Polymer, cross-linked anion-exchange membrane and preparation method and application of cross-linked anion-exchange membrane

Abstract

The invention provides a polymer, a cross-linked anion exchange membrane and a preparation method and application thereof. According to the polymer and the cross-linked anion exchange membrane, aryl compounds, trifluoroketone compounds and N-methylpiperidone are polymerized to form a main chain, the main chain has excellent rigidity and flexibility, a quaternary ammonium salt alkenyl compound is introduced as a cross-linking agent, cross-linking is completed through heating in the membrane forming process, and the cross-linked anion exchange membrane is prepared. The quaternary ammonium salt side chain introduced into the side chain has excellent hydrophilic and hydrophobic phase separation characteristics. The polymer and the cross-linked anion exchange membrane have excellent oxidation-reduction resistance and alkali resistance, have the characteristics of stable physical and chemical properties, excellent ion flux, excellent mechanical properties (the elongation at break is greater than 60%) and simple process, and can be widely applied to the fields of hydrogen production by water electrolysis and the like.

Description

Technical Field

[0001] The invention relates to anion exchange membrane technology, and in particular to a polymer, a cross-linked anion exchange membrane, and a preparation method and application thereof. Background Art

[0002] As the cornerstone of energy in the new era, clean energy plays a vital role in the development of the energy world in the next stage. Although most renewable energy resources such as solar energy and wind energy are relatively abundant, they are unstable and discontinuous due to time and geographical limitations, which greatly reduces the utilization rate of such resources. Green hydrogen production technology that can adapt to fluctuating energy is particularly important. Hydrogen is a clean and high-energy fuel that can be produced by electrolyzing water with electricity converted from renewable energy such as solar energy and can be efficiently stored as chemical energy. Currently, common water electrolysis hydrogen production technologies include cation exchange membrane water electrolysis technology (PEMWE) and anion exchange membrane water electrolysis technology (AEMWE). A large number of studies have shown that AEMWE has the advantage of faster electrode reactions.

[0003] Anion exchange membrane (AEM) is an important component of AEMWE system. Its function is to limit the transfer of gas and other electrons between electrodes while ensuring OH -Conducted from the cathode to the anode. Common anion exchange membranes used for electrolysis of water to produce hydrogen usually use aromatic compounds as rigid main chains, and then provide relatively stable ion exchange capacity through the quaternary ammonium salt structure obtained by quaternization reaction of nitrogen-containing heterocyclic compounds with strong alkaline resistance. Patent document CN 114989437B discloses a method for preparing a polymer for anion exchange membrane, which uses polyaryl as the main chain and draws flexible long-chain alkyl side chains from the main chain, but the polymer does not use cross-linking and other structures to construct a multidimensional membrane. Patent documents CN116693785B, CN 117285701A, and CN 117285819A disclose applications of nitrogen-containing heterocyclic polymers and polymer films, in which nitrogen-containing heterocyclic rings such as piperidine and quinine are used with hydrophobic copolymer units such as alkyl, trifluoromethyl, pyridyl, and phenyl groups to form the main chain, and main chain crosslinkers such as triphenylbenzene or flexible quaternary ammonium salt-type side chain crosslinkers are used to construct a cross-linked film to improve the physical and chemical properties of the film. However, the degree of crosslinking brought about by this crosslinking method is easily limited by the properties of the polymer itself (such as viscosity and solubility). The anion exchange membranes currently used for hydrogen production by water electrolysis still have the following problems to varying degrees: 1) Some main chains are too rigid, resulting in poor mechanical properties, especially low elongation at break, which cannot meet the requirements of subsequent AEMWE use; 2) The two-dimensional membrane structure constructed to reduce the swelling coefficient and electrolyte transmembrane permeability has a low degree of cross-linking due to the choice of cross-linking agent; 3) The heterocyclic structure in some structural polymers cannot meet the high alkali resistance and oxidation resistance required for hydrogen production by water electrolysis, and the high ionic conductivity brings new challenges to anion exchange membranes. Summary of the invention

[0004] The purpose of the present invention is to propose a polymer, cross-linked anion exchange membrane in view of the above-mentioned problems existing in traditional anion exchange membranes. The anion exchange membrane has the advantages of high mechanical properties, high ion flux, and low membrane resistance, while ensuring excellent corrosion resistance and alkali resistance, strong anti-swelling property, and long service life. The polymer, cross-linked anion exchange membrane of the present invention has good application prospects and large-scale promotion potential in the field of hydrogen production by water electrolysis.

[0005] It should be noted that, in the present invention, unless otherwise specified, the specific meaning of "including" in relation to composition limitations and descriptions includes both open-ended "including", "comprising", etc. and similar meanings, as well as closed-ended "composed of", "composed of", etc. and similar meanings.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is: a polymer, cross-linked anion exchange membrane, the general formula of which is shown in Formula 1:

[0007]

[0008] wherein Ar is independently any one or more of benzene, diphenyl, p-terphenyl, m-terphenyl, p-quaterphenyl, fluorene and dimethylfluorene;

[0009] R is Formula 2 or Formula 3:

[0010]

[0011] In Formula 1, Formula 2 and Formula 3, 10≤m≤1000, 10≤n≤1000, 1≤x≤9, 1≤y≤5, and m, n, x, y are all positive integers;

[0012] Furthermore, the counter ion of the polymer and the cross-linked anion exchange membrane is any one of iodine ion, bromide ion, chloride ion, hydroxide ion and bicarbonate ion. The polymer and the ion exchange membrane are both positively charged structures, which require negative ions to ensure balance, and the negative ions are counter ions.

[0013] Furthermore, the counter ions of the polymer and the cross-linked anion exchange membrane are preferably bromide ions and / or chloride ions.

[0014] Furthermore, each of the Ars is independently p-terphenyl and / or m-terphenyl.

[0015] Furthermore, in Formula 1, Formula 2 and Formula 3, 200≤m≤500, 300≤n≤500, x=4, y=2, and m and n are both positive integers.

[0016] Another object of the present invention is to disclose a method for preparing a polymer and a cross-linked anion exchange membrane, wherein one or more aromatic compounds are used as the main chain of the polymer monomer, and the polymer intermediate is obtained by condensation with trifluoroketone compounds and N-methyl piperidone under the catalytic action of a superacid, and a flexible quaternary ammonium salt type olefinic compound is introduced as a cross-linking agent, and cross-linking is completed by heating during the film forming process. The introduction of a long-chain carbonyl compound is conducive to reducing the strong rigidity caused by the piperidine structure in the main chain and enhancing the toughness of the membrane. At the same time, the alkyl long chain and the quaternary ammonium salt type side chain in the structure can effectively control the separation of the hydrophilic and hydrophobic phases, which is conducive to the construction of ion exchange channels, and the introduction of an olefinic cross-linking agent is conducive to the construction of a two-dimensional membrane structure, which can improve the mechanical properties of the anion exchange membrane and reduce the swelling coefficient of the ion exchange membrane when it is used; the anion exchange membrane has excellent spatial dimensional stability and membrane skeleton stability, strong redox resistance and alkali resistance, and can be applied to the fields of electrolysis of water to produce hydrogen.

[0017] To achieve the above object, the technical solution adopted by the present invention is: a method for preparing a polymer cross-linked anion exchange membrane, comprising the following steps:

[0018] (1) Aromatic compounds, N-methylpiperidone and trifluoroketone compounds are polymerized in dichloromethane under the catalytic action of a superacid catalyst at -10-25°C. After the reaction for 6-18 hours, the mixture is soaked in an aqueous sodium hydroxide solution, hardened and crushed, washed with deionized water and dried in a vacuum to obtain a polymer intermediate 1, wherein X is Cl, Br or I, x is a positive integer between 1 and 9, and preferably 4, m is a positive integer between 200 and 500, and n is a positive integer between 300 and 500. The reaction principle is as follows:

[0019]

[0020] (2) Adding polymer intermediate 1, potassium carbonate and iodomethane to an organic solvent, reacting at 35-45° C. for 24-36 hours, adding acetone after the reaction, precipitating a solid product, washing and drying to obtain polymer intermediate 2, wherein X is Cl, Br or I, x is a positive integer between 1 and 9, and preferably 4, m is a positive integer between 200 and 500, and n is a positive integer between 300 and 500; the reaction principle is as follows:

[0021]

[0022] (3) Adding polymer intermediate 2, potassium carbonate, and quaternary ammonium salt type alkenyl compound to an organic solvent, reacting at 45-65° C. for 48-72 hours, adding acetone after the reaction, precipitating a solid product, washing and drying to obtain a film powder, wherein X is Cl, Br or I, x is a positive integer between 1 and 9, and preferably 4, m is a positive integer between 200 and 500, and n is a positive integer between 300 and 500; the reaction principle is as follows:

[0023]

[0024] (4) Applying an organic solvent mixed with membrane powder on the base membrane, and scraping the base membrane with a scraper to obtain a wet film with a thickness of 500-800 μm and a smooth membrane surface, and drying to obtain a polymer, cross-linked anion exchange membrane. Figure 2 As shown, the reaction principle is as follows:

[0025]

[0026] Furthermore, in step (1), the molar ratio of the aromatic compound, N-methylpiperidone, and trifluoroketone compound is 1:0.2-1.0:0.15-0.5.

[0027] Furthermore, in step (1), the molar ratio of the aromatic compound, dichloromethane, and superacid catalyst is 1:5-8.5:10.5-14. Since the reaction is a condensation reaction catalyzed by a superacid, a high molecular weight polymer (greater than 50,000) is obtained from a small molecule, which requires an excess of acid for catalysis, so the amount of superacid added is relatively high.

[0028] Furthermore, in step (1), the superacid catalyst is one or more of trifluoroacetic acid, methanesulfonic acid, trifluoromethanesulfonic acid, acetic acid, pentafluoropropionic acid and tellurium pentafluoride.

[0029] Furthermore, in step (1), the aromatic compound is one or more of benzene, diphenyl, p-terphenyl, m-terphenyl, p-quaterphenyl, fluorene and dimethylfluorene.

[0030] Furthermore, in step (1), the trifluoroketone compound has the general formula Wherein X is Cl or Br.

[0031] Furthermore, in step (1), after the reaction is completed, the product is soaked in 1-1.5M sodium hydroxide ice water solution, hardened, crushed, washed with deionized water for multiple times, and vacuum dried at 45-50°C to obtain a polymer intermediate 1.

[0032] Furthermore, in step (2), the mass ratio of the polymer intermediate 1, potassium carbonate and methyl iodide is 1:0.05-0.2:0.5-2.

[0033] Furthermore, in step (2), the mass ratio of the polymer intermediate 1 to the organic solvent is 1:6-10.

[0034] Furthermore, in step (2), the volume ratio of the organic solvent to acetone is 1:3-6.

[0035] Furthermore, in step (2), the organic solvent is one or more of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone.

[0036] Furthermore, in step (2), the drying temperature is 55-60°C.

[0037] Furthermore, in step (2), acetone is used for washing.

[0038] Furthermore, in step (3), the mass ratio of the polymer intermediate 2, potassium carbonate and quaternary ammonium salt type olefinic compound is 1:0.05-0.2:0.15-0.5.

[0039] Furthermore, in step (3), the mass ratio of the polymer intermediate 2 to the organic solvent is 1:6-10.

[0040] Furthermore, in step (3), the volume ratio of the organic solvent to acetone is 1:3-6.

[0041] Furthermore, in step (3), the organic solvent is one or more of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone.

[0042] Furthermore, in step (3), the drying temperature is 55-60°C.

[0043] Furthermore, in step (3), the quaternary ammonium salt type alkenyl compound is of formula 4 or formula 5:

[0044]

[0045] In formula 5, 1≤y≤5, y is a positive integer, and y is preferably 2.

[0046] Furthermore, in step (3), acetone is used for washing.

[0047] Furthermore, in step (4), the mass ratio of the membrane powder to the organic solvent is 1:2.5-6.

[0048] Furthermore, in step (4), the organic solvent is one or more of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone.

[0049] Furthermore, in step (4), the film powder is stirred evenly in an organic solvent, coated on a PET base film preheated to 40-45°C through an underlying glass plate, and a scraper provided with a coating machine is used to scrape the base film at a speed of 5-7 mm / s to obtain a wet film, wherein the wet film has a thickness of 500-800 μm and the film surface is flat.

[0050] Furthermore, in step (4), the drying conditions are as follows: drying at 60-65°C for 2-2.5h, then heating to 90-95°C for drying for 6-6.5h, and finally drying at 120-125°C for 4-4.5h to obtain a cross-linked polyaryl anion exchange membrane.

[0051] Another object of the present invention is to disclose the application of a polymer, cross-linked anion exchange membrane in the field of hydrogen production by water electrolysis.

[0052] The polymer, cross-linked anion exchange membrane and preparation method and application thereof of the present invention have the following advantages compared with the prior art:

[0053] (1) The dense ether-free polymer main chain reduces the water absorption of the main skeleton chain and ensures the spatial stability of the skeleton.

[0054] (2) The olefinic structure is introduced as a cross-linking agent to construct a planar two-dimensional rigid membrane structure, enhance the anti-swelling performance, and inhibit the attenuation of membrane efficiency during long-term use.

[0055] (3) The high degree of polymerization aromatic skeleton, trifluoromethyl-substituted nitrogen-containing heterocycle and heterocyclic structure in quaternary ammonium salt-type olefinic compounds greatly improve the oxidation resistance and alkali resistance of the overall film.

[0056] (4) The use of a high-polymerization aromatic skeleton and the use of a partial trifluoromethyl long-chain structure to replace the piperidone structure increase the flexibility while ensuring the rigidity of the polymer main chain, thereby improving the overall mechanical properties of the anion exchange membrane, such as tensile strength and elongation at break.

[0057] (5) The introduction of flexible side chains and some quaternary ammonium salt-type olefinic compounds as cross-linking agents can effectively construct a hydrophilic-hydrophobic phase separation structure, which is beneficial to the construction of a stable ion transport channel to increase the conductivity.

[0058] (6) Olefin free radical crosslinking occurs under heating conditions, which avoids the situation where the addition amount of main chain crosslinking agent and side chain double-terminal quaternary ammonium salt crosslinking agent is inhibited due to excessive polymer viscosity and reduced solubility, and increases the possibility of highly crosslinked anion exchange membrane;

[0059] The cross-linked polyaryl anion exchange membrane prepared by the present invention has the advantages of high mechanical properties, high ion flux, and low membrane resistance, while ensuring excellent corrosion resistance and alkali resistance, strong anti-swelling property, and long service life. The polymer and cross-linked anion exchange membrane of the present invention have good application prospects and large-scale promotion potential in the field of hydrogen production by water electrolysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 is the OH of the anion exchange membrane described in Example 5 and Comparative Example 2 - ConductivityConductivity curves at different temperatures;

[0061] Figure 2 This is a schematic diagram of the cross-linking reaction that occurs during the heating process of the wet membrane in the process of preparing the polymer and cross-linked anion exchange membrane of the present invention;

[0062] Figure 3 The performance test curves of water electrolysis using anion exchange membranes of Examples 3-5 and Comparative Examples 1-2 are shown. DETAILED DESCRIPTION

[0063] The present invention is further described below with reference to the examples. The description of the technical features described below is based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:

[0064] Unless otherwise stated, the units used in this specification are all international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0065] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints numerical values ​​A and B.

[0066] In the present specification, a numerical range expressed using "above" or "below" means a numerical range including the number.

[0067] In this specification, the word "may" means both performing a certain process and not performing a certain process.

[0068] In this specification, the use of "optional" or "optional" indicates that certain substances, components, execution steps, application conditions and other factors are used or not used.

[0069] In this specification, when "normal temperature" or "room temperature" is used, the temperature may be 15-25°C.

[0070] In this manual, the reagents or instruments used without indicating the manufacturer are all conventional products that can be obtained through commercial purchase.

[0071] Example 1

[0072]

[0073] This embodiment discloses a quaternary ammonium salt type alkenyl compound 1, whose general formula is shown in Formula VI, and its preparation method comprises the following steps:

[0074] 1,4-Diazidobicyclo[2,2,2]octane (112.2 g, 1.0 mol) and acetonitrile (300 mL) were placed in a 1L four-necked flask, heated to reflux at 90°C, stirred until completely dissolved, and then a solution of 4-vinylbenzyl chloride (76.3 g, 0.5 mol) in acetonitrile (250 mL) was slowly added dropwise to the four-necked flask, and the reaction was kept at 90°C for 48 hours. After waiting for the reaction to end, the reaction solution was poured into ethyl acetate while hot, and the precipitated light yellow viscous solid was the quaternary ammonium salt type olefin compound 1, which was washed with ethyl acetate and dried at 80°C to obtain 122.6 g of yellow block solid with a yield of 92.6%.

[0075] 1 H NMR (400 MHz, D 2 O,ppm)δ7.55(2H),7.40(2H),6.76(1H),5.87(1H),5.34(1H),4.40(2H),3.37(6H),3.09(6H).

[0076] Example 2

[0077]

[0078] This embodiment discloses a quaternary ammonium salt type alkenyl compound 2, the general formula of which is shown in Formula VII, and the preparation method thereof comprises the following steps:

[0079] 1,4-Diazidobicyclo[2,2,2]octane (112.2 g, 1.0 mol) and acetonitrile (300 mL) were placed in a 1L four-necked flask, heated to reflux at 90°C, stirred until completely dissolved, and then a solution of 5-bromo-1-pentene (74.5 g, 0.5 mol) in acetonitrile (250 mL) was slowly added dropwise to the four-necked flask, and the reaction was kept at 90°C for 48 hours. After waiting for the reaction to end, the reaction solution was poured into ethyl acetate while hot, and the precipitated white solid was the quaternary ammonium salt type olefin compound 2, which was washed with ethyl acetate and dried at 80°C to obtain 118.4 g of a white solid with a yield of 90.6%.

[0080] 1 H NMR (400 MHz, D 2 O,ppm)δ5.98(1H),5.46(1H),5.26(1H),3.34(6H),3.20(2H),3.09(6H),2.26(2H),1.88(2H).

[0081] Example 3

[0082] This embodiment discloses a method for preparing a polymer cross-linked anion exchange membrane, comprising the following steps:

[0083] Step (1) Synthesis of Intermediate 1

[0084] Add biphenyl (30.8 g, 0.2 mol), N-methylpiperidone (18.1 g, 0.16 mol) and dichloromethane (70 mL) to a 1L reactor, slowly drop trifluoroacetic acid (32.2 g, 0.28 mol), stir for 0.5 h after the addition, add 7-bromo-1,1,1-trifluoro-2-heptanone (19.8 g 0.08 mol), stir again for 0.5 h, slowly drop trifluoromethanesulfonic acid (345.0 g, 2.3 mol) again, react for 12 h, and keep the temperature at about 0 ° C throughout the above process. After waiting for the reaction to end, pour the dark blue-purple viscous liquid obtained by the reaction into an ice-water solution of 1M sodium hydroxide, keep the precipitation temperature below 10 ° C throughout the process, wash with deionized water several times after hardening, and obtain a white solid (55.3 g, yield 94.8%) as polymer intermediate 1 after vacuum drying at 45 ° C.

[0085] 1 H NMR (400 MHz, CDCl3 ,ppm)δ7.8-7.0(16H),3.62(0.7H),2.58(5.3H),2.2-1.8(12H),1.31(2.6H).

[0086] Step (2) Synthesis of polymer intermediate 2

[0087] Into a 500 mL round-bottom flask, the polymer intermediate 1 (39.0 g) obtained in step (1), potassium carbonate (5.8 g), dimethyl sulfoxide (270.0 g) and iodomethane (45.0 g) were added and stirred at 40 ° C for 48 h; acetone (850 mL) was added and stirred thoroughly. The obtained yellow precipitate was washed with deionized water several times, dried at 55 ° C and crushed to obtain a light yellow polymer intermediate 2, 49.3 g, with a yield of 96.3%.

[0088] Step (3) Synthesis of membrane powder

[0089] Into a 500 mL round-bottom flask, the polymer intermediate 2 (49.8 g) obtained in step (2), potassium carbonate (3.2 g), dimethyl sulfoxide (300.0 g) and the quaternary ammonium salt type alkenyl compound 1 (13.5 g) obtained in Example 1 were added, and stirred at 60 ° C for 60 h; acetone (950 mL) was added and stirred thoroughly. The obtained yellow precipitate was washed with deionized water several times, dried at 55 ° C, and then crushed to obtain 58.4 g of light yellow film powder, with a yield of 95.1%.

[0090] 1 H NMR (400 MHz, DMSO-d 6 ,ppm)δ7.8-7.0(18.6H),6.72(0.7H),5.66(0.7H),5.35(0.7H),4.55(1. 3H),3.68(8H),3.3-3.0(14.5H),2.22(5H),1.8-1.6(2.6H),1.33(2.6H).

[0091] Step (4) Preparation of anion exchange membrane

[0092] Put 40 g of the membrane powder obtained in step (3) and 120 g of dimethyl sulfoxide into a round-bottom flask, stir at 45°C, wait for complete dissolution, and apply the mixed homogeneous viscous solution on a PET base film preheated to 40°C through a bottom glass plate, and use a scraper provided with the coating machine to scrape the base film at a speed of 5 mm / s to keep the thickness controlled at 550 μm and the membrane surface flat, dry at 60°C for 2 h, then heat to 90°C and dry for 6 h, and finally dry at 120°C for 4 h to obtain a cross-linked polyaryl anion exchange membrane with a thickness of 48±2 μm.

[0093] The film forming principle of this embodiment is as follows:

[0094]

[0095] Among them, 200≤m≤500, 300≤n≤500.

[0096] Example 4

[0097] This embodiment discloses a method for preparing a polymer cross-linked anion exchange membrane, comprising the following steps:

[0098] Step (1) Synthesis of Intermediate 1

[0099] Add p-terphenyl (46.1 g, 0.2 mol), N-methylpiperidone (18.1 g, 0.16 mol) and dichloromethane (70 mL) to a 1 L reactor, slowly drop trifluoroacetic acid (32.2 g, 0.28 mol), stir for 0.5 h after the addition, add 7-bromo-1,1,1-trifluoro-2-heptanone (19.8 g 0.08 mol), stir again for 0.5 h, slowly drop trifluoromethanesulfonic acid (345.0 g, 2.3 mol) again, react for 12 h, and keep the temperature at about 0 ° C throughout the above process. After waiting for the reaction to end, pour the dark blue-purple viscous liquid obtained by the reaction into an ice-water solution of 1M sodium hydroxide, keep the precipitation temperature below 10 ° C throughout the process, wash with deionized water several times after hardening, and obtain a white solid (70.1 g, yield 95.4%) as polymer intermediate 1 after vacuum drying at 45 ° C.

[0100] 1 H NMR (400 MHz, CDCl 3 ,ppm)δ7.8-7.0(24H),3.59(0.7H),2.62(5.3H),2.2-1.8(12H),1.28(2.6H).

[0101] Step (2) Synthesis of polymer intermediate 2

[0102] Into a 500 mL round-bottom flask, the polymer intermediate 1 (46.0 g) obtained in step (1), potassium carbonate (4.6 g), dimethyl sulfoxide (368.0 g) and methyl iodide (48.0 g) were added and stirred at 40 ° C for 48 h; acetone (1200 mL) was added and stirred thoroughly. The obtained yellow precipitate was washed with deionized water several times, dried at 55 ° C and crushed to obtain a light yellow polymer intermediate 2, 55.7 g, with a yield of 96.5%.

[0103] Step (3) Synthesis of membrane powder

[0104] Into a 500 mL round-bottom flask, the polymer intermediate 2 (55.7 g) obtained in step (2), potassium carbonate (3.9 g), dimethyl sulfoxide (390.0 g) and the quaternary ammonium salt type alkenyl compound 2 (15.5 g) obtained in Example 2 were added, and stirred at 60 ° C for 60 h; acetone (950 mL) was added and stirred thoroughly. The obtained yellow precipitate was washed with deionized water several times, dried at 55 ° C, and then crushed to obtain 63.1 g of light yellow film powder, with a yield of 94.9%.

[0105] 1 H NMR (400 MHz, DMSO-d 6 ,ppm)δ7.8-7.0(24H),5.88(0.7H),5.19(0.7H),4.81(0.7H),3.68(8H ),3.3-3.1(16H),2.45(5.3H),2.17(1.1H),1.9-1.7(4H),1.32(2.5H).

[0106] Step (4) Preparation of anion exchange membrane

[0107] Put 40 g of the membrane powder obtained in step (3) and 170 g of dimethyl sulfoxide into a round-bottom flask, stir at 45°C, wait for complete dissolution, and apply the mixed homogeneous viscous solution on a PET base film preheated to 40°C through a bottom glass plate, and use a scraper provided with the coating machine to scrape the base film at a speed of 5 mm / s to keep the thickness controlled at 650 μm and the membrane surface flat, dry at 60°C for 2 h, then heat to 90°C and dry for 6 h, and finally dry at 120°C for 4 h to obtain a cross-linked polyaryl anion exchange membrane with a thickness of 49±2 μm.

[0108] The film forming principle of this embodiment is as follows:

[0109]

[0110] Among them, 200≤m≤500, 300≤n≤500.

[0111] Example 5

[0112] This embodiment discloses a method for preparing a polymer cross-linked anion exchange membrane, comprising the following steps:

[0113] Step (1) Synthesis of Intermediate 1

[0114] To a 1L reactor, add p-terphenyl (23.1 g, 0.1 mol), m-terphenyl (23.1 g, 0.1 mol), N-methylpiperidone (18.1 g, 0.16 mol) and dichloromethane (70 mL), slowly add trifluoroacetic acid (32.2 g, 0.28 mol), stir for 0.5 h after the addition is completed, add 7-bromo-1,1,1-trifluoro-2-heptanone (19.8 g 0.08 mol), stir again for 0.5 h, slowly add trifluoromethanesulfonic acid (345.0 g, 2.3 mol) again, and react for 12 h. Keep the temperature at about 0 °C throughout the above process. After waiting for the reaction to be completed, the dark blue-purple viscous liquid obtained by the reaction was poured into an ice-water solution of 1M sodium hydroxide, and the precipitation temperature was kept below 10°C throughout the process. After hardening, it was washed with deionized water for multiple times and vacuum-dried at 45°C to obtain a white solid (70.1 g, yield 95.4%) as polymer intermediate 1.

[0115] 1 H NMR (400 MHz, CDCl 3 ,ppm)δ7.8-7.0(24H),3.59(0.7H),2.62(5.3H),2.2-1.8(12H),1.28(2.6H).

[0116] Step (2) Synthesis of Intermediate 2

[0117] Into a 500 mL round-bottom flask, the polymer intermediate (50.0 g) obtained in step (1), potassium carbonate (5.5 g), dimethyl sulfoxide (350.0 g) and methyl iodide (52.0 g) were added and stirred at 40 ° C for 48 h; acetone (1200 mL) was added and stirred thoroughly. The obtained yellow precipitate was washed several times with deionized water, dried at 55 ° C and crushed to obtain a light yellow intermediate 2, 59.5 g, with a yield of 94.9%.

[0118] Step (3) Synthesis of membrane powder

[0119] Into a 500 mL round-bottom flask, the intermediate 2 (59.5 g) obtained in step (2), potassium carbonate (4.8 g), dimethyl sulfoxide (386.0 g) and the quaternary ammonium salt type alkenyl compound 2 (16.6 g) obtained in Example 2 were added and stirred at 60 ° C for 60 h; acetone (950 mL) was added and stirred thoroughly. The obtained yellow precipitate was washed with deionized water several times, dried at 55 ° C and crushed to obtain 68.4 g of light yellow film powder, with a yield of 96.2%.

[0120] 1 H NMR (400 MHz, DMSO-d 6,ppm)δ8.0-7.1(26.6H),6.77(0.7H),5.86(0.7H),5.33(0.7H),4.52(1.4H),3 .72(8H)3.4-3.1(14.6H),2.48(5.3H),1.91(1.2H),1.73(1.3H),1.35(2.8H).

[0121] Step (4) Preparation of anion exchange membrane

[0122] Put 40 g of the membrane powder obtained in step (3) and 180 g of dimethyl sulfoxide into a round-bottom flask, stir at 45°C, wait for complete dissolution, and apply the mixed homogeneous viscous solution on a PET base film preheated to 40°C through a bottom glass plate, and use a scraper provided with the coating machine to scrape the base film at a speed of 5 mm / s to keep the thickness controlled at 660 μm and the membrane surface flat, dry at 60°C for 2 h, then heat to 90°C and dry for 6 h, and finally dry at 120°C for 4 h to obtain a cross-linked polyaryl anion exchange membrane with a thickness of 48±2 μm.

[0123] The film forming principle of this embodiment is as follows:

[0124]

[0125] Among them, 200≤m≤500, 300≤n≤500.

[0126] Comparative Example 1

[0127]

[0128] Among them, 200≤m≤500, 300≤n≤500.

[0129] This comparative example discloses a method for preparing a film, comprising the following steps:

[0130] Step (1) Synthesis of Intermediate 1

[0131] The synthesis steps are the same as those of Intermediate 1 in Example 4.

[0132] Step (2) Synthesis of Intermediate 2

[0133] Into a 500 mL round-bottom flask, the polymer intermediate (46.0 g) obtained in step (1), potassium carbonate (4.6 g), dimethyl sulfoxide (368.0 g) and methyl iodide (48.0 g) were added and stirred at 40 ° C for 48 h; acetone (1200 mL) was added and stirred thoroughly. The obtained yellow precipitate was washed several times with deionized water, dried at 55 ° C and crushed to obtain a light yellow intermediate 2, 54.7 g, with a yield of 94.8%.

[0134] Step (3) Synthesis of membrane powder

[0135] Into a 500 mL round-bottom flask, the intermediate 2 (54.7 g) obtained in step (2), potassium carbonate (3.9 g) and dimethyl sulfoxide (390.0 g) were added, and after stirring, trimethylamine gas (5.0 g) was slowly introduced, and stirred at 60 ° C for 60 h; acetone (950 mL) was added and stirred thoroughly. The obtained yellow precipitate was washed with deionized water several times, dried at 55 ° C, and then crushed to obtain 55.9 g of light yellow film powder, with a yield of 98.1%.

[0136] 1 H NMR (400 MHz, DMSO-d 6 ,ppm)δ7.8-7.0(24H),3.4-3.2(20.5H),2.52(5.3H),1.87(1.3H),1.77(1.2H),1.37(2.7H).

[0137] Step (4) Preparation of anion exchange membrane

[0138] Put 40 g of the membrane powder obtained in step (3) and 160 g of dimethyl sulfoxide into a round-bottom flask, stir at 45°C, wait for complete dissolution, and apply the mixed homogeneous viscous solution on a PET base film preheated to 40°C through a bottom glass plate, and use a scraper provided with the coating machine to scrape the base film at a speed of 5 mm / s to keep the thickness controlled at 650 μm and the membrane surface flat, dry at 60°C for 2 h, then heat to 90°C and dry for 6 h, and finally dry at 120°C for 4 h to obtain a cross-linked polyaryl anion exchange membrane with a thickness of 48±2 μm.

[0139] Comparative Example 2

[0140] This comparative example discloses a method for preparing a film, comprising the following steps:

[0141] Step (1) Synthesis of Intermediate 1

[0142] Add p-terphenyl (23.1 g, 0.1 mol), m-terphenyl (23.1 g, 0.1 mol), N-methylpiperidone (27.2 g, 0.24 mol) and dichloromethane (70 mL) to a 1L reactor, slowly dropwise add trifluoroacetic acid (32.2 g, 0.28 mol) and trifluoromethanesulfonic acid (345.0 g, 2.3 mol), and react for 12 hours. The temperature is kept at about 0°C throughout the above process. After waiting for the reaction to end, pour the dark blue-purple viscous liquid obtained by the reaction into an ice-water solution of 1M sodium hydroxide, wash it with deionized water several times after hardening, and obtain a white solid (63.0 g, yield 96.8%) as polymer intermediate 1 after vacuum drying at 85°C.

[0143] 1 H NMR (400 MHz, CDCl 3 ,ppm)δ8.0-7.0(24H),2.48(8H),2.3-1.9(14H).

[0144] Step (2) Synthesis of membrane powder

[0145] Into a 500 mL round-bottom flask, the intermediate (40 g) obtained in step (1), potassium carbonate (7.6 g), 4-vinylbenzyl chloride (2.8 g) and dimethyl sulfoxide (264.0 g) were added, and the mixture was reacted at 45 ° C for 48 h. Then, methyl iodide (51.1 g) was added, and the reaction was maintained at 35 ° C for 48 h. After the reaction was completed, acetone (950 mL) was added and stirred thoroughly. The obtained yellow precipitate was washed with deionized water several times, dried at 55 ° C, and then crushed to obtain 52.9 g of light yellow film powder with a yield of 94.5%.

[0146] 1 H NMR (400 MHz, DMSO-d 6 ,ppm)δ8.0-7.2(24H),6.8(0.3H),5.83(0.3H),5.40(0.3H),4.62(0.6H),3.4-3.15(19H),2.32(8H).

[0147] Step (3) Preparation of anion exchange membrane

[0148] Put 40 g of the membrane powder obtained in step (2) and 130 g of dimethyl sulfoxide into a round-bottom flask, stir at 45°C until completely dissolved, and apply the mixed homogeneous viscous solution on a PET base film preheated to 40°C through a bottom glass plate, and use a scraper provided with the coating machine to scrape the base film at a speed of 5 mm / s to keep the thickness controlled at 580 μm and the membrane surface flat, dry at 60°C for 2 h, then heat to 90°C and dry for 6 h, and finally dry at 120°C for 4 h to obtain a cross-linked polyaryl anion exchange membrane with a thickness of 48±2 μm.

[0149] The film forming principle of this comparative example is as follows:

[0150]

[0151] Among them, 200≤m≤500, 300≤n≤500.

[0152] The anion exchange membranes of Examples 3-5 and Comparative Examples 1-2 were tested respectively, and the test results are as follows:

[0153] The tensile strength and elongation at break of the anion exchange membranes obtained in Examples 3-5 and Comparative Examples 1-2 were measured using a universal tensile testing machine. The data are shown in Table 1.

[0154] The swelling rate of the anion exchange membranes obtained in Examples 3-5 and Comparative Examples 1-2 was tested, and the data are shown in Table 1.

[0155] The swelling rate test method is: put the membrane into an oven to dry to constant weight and then soak it in pure water for 24 hours, take it out and wipe the surface water, the size is S 1 Then put it into a 60℃ oven for drying for 24 hours and take out the size of S 2 , the swelling rate is (S 1 -S 2 ) / S 2* 100%

[0156] The gel fraction (GF) of the anion exchange membranes obtained in Examples 3-5 and Comparative Examples 1-2 was tested, and the data are shown in Table 1.

[0157] The gel fraction can be used to directly judge the degree of crosslinking. The test method is as follows: the anion exchange membrane is dried to a constant weight, with a mass of m 1 , dissolve it in dimethyl sulfoxide, wait for 24 hours, filter out the insoluble matter, and dry it again to a constant weight of m 2 , GF=m 2 / m 1 *100%.

[0158] The hydroxide ion conductivity of the anion exchange membranes obtained in Examples 3-5 and Comparative Examples 1-2 was measured, and the membranes were immersed in a 1M NaOH solution at 80° C. for 30 days to detect their alkali resistance and the change in conductivity before and after the alkali resistance test. The specific data are shown in Table 1.

[0159] Table 1: Test results

[0160]

[0161] As can be seen from Table 1, by comparing Examples 3-5 with Comparative Example 1, the mechanical properties of the film are improved after cross-linking with the quaternary ammonium vinyl compound, indicating that cross-linking brings about an improvement in tensile strength and elongation at break.

[0162] By comparing Examples 3-5 with Comparative Example 2, it can be seen that the elongation at break of the film is significantly improved, indicating that the doping of trifluoroketone compounds is beneficial to reducing the rigidity of the main chain structure of the film.

[0163] By comparing Examples 3-5 with Comparative Example 2, it can be seen that the difference in gel fraction can prove that the quaternary ammonium vinyl crosslinking agent used in Examples 3-5 has higher crosslinking activity.

[0164] By comparing Examples 3-5 with Comparative Examples 1-2, it can be seen that the anion exchange membrane of the patented structure of the present invention has a lower swelling rate, indicating that it has higher skeleton stability and a more stable two-dimensional membrane structure.

[0165] By comparing Examples 3-5 with Comparative Examples 1-2, it can be seen that the anion exchange membrane of the patented structure of the present invention has a higher hydroxide ion conductivity, indicating that the long-chain alkane and the quaternary ammonium salt structure side chain are conducive to the separation of hydrophilic and hydrophobic phases and the construction of ion channels.

[0166] From the alkali immersion experiments of Examples 3-5, it can be seen that the anion exchange membrane of the patented structure of the present invention has excellent alkali resistance.

[0167] The hydroxyl ion conductivity curves at different temperatures of Example 5 and Comparative Example 2 are as follows: Figure 1 As shown, it can be seen that the hydroxide ion conductivity of the anion exchange membrane obtained in Example 5 at different temperatures is higher than that of the anion exchange membrane in Comparative Example 2.

[0168] After soaking the AEM membranes described in Examples 3-5 and Comparative Examples 1-2 in alkali solution, the membranes were cut into pieces of 5 cm × 5 cm in size and assembled into a single electrolytic cell in the order of end plate, cathode current collector, PTFE gasket, nickel foam, cathode, AEM membrane, anode, PTFE gasket, nickel foam, anode current collector, and end plate. The electrolytic cell was tightened diagonally with a wrench and the electrode clamp was clamped. The effective area of ​​the single electrolytic cell was 20.25 cm 2 . Under the working condition of 80℃, 30wt% KOH solution was introduced and the performance of water electrolysis was tested at a voltage of 2V. Figure 3 shown.

[0169] From the comparison of the water electrolysis tests of Examples 3-5 and Comparative Examples 1-2, it can be seen that the anion exchange membrane with the patented structure of the present invention has more excellent water electrolysis performance and stability.

[0170] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A polymer, cross-linked anion exchange membrane, characterized in that: Its general formula is shown in Formula 1: wherein Ar is independently any one or more of benzene, diphenyl, p-terphenyl, m-terphenyl, p-quaterphenyl, fluorene and dimethylfluorene; R is Formula 2 or Formula 3: In Formula 1, Formula 2 and Formula 3, 10≤m≤1000, 10≤n≤1000, 1≤x≤9, 1≤y≤5, and m, n, x, y are all positive integers.

2. A method for preparing the polymer cross-linked anion exchange membrane according to claim 1, characterized in that: The following steps are involved: (1) Aromatic compounds, N-methylpiperidone, and trifluoroketone compounds are polymerized in dichloromethane under the catalytic action of a superacid catalyst at -10-25°C. After reacting for 6-18 hours, the mixture is soaked in an aqueous sodium hydroxide solution, hardened, and crushed. The mixture is washed with deionized water and vacuum dried to obtain a polymer intermediate 1. (2) adding polymer intermediate 1, potassium carbonate and methyl iodide to an organic solvent, reacting at 35-45° C. for 24-36 hours, adding acetone after the reaction, precipitating a solid product, washing and drying to obtain polymer intermediate 2; (3) adding polymer intermediate 2, potassium carbonate, and quaternary ammonium salt type alkenyl compound to an organic solvent, reacting at 45-65° C. for 48-72 hours, adding acetone after the reaction, precipitating a solid product, washing, and drying to obtain a membrane powder; (4) coating an organic solvent mixed with membrane powder on the base membrane, and using a scraper to scrape the base membrane to obtain a wet film with a thickness of 500-800 μm, and drying to obtain a polymer, cross-linked anion exchange membrane.

3. The method for preparing a polymer cross-linked anion exchange membrane according to claim 2, characterized in that: In step (1), the molar ratio of the aromatic compound, N-methylpiperidone, and trifluoroketone compound is 1:0.2-1.0:0.15-0.5; And / or, in step (1), the molar ratio of the aromatic compound, dichloromethane and superacid catalyst is 1:5-8.5:10.5-14.

4. The method for preparing a polymer cross-linked anion exchange membrane according to claim 2, characterized in that: In step (1), the superacid catalyst is one or more of trifluoroacetic acid, methanesulfonic acid, trifluoromethanesulfonic acid, acetic acid, pentafluoropropionic acid and tellurium pentafluoride; And / or, in step (1), the aromatic compound is one or more of benzene, diphenyl, p-terphenyl, m-terphenyl, p-quaterphenyl, fluorene and dimethylfluorene.

5. The method for preparing a polymer cross-linked anion exchange membrane according to claim 3, characterized in that: In step (1), after the reaction is completed, the product is soaked in 1-1.5M sodium hydroxide ice water solution, hardened, crushed, washed with deionized water for multiple times, and vacuum dried at 45-50° C. to obtain a polymer intermediate 1.

6. The method for preparing the polymer cross-linked anion exchange membrane according to claim 3, characterized in that: In step (2), the mass ratio of the polymer intermediate 1, potassium carbonate and methyl iodide is 1:0.05-0.2:0.5-2; And / or, in step (2), the mass ratio of the polymer intermediate 1 to the organic solvent is 1:6-10; And / or, in step (2), the volume ratio of the organic solvent to acetone is 1:3-6; And / or, in step (2), the organic solvent is one or more of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone.

7. The method for preparing the polymer cross-linked anion exchange membrane according to claim 3, characterized in that: In step (3), the mass ratio of the polymer intermediate 2, potassium carbonate, and quaternary ammonium salt type olefinic compound is 1:0.05-0.2:0.15-0.5; And / or, in step (3), the mass ratio of the polymer intermediate 2 to the organic solvent is 1:6-10; And / or, in step (3), the volume ratio of the organic solvent to acetone is 1:3-6; And / or, in step (3), the organic solvent is one or more of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone; And / or, in step (3), the quaternary ammonium salt type alkenyl compound is of formula 4 or formula 5: In Formula 5, 1≤y≤5, and y is a positive integer.

8. The method for preparing the polymer cross-linked anion exchange membrane according to claim 3, characterized in that: In step (4), the mass ratio of the membrane powder to the organic solvent is 1:2.5-6; And / or, in step (4), the organic solvent is one or more of dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone.

9. The method for preparing the polymer cross-linked anion exchange membrane according to claim 3, characterized in that: In step (4), the film powder is stirred evenly in an organic solvent, and coated on a PET base film preheated to 40-45° C. through a bottom glass plate, and a scraper provided with a coating machine is used to scrape the base film at a speed of 5-7 mm / s to obtain a wet film with a thickness of 500-800 μm and a smooth film surface; And / or, in step (4), the drying conditions are as follows: drying at 60-65°C for 2-2.5h, then heating to 90-95°C for drying for 6-6.5h, and finally drying at 120-125°C for 4-4.5h to obtain a cross-linked polyaryl anion exchange membrane.

10. Use of the polymer and cross-linked anion exchange membrane according to claim 1 or 2 in the field of hydrogen production by water electrolysis.

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