Preparation method of anion exchange membrane cross-linked after membrane formation

Abstract

The invention relates to a preparation method of a solid-phase free radical cross-linking enhanced anion exchange membrane, and belongs to the field of electrolyzed water. The preparation method comprises the following steps: (1) preparing allyl grafted poly-p-terphenyl piperidyl ion exchange resin; and (2) a solid-phase free radical crosslinking method and a preparation method of the enhanced anion exchange membrane. The reinforcing means provided by the invention is efficient and convenient, solves the membrane forming problem caused by poor solubility of the traditional cross-linked resin, and accurately strengthens multiple mechanical properties of the cross-linked anion exchange membrane. The prepared cross-linked anion exchange membrane has good dimensional stability, mechanical tensile property and electrolytic property, and has further industrial application prospects.

Description

Technical Field

[0001] The present invention relates to a preparation method of a novel anion exchange membrane, and in particular to a reinforcement strategy for improving mechanical strength and stability through solid-phase free radical crosslinking, belonging to the technical field of water electrolysis. Background Art

[0002] The production of green hydrogen by water electrolysis is an environmentally friendly, efficient and sustainable method of hydrogen production that can effectively utilize renewable energy. Water electrolysis (WE) is further divided into three main technologies: alkaline water electrolysis (AWE), proton exchange membrane water electrolysis (PEMWE), anion exchange membrane water electrolysis (AEMWE) and solid oxide water electrolysis (SOEC). Anion exchange membrane water electrolysis combines the technical advantages of alkaline water electrolysis and proton exchange membrane water electrolysis. It can operate under low-concentration alkaline solutions or pure water conditions. It has outstanding advantages such as high energy utilization efficiency, high gas purity, and strong anti-fluctuation ability. In particular, it can avoid the use of precious metal catalysts. Therefore, it has attracted the attention of scientific research and industry in recent years.

[0003] Anion exchange membranes (AEMs) are key materials in water electrolyzers. As a type of functional polymer in membrane form, they typically consist of functional groups attached to a polymer backbone, enabling high-speed anion transport. However, the lifespan and mechanical properties of the membrane materials remain shortcomings of AEMWE technology. Statistics show that in practical AEMWE applications, power density often decreases significantly after 500 hours of operation. Therefore, improving the lifespan and mechanical strength of AEM materials has become a key research focus in this field.

[0004] Cross-linking strategy is an effective method to improve the lifespan and mechanical strength of AEM materials. Studies have found that establishing a three-dimensional cross-linked structure of the polymer backbone through covalent or non-covalent bonds can effectively improve the mechanical strength of the material and extend its service life. However, the establishment of the cross-linked structure will lead to a decrease in the solubility of the ionomer, thereby affecting the film-forming process. Therefore, the present invention has designed a solid-phase free radical cross-linking strategy, which can effectively solve the solubility problem caused by traditional cross-linking, inhibit the swelling of the membrane material, improve the mechanical strength, and maintain the original high conductivity of the membrane. The biphenylpiperidine ionomer prepared using this strategy has the characteristics of high chemical stability, high mechanical strength and long service life. Summary of the Invention

[0005] The purpose of the present invention is to address the above deficiencies and provide an application method of a solid-phase free radical crosslinking strategy, as well as a preparation method and application of a reinforced poly(p-terphenylpiperidine)-based anion exchange membrane material. By introducing allyl groups as sites for free radical crosslinking reactions on the polymer backbone, a solid-phase crosslinking reaction is initiated after film formation to improve the mechanical strength of the material. Resin polymers with a high degree of crosslinking often have the problem of decreased solubility, which affects the further transformation of the polymer and the controllable preparation of the film. The strategy of "forming a film first, then crosslinking" can effectively solve this problem, while fixing the phase distribution of the resin polymer to reduce the chain entanglement caused by crosslinking, so that OH - The transmission channels are unobstructed to maintain high ion conductivity.

[0006] The present invention provides a method for preparing a poly(p-terphenylpiperidinyl)-based ion exchange resin grafted with allyl side chains, and the reaction route equation is:

[0007]

[0008] The target product (QPTPpi-allyl-x) is divided into a functional structural unit and a cross-linked side chain functional structural unit, wherein the content of the cross-linked side chain functional structural unit is x=0.1-1.0; and the content of the functional structural unit is y=1-x=0-0.9.

[0009] The specific steps are:

[0010] Step A. Preparation of poly (p-terphenyl piperidinyl) polymer (PTPpi): p-terphenyl, N-methyl-4-piperidone, and dichloromethane were added to a three-necked flask and stirred continuously in an ice bath until the temperature dropped to 0°C. Trifluoromethanesulfonic acid was then added, and the reaction was continued at 0°C for 12 hours. After the reaction was completed, the reaction solution was transferred to an alkaline solution for solidification to obtain a white solid. The solid was filtered and washed several times with deionized water. It was then dried in a vacuum oven to a constant weight to obtain a poly (p-terphenyl piperidinyl) polymer.

[0011] The target product: poly (p-terphenylpiperidinyl) polymer (PTPpi) has the structural formula shown in Formula 1:

[0012]

[0013] Step B. Preparation of allyl-grafted poly (p-terphenylpiperidinyl) quaternary ammonium products (QPTPpi-allyl-x): Nucleophilic substitution reaction was performed on the polymer using varying ratios of 3-propene bromide and methyl iodide. The reaction was performed in the well-soluble solvent DMSO at 40°C for 48 hours in the dark with the aid of the organic base N,N-diisopropylethylamine. A series of allyl-grafted poly (p-terphenylpiperidinyl) quaternary ammonium products were synthesized by varying the ratio of the introduced allyl group (x).

[0014] The reaction formula of this process is:

[0015]

[0016] The target product: Allyl-grafted poly (p-terphenylpiperidinyl) quaternary ammonium product (QPTPpi-allyl-x) has the structural formula shown in Formula 2:

[0017]

[0018] Furthermore, in the step A, the molar ratio of the p-terphenyl to N-methyl-4-piperidone is 1:0.2 to 1:5.0.

[0019] Furthermore, in step A, the molar ratio of p-terphenyl to trifluoromethanesulfonic acid is 1:0.5 to 1:30.

[0020] Furthermore, in the step B, the molar ratio of the poly(p-terphenylpiperidine) polymer to N,N-diisopropylethylamine is 1:0.2 to 1:5.0.

[0021] Furthermore, in the step B, the molar ratio of the poly(p-terphenylpiperidine) polymer to methyl iodide is 1:0.1 to 1:10.0.

[0022] Furthermore, in the step B, the molar ratio of the poly(p-terphenyl piperidine) polymer to 3-bromopropylene is 1:0.1 to 1:5.0.

[0023] The second aspect of the present invention also provides a solid-phase free radical crosslinking strengthening method based on the above-mentioned allyl-grafted poly(p-terphenylpiperidinyl)-based ion exchange resin and a method for preparing a strengthened anion exchange membrane. The solid-phase free radical crosslinking reaction equation is:

[0024]

[0025] The specific steps are:

[0026] Step C. Preparation of the allyl-grafted poly(p-terphenylpiperidinyl) anion exchange membrane material to be cross-linked: The allyl-grafted poly(p-terphenylpiperidinyl) quaternized product prepared in Step B and a free radical initiator are dissolved in dimethyl sulfoxide. After the solid is completely dissolved, undissolved solids and impurities are filtered using a filter. The filtrate is poured into a mold, and the solvent is evaporated by casting to obtain the allyl-grafted poly(p-terphenylpiperidinyl) anion exchange membrane to be cross-linked.

[0027] The structural formula of the free radical initiator is shown in Formula 3:

[0028]

[0029] Step D: Solid-phase free radical crosslinking and strengthening strategy: The film to be crosslinked, prepared in Step C, is placed between two ultra-flat glass plates, with a certain amount of pressure applied to both sides. The entire apparatus is then placed at a specific crosslinking temperature to initiate a free radical reaction within the solid film. The crosslinking duration is then controlled to achieve the desired crosslinking effect. Upon completion of the crosslinking reaction, a solid-phase crosslinked and strengthened anion exchange membrane is obtained.

[0030] Furthermore, in the step C, the mass ratio of the free radical initiator to the allyl-grafted poly(p-terphenylpiperidinyl) quaternary ammonium product is 0.1:100 to 50:100.

[0031] Furthermore, in the step D, the cross-linking temperature is 30°C to 200°C.

[0032] Furthermore, in the step D, the cross-linking time is 1 min to 24 h.

[0033] The third aspect of the present invention also provides the obvious mechanical advantage of the solid-phase free radical crosslinking strategy on the poly(p-terphenylpiperidine)-based anion exchange membrane material, and proves that the enhanced anion exchange membrane material has good application performance in alkaline water electrolyzers.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) The present invention proposes and applies a solid-phase free radical cross-linking strategy, introducing allyl groups on the polymer backbone as sites for free radical cross-linking reactions. The constructed cross-linked structure effectively improves the mechanical properties of the polymer membrane material; the uniform microphase separation is fixed through the steps of "forming the membrane first and then cross-linking", thereby maintaining the high ionic conductivity of the membrane material.

[0036] (2) The solid-phase cross-linked reinforced anion exchange membrane provided by the present invention has excellent mechanical tensile properties and dimensional stability. As a key material in an alkaline water electrolyzer, it exhibits excellent comprehensive electrolytic performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The synthetic route of the allyl-grafted poly (p-terphenylpiperidinyl) ion exchange resin (QPTPpi-allyl-x) of the present invention is as follows;

[0038] Figure 2 is the NMR spectrum of the poly(p-terphenylpiperidinyl) polymer (PTPpi) prepared in Example 1 of the present invention;

[0039] Figure 3 The NMR spectra of the allyl-grafted poly (p-terphenylpiperidinyl) quaternary ammonium products (QPTPpi-allyl-x) prepared in Examples 1, 2, 3, and 4 of the present invention are shown;

[0040] Figure 4 This is an NMR spectrum that proves the occurrence of solid-phase free radical cross-linking reaction in Example 2 of the present invention;

[0041] Figure 5 Graphs showing the water absorption rates of the uncrosslinked and crosslinked allyl-grafted poly(p-terphenylpiperidine)-based anion exchange membranes in Examples 1, 2, 3, and 4 of the present invention;

[0042] Figure 6 Graphs showing the swelling rates of the uncrosslinked and crosslinked allyl-grafted poly(p-terphenylpiperidine)-based anion exchange membranes in Examples 1, 2, 3, and 4 of the present invention;

[0043] Figure 7 Mechanical stretching diagrams of the poly(p-terphenylpiperidine)-based anion exchange membrane with an allyl grafting ratio of 20% prepared in Example 2 of the present invention before and after cross-linking;

[0044] Figure 8 This is a linear sweep voltammogram of the uncrosslinked poly(p-terphenylpiperidine)-based anion exchange membrane with an allyl grafting ratio of 20% prepared in Example 2 of the present invention;

[0045] Figure 9 This is a linear sweep voltammogram of the cross-linked poly(p-terphenylpiperidine)-based anion exchange membrane with a 20% allyl grafting ratio prepared in Example 2 of the present invention;

[0046] Figure 10 This is a durability test of the cross-linked poly(p-terphenylpiperidine)-based anion exchange membrane prepared in Example 2 of the present invention and having an allyl grafting ratio of 20%. Specific implementation methods

[0047] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification. Unless otherwise specified, the methods are all conventional methods, and the raw materials can be obtained from public commercial channels unless otherwise specified.

[0048] As used herein, "one embodiment" or "embodiment" refers to a specific structure, configuration, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0049] The sources of the drugs and reagents described in the examples are as follows:

[0050] p-Terphenyl: Anaiji Chemical, 98.0%

[0051] N-methyl-4-piperidone: Anaiji Chemical, 98.0%

[0052] Trifluoromethanesulfonic acid: Anaiji Chemical, 99%

[0053] Iodomethane: Anaiji Chemical, 99.5%

[0054] 3-Propylene bromide: Anaiji Chemical, 98.0%

[0055] N,N-Diisopropylethylamine: Dama Chemical, 99.5%

[0056] Azobisisobutyronitrile: Coupling Technology, 99%

[0057] Benzoyl peroxide: Beijing Chemical Plant, 99%

[0058] Dicumyl peroxide: Beijing Chemical Plant, 99%

[0059] Dichloromethane: Beijing Chemical Plant, reagent grade

[0060] Dimethyl sulfoxide: Beijing Chemical Plant, reagent grade

[0061] according to Figure 1 The synthesis was carried out according to the reaction scheme shown.

[0062] The following is a detailed description of the raw material feeding amounts and specific reaction conditions in the examples.

[0063] Example 1

[0064] Step A. Preparation of poly (p-terphenyl piperidinyl) polymer: 2.48 g p-terphenyl and 1.37 mL N-methyl-4-piperidone were accurately weighed and added to a 250 mL three-necked flask, and 4 mL dichloromethane was added as solvent. The mixture was stirred at 400 r min. -1 Stir and dissolve at a constant speed for 15 minutes. Then, add 10 mL of trifluoromethanesulfonic acid (TFSA) in batches, causing the solution to turn dark blue. Continue the reaction at 0°C until the system reaches maximum viscosity, terminating the reaction. Transfer the viscous reaction solution to a 1 M K2CO3 solution in multiple batches to obtain a fluffy, slightly yellowish solid. The separated solid is washed with deionized water until neutral and dried at 70°C to constant weight to obtain poly(p-terphenylpiperidinyl) polymer (PTPpi).

[0065] The PTPpi NMR spectrum was measured by sampling. Figure 2 shown.

[0066] Step B. Preparation of a quaternized product of poly(p-terphenylpiperidinyl) with a 10% allyl grafting ratio: Accurately weigh 0.3 g of PTPpi polymer solid and 2 mL of dimethyl sulfoxide, add them to a 10 mL round-bottom flask wrapped in tin foil, stir thoroughly until the polymer solid is dissolved as much as possible, add 6.9 μL of 3-bromopropylene and 20.4 μL of iodomethane to the reaction system using a microinjector, and incubate at 40°C and 450 r min. -1 The reaction was continued for 24 hours under the appropriate conditions. 34.0 μL of N,N-diisopropylethylamine and 51.2 μL of iodomethane were then added to the system and the reaction continued for another 24 hours, resulting in a dark brown solution. Post-treatment in ethyl acetate yielded a pale yellow flocculent precipitate. The filtered precipitate was washed and dried to yield a quaternized poly(p-terphenylpiperidinyl) (QPTPpi-allyl-0.1) with a 10% allyl grafting ratio.

[0067] The NMR spectrum of QPTPpi-allyl-0.1 was measured by sampling. Figure 3 shown.

[0068] Step C. Preparation of the cross-linked allyl-grafted poly(p-terphenylpiperidinyl) anion exchange membrane material: Accurately weigh 0.1g of the polymer QPTPpi-allyl-0.1 and 5wt% of a DCP sample and thoroughly dissolve them in 2mL of dimethyl sulfoxide (DMSO) to prepare a 5wt% casting solution. Undissolved solids and impurities are filtered using a syringe and syringe filter combination to obtain a uniform, smooth film. By controlling the amount of polymer added to the casting solution, uniform, transparent, light yellow films of varying thickness can be obtained.

[0069] Step D. Solid-phase free radical crosslinking and strengthening of the anion exchange membrane: After obtaining the dried film, place it flat between two glass plates, apply a certain pressure to the outside of the glass, and place the pressure-applied glass plates at 150°C for 30 minutes.

[0070] Example 2

[0071] Step A. Preparation of Poly(p-terphenylpiperidinyl) Polymer

[0072] Same as step A in Example 1.

[0073] Step B. Preparation of a quaternized product of poly(p-terphenylpiperidinyl) with an allyl grafting ratio of 20%: Accurately weigh 0.3 g of PTPpi polymer solid and 2 mL of dimethyl sulfoxide, add them to a 10 mL round-bottom flask wrapped in tin foil, stir thoroughly until the polymer solid is dissolved as much as possible, add 13.9 μL of 3-bromopropylene and 15.3 μL of iodomethane to the reaction system using a microinjector, and incubate at 40°C and 450 r min. -1The reaction was continued for 24 hours under the appropriate conditions. 34.0 μL of N,N-diisopropylethylamine and 51.2 μL of iodomethane were then added to the system and the reaction continued for another 24 hours, resulting in a dark brown solution. Post-treatment in ethyl acetate yielded a pale yellow flocculent precipitate. The filtered precipitate was washed and dried to yield a quaternized poly(p-terphenylpiperidinyl) (QPTPpi-allyl-0.2) with a 20% allyl grafting ratio.

[0074] The NMR spectrum of QPTPpi-allyl-0.2 was measured by sampling. Figure 3 shown.

[0075] Step C. Preparation of allyl grafted poly(p-terphenylpiperidine)-based anion exchange membrane material to be cross-linked

[0076] Same as step C in Example 1

[0077] Step D. Solid-phase free radical cross-linking strengthening step of anion exchange membrane

[0078] Same as step D in Example 1

[0079] The NMR spectrum that proves that the QPTPpi-allyl-0.2 film undergoes free radical addition crosslinking reaction is as follows Figure 4 shown.

[0080] Example 3

[0081] Step A. Preparation of Poly(p-terphenylpiperidinyl) Polymer

[0082] Same as step A in Example 1.

[0083] Step B. Preparation of a quaternized poly(p-terphenylpiperidinyl) product with a 50% allyl grafting ratio: Accurately weigh 0.3 g of PTPpi polymer solid and 2 mL of dimethyl sulfoxide, add them to a 10 mL round-bottom flask wrapped in tin foil, stir thoroughly until the polymer solid is fully dissolved, add 34.5 μL of 3-bromopropylene to the reaction system using a microinjector, and incubate at 40°C and 450 rpm. -1 The reaction was continued for 24 hours under the appropriate conditions. 34.0 μL of N,N-diisopropylethylamine and 51.2 μL of iodomethane were then added to the system and the reaction continued for another 24 hours, resulting in a dark brown solution. Post-treatment in ethyl acetate yielded a pale yellow flocculent precipitate. The filtered precipitate was washed and dried to yield a quaternized poly(p-terphenylpiperidinyl) (QPTPpi-allyl-0.5) with a 50% allyl grafting ratio.

[0084] The NMR spectrum of QPTPpi-allyl-0.5 was measured by sampling. Figure 3 shown.

[0085] Step C. Preparation of allyl grafted poly(p-terphenylpiperidine)-based anion exchange membrane material to be cross-linked

[0086] Same as step C in Example 1

[0087] Step D. Solid-phase free radical cross-linking strengthening step of anion exchange membrane

[0088] Same as step D in Example 1

[0089] Example 4

[0090] Step A. Preparation of Poly(p-terphenylpiperidinyl) Polymer

[0091] Same as step A in Example 1.

[0092] Step B. Preparation of a quaternized poly(p-terphenylpiperidinyl) product with 100% allyl grafting ratio: Accurately weigh 0.3 g of PTPpi polymer solid and 2 mL of dimethyl sulfoxide, add them to a 10 mL round-bottom flask wrapped in tin foil, stir thoroughly until the polymer solid is dissolved as much as possible, add 69 μL of 3-bromopropylene to the reaction system using a microinjector, and heat at 40°C and 450 rpm. -1 The reaction was continued for 24 hours under the appropriate conditions. 34.0 μL of N,N-diisopropylethylamine and 25.6 μL of iodomethane were then added to the system and the reaction continued for another 24 hours, resulting in a dark brown solution. Post-treatment in ethyl acetate yielded a pale yellow flocculent precipitate. The filtered precipitate was washed and dried to obtain a quaternized poly(p-terphenylpiperidinyl) (QPTPpi-allyl-1.0) with a 100% allyl grafting ratio.

[0093] The NMR spectrum of QPTPpi-allyl-1.0 was obtained by sampling. Figure 3 shown.

[0094] Step C. Preparation of allyl grafted poly(p-terphenylpiperidine)-based anion exchange membrane material to be cross-linked

[0095] Same as step C in Example 1

[0096] Step D. Solid-phase free radical cross-linking strengthening step of anion exchange membrane

[0097] Same as step D in Example 1

[0098] The IEC values of the solid-phase cross-linked reinforced anion exchange membranes obtained in Examples 1-4 are shown in Table 1.

[0099] Table 1

[0100]

[0101] Table: IEC tis the theoretical value;

[0102] IEC e Measured by titration;

[0103] Unlink indicates a membrane that has not been subjected to solid-phase free radical cross-linking;

[0104] Linked indicates that the membrane has been subjected to solid phase free radical cross-linking.

[0105] As can be seen from Table 1, the QPTPpi-allyl-x series anion exchange membranes prepared by the present invention have ideal IEC values ranging from 2.45 to 2.64 mmol g -1 This provides sufficient cations for ideal conductivity and electrolytic performance. Furthermore, the optimal IEC value prevents overhydration of the membrane material, resulting in excellent dimensional stability. The solid-phase crosslinking strategy not only builds the crosslinked structure but also ensures the smooth flow of ion exchange channels, resulting in a decrease of less than 2% in the actual IEC value of the crosslinked membrane.

[0106] The solid-phase free radical crosslinking strategy significantly improved the dimensional stability of the membrane material. Figure 5 and Figure 6 The water absorption and swelling rates of the uncross-linked and cross-linked membranes were analyzed. The overall swelling rate decreased by 50-60%, while the water absorption rate decreased by 40-50%. Furthermore, the water absorption and swelling rates increased with increasing temperature, as the temperature increases, providing energy for the thermal motion of molecules and accelerating their movement. The QPTPpi-allyl-0.2-linked cross-linked membrane exhibited the most ideal water absorption and swelling rates, with a water absorption rate of 22.8% and a swelling rate of 11.5% at 30°C.

[0107] The solid-phase cross-linking strategy forms new covalent bonds between polymer segments, and the constructed three-dimensional cross-linked network provides the membrane material with stronger tensile strength. Figure 7 As shown in the figure, after solid phase free radical crosslinking, the tensile strength increased from 55.3 MPa to 65.09 MPa, and the elongation at break increased from 16.8% to 22.6%.

[0108] Water electrolysis test is the key to evaluate whether the membrane material has the potential for industrialization. The linear sweep voltammetry curve of the AEMWE device based on the QPTPpi-allyl-0.2-unlink uncrosslinked membrane is as follows: Figure 8 The linear sweep voltammetry curve of the AEMWE device based on the QPTPpi-allyl-0.2-linked cross-linked membrane is shown in Figure 9The current density of the two AEMWEs increases with increasing temperature. When the electrolysis device reaches 80°C, the current density of the two AEMWEs exceeds 3A cm -2 @2.2V. More importantly, the cross-linking strategy significantly improves the mechanical strength without affecting the electrolytic performance and conductivity of the membrane material. AEMWE based on QPTPpi-allyl-0.2-linked cross-linked membrane still has a conductivity of 3.15Acm at 80°C. -2 The cross-linked membrane was further used to perform the experiment at a constant current density of 1 A cm -2 and 5A cm -2 In situ durability testing was conducted under the Figure 10 In the first 200 hours, the voltage was very stable with almost no significant attenuation. In order to accelerate the durability test, the current density was increased to 5A cm -2 , the voltage was increased to about 2.7 V, and there was no obvious change within 300 h, which proved that the cross-linked film had excellent durability.

[0109] While various embodiments of the present invention have been described above, the above descriptions are illustrative and non-exhaustive, and are not intended to be limiting of the disclosed embodiments. Modifications and variations in the art without departing from the scope and technical principles of the described embodiments should also be considered within the scope of the present invention.

Claims

1. A method for synthesizing an allyl-grafted poly(p-terphenylpiperidinyl) ion exchange resin, characterized in that: The molecular structure of the polymer is shown in Formula 1: Formula 1 is divided into functional structural units and cross-linked side chain functional structural units, wherein the content of the cross-linked side chain functional structural units is x=0.1-1.0; the content of the functional structural units is y=1-x=0-0.9; The specific steps are as follows: Step A. Preparation of poly (p-terphenyl piperidinyl) polymer (PTPpi): p-terphenyl, N-methyl-4-piperidone, and dichloromethane were added to a three-necked flask and stirred continuously in an ice bath until the system dropped to 0°C. Trifluoromethanesulfonic acid was added thereto and the reaction was continued at 0°C for 12 hours. After the reaction was terminated, the reaction solution was transferred to an alkaline solution for solidification to obtain a white block solid. The solid was filtered and washed with deionized water several times, and then dried in a vacuum oven to constant weight to obtain a poly (p-terphenyl piperidinyl) polymer. Step B. Preparation of allyl-grafted poly (p-terphenyl piperidinyl) quaternary ammonium products (QPTPpi-allyl-x): Using different proportions of 3-bromopropylene and iodomethane to react with the polymer for nucleophilic substitution reaction, with the assistance of the organic base N,N-diisopropylethylamine, using the well-soluble solvent DMSO, the reaction was carried out at 40°C in the dark for 48 hours, and the introduction ratio of the allyl group (x) was changed to synthesize a series of allyl-grafted poly (p-terphenyl piperidinyl) quaternary ammonium products.

2. A post-film crosslinking method for an allyl-grafted poly(p-terphenylpiperidinyl) anion exchange membrane, characterized in that: The cross-linking reaction is based on the addition reaction of free radicals to double bonds, and the reaction occurs in the solid phase anion exchange membrane. The specific steps are as follows: Step C. Preparation of an allyl-grafted poly (p-terphenyl piperidine)-based anion exchange membrane material to be cross-linked: dissolving the allyl-grafted poly (p-terphenyl piperidine)-based quaternized product prepared in step B and a free radical initiator in dimethyl sulfoxide. After the solid is completely dissolved, filtering out undissolved solids and impurities using a filter device, pouring the filtrate into a mold, and volatilizing the solvent by a casting method to obtain an allyl-grafted poly (p-terphenyl piperidine)-based anion exchange membrane to be cross-linked; Step D. Solid-phase free radical crosslinking strengthening method: Place the film to be crosslinked prepared in step C between two ultra-flat glass plates, apply a certain pressure on both sides of the glass plates, and place the entire device at a specific crosslinking temperature to induce a free radical reaction in the solid film. By controlling the crosslinking time to obtain the ideal crosslinking effect, the crosslinking reaction is terminated to obtain an anion exchange membrane strengthened by solid-phase crosslinking.

3. The method for synthesizing an allyl-grafted poly(p-terphenylpiperidinyl) resin polymer according to claim 1, wherein: In the step A, the molar ratio of the p-terphenyl to N-methyl-4-piperidone is 1:0.2 to 1:5.

0.

4. The method for synthesizing an allyl-grafted poly(p-terphenylpiperidinyl) resin polymer according to claim 1, wherein: In the step A, the molar ratio of p-terphenyl to trifluoromethanesulfonic acid is 1:0.5 to 1:

30.

5. The method for synthesizing an allyl-grafted poly(p-terphenylpiperidinyl) resin polymer according to claim 1, wherein: In the step B, the molar ratio of the poly(p-terphenylpiperidinyl) polymer to N,N-diisopropylethylamine is 1:0.2 to 1:5.

0.

6. The method for synthesizing an allyl-grafted poly(p-terphenylpiperidinyl) resin polymer according to claim 1, wherein: In the step B, the molar ratio of the poly(p-terphenylpiperidinyl) polymer to methyl iodide is 1:0.1 to 1:10.

0.

7. The method for synthesizing an allyl-grafted poly(p-terphenylpiperidinyl) resin polymer according to claim 1, wherein: In the step B, the molar ratio of the poly(p-terphenyl piperidine) polymer to 3-bromopropylene is 1:0.1 to 1:5.

0.

8. The solid phase free radical crosslinking method for an allyl-grafted poly(p-terphenylpiperidinyl) anion exchange membrane according to claim 2, wherein: In step C, the types of the free radical initiator include but are not limited to azobisisobutyronitrile, dibenzoyl peroxide, and dicumyl peroxide.

9. A solid phase free radical crosslinking method based on an allyl grafted poly(p-terphenylpiperidinyl) anion exchange membrane according to claim 2, characterized in that: In the step C, the mass ratio of the free radical initiator to the allyl-grafted poly(p-terphenylpiperidinyl) quaternary ammonium product is 0.1:100 to 50:

100.

10. A solid phase free radical crosslinking method for an allyl-grafted poly(p-terphenylpiperidinyl) anion exchange membrane according to claim 2, characterized in that: In the step D, the cross-linking temperature is 30°C to 200°C.

11. A solid phase free radical crosslinking method for an allyl grafted poly(p-terphenylpiperidinyl) anion exchange membrane according to claim 2, characterized in that: In the step D, the cross-linking time is 1 min to 24 h.

12. Use of the solid-phase free radical cross-linked anion exchange membrane material according to claim 2, characterized in that: The mechanical properties of the prepared anion exchange membrane material are significantly improved, and it can be used as a key component in alkaline water electrolyzers and alkaline anion exchange membrane fuel cells.

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