阅读说明：本技术 季铵化交联型聚合物、阴离子交换膜及其制备与应用方法 (Quaternized crosslinked polymer, anion exchange membrane and preparation and application methods thereof ) 是由 王芳辉 崔亚慧 朱红 于 2021-09-22 设计创作，主要内容包括：本发明公开了季铵化交联型聚合物、阴离子交换膜及其制备与应用方法,其中所述聚合物含有如式(I)所示的结构式,所得聚合物在成膜后具有良好的微相分离结构、低溶胀、高尺寸稳定性和化学稳定性：(The invention discloses a quaternized cross-linked polymer, an anion exchange membrane, and preparation and application methods thereof, wherein the quaternized cross-linked polymer and the anion exchange membrane are providedThe polymer contains a structural formula shown as a formula (I), and the obtained polymer has a good microphase separation structure, low swelling, high dimensional stability and chemical stability after film forming:)

1. A quaternized crosslinked polymer characterized by comprising a structural formula represented by formula (I):

wherein the content of the first and second substances,

ar is selected from aromatic hydrocarbon radicals;

R₃is selected from

R₂＝R₃Or selected from H, methyl or ethyl;

R₁any one of the following structures:

and:

(x+y)＝0.18-0.26，(m+n)＝0.74-0.82，0<y/(x+y)≤1，0<p≤1，0≤q<1；n1＝1～7，n2＝1～3。

2. the quaternized crosslinked polymer of claim 1, wherein the aromatic hydrocarbon group is selected from any one of the following structures:

3. a method of making a quaternized crosslinked polymer, comprising:

performing chloromethylation reaction on the hydrogenated styrene-butadiene block copolymer to obtain a chloromethylated first copolymer;

reacting the chloromethylated block copolymer with a quaternary ammonium reactant to obtain a second copolymer containing a quaternary ammonium group branched chain, wherein the quaternary ammonium reactant is alkyl tertiary amine and/or a multi-cationic side chain;

copolymerizing aromatic hydrocarbon and 4-acetylpyridine to obtain a polyarylpyridine copolymer;

heating the polyarylpyridine copolymer and the second copolymer to react to obtain the quaternized cross-linked polymer;

preferably, the quaternary ammonium reactant is selected from the group consisting of N, N' -pentamethyl-1-amino-6-ammonium iodide; and/or the aromatic hydrocarbon is selected from one or more of biphenyl, p-terphenyl, m-terphenyl and quaterphenyl.

4. The method according to claim 3, characterized in that it comprises in particular:

(1) synthesis of the first copolymer:

dissolving hydrogenated styrene-butadiene block copolymer, adding chloromethylation reagent and catalyst into the solution to carry out chloromethylation reaction, and extracting the product to obtain the first copolymer, wherein the reaction temperature is 0-60 ℃, and/or the reaction time is 2-72 h;

(2) synthesis of the polyarylpyridine copolymer:

adding aromatic hydrocarbon and 4-acetylpyridine into dichloromethane, adding a protonation reagent and a catalyst into the mixed solution, reacting at room temperature until the solution becomes viscous, and extracting a product to obtain the polyarylpyridine copolymer;

(3) synthesis of the second copolymer:

dissolving the obtained first copolymer, adding tertiary amine containing 4-16 alkyl chains with carbon atoms or polycation with 2-6 carbon atoms in a side chain into the solution of the first copolymer for reaction at the temperature of 20-60 ℃ and/or for 6-72 hours to obtain a second copolymer;

(4) synthesis of the quaternized cross-linked polymer:

and mixing the polyarylpyridine copolymer and the second copolymer to form a homogeneous mixed solution, heating and reacting to obtain the crosslinking copolymer.

5. The method of claim 4, wherein: wherein, the solvent used for dissolving in (1) is selected from one or more of trichloromethane, tetrahydrofuran, toluene and dichloroethane, and/or the chloromethylation reagent is selected from one or more of 1, 4-dichloromethoxybutane, 1,3, 5-trioxane and trimethylchlorosilane, and/or the catalyst thereof is selected from anhydrous stannic chloride; and/or the protonating agent in (2) is selected from trifluoromethanesulfonic acid, and/or its catalyst is selected from trifluoroacetic acid; and/or the solvent used for the dissolution in (3) is selected from chloroform; and/or the mixed solution in (4) contains N, N-dimethylformamide as a solvent.

6. The method of claim 4, wherein: wherein the extracting in (1) comprises: adding a first precipitator into the reacted system, and then carrying out first purification on the separated substances to obtain a first copolymer; and/or the reaction time in (2) is 2-72h, and/or the extraction comprises: adding a second precipitator into the reacted system, and then carrying out second purification on the separated substances to obtain the polyarylpyridine copolymer; preferably, the first precipitator is selected from one or more of methanol, ethanol or ethyl acetate; and/or the second precipitator is selected from one or more of water, methanol and ethanol or NaOH and Na₂CO₃、NaHCO₃One or more of a solution; preferably, the first purification comprises: adding tetrahydrofuran and/or an alcohol solution into the separated substances for purification; and/or, the second purification comprises: separating, washing and drying the precipitated substances, dissolving the precipitated substances in a second solvent, adding a third precipitating agent, separating and drying the precipitated substances again, wherein the second solvent is selected from one or more of dichloromethane, trichloromethane, tetrahydrofuran, 1-methyl-2-pyrrolidone and cyclohexanone, and/or the third precipitating agent is selected from methanol and/or ethanol.

7. The method of claim 4, wherein: wherein, in a solution obtained by dissolving the hydrogenated styrene-butadiene block copolymer, the volume ratio of the mass of the block copolymer to the solvent thereof is 1:15-1:60 g/mL; and/or the mass ratio of the hydrogenated styrene-butadiene block copolymer to the catalyst thereof is 800:1 to 400: 1; and/or the mass ratio of the mass of the hydrogenated styrene-butadiene block copolymer to the mass of the chloromethylation reagent is 300:1-1: 2; and/or, the dosage of the chloromethylation reagent is 1.0 to 2.0 times of the theoretical calculation quantity; and/or the concentration of the aromatic hydrocarbon in dichloromethane is 0.1-1 mol/L; and/or the molar ratio of the 4-acetylpyridine to the aromatic hydrocarbon is 1:1 to 1.5: 1; and/or the molar ratio of the 4-acetylpyridine to the catalyst thereof is 1:5 to 1: 10; and/or the molar ratio of the 4-acetylpyridine to the protonating agent is from 1:5 to 1: 20; and/or, in a solution obtained by dissolving the obtained first copolymer, the volume ratio of the mass of the first copolymer to the solvent thereof is 1:15-1:50g/mL, and/or the volume ratio of the mass of the polyarylpyridine to the solvent is 1:300-1:600 g/mL; and/or the volume ratio of the solvent to the homogeneous mixed solution in the homogeneous mixed solution is 1:10-2: 3.

8. An anion exchange membrane obtained by molding the quaternized crosslinked polymer according to claim 1 or 2 and/or the quaternized crosslinked polymer obtained by the production method according to any one of claims 3 to 7, and/or by reacting with an alkaline solution after molding.

9. The method for preparing an anion exchange membrane from the quaternized crosslinked polymer according to claim 1 or 2 and/or the quaternized crosslinked polymer prepared by the preparation method according to any one of claims 3 to 7, comprising:

salivating the solution of the cross-linked copolymer to form a film, and then drying and cooling to obtain the anion exchange membrane;

or the like, or, alternatively,

forming a film by using the solution of the cross-linked copolymer, then placing the film into a sodium hydroxide and/or potassium hydroxide solution for soaking for 12-60h, and then washing the film to be neutral to obtain the anion exchange membrane;

preferably, the concentration of the sodium hydroxide and/or potassium hydroxide solution is 0.1-3 mol/L;

preferably, it further comprises:

soaking the membrane material obtained by the membrane formation in an organic solution of halogenated alkane, wherein the halogenated alkane is more preferably selected from methyl iodide and/or ethyl bromide, and/or the solvent of the organic solution is selected from ethanol, and the solute mass fraction of the solution is 10-50%.

10. Use of the quaternized crosslinked polymer of claim 1 or 2, and/or the quaternized crosslinked polymer prepared by the preparation method of any one of claims 3-7, and/or the anion exchange membrane of claim 8, and/or the anion exchange membrane prepared by the preparation method of claim 9 in an anion exchange membrane fuel cell.

Technical Field

The invention belongs to the technical field of anion exchange membrane fuel materials, and particularly relates to a quaternized cross-linked polymer anion exchange membrane and a preparation method thereof.

Background

Anion Exchange Membrane Fuel Cells (AEMFCs) are a new energy technology and have attracted extensive attention due to the advantages of fast oxygen reduction kinetics, the availability of inexpensive non-noble metal catalysts, and the like. Anion Exchange Membranes (AEMs) are the core of AEMFCs and are key components for ion transport, and in particular the polymer backbone of AEMs fundamentally determines the life of fuel cells.

Hydrogenated styrene-butadiene block copolymers (SEBS) have a great application prospect in the aspects of obvious phase separation and good alkali resistance in construction due to the unique characteristics of alternating soft and hard blocks and an all-carbon main chain, and are widely used as AEMs (ethylene-based organic Compounds) manufacturing materials. However, SEBS-based alkaline membranes exhibit high swelling and low dimensional stability due to the special fatty chain backbone structure, and mechanical properties are generally poor. In order to overcome the problems, SEBS and polymers such as poly (2, 6-dimethylphenylene oxide) (PPO), polyarylpiperidine (PAP) and the like are often used for crosslinking, and the mechanical properties are selectively improved by controlling the proportion of reactants, but previous researches prove that in the crosslinking process, because the polarity change is too large, the phenomena of gelation and precipitation often occur, side reactions sometimes also occur, even the alkali resistance of AEMs is reduced, and the improvement of the comprehensive properties is hindered. Therefore, the development of a new crosslinking way becomes the key for improving the performance of the SEBS-based anion-exchange membrane.

Disclosure of Invention

In view of the defects of the prior art, the invention aims to provide a quaternized cross-linked polymer with good microphase separation structure, low swelling, high dimensional stability and chemical stability and an anion exchange membrane prepared by the quaternized cross-linked polymer. The invention also aims to provide a high-efficiency and stable preparation method of the polymer and/or the anion exchange membrane, which reduces the risk of gel caused by overlarge polarity change, avoids side reaction, can induce crosslinking of hydrogenated styrene-butadiene block copolymer (SEBS) and polyarylpyridine (PAPY) under the condition of no crosslinking agent, and simultaneously carries out crosslinking and quaternization reaction, thereby not only improving the dimensional stability and mechanical strength of the obtained material, but also effectively improving quaternization efficiency. It is also an object of the present invention to provide some specific applications of the above-mentioned polymers and/or anion exchange membranes or the above-mentioned preparation methods.

The invention firstly provides the following technical scheme:

a quaternized crosslinked polymer comprising a formula as shown in formula (I):

wherein the content of the first and second substances,

ar is selected from aromatic hydrocarbon radicals;

R₃is selected from

R₂＝R₃Or selected from H, methyl or ethyl;

wherein (x + y) is 0.18-0.26, and (m + n) is 0.74-0.82, 0< y/(x + y) is less than or equal to 1, 0< p is less than or equal to 1, and 0< q is less than or equal to 1;

R₁any one of the following structures:

wherein n1 is 1-7, and n2 is 1-3.

According to some preferred embodiments of the invention, the aromatic hydrocarbon group is selected from any of the following structures:

the invention further provides a preparation method of the quaternized cross-linked polymer, which comprises the following steps:

performing chloromethylation reaction on the hydrogenated styrene-butadiene block copolymer to obtain a chloromethylated first copolymer;

reacting the chloromethylated block copolymer with a quaternary ammonium reactant to obtain a second copolymer containing a quaternary ammonium group branched chain, wherein the quaternary ammonium reactant is alkyl tertiary amine and/or a multi-cationic side chain;

copolymerizing aromatic hydrocarbon and 4-acetylpyridine to obtain a polyarylpyridine copolymer;

and carrying out heating reaction on the polyarylpyridine copolymer and the second copolymer to obtain the quaternized crosslinking polymer.

According to some preferred embodiments of the present invention, the quaternary ammonium reactant is selected from the group consisting of N, N' -pentamethyl-1-amino-6-ammonium iodide.

According to some preferred embodiments of the present invention, the aromatic hydrocarbon is selected from one or more of biphenyl, p-terphenyl, m-terphenyl and quaterphenyl.

According to some preferred embodiments of the invention, the preparation method specifically comprises:

(1) synthesis of the first copolymer:

dissolving hydrogenated styrene-butadiene block copolymer, adding chloromethylation reagent and catalyst into the solution to carry out chloromethylation reaction, and extracting the product to obtain the first copolymer, wherein the reaction temperature is 0-60 ℃, and/or the reaction time is 2-72 h;

(2) synthesis of the polyarylpyridine copolymer:

adding aromatic hydrocarbon and 4-acetylpyridine into dichloromethane, adding a protonation reagent and a catalyst into the mixed solution, reacting at room temperature until the solution becomes viscous, and extracting a product to obtain the polyarylpyridine copolymer;

(3) synthesis of the second copolymer:

dissolving the obtained first copolymer, adding tertiary amine containing 4-16 alkyl chains with carbon atoms or polycation with 2-6 carbon atoms in a side chain into the solution of the first copolymer for reaction at the temperature of 20-60 ℃ and/or for 6-72 hours to obtain a second copolymer;

(4) synthesis of the quaternized cross-linked polymer:

and mixing the polyarylpyridine copolymer and the second copolymer to form a homogeneous mixed solution, heating and reacting to obtain the crosslinking copolymer.

According to some preferred embodiments of the present invention, the reaction time in (2) is 2 to 72 hours,

according to some preferred embodiments of the present invention, the solvent used for the dissolution in (1) is selected from one or more of chloroform, tetrahydrofuran, toluene, and dichloroethane.

According to some preferred embodiments of the present invention, the chloromethylation reagent in (1) is selected from one or more of 1, 4-dichloromethoxybutane, 1,3, 5-trioxahexacyclo, trimethylchlorosilane, and/or the catalyst thereof is selected from anhydrous tin tetrachloride.

According to some preferred embodiments of the invention, the protonating agent in (2) is selected from trifluoromethanesulfonic acid, and/or the catalyst thereof is selected from trifluoroacetic acid.

According to some preferred embodiments of the present invention, the solvent used for the dissolution in (3) is selected from chloroform.

According to some preferred embodiments of the present invention, the mixed solution in (4) contains N, N-dimethylformamide as a solvent.

According to some preferred embodiments of the present invention, the extracting in (1) comprises: and adding a first precipitator into the reacted system, and then carrying out first purification on the separated substances to obtain the first copolymer.

According to some preferred embodiments of the present invention, the extracting in (2) comprises: and adding a second precipitator into the reacted system, and then carrying out second purification on the separated substances to obtain the polyarylpyridine copolymer.

According to some preferred embodiments of the present invention, the first precipitating agent is selected from one or more of methanol, ethanol or ethyl acetate.

According to some preferred embodiments of the present invention, the second precipitating agent is selected from one or more of water, methanol, ethanol or NaOH, Na₂CO₃、NaHCO₃In solutionOne or more of them.

According to some preferred embodiments of the invention, the first purification comprises: adding tetrahydrofuran and/or an alcohol solution to the precipitated substance to purify the same.

According to some preferred embodiments of the invention, the second purification comprises: separating, washing and drying the precipitated substances, dissolving the precipitated substances in a second solvent, adding a third precipitating agent, separating and drying the precipitated substances again, wherein the second solvent is selected from one or more of dichloromethane, trichloromethane, tetrahydrofuran, 1-methyl-2-pyrrolidone and cyclohexanone, and/or the third precipitating agent is selected from methanol and/or ethanol.

According to some preferred embodiments of the present invention, in the solution obtained by dissolving the hydrogenated styrene-butadiene block copolymer, the ratio of the mass of the block copolymer to the volume of the solvent is 1:15 to 1:60 g/mL.

According to some preferred embodiments of the present invention, the mass ratio of the hydrogenated styrene-butadiene block copolymer to the catalyst thereof is from 800:1 to 400: 1.

According to some preferred embodiments of the present invention, the mass ratio of the hydrogenated styrene-butadiene block copolymer to the chloromethylating agent is from 300:1 to 1: 2.

According to some preferred embodiments of the present invention, the chloromethylating agent is used in an amount of 1.0 to 2.0 times its theoretical calculated amount.

According to some preferred embodiments of the invention, the concentration of the aromatic hydrocarbon in dichloromethane is between 0.1 and 1 mol/L.

According to some preferred embodiments of the invention, the molar ratio of the 4-acetylpyridine to the aromatic hydrocarbon is from 1:1 to 1.5: 1.

According to some preferred embodiments of the invention, the molar ratio of the 4-acetylpyridine to its catalyst is from 1:5 to 1: 10.

According to some preferred embodiments of the invention, the molar ratio of the 4-acetylpyridine to the protonating agent is from 1:5 to 1: 20.

According to some preferred embodiments of the present invention, the ratio of the mass of the first copolymer to the volume of the solvent in the solution resulting from the dissolution of the resulting first copolymer is from 1:15 to 1:50 g/mL.

According to some preferred embodiments of the invention, the ratio of the mass of the polyarylpyridine to the volume of the solvent is from 1:300 to 1:600 g/mL.

According to some preferred embodiments of the present invention, the volume ratio of the solvent to the homogeneous mixed solution in the homogeneous mixed solution is 1:10 to 2: 3.

The invention further discloses an anion exchange membrane which is obtained by molding the quaternized cross-linked polymer and/or the quaternized cross-linked polymer prepared by the preparation method.

The invention further discloses an anion exchange membrane which is obtained by molding the quaternized cross-linked polymer and/or the quaternized cross-linked polymer prepared by the preparation method and then reacting the molded quaternized cross-linked polymer with an alkali solution.

The invention further discloses a preparation method of the anion exchange membrane, which comprises the following steps:

and (3) casting the solution of the cross-linked copolymer into a film, and then drying and cooling to obtain the anion exchange membrane.

Preferably, it further comprises:

soaking the membrane material obtained by the membrane formation in an organic solution of halogenated alkane.

More preferably, the halogenated alkane is selected from methyl iodide and/or ethyl bromide, and/or the solvent of the organic solution is selected from ethanol, and the solute mass fraction of the solution is 10-50%.

The invention further discloses a preparation method of the anion exchange membrane, which comprises the following steps:

and (2) forming a film by using the solution of the cross-linked copolymer, soaking the film in a sodium hydroxide and/or potassium hydroxide solution for 12-60h, and washing the film to be neutral to obtain the anion exchange membrane.

Preferably, it further comprises:

soaking the membrane material obtained by the membrane formation in an organic solution of halogenated alkane, then washing, drying and then soaking in the sodium hydroxide and/or potassium hydroxide solution.

According to some preferred embodiments of the invention, the concentration of the sodium hydroxide and/or potassium hydroxide solution is 0.1 to 3 mol/L.

The invention takes the SEBS polymer as the substrate, and the functionalized SEBS and the PAPY are crosslinked to obtain the quaternized crosslinked polymer, and the further obtained crosslinked anion-exchange membrane shows a controllable microphase separation structure, has lower swelling, excellent size stability and chemical stability, and has wide application prospect in alkaline anion-exchange membrane fuel cells.

In the preparation of the quaternized cross-linked polymer and/or anion exchange membrane, chloromethylated SEBS can be modified by different cations, and can be quaternized again in the casting film forming process after cross-linking, the cross-linked structure of the quaternized cross-linked polymer and/or anion exchange membrane contains SEBS and PAPY polymer frameworks with different mechanical properties, so that the size stability and the mechanical properties of AEMs can be synergistically enhanced by integrating the characteristics of the two polymers such as elasticity and toughness, the main chains of the SEBS and the PAPY polymer in the product are free of heteroatoms, an all-carbon chain framework is formed, and good chemical stability is achieved.

All the membrane materials prepared by the preparation method of the invention have uniform and flat surfaces, and the occurrence of the gel phenomenon can be completely avoided by controlling the type of the solvent and the reaction time in some more specific embodiments.

The crosslinked films prepared according to the invention have a low swelling (< 15% at 80 ℃) and good dimensional stability.

In some embodiments, the preparation method of the invention can obtain flexible films with different mechanical strengths by controlling the feeding ratio of the SEBS to the PAPY, and can effectively prevent the phenomena of edge failure and the like in practical application of the fuel cell.

In some embodiments, the preparation method of the invention can realize rapid conduction of OH-ions in the obtained exchange membrane by adjusting the side chain structure.

The method for preparing the anion exchange membrane is simple and efficient, the raw materials are easy to obtain and pollution-free, and the prepared alkaline membrane has good comprehensive performance and can be applied to the field of fuel cells.

Drawings

FIG. 1 is a graph comparing ATR-FTIR spectra of examples 1 to 4 and comparative example 1.

FIG. 2 is a phase comparison graph of AFM of the products obtained in examples 1 to 4 (ratio: 1. mu. m.times.1 μm).

FIG. 3 is a graph comparing the swelling of the products obtained in examples 2 to 4 with that of comparative example 1.

FIG. 4 is a graph comparing the mechanical properties of the products obtained in example 1, example 2 and comparative example 1.

Detailed Description

The present invention is described in detail below with reference to the following embodiments and the attached drawings, but it should be understood that the embodiments and the attached drawings are only used for the illustrative description of the present invention and do not limit the protection scope of the present invention in any way. All reasonable variations and combinations that fall within the spirit of the invention are intended to be within the scope of the invention.

According to the technical scheme of the invention, the preparation method of the specific alkaline quaternized crosslinked polymer anion-exchange membrane comprises the following steps:

(1) preparation of chloromethylated Polymer:

dissolving SEBS polymer in a first solvent, adding a chloromethylation reagent and anhydrous stannic chloride to carry out chloromethylation reaction, controlling the temperature to react for a period of time, adding a first precipitator to separate out, preferably, further purifying by using tetrahydrofuran and an alcohol solution to obtain chloromethylated SEBS (CMSEBS);

(2) synthesis of polyarylpyridine copolymer:

adding aromatic hydrocarbon and 4-acetylpyridine into dichloromethane, stirring and dissolving in ice bath, adding trifluoromethanesulfonic acid and trifluoroacetic acid into the mixed solution as a protonation reagent and a catalyst, reacting at room temperature until the solution becomes viscous, pouring the product into a second precipitator for soaking to remove excessive acid, filtering and washing with water to obtain a light yellow copolymer; drying, dissolving the product in a second solvent, pouring the product into a third precipitator for cleaning, filtering and drying to obtain a pure white fibrous polymer, namely the polyarylpyridine copolymer;

(3) amination of chloromethylated polymers:

dissolving the CMSEBS obtained in the step (1) in chloroform, adding tertiary amine containing 4-16 alkyl chains with carbon atoms or polycation with a side chain of 2-6 carbon atoms into the obtained solution for reaction, and reacting for 6-72h at 20-60 ℃ under the controlled reaction condition to obtain a copolymer solution with quaternary ammonium group branched chains;

(4) preparation of a crosslinked copolymer solution:

dissolving the aromatic pyridine copolymer obtained in the step (2) in the copolymer solution with quaternary ammonium group branched chains obtained in the step (3), adding a proper amount of N, N-dimethylformamide to form a homogeneous mixed solution, heating and reacting to obtain the crosslinking copolymer;

(5) preparing a pyridine quaternized anion exchange membrane:

pouring the copolymer solution obtained in the step (4) into a flat plate mold for direct tape casting to form a film, drying and cooling to room temperature to obtain a crosslinked and quaternized anion exchange membrane;

preferably, in order to enhance the complete quaternization of pyridine, the crosslinked polymer anion exchange membrane can be soaked in an organic solution of halogenated alkane, such as an ethanol solution of the halogenated alkane, in a dark state, and after the reaction is finished, the crosslinked polymer anion exchange membrane is washed and dried by an organic solvent, such as ethanol, so that the quaternized anion exchange membrane is obtained.

(6) Preparation of a basic anion exchange membrane:

and (3) soaking the membrane obtained in the step (5) in an alkali solution such as a sodium hydroxide solution and/or a potassium hydroxide solution at room temperature, and washing with deionized water until the pH value of a washing solution is 7 to obtain the OH-form alkaline anion exchange membrane.

Some preferred embodiments are as follows:

the first solvent is selected from one or more of chloroform, tetrahydrofuran, toluene and dichloroethane.

The chloromethylation reagent is selected from one or more of 1, 4-dichloromethoxybutane, 1,3, 5-trioxahexacyclo and trimethylchlorosilane in any proportion.

The volume ratio of the mass of the SEBS polymer to the first solvent is 1:15-1:60 g/mL.

The mass ratio of the mass of the SEBS polymer to the mass of the catalyst anhydrous tin tetrachloride is 800:1-400: 1.

The mass ratio of the SEBS polymer to the chloromethylation reagent is 300:1-1: 2.

The chloromethylating reagent is present in an amount of 1.0 to 2.0 times the amount required for the theoretical product.

The temperature of the chloromethylation reaction is 0-60 ℃, and/or the reaction time is 2-72 h.

The first precipitator is selected from one or more of methanol, ethanol or ethyl acetate.

The aromatic hydrocarbon is selected from one or more of biphenyl, p-terphenyl, m-terphenyl and quaterphenyl in any proportion.

The concentration of the aromatic hydrocarbon in the dichloromethane is 0.1-1 mol/L.

The molar ratio of the 4-acetylpyridine to the aromatic hydrocarbon is 1:1-1.5: 1.

The molar ratio of the 4-acetylpyridine to the trifluoroacetic acid is 1:5 to 1: 10; and/or the molar ratio of the 4-acetylpyridine to the trifluoromethanesulfonic acid is from 1:5 to 1: 20.

The reaction time of the step (2) is 2-72 h.

The second precipitator 2 is water, methanol, ethanol, NaOH and Na₂CO₃、NaHCO₃And (3) solution.

The second solvent is selected from one or more of dichloromethane, trichloromethane, tetrahydrofuran, 1-methyl-2-pyrrolidone and cyclohexanone.

The third precipitating agent is selected from methanol and/or ethanol.

The volume ratio of the mass of the CMSEBS to the chloroform is 1:15-1:50 g/mL.

The volume ratio of the mass of the polyarylpyridine in the step (4) to the chloroform in the step (3) is 1:300-1:600g/mL, and/or the volume ratio of the N, N-dimethylformamide to the homogeneous mixed solution is 1:10-2: 3.

The reaction temperature in the step (4) is 20-60 ℃, and/or the reaction time is 6-72 h.

The temperature of the film forming in the step (5) is 20-60 ℃, and/or the time of the film forming is 6-48 h.

The halogenated alkane is selected from methyl iodide and/or ethyl bromide, and more preferably, the mass fraction of the ethanol solution is 10-50%.

The temperature of the pyridine quaternization reaction is 20-40 ℃, and/or the reaction time is 12-72 h.

In the step (6), the concentration of the sodium hydroxide and/or potassium hydroxide solution is 0.1-3mol/L, and/or the soaking time is 12-60 h.

Some of the quaternized crosslinked polymers prepared in the above preparation methods were subjected to structural characterization, and confirmed to have the following general structural formula (I):

R₃is selected from

R₂＝R₃Or selected from H, methyl or ethyl;

wherein (x + y) is 0.18-0.26, and (m + n) is 0.74-0.82, 0< y/(x + y) is less than or equal to 1, 0< p is less than or equal to 1, and 0< q is less than or equal to 1;

R₁selected from the following structures:

wherein n1 is 1-7, and n2 is 1-3.

Ar is selected from aromatic hydrocarbon groups, which may be further selected from any of the following structures:

for further understanding of the present invention, the preparation method provided by the present invention is described in more detail by the following specific examples, and the scope of the present invention is not limited by the following examples, and all of the raw materials mentioned in the examples are commercially available.

Example 1

(1) Preparation of chloromethylated Polymer: 4.0g of SEBS powder (A1535) having a styrene content of 58 wt% and a molecular weight of about 70,000 was dissolved in 120mL of commercial chloroform, and a mixed solution of 18.4mL of 1, 4-dichloromethoxybutane and 2.8mL of anhydrous tin tetrachloride was added dropwise from a dropping funnel, and after completion of the addition, the temperature of the oil bath was raised to 55 ℃ and the reaction was stirred for 3 hours. And (3) cooling the reaction solution to room temperature, pouring the reaction solution into 300mL of anhydrous methanol to separate out a light purple solid, dissolving the product in tetrahydrofuran, pouring the product into methanol again to precipitate, and repeating the operation for three times to obtain a white solid. The white solid was dried under vacuum at room temperature for 24 hours to give the CMSEBS polymer.

(2) Preparation of cationic N, N' -pentamethyl-1-amino-6-ammonium iodide: at room temperature, 1.25mL of methyl iodide was slowly dropped into a mixed solution of 21.38mL of N, N, N ', N' -tetramethyl-1, 6-hexanediamine and 120mL of tetrahydrofuran. After 6 hours of reaction in the dark, the precipitated white precipitate was filtered and washed thoroughly with tetrahydrofuran and dried at room temperature to give the pure product.

(3) Preparation of polybiphenylpyridine (PBPY) copolymer: 1g of biphenyl and 1.02g of 4-acetylpyridine were dissolved in 2mL of dichloromethane, and after ice-bath, 0.63mL of trifluoroacetic acid (TFA) and 12mL of trifluoromethanesulfonic acid (TFSA) were added in that order. After magnetically stirring for 2.5h at room temperature, the purple homogeneous solution with a certain viscosity was poured into NaOH solution. Soaking in water and cleaning to obtain light yellow solid. After drying, the product was dissolved in 1-methyl-2-pyrrolidone and precipitated in hot methanol solution. Extracting with methanol, and air drying at room temperature to obtain white fibrous polymer.

(4) Amination of chloromethylated polymers: dissolving 0.5g of CMSEBS obtained in the step (1) in 20mL of chloroform, adding 0.270g of the N, N, N, N ', N' -pentamethyl-1-amino-6-ammonium iodide prepared in the step (2) into the obtained solution for reaction, and stirring the mixture at the temperature of 45 ℃ for about 48 hours to obtain a light yellow copolymer solution.

(5) Preparation of a crosslinked copolymer solution: and (3) placing 0.0412g of PBPY polymer obtained in the step (3) in the aminated polymer solution obtained in the step (4) for dissolving, adding 5mLN, N-dimethylformamide to form a homogeneous mixed solution, and stirring and reacting at the temperature of 55 ℃ for about 48 hours to obtain a yellow cross-linked copolymer solution.

(6) Preparation of a basic anion exchange membrane: and (5) casting the homogeneous transparent solution obtained in the step (5) into a film, drying, and cooling to room temperature to obtain the crosslinked and quaternized anion-exchange membrane. Soaking the obtained membrane in 2mol/LNaOH solution, washing with deionized water until the pH value of the washing solution is 7 to obtain OH^-A basic anion exchange membrane in the form.

The resulting product was tested to have the following structural formula:

the degree of crosslinking of PBPY and SEBS was 10%, i.e., y-0.2676 × 10%, x-0.2676 × 90%, m-0.3479, and n-0.3845.

Comparative example 1

(1) Preparation of chloromethylated Polymer: the same as in example 1.

(2) Preparation of cationic N, N' -pentamethyl-1-amino-6-ammonium iodide: the same as in example 1.

(3) Amination of chloromethylated polymers: dissolving 0.5g of CMSEBS obtained in the step (1) in 20mL of chloroform, adding 0.3g of the N, N, N, N ', N' -pentamethyl-1-amino-6-ammonium iodide prepared in the step (2) into the obtained solution for reaction, and stirring and reacting at 45 ℃ for about 48 hours to obtain a light yellow copolymer solution.

(4) Preparation of a basic anion exchange membrane: pouring the solution obtained in the step (3) into a mould for casting to form a film, drying and cooling to room temperature to obtain Cl^-Formal anion exchangeReplacing the membrane, soaking the obtained membrane in 2mol/LNaOH solution and washing with deionized water to obtain OH^-A basic anion exchange membrane in the form.

The resulting product was tested to have the following structural formula:

wherein, x is 0.2676, m is 0.3479, and n is 0.3845.

Example 2

(1) Preparation of chloromethylated Polymer: the same as in example 1.

(2) Preparation of cationic N, N' -pentamethyl-1-amino-6-ammonium iodide: the same as in example 1.

(3) Preparation of polybiphenylpyridine (PBPY) copolymer: the same as in example 1.

(4) Amination of chloromethylated polymers: dissolving 0.5g of CMSEBS obtained in the step (1) in 20mL of chloroform, adding 0.240g of the N, N, N, N ', N' -pentamethyl-1-amino-6-ammonium iodide prepared in the step (2) into the obtained solution for reaction, and stirring the mixture at the temperature of 45 ℃ for about 48 hours to obtain a light yellow copolymer solution.

(5) Preparation of a crosslinked copolymer solution: 0.0823g of PBPY polymer obtained in the step (3) is placed in the aminated polymer solution obtained in the step (4) to be dissolved, 5ml of N-dimethylformamide is added to form a homogeneous mixed solution, and the homogeneous mixed solution is stirred and reacted for about 48 hours at the temperature of 55 ℃ to obtain a yellow cross-linked copolymer solution.

(6) Preparation of a basic anion exchange membrane: and (5) casting the homogeneous transparent solution obtained in the step (5) into a film, drying, and cooling to room temperature to obtain the crosslinked and quaternized anion-exchange membrane. Soaking the obtained membrane in 2mol/LNaOH solution, washing with deionized water until the pH value of the washing solution is 7 to obtain OH^-A basic anion exchange membrane in the form.

The resulting product was tested to have the following structural formula:

the degree of crosslinking of PBPY and SEBS was 20%, i.e., y-0.2676 × 20%, x-0.2676 × 80%, m-0.3479, and n-0.3845.

Example 3

(1) Preparation of chloromethylated Polymer: 4.0g of SEBS powder (A1535) having a styrene content of 58% by weight and a molecular weight of approximately 70,000 were dissolved in 120mL of commercial trichloromethane, and 28mL of trimethylchlorosilane (220.88mmol) and 6.72g of 1,3, 5-trioxane (74.60mmol) were slowly added. 3.3mL of anhydrous tin tetrachloride (28.20mmol) was added dropwise to the flask at 0 ℃ and stirred in an ice bath for 30min, followed by reaction at room temperature for 24 h. The product precipitated in ethanol solution, precipitating out a pale purple solid. The product was dissolved in tetrahydrofuran and then poured into ethanol again for precipitation, and the operation was repeated three times, and the solid became white. The white solid was dried under vacuum at room temperature for 24 hours to give the CMSEBS polymer.

(2) Preparation of cationic N, N' -pentamethyl-1-amino-6-ammonium iodide: the same as in example 1.

(3) Preparation of polybiphenylpyridine (PBPY) copolymer: the same as in example 1.

(4) Amination of chloromethylated polymers: the same as in example 2.

(5) Preparation of a crosslinked copolymer solution: 0.0862g of PBPY polymer obtained in the step (3) was dissolved in the aminated polymer solution obtained in the step (4), and 5ml of N, N-dimethylformamide was added to form a homogeneous mixed solution, which was then stirred at 55 ℃ for about 48 hours to obtain a yellow crosslinked copolymer solution.

(6) Preparing a pyridine quaternized anion exchange membrane: pouring the copolymer solution obtained in the step (5) into a flat plate mold for direct tape casting to form a film, drying, cooling to room temperature to obtain a crosslinked and quaternized anion-exchange membrane, soaking the crosslinked polymer anion-exchange membrane in an ethanol solution (with the mass fraction of 30%) of methyl iodide in a dark state in order to ensure complete quaternization of pyridine, and washing and drying with ethanol after the reaction is finished to obtain the pyridine quaternized anion-exchange membrane.

(7) Preparation of a basic anion exchange membrane: placing the film obtained in the step (6) at room temperature in a 2mol/LN atmosphereSoaking in aOH solution, washing with deionized water until the pH of the washing solution is 7 to obtain OH^-A basic anion exchange membrane in the form.

The resulting product was tested to have the following structural formula:

wherein, y is 0.2676 × 20%, x is 0.2676 × 80%, m is 0.3479, n is 0.3845, p is 0.2, and q is 0.8.

Example 4

(1) Preparation of chloromethylated Polymer: the same as in example 3.

(2) Preparation of polyparaterphenyl pyridine (PTPY) copolymer: 1g of p-terphenyl and 0.684g of 4-acetylpyridine are dissolved in 2mL of dichloromethane and, after ice-cooling, 0.21mL of trifluoroacetic acid (TFA) and 5mL of trifluoromethanesulfonic acid (TFSA) are added in succession. After magnetic stirring at room temperature for 5h, the purple homogeneous solution with a certain viscosity was poured into NaOH solution. Soaking in water and cleaning to obtain light yellow solid. After drying, the product was dissolved in 1-methyl-2-pyrrolidone and precipitated in hot ethanol solution. Extracting with ethanol under heating, and air drying at room temperature to obtain white fibrous polymer.

(3) Amination of chloromethylated polymers: 0.5g of CMSEBS obtained in the step (1) was dissolved in 20mL of chloroform, and 0.345g of commercially available cetyldimethyl tertiary amine was added to the resulting solution to carry out a reaction, and the reaction was stirred at 45 ℃ for about 48 hours to obtain a pale yellow copolymer solution.

(4) Preparation of a crosslinked copolymer solution: 0.111g of the PTPY polymer obtained in the step (2) was dissolved in the aminated polymer solution obtained in the step (3), and 10ml of N, N-dimethylformamide was added to form a homogeneous mixed solution, which was then stirred at 55 ℃ for about 48 hours to obtain a yellow crosslinked copolymer solution.

(5) Preparation of a basic anion exchange membrane: and (4) pouring the copolymer solution obtained in the step (4) into a flat plate mold for direct tape casting to form a film, drying and cooling to room temperature to obtain the crosslinked and quaternized anion exchange membrane. Soaking the obtained membrane in 2mol/LNaOH solution, and removingRinsing with water until pH of the washing solution is 7 to obtain OH^-A basic anion exchange membrane in the form.

The resulting product was tested to have the following structural formula:

the degree of crosslinking of PTPY with SEBS was 20%, i.e., y-0.2676 × 20%, x-0.2676 × 80%, m-0.3479, and n-0.3845.

Using a Nicolet 6700 spectrometer at 4000-^-1Fourier Transform Infrared (FTIR) spectra of examples 1 to 4 and comparative example 1 were measured in the wave number range of (a), and the results are shown in fig. 1. It can be seen that the introduction of the quaternary ammonium salt and the Menshutkin reaction occurred after grafting the cation and PAPY such that it was at 1220cm^-1To obtain quaternary ammonium peak. Comparative example 1 at 1632cm^-1The unique peak of (A) is related to the C-N stretch of the aminated product, and due to the occurrence of the cross-linking reaction, examples 1 to 4 are at 1643cm^-1A new peak appears, which is a characteristic peak of C-N of the quaternized pyridine ring. By observing the characteristic signals in FIG. 1, it can be judged that the quaternary amination reaction proceeded smoothly.

To observe the ion cluster morphology of the film samples, examples 1-4 were tested in tapping mode with an atomic force microscope (AFM, DI Multimode V, Bruker Co.). As can be seen from FIG. 2, examples 1, 2 and 3, in which dicationic side chains were grafted, all had excellent microphase separation effect, and there was no significant difference in AFM phase diagram. The comparison shows that the microphase separation form of the embodiment 3 is more obvious, which shows that the polymer membrane enhances the complete quaternization of pyridine and increases the ion transmission sites after being soaked in the organic solution of halogenated alkane. The microphase separation of examples 1 to 3 was better than that of example 4, which demonstrates that controllable microphase separation can be achieved by controlling the kind of side chain and the type of crosslinking.

The anion exchange membranes prepared in examples 2 to 4 and comparative example 1, which have a certain size, were cut, soaked in distilled water, soaked at a constant temperature for 5 hours, taken out, the water on the membrane surface was removed by filter paper, the side length was recorded, and the swelling ratio of the membrane samples at different temperatures was recorded, and the results are shown in fig. 3. As can be seen from fig. 3, the swelling ratios of all membranes increased with increasing temperature, but the swelling ratios of examples 2 to 4 were significantly decreased relative to comparative example 1, which indicates that the present invention forms an intermingled and crosslinked polymer backbone, which can effectively suppress dimensional expansion, contributing to the improvement of the dimensional stability of the anion exchange membrane.

The anion exchange membranes prepared in examples 1, 2 and 1 were characterized for mechanical properties using a universal tensile tester, and the change in tensile strength (Ts) and elongation at break (Eb) of the membranes during the test was recorded. Before testing, all film samples were cut into 4mm by 50mm dumbbells with a test speed of 10.0mm/min, and the test results are shown in fig. 4. It can be seen from the figure that compared with comparative example 1, the products obtained in examples 1 and 2 of the present invention have significantly increased tensile strength, and when the degree of crosslinking reaches 20%, that is, the product obtained in example 2 has a tensile strength Ts of 19.96MPa and an elongation at break Eb of 78.54%, which indicates that the introduction of the polyarylpyridine is beneficial to improving the mechanical properties of the membrane and the application of the fuel cell.

Based on the method, the polymer quaternized crosslinked anion-exchange membrane prepared by the invention shows a controllable microphase separation structure, lower swelling, excellent dimensional stability and chemical stability, and has wide application prospect in alkaline anion-exchange membrane fuel cells.

The above detailed description is intended to illustrate the objects, aspects and advantages of the present invention, and it should be understood that the above detailed description is only exemplary of the present invention and is not intended to limit the scope of the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.