membranes.

[0061] Test Example 2 The QPVBC prepared in Example 1 800 / QBPEI, QPVBC prepared in Example 2 150 / QBPEI and QPVBC prepared in Example 3 300 / QBPEI was tested for tensile strength and conductivity. The tensile strength results were as follows: Figure 7 The conductivity results are shown in Figure 8 As shown, the tensile strength and conductivity testing methods are as follows: Tensile strength test: Use a cutter to cut QPVBC 800 / QBPEI, QPVBC 150 / QBPEI and QPVBC 300 / QBPEI was cut into three 4 cm × 1 cm × 0.4 cm (length × width × thickness) strips. The tensile speed was set at 1 mm / min. An electronic tensile testing machine (XML(EC)-A, Jinan Languang Electromechanical Co., Ltd.) was used to test the strips according to GB / T1040.1-2006 standard to obtain the tensile fracture load (P). The following formula was used: T s = P / (b×d) Calculate the tensile strength ( T s ), where b is the initial width and d is the initial thickness; Conductivity detection: Using an electrochemical workstation (CHI760E, Shanghai Chenhua Instrument Co., Ltd.), QPVBC 800 / QBPEI, QPVBC 150 / QBPEI and QPVBC 300 / QBPEI were cut into 2cm×3cm sizes, placed in the electrochemical workstation, and the experimental parameters were adjusted and the test started; pass Figure 7 and Figure 8 It can be seen that with the increase of the molecular weight of QPVBC, the tensile strength of the QPVBC / QBPEI membrane gradually increases, reaching a maximum of 10.2 MPa; with the increase of the molecular weight of QPVBC and the test temperature, the ionic conductivity of the QPVBC / QBPEI membrane gradually increases, reaching a maximum of 21.037 mS / cm; in the present invention, with the increase of the number of repeating units of QPVBC, the mechanical properties of the diquaternized QPVBC / QBPEI anion exchange membrane increase, and the conductivity also gradually increases.

[0062] It should be understood that parts not elaborated in detail in this specification belong to the prior art.

[0063] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for preparing a diquaternized QPVBC / QBPEI anion exchange membrane, characterized in that: The following steps are involved: 4-vinylbenzyl chloride, an azo initiator, and a free radical polymerization solvent are mixed to perform a free radical polymerization reaction, followed by quenching, and the quenched material is precipitated and dried to obtain poly-4-vinylbenzyl chloride; The poly (4-vinylbenzyl chloride), a first quaternizing agent, and a first organic solvent are mixed to carry out a quaternization reaction, and then solidified to obtain quaternized poly (4-vinylbenzyl chloride); The branched polyethyleneimine, the second quaternizing agent and the second organic solvent are mixed to carry out condensation reflux reaction, followed by rotary evaporation and drying to obtain the quaternized branched polyethyleneimine; The quaternized poly (4-vinylbenzyl chloride), the quaternized branched polyethyleneimine and the third organic solvent are mixed, and then stirred and cross-linked to obtain a diquaternized QPVBC / QBPEI anion exchange membrane.

2. The method for preparing a diquaternized QPVBC / QBPEI anion exchange membrane according to claim 1, wherein: The azo initiator is selected from one or more of azobisisobutyronitrile, azobisisoheptanenitrile and dimethyl azobisisobutyrate; The molar ratio of the azo initiator to 4-vinylbenzyl chloride is 1:50-1000; The free radical polymerization reaction solvent is selected from one or more of tetrahydrofuran, isobutanol and toluene.

3. The method for preparing a diquaternized QPVBC / QBPEI anion exchange membrane according to claim 1 or 2, wherein: The conditions of the free radical polymerization reaction include: temperature of 50-90°C and time of 2-48 hours; The drying conditions include: a temperature of 20-40° C. and a drying time of 24-48 hours.

4. The method for preparing a diquaternized QPVBC / QBPEI anion exchange membrane according to claim 1, wherein: The first quaternizing agent is selected from one or more of trimethylamine aqueous solution, triethylamine and tripropylamine; The first organic solvent is selected from one or more of dimethyl sulfoxide, N-methylpyrrolidone and N,N-dimethylformamide; The solid-liquid ratio of the poly (4-vinylbenzyl chloride) to the first organic solvent is 1 g: 5 to 500 mL; The solid-liquid ratio of the poly (4-vinylbenzyl chloride) to the first quaternary ammonium reagent is 1 g: 50-5000 μL.

5. The method for preparing a diquaternized QPVBC / QBPEI anion exchange membrane according to claim 1 or 4, characterized in that: The conditions of the quaternization reaction include: temperature of 0-30°C and time of 20-60 minutes; The curing conditions include: a temperature of 60-90° C. and a curing time of 10-15 hours.

6. The method for preparing a diquaternized QPVBC / QBPEI anion exchange membrane according to claim 1, wherein: The second quaternizing agent is selected from ethyl bromide and / or 1-propane bromide; The second organic solvent is selected from one or more of methanol, ethanol and isobutanol; The solid-liquid ratio of the branched polyethyleneimine to the second organic solvent is 1g:5~500mL; The molar ratio of the second quaternary ammonium agent to the total number of amine groups of the branched polyethyleneimine is 0.2-1:

1.

7. The method for preparing a diquaternized QPVBC / QBPEI anion exchange membrane according to claim 1 or 6, characterized in that: The condensation reflux conditions include: temperature of 30-80°C and time of 0.2-6 hours; The temperature of the rotary evaporation is 60-75°C; The drying conditions include: a temperature of 70-90° C. and a drying time of 6-48 hours.

8. The method for preparing a diquaternized QPVBC / QBPEI anion exchange membrane according to claim 1, wherein: The third organic solvent is dimethyl sulfoxide; The quaternized poly (4-vinylbenzyl chloride), the quaternized branched polyethyleneimine and the third organic solvent are used in a ratio of 1 g: 0.1-1 g: 5-50 mL; The stirring time is 5 to 60 minutes; The cross-linking reaction conditions include: temperature of 50-90° C. and time of 0.5-5 hours.

9. A diquaternized QPVBC / QBPEI anion exchange membrane prepared by the method for preparing a diquaternized QPVBC / QBPEI anion exchange membrane according to any one of claims 1 to 8.

10. Use of the diquaternized QPVBC / QBPEI anion exchange membrane according to claim 9 in a fuel cell membrane.

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