Low-unsaturation long-life anion exchange membrane

Abstract

The invention discloses a low-unsaturation long-life anion exchange membrane, and relates to the technical field of anion exchange membranes. The problems that an anion exchange membrane in the prior art is prone to embrittlement, perforation and the like after long-time operation are solved. The preparation method of the anion exchange membrane comprises the following steps: synthesizing an aryl piperidine type polymer; a hydrogenated aryl piperidine type polymer; preparing an anionic polymer through a quaternization process of the hydrogenated aryl piperidine type polymer; forming an anion exchange membrane; the invention also discloses a synthesis method of the aryl piperidine type polymer. The skeleton of the aryl piperidine cationic polymer is hydrogenated, unsaturated bonds in polyaryl piperidine macromolecules are converted into saturated bonds, and the stability of the anionic membrane in an AEM electrolytic cell is remarkably improved; the AEM film can still normally operate for 800 hours under the condition of accelerated electrolysis test, obvious damage or embrittlement of the film is not observed, and the purpose of improving the oxidation resistance and mechanical stability of the AEM film is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of anion exchange membranes, in particular to a low-unsaturation long-life anion exchange membrane. Background Art

[0002] Currently, hydrogen production from water electrolysis is experiencing rapid development. The production of green hydrogen from renewable energy (such as solar and wind energy) combined with water electrolysis will become a key technological solution for global carbon reduction. The next-generation AEM electrolyzer technology combines the advantages of alkaline water hydrogen production (ALK) and proton exchange membrane electrolysis (PEMWE). It can use a solid alkaline anion membrane (AEM) and non-precious metals (such as Ni, Fe, Co, and Mn) as electrocatalysts in low-concentration alkaline solutions or pure water. By optimizing the electrolyzer structure design, it can achieve current density and conversion efficiency comparable to PEMWE while retaining the low-cost advantage of ALK, which does not rely on precious metals such as platinum and iridium. This represents the next generation of transformative water electrolysis hydrogen production technology.

[0003] AEM electrolysis technology is still in the R&D and demonstration application stages. Limited by the performance of key membrane materials, AEM's operational stability and lifespan lag significantly behind those of ALK and PEM electrolyzers. According to AEM electrolyzer manufacturers, current AEM membranes are prone to perforation after prolonged operation, allowing hydrogen to penetrate into the oxygen side, posing a safety hazard. The ion exchange membrane becomes brittle after operation, and bending the membrane can cause surface fractures. To extend the operational life of AEM systems, the brittleness and perforation of the ion exchange membrane must be addressed.

[0004] Most commercially available ion exchange membranes are based on polyaromatic hydrocarbons. Under electrolysis conditions, the anode generates reactive species such as oxygen, peroxides, and hydroxyl radicals, which can oxidize the aromatic structures and potentially contribute to the deterioration of the mechanical properties of AEM membranes. Therefore, we propose an anion exchange membrane based on hydrogenated polyarylpiperidines. By reducing the content of unsaturated structures in the membrane, we improve the oxidation resistance and mechanical stability of the AEM membrane. Summary of the Invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a low-unsaturation long-life anion exchange membrane.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A low-unsaturation, long-life anion exchange membrane, the skeleton structure of the anion exchange membrane is as follows:

[0008]

[0009] The polymer chain contains a branching unit crosslinking Ar3, which is selected from one of 1,3,5-triphenylbenzene, triphenylene, and 9,9'-spirobifluorene, and has the following structure:

[0010]

[0011] In the general formula, the structures of Ar1 and Ar2 are one of biphenyl, 1,4-diphenylbenzene, 1,1':4',1":4",1''-quaterphenyl, 1,3-diphenylbenzene, and fluorene, and the structural formula is as follows:

[0012]

[0013] In the general formula, the aromatic ring is in the form of a benzene ring or a cyclohexyl group, and the hydrogenation ratio of the benzene ring is controlled in the range of 80-99%.

[0014] Preferably, the method for preparing the anion exchange membrane comprises the following:

[0015] S1: Synthesis of arylpiperidine-type polymers;

[0016] S2: hydrogenated arylpiperidine type polymer;

[0017] S3: Quaternization of hydrogenated arylpiperidine-type polymers to prepare anionic polymers;

[0018] S4: Formation of anion exchange membrane.

[0019] Preferably, the method for synthesizing the arylpiperidine polymer comprises the following aspects:

[0020] A1: Dissolve the aromatic monomer in solvent M, and add N-methyl-4-piperidone after dissolution;

[0021] A2: Then, trifluoroacetic acid and trifluoromethanesulfonic acid were added dropwise under ice bath conditions. After 1.5 h, the ice bath was removed and the mixture was reacted at room temperature for 0.5-3 h to obtain a viscous reaction liquid.

[0022] A3: Pour the viscous reaction liquid into solvent N to quench the reaction;

[0023] A4: Wash with 5% K2CO3 solution until the pH of the washed solution is neutral;

[0024] A5: Finally, dry it in an oven at 70°C.

[0025] Preferably: the aromatic monomer comprises Ar1 monomer, Ar2 monomer and Ar3 monomer, and the molar ratio of Ar1 monomer:Ar2 monomer:Ar3 monomer is 0-1:0-1:0-0.03;

[0026] The molar ratio of the N-methyl-4-piperidone to the aromatic monomer is 1:1;

[0027] The solvent M is dichloromethane or chloroform; the molar concentration of the N-methyl-4-piperidone in the solvent M is 0.8-1.0 mol / L.

[0028] Preferably, the molar ratio of N-methyl-4-piperidone to trifluoroacetic acid is 1:1;

[0029] The molar ratio of N-methyl-4-piperidone to trifluoromethanesulfonic acid is 1:6-12;

[0030] The solvent N is ethanol or water.

[0031] Preferably, the hydrogenation method of the arylpiperidine polymer comprises the following contents:

[0032] B1: In a reaction vessel, add polyarylpiperidine to solvent L to dissolve to form a 5-10 wt% solution, then add 2-5 wt% catalyst, stir and ultrasonically disperse for 10 min;

[0033] B2: After sealing the reactor, introduce hydrogen and carry out hydrogenation reaction at 120-160°C and hydrogen pressure of 3-6 MPa for 12-48 hours to obtain a hydrogenated product;

[0034] B3: Filter the hydrogenated product through a 10 μm filter to remove the catalyst, and then pour it into ice water to obtain a polymer solid;

[0035] B4: The polymer solid is repeatedly washed with water and then dried in an oven.

[0036] Preferably: the solvent L is N,N-dimethylacetamide or N-methylpyrrolidone;

[0037] The catalyst is a noble metal catalyst represented by Pt or Pd, the carrier on which the catalyst is loaded is macroporous silica gel, BaSO4 or carbon nanotube with an average particle size of 150-250 μm, and the loading amount of the catalyst is 0.5-2.0 wt %.

[0038] Preferably, the preparation method of the anionic polymer is as follows:

[0039] C1: Dissolve the hydrogenated arylpiperidine polymer in solvent O, add K2CO3 after dissolution, stir evenly, then add iodomethane, and react at room temperature in the dark for 36-72 hours;

[0040] C2: After completion, the reaction solution is slowly poured into solvent P to precipitate the polymer solid;

[0041] C3: Wash repeatedly with solvent O and water three times respectively until the conductivity of the washing liquid is lower than 10uS / cm, and then filter and dry to obtain.

[0042] Preferably, the solvent O is one of N,N-dimethylacetamide, N-methylpyrrolidone or dimethyl sulfoxide, and the mass fraction of the hydrogenated arylpiperidine polymer in the solvent O is 5-12 wt %;

[0043] The molar ratio of the hydrogenated arylpiperidine polymer: iodomethane: K2CO3 is 1:1.5:1.5;

[0044] The solvent P is ethanol or ethyl acetate.

[0045] Preferably, the anion exchange membrane forming process includes the following:

[0046] D1: heating and dissolving the quaternized polymer in solvent F to obtain a mixture;

[0047] D2: Filter the mixture with a 5 μm filter to obtain the casting solution;

[0048] D3: Cast the film on a glass plate, scrape it to the specified thickness with a scraper, and dry it at 70-90℃ for 24h to form a film;

[0049] The solvent F is one of DMA, NMP or DMSO,

[0050] The mass concentration of the casting solution is 10-20 wt%.

[0051] The beneficial effects of the present invention are:

[0052] 1. The present invention converts the unsaturated bonds in the polyarylpiperidine cationic polymer into saturated bonds by hydrogenating the backbone of the polyarylpiperidinium cationic polymer, significantly increasing the stability of the anionic membrane in the AEM electrolytic cell. Under accelerated electrolysis test conditions, the membrane can still operate normally for 800 hours without significant damage or embrittlement, thus achieving the purpose of improving the oxidation resistance and mechanical stability of the AEM membrane.

[0053] 2. Compared with the unhydrogenated arylpiperidinium cationic polymer, the anion exchange membrane formed by the present invention can maintain higher conductivity and tensile strength, and the elongation at break is significantly increased, indicating that this type of membrane has stronger toughness. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 The present invention provides a schematic flow chart of a method for preparing a low-unsaturation, long-life anion exchange membrane. DETAILED DESCRIPTION

[0055] The technical solution of this patent is further described in detail below in conjunction with specific implementation methods.

[0056] The following describes in detail embodiments of the present invention, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0057] Example 1:

[0058] A low-unsaturation, long-life anion exchange membrane, the skeleton structure of the anion exchange membrane is as follows:

[0059]

[0060] The polymer chain contains a branching unit crosslinking Ar3, which is selected from one of 1,3,5-triphenylbenzene, triphenylene, and 9,9'-spirobifluorene, and has the following structure:

[0061]

[0062] In the general formula, the structures of Ar1 and Ar2 are one of biphenyl, 1,4-diphenylbenzene, 1,1':4',1":4",1''-quaterphenyl, 1,3-diphenylbenzene, and fluorene, and the structural formula is as follows:

[0063]

[0064] In the general formula, the aromatic ring is in the form of a benzene ring or a cyclohexyl group, and the hydrogenation ratio of the benzene ring is controlled in the range of 80-99%.

[0065] The present invention significantly increases the stability of the membrane by hydrogenating the skeleton of the arylpiperidinium cationic polymer. Under the conditions of accelerated electrolysis test, the membrane can still operate normally for 800 hours without obvious damage or embrittlement of the membrane being observed.

[0066] Example 2:

[0067] A low unsaturation long life anion exchange membrane, such as Figure 1 As shown, the invention also includes a method for preparing an anion exchange membrane, which specifically includes the following contents:

[0068] S1: Synthesis of arylpiperidine-type polymers;

[0069] Furthermore, the synthesis method of the arylpiperidine polymer includes the following aspects:

[0070] A1: Dissolve the aromatic monomer in solvent M, and add N-methyl-4-piperidone after dissolution;

[0071] Preferably, the aromatic monomer may contain Ar1 monomer, Ar2 monomer and Ar3 monomer;

[0072] Further preferably, the molar ratio of Ar1 monomer:Ar2 monomer:Ar3 monomer is 0-1:0-1:0-0.03;

[0073] Preferably, the solvent M is dichloromethane or chloroform; in this embodiment, the molar concentration of N-methyl-4-piperidone in dichloromethane is 0.8-1.0 mol / L;

[0074] Preferably, the molar ratio of N-methyl-4-piperidone to the aromatic monomer is 1:1.

[0075] A2: Then, trifluoroacetic acid and trifluoromethanesulfonic acid were added dropwise under ice bath conditions. After 1.5 h, the ice bath was removed and the mixture was reacted at room temperature for 0.5-3 h to obtain a viscous reaction liquid.

[0076] Preferably, the molar ratio of N-methyl-4-piperidone to trifluoroacetic acid is 1:1;

[0077] Preferably, the molar ratio of N-methyl-4-piperidone to trifluoromethanesulfonic acid is 1:6-12.

[0078] A3: Pour the viscous reaction liquid into solvent N to quench the reaction;

[0079] Preferably, the solvent N is ethanol or water.

[0080] A4: Wash with 5% K2CO3 solution until the pH of the washed solution is neutral; then wash with water to remove excess trifluoroacetic acid and trifluoromethanesulfonic acid.

[0081] A5: Finally, dry it in an oven at 70°C.

[0082] S2: hydrogenated arylpiperidine type polymer;

[0083] Furthermore, the hydrogenation method of the arylpiperidine type polymer comprises the following steps:

[0084] B1: In a reaction vessel, add polyarylpiperidine to solvent L to dissolve to form a 5-10 wt% solution, then add 2-5 wt% catalyst, stir and ultrasonically disperse for 10 min;

[0085] Preferably, the solvent L is N,N-dimethylacetamide (DMA) or N-methylpyrrolidone (NMP);

[0086] Preferably, the catalyst is a noble metal catalyst represented by Pt or Pd, the carrier on which the catalyst is loaded is macroporous silica gel, BaSO4 or carbon nanotubes (CNTs) with an average particle size of 150-250 μm, and the loading amount of the catalyst is 0.5-2.0 wt%.

[0087] B2: After sealing the reactor, introduce hydrogen and carry out hydrogenation reaction at 120-160°C and hydrogen pressure of 3-6 MPa for 12-48 hours to obtain a hydrogenated product;

[0088] B3: Filter the hydrogenated product through a 10 μm filter to remove the catalyst, and then pour it into ice water to obtain a polymer solid;

[0089] B4: The polymer solid is repeatedly washed with water and then dried in an oven.

[0090] Furthermore, the hydrogenation rate of the arylpiperidine polymer is measured using hydrogen nuclear magnetic resonance spectroscopy.

[0091] S3: Quaternization of hydrogenated arylpiperidine-type polymers to prepare anionic polymers;

[0092] Furthermore, the preparation method of the anionic polymer is as follows:

[0093] C1: Dissolve the hydrogenated arylpiperidine polymer in solvent O, add K2CO3 after dissolution, stir evenly, then add iodomethane, and react at room temperature in the dark for 36-72 hours;

[0094] Preferably, the solvent O is one of N,N-dimethylacetamide, N-methylpyrrolidone or dimethyl sulfoxide (DMSO), and the mass fraction of the hydrogenated arylpiperidine type polymer in the solvent O is 5-12 wt %;

[0095] Preferably, the molar ratio of the hydrogenated arylpiperidine polymer (based on N atoms): iodomethane: K2CO3 is 1:1.5:1.5;

[0096] C2: After completion, the reaction solution is slowly poured into solvent P to precipitate the polymer solid;

[0097] Preferably, the solvent P is selected from ethanol or ethyl acetate.

[0098] C3: Wash repeatedly with solvent O and water three times respectively until the conductivity of the washing liquid is lower than 10uS / cm, and then filter and dry to obtain.

[0099] S4: Formation of anion exchange membrane.

[0100] Furthermore, the anion exchange membrane forming process includes the following:

[0101] D1: heating and dissolving the quaternized polymer in solvent F to obtain a mixture;

[0102] Preferably, solvent F is one of DMA, NMP or DMSO,

[0103] D2: Filter the mixture with a 5 μm filter to obtain the casting solution;

[0104] D3: Cast the film on a glass plate, scrape it to the specified thickness with a scraper, and dry it at 70-90℃ for 24h to form a film;

[0105] Preferably, the mass concentration of the casting solution is 10-20 wt%.

[0106] The present invention converts unsaturated bonds in the polyarylpiperidine polymer into saturated bonds through hydrogenation, significantly improving the stability of the anion exchange membrane in an AEM electrolyzer. Under accelerated electrolysis testing conditions, the membrane maintained normal operation for 800 hours without significant damage or embrittlement. Compared to unhydrogenated arylpiperidine cationic polymers, the resulting anion exchange membrane maintains higher conductivity and tensile strength, while significantly increasing its elongation at break, demonstrating its enhanced toughness.

[0107] Test Example 1:

[0108] To 40 mL of DCM solvent, add 4.0 mmol of N-methyl-4-piperidone and 4.0 mmol of 1,4-diphenylbenzene. After stirring to dissolve, slowly add 0.3 mL (4 mmol) of trifluoroacetic acid and 3.6 mL (40 mmol) of trifluoromethanesulfonic acid in an ice bath. After 1.5 hours, allow the reaction system to gradually warm to room temperature. After approximately 1 hour, the reaction solution becomes highly viscous. Pour the reaction solution into ice water to quench the reaction. Finally, wash with water and 5% K₂CO₃ to remove excess trifluoroacetic acid and trifluoromethanesulfonic acid until the pH of the washed solution is neutral. Oven dry at 70°C to obtain arylpiperidine polymer A.

[0109] In a reaction vessel, polyarylpiperidine A was dissolved in DMF to form a 5 wt% solution. 3 wt% of a silica-gel-supported Pd catalyst (loading: 1.2 wt%) was then added, stirred, and ultrasonically dispersed for 10 minutes. The vessel was sealed, and hydrogen was introduced. A hydrogenation reaction was carried out at 140°C and a hydrogen pressure of 5 MPa for 36 hours. The resulting hydrogenated polyarylpiperidine A (H) was determined to have a degree of hydrogenation of 95.3%.

[0110] The hydrogenated polymer A(H) was dissolved in DMF, K2CO3 was added after dissolution, iodomethane was added after stirring evenly, and the reaction was carried out at room temperature in the dark for 36 hours; after the reaction was completed, the solution was slowly poured into ethyl acetate to precipitate the polymer solid; the solution was washed repeatedly with ethyl acetate 3 times; the solution was washed repeatedly with water 3 times until the conductivity of the washing liquid was less than 10uS / cm; the polymer solid was filtered and dried to obtain the target anionic polymer A(H,Me).

[0111] The structure of A(H,Me) is as follows:

[0112]

[0113] Membrane formation of hydrogenated anion polymer exchange membrane: The quaternized polymer was heated and dissolved in DMA (18 wt%) solvent, and the polymer solution was filtered through a 5 μm filter to obtain a casting solution; the casting solution was cast on a glass plate, scraped to 600 μm with a scraper, and dried at 90°C for 24 h to form an ion exchange membrane MA (H, Me).

[0114] Basic performance tests of the MA (H, Me) ion exchange membrane revealed a dry membrane tensile strength of 52 MPa and a break elongation of 75%. The membrane's ionic conductivity in the hydroxide form was measured to be 152 mS / cm at 80°C. The membrane was assembled into an AEM electrolyzer (NiFeOx anode + platinum carbon cathode) for accelerated testing at 80°C, 1 M KOH, and 1.5 A / cm 2 Operating at a current density of 1.5 volts, the initial cell voltage (after 24 hours of operation) was 1.82 V. After 800 hours of continuous operation, the cell voltage slowly rose to 1.86 V. Upon stopping electrolysis and removing the ion exchange membrane, the membrane remained flexible and showed no obvious damage.

[0115] At 60°C, 1 M KOH, 1.0 A / cm 2 The initial cell voltage (after 24 hours of operation) was 1.76 V. Currently, after nearly 2400 hours of operation, the cell voltage is about 1.79 V.

[0116] Test Example 2:

[0117] Using 1,3-diphenylbenzene as a raw material, the arylpiperidine polymer B was obtained by referring to the polymerization method of Experimental Example 1.

[0118] In a reaction vessel, polyarylpiperidine B was dissolved in DMA to form a 5 wt% solution. 3 wt% of a silica-gel-supported Pt catalyst (loading: 1.0 wt%) was then added, stirred, and ultrasonically dispersed for 10 minutes. The vessel was sealed, hydrogen was introduced, and a hydrogenation reaction was carried out at 140°C and a hydrogen pressure of 5 MPa for 36 hours. The resulting hydrogenated polyarylpiperidine B (H) was determined to have a degree of hydrogenation of 98.3%.

[0119] An ion exchange membrane M-B(H,Me) was prepared by the methylation and membrane formation method of Test Example 1. The structure of the polymer B(H,Me) is as follows:

[0120]

[0121] The ion exchange membrane M-B(H,Me) was tested for basic properties: the dry film tensile strength was 42 MPa, and the breaking elongation was 82%. The ion conductivity of the membrane was measured to be 148 mS / cm at 80°C in the hydroxide form; the membrane was assembled into an AEM electrolyzer (NiFeOx anode + platinum carbon cathode) for accelerated testing, and was operated at 80°C, 1M KOH, 1.5 A / cm 2 of current density, and the initial cell voltage (when operated for 24h) was 1.84V. After continuous operation for 800h, the cell voltage slowly rose to 1.92V. After stopping electrolysis, the ion exchange membrane was found to retain a certain degree of flexibility, and no obvious damage was found.

[0122] Test Example 3:

[0123] An arylpiperidine polymer C was obtained by the polymerization method of Test Example 1 using 1,4-diphenylbenzene as the raw material, and adding 1.0% of 1,3,5-triphenylbenzene as a branching unit.

[0124] The polyarylpipeidine C was dissolved in DMA in a reaction kettle to form a 5wt% solution, and 3wt% of carbon nanotube-supported Pt catalyst (loading: 2.0wt%) was added, and stirred and ultrasonically dispersed for 10min; the reaction kettle was sealed, hydrogen was introduced, and the hydrogenation reaction was carried out at 160°C under a hydrogen pressure of 5MPa for 36h. The hydrogenated polyarylpipeidine C(H) obtained by the reaction was determined to have a hydrogenation degree of 96.2%.

[0125] An ion exchange membrane M-C(H,Me) was prepared by the methylation and membrane formation method of Test Example 1. The structure of the polymer C(H,Me) is as follows:

[0126]

[0127] The ion exchange membrane M-C(H,Me) was tested for basic properties: the dry film tensile strength was 54 MPa, and the breaking elongation was 80%. The ion conductivity of the membrane was measured to be 172 mS / cm at 80°C in the hydroxide form; the membrane was assembled into an AEM electrolyzer (NiFeOx anode + platinum carbon cathode) for accelerated testing, and was operated at 80°C, 1M KOH, 1.5 A / cm 2Operating at a current density of 1.5 volts, the initial cell voltage (after 24 hours of operation) was 1.80 V. After 800 hours of continuous operation, the cell voltage slowly rose to 1.85 V. Upon stopping electrolysis and removing the ion exchange membrane, the membrane remained flexible and showed no obvious damage.

[0128] Comparative Example 1:

[0129] The polymer synthesis was carried out in accordance with Experimental Example 1, without the hydrogenation process. The methylation and membrane formation processes were the same as in Experimental Example 1 to obtain the ion exchange membrane MA(Me). The polymer structure is as follows:

[0130]

[0131] Basic performance testing of the ion exchange membrane MA(Me) was conducted: the dry membrane tensile strength was 75 MPa, and the elongation at break was 23%. The membrane's ionic conductivity in the hydroxide form was measured to be 160 mS / cm at 80°C. The membrane was assembled into an AEM electrolytic cell (NiFeOx anode + platinum carbon cathode) for accelerated testing. The cell operated at 80°C, 1 M KOH, and a current density of 1.5 A / cm², with an initial cell voltage (after 24 hours of operation) of 1.80 V. After 123 hours of continuous operation, abnormal hydrogen flow was observed. Electrolysis was stopped, and the ion exchange membrane was removed, revealing perforations. Bending the ion exchange membrane resulted in brittle cracks on the membrane surface.

[0132] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A low unsaturation long-life anion exchange membrane, characterized in that: The skeleton structure of the anion exchange membrane is as follows: The polymer chain contains a branching unit crosslinking Ar3, which is selected from one of 1,3,5-triphenylbenzene, triphenylene, and 9,9'-spirobifluorene, and has the following structure: In the general formula, the structures of Ar1 and Ar2 are one of biphenyl, 1,4-diphenylbenzene, 1,1':4',1":4",1''-quaterphenyl, 1,3-diphenylbenzene, and fluorene, and the structural formula is as follows: In the general formula, the aromatic ring is in the form of a benzene ring or a cyclohexyl group, and the hydrogenation ratio of the benzene ring is controlled in the range of 80-99%.

2. A low unsaturation long life anion exchange membrane according to claim 1, characterized in that: The preparation method of the anion exchange membrane comprises the following contents: S1: Synthesis of arylpiperidine-type polymers; S2: hydrogenated arylpiperidine type polymer; S3: Quaternization of hydrogenated arylpiperidine-type polymers to prepare anionic polymers; S4: Formation of anion exchange membrane.

3. A low unsaturation long life anion exchange membrane according to claim 2, characterized in that: The synthesis method of the arylpiperidine type polymer comprises the following aspects: A1: Dissolve the aromatic monomer in solvent M, and add N-methyl-4-piperidone after dissolution; A2: Then, trifluoroacetic acid and trifluoromethanesulfonic acid were added dropwise under ice bath conditions. After 1.5 h, the ice bath was removed and the mixture was reacted at room temperature for 0.5-3 h to obtain a viscous reaction liquid. A3: Pour the viscous reaction liquid into solvent N to quench the reaction; A4: Wash with 5% K2CO3 solution until the pH of the washed solution is neutral; A5: Finally, dry it in an oven at 70°C.

4. A low-unsaturation, long-life anion exchange membrane according to claim 3, characterized in that: The aromatic monomer comprises Ar1 monomer, Ar2 monomer and Ar3 monomer, and the molar ratio of Ar1 monomer:Ar2 monomer:Ar3 monomer is 0-1:0-1:0-0.03; The molar ratio of the N-methyl-4-piperidone to the aromatic monomer is 1:1; The solvent M is dichloromethane or chloroform; the molar concentration of the N-methyl-4-piperidone in the solvent M is 0.8-1.0 mol / L.

5. A low-unsaturation, long-life anion exchange membrane according to claim 4, characterized in that: The molar ratio of N-methyl-4-piperidone to trifluoroacetic acid is 1:1; The molar ratio of N-methyl-4-piperidone to trifluoromethanesulfonic acid is 1:6-12; The solvent N is ethanol or water.

6. A low unsaturation long life anion exchange membrane according to claim 2, characterized in that: The hydrogenation method of the arylpiperidine type polymer comprises the following contents: B1: Add polyarylpiperidine to solvent L in a reaction kettle to dissolve to form a 5-10 wt% solution, then add 2-5 wt% catalyst, stir and ultrasonically disperse for 10 min; B2: After sealing the reactor, introduce hydrogen and carry out hydrogenation reaction at 120-160°C and hydrogen pressure of 3-6 MPa for 12-48 hours to obtain a hydrogenated product; B3: Filter the hydrogenated product through a 10 μm filter to remove the catalyst, and then pour it into ice water to obtain a polymer solid; B4: The polymer solid is repeatedly washed with water and then dried in an oven.

7. A low-unsaturation, long-life anion exchange membrane according to claim 6, characterized in that: The solvent L is N,N-dimethylacetamide or N-methylpyrrolidone; The catalyst is a noble metal catalyst represented by Pt or Pd, the carrier on which the catalyst is loaded is macroporous silica gel, BaSO4 or carbon nanotube with an average particle size of 150-250 μm, and the loading amount of the catalyst is 0.5-2.0 wt %.

8. A low unsaturation long life anion exchange membrane according to claim 2, characterized in that: The preparation method of the anionic polymer is as follows: C1: Dissolve the hydrogenated arylpiperidine polymer in solvent O, add K2CO3 after dissolution, stir evenly, then add iodomethane, and react at room temperature in the dark for 36-72 hours; C2: After completion, the reaction solution is slowly poured into solvent P to precipitate the polymer solid; C3: Wash repeatedly with solvent O and water three times respectively until the conductivity of the washing liquid is lower than 10uS / cm, and then filter and dry to obtain.

9. A low-unsaturation, long-life anion exchange membrane according to claim 8, characterized in that: The solvent O is one of N,N-dimethylacetamide, N-methylpyrrolidone or dimethyl sulfoxide, and the mass fraction of the hydrogenated arylpiperidine type polymer in the solvent O is 5-12wt%; The molar ratio of the hydrogenated arylpiperidine polymer: iodomethane: K2CO3 is 1:1.5:1.5; The solvent P is ethanol or ethyl acetate.

10. A low-unsaturation, long-life anion exchange membrane according to claim 2, characterized in that: The anion exchange membrane forming process includes the following contents: D1: heating and dissolving the quaternized polymer in solvent F to obtain a mixture; D2: Filter the mixture with a 5 μm filter to obtain the casting solution; D3: Cast the film on a glass plate, scrape it to the specified thickness with a scraper, and dry it at 70-90℃ for 24h to form a film; The solvent F is one of DMA, NMP or DMSO, The mass concentration of the casting solution is 10-20 wt%.

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