CN105789669B - A kind of poly- imino group benzimidazole high temperature proton exchange film of phosphonic acids doping cross-linking sulfonation and preparation method thereof - Google Patents

Abstract

The invention relates to a phosphonic acid-doped cross-linked sulfonated polyiminobenzimidazole high-temperature proton exchange membrane and a preparation method thereof. The proton exchange membrane is prepared by the following method: 1) under a nitrogen atmosphere, diamino di Dissolve sulfonic acid in a solvent to obtain a diaminodisulfonic acid solution, add benzidine, aminophenylbenzimidazole and naphthalene tetracarboxylic dianhydride to the diaminodisulfonic acid solution, stir well at room temperature, heat to react, and then cool naturally to room temperature, then add diluent, stir well, filter, wash and dry the filtered solid matter to obtain sulfonated polyiminobenzimidazole; 2) dissolve sulfonated polyiminobenzimidazole in dimethyl sulfoxide , to obtain a solution, then add dibromodiphenyl ether, mix evenly, and react to obtain a high-temperature proton exchange membrane; 3) soak the high-temperature proton exchange membrane in an aqueous solution of aminotrimethylene phosphonic acid, wash again, and heat to react to obtain a phosphonic acid-doped Hybridized bisulfonated polyiminobenzimidazole high temperature proton exchange membrane.

Description

A kind of phosphonic acid doped cross-linked sulfonated polyiminobenzimidazole high temperature proton exchange membrane and its its preparation method

technical field

The invention belongs to the technical field of fuel cells, and in particular relates to a phosphonic acid-doped cross-linked sulfonated polyiminobenzimidazole high-temperature proton exchange membrane and a preparation method thereof.

Background technique

Proton exchange membrane fuel cell is a new type of fuel cell that converts fuel chemical energy into electrical energy. It has the advantages of no noise, no pollution and high efficiency. Proton exchange membrane is the key material of proton exchange membrane fuel cell. At present, DuPont's nafion membrane is widely used. The transfer of protons mainly depends on the sulfonic acid group in the molecule, but the sulfonic acid group has high requirements on the environmental humidity. The proton conductivity decreases sharply under high temperature and low humidity conditions, and the use environment of proton exchange membranes requires high mechanical properties, high temperature resistance, and chemical resistance, and requires stable and efficient proton conductivity under high temperature and low humidity conditions. Therefore, it is of far-reaching significance to synthesize new proton exchange membranes that can work in high temperature and low humidity environments.

Phosphonic acid is a kind of amphoteric acid, which can be used as a proton donor or a proton acceptor. The phosphoric acid group has self-dissociation, and it can still carry out proton transfer even under high temperature conditions. Therefore, high-temperature proton exchange based on phosphonic acid group Membranes have become a hot research topic at present. Phosphonic acid mainly has two states in the high temperature proton exchange membrane, one is to graft the phosphoric acid group to the main chain of the molecule through chemical bonding, and the other is to make the phosphoric acid group and the molecule The atoms on the inner main chain form some kind of interaction force to achieve the effect of transferring protons. However, the currently prepared phosphate-based proton exchange membranes still have problems such as poor thermal stability, low proton conductivity, and inability to be used under high-temperature anhydrous conditions.

Contents of the invention

The technical problem to be solved by the present invention is to provide a phosphonic acid-doped cross-linked sulfonated polyiminobenzimidazole high-temperature proton exchange membrane and a preparation method thereof. The main chain of the proton exchange membrane is The structure contains a benzene ring structure, which has good toughness and thermal stability (high temperature resistance up to 262-283°C, tensile strength up to 51.7-67.6MPa), and still has high proton conductivity under high temperature and anhydrous conditions ( The proton conductivity reaches 0.058-0.073S/cm under dry and anhydrous conditions at 180°C).

In order to solve the problems of the technologies described above, the technical solution provided by the invention is:

A high-temperature proton exchange membrane of phosphonic acid-doped cross-linked sulfonated polyiminobenzimidazole is provided, which is prepared by the following method:

1) Under a nitrogen atmosphere, diaminodisulfonic acid is dissolved in a solvent to obtain a diaminodisulfonic acid solution, and benzidine, aminophenylbenzimidazole and naphthalenetetracarboxylic dianhydride are added to the diaminodisulfonic acid solution , stir well at room temperature, heat at 70-90°C for 5-6h, then heat at 165-180°C for 18-24h, cool to room temperature naturally, then add diluent, stir well, filter, and wash the filtered solid matter , drying to obtain sulfonated polyiminobenzimidazole;

2) Dissolve the sulfonated polyiminobenzimidazole obtained in step 1) in dimethyl sulfoxide to obtain a sulfonated polyiminobenzimidazole solution, and then add dibromodiphenyl ether to make the amino group and benzyl bromide mole in the solution The ratio is 1:1, after mixing evenly, react at 75-80°C for 18-24h, then heat at 150-160°C for 2-4h to obtain a high-temperature proton exchange membrane;

3) Soak the high-temperature proton exchange membrane obtained in step 2) in an aqueous solution of aminotrimethylene phosphonic acid for 36-48 hours, then wash with deionized water, then heat at 70-90°C for 5-6h, and finally heat at 150-160°C After 18-24 hours, a phosphonic acid-doped cross-linked sulfonated polyiminobenzimidazole high-temperature proton exchange membrane was obtained.

According to the above scheme, the diaminodisulfonic acid in step 1) is 4,4'-diamino-2,2'-disulfonic acid, 4,4'-diaminostilbene-2,2'-disulfonic acid One of acid, 4,4'-diaminodiphenyl ether-2,2'-disulfonic acid.

According to the above scheme, the solvent in step 1) is a mixed solvent obtained by mixing m-cresol and triethylamine at a volume ratio of 18-25:1; the concentration of the diaminodisulfonic acid solution is 0.05-0.12mol/L.

According to the above scheme, the benzidine in step 1) is 3,3'-bis(4-sulfonic acid phenyl)benzidine; the aminophenyl-containing benzimidazole is 6,6'-bis[2-(4 -aminophenyl)]benzimidazole; the mol ratio of described benzidine, aminophenyl benzimidazole and naphthalene tetranic dianhydride is 1.4-1.8:1:2-2.6, and diaminodisulfonic acid and containing The molar ratio of aminophenylbenzimidazole is 1:1.

According to the above scheme, the diluent in step 1) is a mixture of m-cresol and acetone, wherein the volume ratio of m-cresol and acetone is 1:5.

Preferably, the mass concentration of the sulfonated polyiminobenzimidazole solution in step 2) is 6%.

According to the above scheme, the concentration of the aminotrimethylene phosphonic acid aqueous solution in step 3) is 0.08-0.12mol/L.

The present invention also includes the preparation method of above-mentioned high-temperature proton exchange membrane, and its steps are as follows:

1) Under a nitrogen atmosphere, diaminodisulfonic acid is dissolved in a solvent to obtain a diaminodisulfonic acid solution, and benzidine, aminophenylbenzimidazole and naphthalenetetracarboxylic dianhydride are added to the diaminodisulfonic acid solution , stir well at room temperature, heat at 70-90°C for 5-6h, then heat at 165-180°C for 18-24h, cool to room temperature naturally, then add diluent, stir well, filter, and wash the filtered solid matter , drying to obtain sulfonated polyiminobenzimidazole;

2) Dissolve the sulfonated polyiminobenzimidazole obtained in step 1) in dimethyl sulfoxide to obtain a sulfonated polyiminobenzimidazole solution, and then add dibromodiphenyl ether to make the amino group and benzyl bromide mole in the solution The ratio is 1:1, after mixing evenly, react at 75-80°C for 18-24h, then heat at 150-160°C for 2-4h to obtain a high-temperature proton exchange membrane;

3) Soak the high-temperature proton exchange membrane obtained in step 2) in an aqueous solution of aminotrimethylene phosphonic acid for 36-48 hours, then wash with deionized water, then heat at 70-90°C for 5-6h, and finally heat at 150-160°C After 18-24 hours, a phosphonic acid-doped cross-linked sulfonated polyiminobenzimidazole high-temperature proton exchange membrane was obtained.

The cross-linked sulfonated poly(iminobenzimidazole) with a benzene ring structure in the main chain is a material with good physical properties. The benzene ring and benzene-like ring structure on the main chain make the polymer have high toughness. Good thermal stability and oxidation resistance. The main chain of the molecule contains multiple N atoms, which can form a hydrogen bond network with the phosphate group, which is beneficial to the attachment of phosphonic acid and the transfer of protons. Benzimidazole polymers have both electron-donating and electron-withdrawing properties, and the same is true for protons. Protons can easily complete the transfer of such substances in the process of proton transfer.

The present invention uses 6,6'-bis[2-(4-aminophenyl)]benzimidazole to provide N-H bonds for the molecular chain of sulfonated polyiminobenzimidazole, and after adding the cross-linking agent dibromodiphenyl ether, The bromine in the dibromodiphenyl ether has a substitution reaction with the hydrogen on the N-H bond in the sulfonated polyiminobenzimidazole, and the following reaction occurs, so that two sulfonated polyiminobenzimidazole molecules are crossed by dibromodiphenyl ether Linked together:

The beneficial effects of the present invention are: 1. The preparation method of the present invention is simple, the experimental conditions are not high and the experimental process is easy to operate; 2. The phosphonic acid doped cross-linked sulfonated polyiminobenzimidazole high-temperature proton exchange membrane prepared by the present invention The main chain contains a benzene ring structure, so it has good mechanical properties, high temperature resistance and oxidation resistance (high temperature resistance up to 262-283°C, tensile strength up to 51.7-67.6MPa), and there are not only sulfonic acid groups in the molecular side chain There are also phosphonic acid groups. Phosphonic acid forms a continuous hydrogen bond network with N on the main chain of the molecule, which makes the proton membrane have high proton conductivity. Even at 180 ° C and anhydrous conditions, the proton conductivity remains Up to 0.058-0.073S/cm. Therefore, the cross-linked sulfonated poly(iminobenzimidazole) proton exchange membrane based on phosphonic acid groups prepared by the present invention has broad application prospects.

Detailed ways

In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below in conjunction with examples.

The raw materials used in the following examples are all analytically pure, with a purity greater than 98 wt%.

Example 1

Preparation of a phosphonic acid-doped cross-linked sulfonated polyiminobenzimidazole high-temperature proton exchange membrane, the steps are as follows:

1) Add 1.8mmol of 4,4'-diaminodiphenyl ether-2,2'-disulfonic acid into a mixed solvent of 15mL of m-cresol and 0.8mL of triethylamine, blow in nitrogen gas, and stir thoroughly until diaminodiphenyl ether Dissolve all the sulfonic acid to obtain diaminodisulfonic acid solution, add 1.4mmol 3,3'-bis(4-sulfonic acid phenyl)benzidine, 1mmol 6,6'-bis[2- (4-Aminophenyl)]benzimidazole and 2mmol 1,4,5,8-naphthalene tetracarboxylic dianhydride, stirred at room temperature for 10min, heated at 80°C for 5h, then heated at 180°C for 24h, and cooled naturally to room temperature, then add 12mL of m-cresol and 100mL of acetone as diluents, stir well and filter, filter out the fibrous precipitate, wash the precipitate with acetone for 3-5 times, and then vacuum dry at 80°C for 10h to obtain Sulfonated polyiminobenzimidazole;

2) dissolving the sulfonated polyiminobenzimidazole obtained in step 1) in dimethyl sulfoxide to obtain a sulfonated polyiminobenzimidazole solution with a mass concentration of 6%, and then adding 1 mmol dibromodiphenyl ether to make benzene The molar ratio of the amino group in imidazole to the benzyl bromide in dibromodiphenyl ether is 1:1. After mixing evenly, pour it into a polytetrafluoroethylene mold, heat at 80°C for 24h, and then heat at 160°C for 3h. It is fully cross-linked to obtain a high-temperature proton exchange membrane;

3) Put the high-temperature proton exchange membrane obtained in step 2) into a 0.1mol/L aqueous solution of aminotrimethylene phosphonic acid, soak it at room temperature for 48 hours, then take it out, wash it with deionized water, and heat it at 80°C for 5 hours , and then heated at 160° C. for 24 h to obtain a phosphonic acid-doped cross-linked sulfonated polyiminobenzimidazole high-temperature proton exchange membrane.

After testing, the linear swelling coefficient of the proton exchange membrane prepared in this example is 6.24% at room temperature, indicating that the exchange membrane has good stability in water, the thermal stability temperature is 265°C, the tensile strength is 52.1MPa, and the ion exchange capacity is 0.80 mmol/g, indicating that the content of phosphonic acid in the exchange membrane is high, and the conductivity measured at 180°C under anhydrous conditions is 0.058S/cm.

Example 2

Preparation of a phosphonic acid-doped cross-linked sulfonated polyiminobenzimidazole high-temperature proton exchange membrane, the steps are as follows:

1) Add 1.8mmol of 4,4'-diaminodiphenyl ether-2,2'-disulfonic acid into a mixed solvent of 15mL of m-cresol and 0.8mL of triethylamine, blow in nitrogen gas, and stir thoroughly until diaminodiphenyl ether Dissolve all the sulfonic acid to obtain diaminodisulfonic acid solution, add 1.4mmol 3,3'-bis(4-sulfonic acid phenyl)benzidine, 1mmol 6,6'-bis[2- (4-Aminophenyl)]benzimidazole and 2.2mmol 1,4,5,8-naphthalene tetracarboxylic dianhydride, fully stirred at room temperature, first heated at 80°C for 5h, then heated at 180°C for 24h, naturally Cool to room temperature, then add 12mL of m-cresol and 100mL of acetone as diluents, stir well and filter, filter out the fibrous precipitate, wash the precipitate with acetone, and then vacuum dry to obtain sulfonated polyiminobenzimidazole;

2) dissolving the sulfonated polyiminobenzimidazole obtained in step 1) in dimethyl sulfoxide to obtain a sulfonated polyiminobenzimidazole solution with a mass concentration of 6%, and then adding 1 mmol dibromodiphenyl ether to make benzene The molar ratio of the amino group in imidazole to the benzyl bromide in dibromodiphenyl ether is 1:1. After mixing evenly, pour it into a polytetrafluoroethylene mold, heat at 80°C for 24h, and then heat at 160°C for 3h. It is fully cross-linked to obtain a high-temperature proton exchange membrane;

3) Put the high-temperature proton exchange membrane obtained in step 2) into a 0.1mol/L aqueous solution of aminotrimethylene phosphonic acid, soak it at room temperature for 48 hours, then take it out, wash it with deionized water, and heat it at 80°C for 5 hours , and then heated at 160° C. for 24 h to obtain a phosphonic acid-doped cross-linked sulfonated polyiminobenzimidazole high-temperature proton exchange membrane.

After testing, the linear swelling coefficient of the proton exchange membrane prepared in this example is 8.34% at room temperature, the thermal stability temperature is 270°C, the tensile strength is 53.1MPa, the ion exchange capacity is 0.90mmol/g, and it is anhydrous at 180°C. The conductivity measured under the conditions is 0.061S/cm.

Example 3

Preparation of a phosphonic acid-doped cross-linked sulfonated polyiminobenzimidazole high-temperature proton exchange membrane, the steps are as follows:

1) Add 1.8mmol of 4,4'-diaminodiphenyl ether-2,2'-disulfonic acid into a mixed solvent of 15mL of m-cresol and 0.8mL of triethylamine, blow in nitrogen gas, and stir thoroughly until diaminodiphenyl ether Dissolve all the sulfonic acid to obtain diaminodisulfonic acid solution, add 1.4mmol 3,3'-bis(4-sulfonic acid phenyl)benzidine, 1mmol 6,6'-bis[2- (4-Aminophenyl)]benzimidazole and 2.4mmol 1,4,5,8-naphthalene tetracarboxylic dianhydride, fully stirred at room temperature, first heated at 80°C for 5h, then heated at 180°C for 24h, naturally Cool to room temperature, then add 12mL of m-cresol and 100mL of acetone as diluents, stir well and filter, filter out the fibrous precipitate, wash the precipitate with acetone, and then vacuum dry to obtain sulfonated polyiminobenzimidazole;

2) dissolving the sulfonated polyiminobenzimidazole obtained in step 1) in dimethyl sulfoxide to obtain a sulfonated polyiminobenzimidazole solution with a mass concentration of 6%, and then adding 1 mmol dibromodiphenyl ether to make benzene The molar ratio of the amino group in imidazole to the benzyl bromide in dibromodiphenyl ether is 1:1. After mixing evenly, pour it into a polytetrafluoroethylene mold, heat at 80°C for 24h, and then heat at 160°C for 3h. It is fully cross-linked to obtain a high-temperature proton exchange membrane;

3) Put the high-temperature proton exchange membrane obtained in step 2) into a 0.1mol/L aqueous solution of aminotrimethylene phosphonic acid, soak it at room temperature for 48 hours, then take it out, wash it with deionized water, and heat it at 80°C for 5 hours , and then heated at 160° C. for 24 h to obtain a phosphonic acid-doped cross-linked sulfonated polyiminobenzimidazole high-temperature proton exchange membrane.

After testing, the linear swelling coefficient of the proton exchange membrane prepared in this example is 8.96% at normal temperature, the thermal stability temperature is 273°C, the tensile strength is 55.7MPa, the ion exchange capacity is 0.95mmol/g, and it is anhydrous at 180°C. The conductivity measured under the conditions is 0.067S/cm.

Example 4

Preparation of a phosphonic acid-doped cross-linked sulfonated polyiminobenzimidazole high-temperature proton exchange membrane, the steps are as follows:

1) Add 1.8mmol of 4,4'-diaminodiphenyl ether-2,2'-disulfonic acid into a mixed solvent of 15mL of m-cresol and 0.8mL of triethylamine, blow in nitrogen gas, and stir thoroughly until diaminodiphenyl ether Dissolve all the sulfonic acid to obtain diaminodisulfonic acid solution, add 1.6mmol 3,3'-bis(4-sulfonic acid phenyl)benzidine, 1mmol 6,6'-bis[2- (4-aminophenyl)]benzimidazole and 2mmol 1,4,5,8-naphthalene tetracarboxylic dianhydride, fully stirred at room temperature, heated at 80°C for 5h, then heated at 180°C for 24h, and cooled naturally to room temperature, then add 12mL of m-cresol and 100mL of acetone as diluents, stir thoroughly and filter, filter out the fibrous precipitate, wash the precipitate with acetone, and then vacuum dry to obtain sulfonated polyiminobenzimidazole;

2) dissolving the sulfonated polyiminobenzimidazole obtained in step 1) in dimethyl sulfoxide to obtain a sulfonated polyiminobenzimidazole solution with a mass concentration of 6%, and then adding 1 mmol of dibromodiphenyl ether to make benzene The molar ratio of the amino group in imidazole to the benzyl bromide in dibromodiphenyl ether is 1:1. After mixing evenly, pour it into a polytetrafluoroethylene mold, heat at 80°C for 24h, and then heat at 160°C for 3h. It is fully cross-linked to obtain a high-temperature proton exchange membrane;

3) Put the high-temperature proton exchange membrane obtained in step 2) into a 0.1mol/L aqueous solution of aminotrimethylene phosphonic acid, soak it at room temperature for 48 hours, then take it out, wash it with deionized water, and heat it at 80°C for 5 hours , and then heated at 160° C. for 24 h to obtain a phosphonic acid-doped cross-linked sulfonated polyiminobenzimidazole high-temperature proton exchange membrane.

After testing, the linear swelling coefficient of the proton exchange membrane prepared in this example is 6.73% at room temperature, the thermal stability temperature is 262°C, the tensile strength is 51.7MPa, the ion exchange capacity is 0.75mmol/g, and it can be dried at 180°C without water. The conductivity measured under the conditions is 0.064S/cm.

Example 5

Preparation of a phosphonic acid-doped cross-linked sulfonated polyiminobenzimidazole high-temperature proton exchange membrane, the steps are as follows:

1) Add 1.8mmol of 4,4'-diaminodiphenyl ether-2,2'-disulfonic acid into a mixed solvent of 15mL of m-cresol and 0.8mL of triethylamine, blow in nitrogen gas, and stir thoroughly until diaminodiphenyl ether Dissolve all the sulfonic acid to obtain diaminodisulfonic acid solution, add 1.8mmol 3,3'-bis(4-sulfonic acid phenyl)benzidine, 1mmol 6,6'-bis[2- (4-aminophenyl)]benzimidazole and 2mmol 1,4,5,8-naphthalene tetracarboxylic dianhydride, fully stirred at room temperature, heated at 80°C for 5h, then heated at 180°C for 24h, and cooled naturally to room temperature, then add 12mL of m-cresol and 100mL of acetone as diluents, stir thoroughly and filter, filter out the fibrous precipitate, wash the precipitate with acetone, and then vacuum dry to obtain sulfonated polyiminobenzimidazole;

2) dissolving the sulfonated polyiminobenzimidazole obtained in step 1) in dimethyl sulfoxide to obtain a sulfonated polyiminobenzimidazole solution with a mass concentration of 6%, and then adding 1 mmol dibromodiphenyl ether to make benzene The molar ratio of the amino group in imidazole to the benzyl bromide in dibromodiphenyl ether is 1:1. After mixing evenly, pour it into a polytetrafluoroethylene mold, heat at 80°C for 24h, and then heat at 160°C for 3h. It is fully cross-linked to obtain a high-temperature proton exchange membrane;

3) Put the high-temperature proton exchange membrane obtained in step 2) into a 0.1mol/L aqueous solution of aminotrimethylene phosphonic acid, soak it at room temperature for 48 hours, then take it out, wash it with deionized water, and heat it at 80°C for 5 hours , and then heated at 160° C. for 24 h to obtain a phosphonic acid-doped cross-linked sulfonated polyiminobenzimidazole high-temperature proton exchange membrane.

After testing, the linear swelling coefficient of the proton exchange membrane prepared in this example is 7.36% at room temperature, the thermal stability temperature is 275°C, the tensile strength is 54.6MPa, the ion exchange capacity is 0.87mmol/g, and it is anhydrous at 180°C. The conductivity measured under the conditions is 0.067S/cm.

Example 6

Preparation of a phosphonic acid-doped cross-linked sulfonated polyiminobenzimidazole high-temperature proton exchange membrane, the steps are as follows:

1) Add 1.8mmol of 4,4'-diaminodiphenyl ether-2,2'-disulfonic acid into a mixed solvent of 15mL of m-cresol and 0.8mL of triethylamine, blow in nitrogen gas, and stir thoroughly until diaminodiphenyl ether Dissolve all the sulfonic acid to obtain diaminodisulfonic acid solution, add 1.8mmol 3,3'-bis(4-sulfonic acid phenyl)benzidine, 1mmol 6,6'-bis[2- (4-Aminophenyl)]benzimidazole and 2.2mmol 1,4,5,8-naphthalene tetracarboxylic dianhydride, fully stirred at room temperature, first heated at 80°C for 5h, then heated at 180°C for 24h, naturally Cool to room temperature, then add 12mL of m-cresol and 100mL of acetone as diluents, stir well and filter, filter out the fibrous precipitate, wash the precipitate with acetone, and then vacuum dry to obtain sulfonated polyiminobenzimidazole;

2) dissolving the sulfonated polyiminobenzimidazole obtained in step 1) in dimethyl sulfoxide to obtain a sulfonated polyiminobenzimidazole solution with a mass concentration of 6%, and then adding 1 mmol dibromodiphenyl ether to make benzene The molar ratio of the amino group in imidazole to the benzyl bromide in dibromodiphenyl ether is 1:1. After mixing evenly, pour it into a polytetrafluoroethylene mold, heat at 80°C for 24h, and then heat at 160°C for 3h. It is fully cross-linked to obtain a high-temperature proton exchange membrane;

3) Put the high-temperature proton exchange membrane obtained in step 2) into a 0.1mol/L aqueous solution of aminotrimethylene phosphonic acid, soak it at room temperature for 48 hours, then take it out, wash it with deionized water, and heat it at 80°C for 5 hours , and then heated at 160° C. for 24 h to obtain a phosphonic acid-doped cross-linked sulfonated polyiminobenzimidazole high-temperature proton exchange membrane.

After testing, the linear swelling coefficient of the proton exchange membrane prepared in this example is 8.95% at room temperature, the thermal stability temperature is 277°C, the tensile strength is 61.3MPa, the ion exchange capacity is 0.85mmol/g, and it can be dried at 180°C without water. The conductivity measured under the conditions is 0.069S/cm.

Example 7

Preparation of a phosphonic acid-doped cross-linked sulfonated polyiminobenzimidazole high-temperature proton exchange membrane, the steps are as follows:

1) Add 1.8mmol of 4,4'-diaminodiphenyl ether-2,2'-disulfonic acid into a mixed solvent of 15mL of m-cresol and 0.8mL of triethylamine, blow in nitrogen gas, and stir thoroughly until diaminodiphenyl ether Dissolve all the sulfonic acid to obtain diaminodisulfonic acid solution, add 1.8mmol 3,3'-bis(4-sulfonic acid phenyl)benzidine, 1mmol 6,6'-bis[2- (4-Aminophenyl)]benzimidazole and 2.4mmol 1,4,5,8-naphthalene tetracarboxylic dianhydride, fully stirred at room temperature, first heated at 80°C for 5h, then heated at 180°C for 24h, naturally Cool to room temperature, then add 12mL of m-cresol and 100mL of acetone as diluents, stir well and filter, filter out the fibrous precipitate, wash the precipitate with acetone, and then vacuum dry to obtain sulfonated polyiminobenzimidazole;

2) dissolving the sulfonated polyiminobenzimidazole obtained in step 1) in dimethyl sulfoxide to obtain a sulfonated polyiminobenzimidazole solution with a mass concentration of 6%, and then adding 1 mmol dibromodiphenyl ether to make benzene The molar ratio of the amino group in imidazole to the benzyl bromide in dibromodiphenyl ether is 1:1. After mixing evenly, pour it into a polytetrafluoroethylene mold, heat at 80°C for 24h, and then heat at 160°C for 3h. It is fully cross-linked to obtain a high-temperature proton exchange membrane;

3) Put the high-temperature proton exchange membrane obtained in step 2) into a 0.1mol/L aqueous solution of aminotrimethylenephosphonic acid, soak it at room temperature for 48 hours, then take it out, wash it with deionized water, and heat it at 80°C for 5 hours, Then heated at 160° C. for 24 hours to obtain a high-temperature proton exchange membrane doped with phosphonic acid and cross-linked sulfonated polyiminobenzimidazole.

After testing, the linear swelling coefficient of the proton exchange membrane prepared in this example is 9.34% at room temperature, the thermal stability temperature is 283°C, the tensile strength is 67.6MPa, the ion exchange capacity is 0.97mmol/g, and it is anhydrous at 180°C. The conductivity measured under the conditions is 0.073S/cm.

Each raw material enumerated in the present invention, and the upper and lower limits of each raw material of the present invention, the interval value, and the upper and lower limits of process parameters (such as temperature, time, etc.), the interval value can realize the present invention, do not enumerate one by one here Example.

Claims (8)

1. a kind of poly- imino group benzimidazole high temperature proton exchange film of phosphonic acids doping cross-linking sulfonation, which is characterized in that it is by following Method is prepared：

1) in a nitrogen atmosphere, diamino disulfonic acid is dissolved in solvent and obtains diamino disulphonic acid, to two sulphur of diamino Benzidine, benzimidazole containing aminophenyl and naphthalenetetracarbacidic acidic dianhydride are added in acid solution, stir thoroughly at room temperature is uniform, in 70-90 DEG C 5-6h is heated, then heats 18-24h in 165-180 DEG C, cooled to room temperature adds diluent, is sufficiently stirred, and filters, The solid matter filtered out is washed, is dried to obtain the poly- imino group benzimidazole of sulfonation；

2) the poly- imino group benzimidazole of sulfonation obtained by step 1) is dissolved in dimethyl sulfoxide, it is molten obtains the poly- imino group benzimidazole of sulfonation Liquid adds dibromodiphenyl ether, and it is 1 to make amino and benzyl bromide molar ratio in solution:1, after mixing in 75-80 DEG C of reaction Then 18-24h heats 2-4h in 150-160 DEG C, obtains high temperature proton exchange film；

3) high temperature proton exchange film obtained by step 2) is placed in aminotrimethylenephosphonic acid aqueous solution and impregnates 36-48h, then spend from Then sub- water washing heats 5-6h in 70-90 DEG C, finally heating 18-24h in 150-160 DEG C obtains phosphonic acids doping cross-linking sulfonation Poly- imino group benzimidazole high temperature proton exchange film；

Step 1) the solvent is m-cresol and triethylamine 18-25 by volume:1 mixed solvent being mixed to get；It is described dilute Release agent be between phenyl methylcarbamate and acetone mixture.

2. high temperature proton exchange film according to claim 1, it is characterised in that step 1) the diamino disulfonic acid is 4, 4'- diamino -2,2'- disulfonic acid, 4,4'- diaminobenzil -2,2'- disulfonic acid, 4,4 '-diaminodiphenyl ethers -2,2 ' - One kind in disulfonic acid.

3. high temperature proton exchange film according to claim 1, it is characterised in that the step 1) solvent be m-cresol with Triethylamine 18-25 by volume:1 mixed solvent being mixed to get；A concentration of 0.05- of diamino disulphonic acid 0.12mol/L。

4. high temperature proton exchange film according to claim 1, it is characterised in that the step 1) benzidine is 3, and 3 '-is bis- (4- sulphenyls) benzidine；The benzimidazole containing aminophenyl is 6,6 '-bis- [2- (4- aminophenyls)] benzimidazoles；It is described The molar ratio of aniline, benzimidazole containing aminophenyl and naphthalene tetracid dianhydride is 1.4-1.8:1:2-2.6, and diamino disulfonic acid with The molar ratio of the benzimidazole containing aminophenyl is 1:1.

5. high temperature proton exchange film according to claim 1, it is characterised in that the step 1) diluent be between phenyl methylcarbamate With the mixture of acetone, in-between phenyl methylcarbamate is 1 with acetone volume ratio：5.

6. high temperature proton exchange film according to claim 1, it is characterised in that the poly- imino group benzo of the step 2) sulfonation The mass concentration of imidazole solution is 6%.

7. high temperature proton exchange film according to claim 1, it is characterised in that step 3) the aminotrimethylenephosphonic acid water Solution concentration is 0.08-0.12mol/L.

8. a kind of preparation method of any high temperature proton exchange films of claim 1-7, it is characterised in that steps are as follows：

1) in a nitrogen atmosphere, diamino disulfonic acid is dissolved in solvent and obtains diamino disulphonic acid, to two sulphur of diamino Benzidine, benzimidazole containing aminophenyl and naphthalenetetracarbacidic acidic dianhydride are added in acid solution, stir thoroughly at room temperature is uniform, in 70-90 DEG C 5-6h is heated, then heats 18-24h in 165-180 DEG C, cooled to room temperature adds diluent, is sufficiently stirred, and filters, The solid matter filtered out is washed, is dried to obtain the poly- imino group benzimidazole of sulfonation；

2) the poly- imino group benzimidazole of sulfonation obtained by step 1) is dissolved in dimethyl sulfoxide, it is molten obtains the poly- imino group benzimidazole of sulfonation Liquid adds dibromodiphenyl ether, and it is 1 to make amino and benzyl bromide molar ratio in solution:1, after mixing in 75-80 DEG C of reaction Then 18-24h heats 2-4h in 150-160 DEG C, obtains high temperature proton exchange film；

3) high temperature proton exchange film obtained by step 2) is placed in aminotrimethylenephosphonic acid aqueous solution and impregnates 36-48h, then spend from Then sub- water washing heats 5-6h in 70-90 DEG C, finally heating 18-24h in 150-160 DEG C obtains phosphonic acids doping cross-linking sulfonation Poly- imino group benzimidazole high temperature proton exchange film.