A modified polybenzimidazole and its preparation method

Abstract

The invention discloses a modified polybenzimidazole, which belongs to the field of fuel cells. The modified polybenzimidazole is prepared by a simple preparation process using raw materials of p-aminophenol, triethylamine, formaldehyde solution, polybenzimidazole, halogenated hydrocarbon, potassium carbonate and potassium iodide. The modified polybenzimidazole prepared by the invention can be cross-linked and cured under heating conditions without the need for an external cross-linking agent, thereby simplifying the preparation process of the cross-linked polybenzimidazole, so that it can be mixed evenly regardless of whether it is in a solution or powder state, which helps to improve the uniformity of the cross-linking density of the cured product, thereby helping to improve the quality stability of the product. In addition, the functional groups on the side chains of the prepared modified polybenzimidazole can help to improve its compatibility, solubility and crystallinity, and can also increase proton conductivity, thereby reducing its dependence on the amount of acid added and thereby alleviating the acid leakage problem.

Description

Technical Field

[0001] The invention relates to the fields of material chemistry and fuel cells, and in particular to a modified polybenzimidazole and a preparation method thereof. Background Art

[0002] Polybenzimidazole is one of the main materials for proton exchange membranes used in high-temperature proton exchange membrane fuel cells. However, polybenzimidazole membranes must be doped with proton acid, usually phosphoric acid, to achieve proton conduction, and their proton conductivity is closely positively correlated with the amount of acid doping. However, the higher the acid doping amount, the more the mechanical strength and thermal stability of the membrane will decrease. In addition, acid leakage and other problems have also become the main bottleneck limiting the application of PBI-type proton exchange membranes.

[0003] Traditional methods mainly improve the mechanical strength, thermal stability and chemical stability of polybenzimidazole proton exchange membranes and their acid-doped composite membranes through cross-linking. Usually, polybenzimidazole needs to be cross-linked with an organic acid or its halide cross-linking agent with bifunctional or multifunctional groups. This process is relatively cumbersome and complicated. When used as a powder, there is a problem of uneven mixing, resulting in uneven cross-linking density after curing, thus affecting the quality stability of the product. Summary of the invention

[0004] Based on this, in order to solve the problems in the prior art of complicated processes, uneven mixing of powder materials, and thus affecting the stability of product quality, the present invention provides a modified polybenzimidazole, and the specific technical scheme is as follows:

[0005] A modified polybenzimidazole, wherein the chemical structural formula of the modified polybenzimidazole is:

[0006] or or ;

[0007] Where R1 is: , , , , as well as R2 is a hydrogen atom or a substituent T, and the same molecular chain contains at least one R2 that is a substituent T.

[0008] Furthermore, it is characterized in that the structural formula of the substituent T is as follows:

[0009] ;

[0010] wherein R3 is a hydrogen atom or a substituent M, and the substituent M is an alkyl group having 1 to 30 carbon atoms and having a substituent, an alkoxy group having 1 to 30 carbon atoms and having a substituent, an aryl group having 6 to 30 carbon atoms and having a substituent, an aralkyl group having 7 to 40 carbon atoms and having a substituent, an alkenyl group having 2 to 30 carbon atoms and having a substituent, an alkynyl group having 2 to 30 carbon atoms and having a substituent, a phosphonic acid group having 1 to 20 carbon atoms and having a substituent, a phosphonate group having 1 to 20 carbon atoms and having a substituent, a sulfonic acid group having 1 to 20 carbon atoms and having a substituent The carbon number of the substituted carboxylic acid group is 1 to 20, the carbon number of the substituted carboxylate group is 1 to 20, the carbon number of the substituted imidazolyl group is 1 to 20, the carbon number of the substituted pyridyl group is 1 to 20, the carbon number of the substituted pyranyl group is 1 to 20, the carbon number of the substituted furanyl group is 1 to 20, the carbon number of the substituted triazolyl group is 1 to 20, the carbon number of the substituted tetrazolyl group is 1 to 20, the carbon number of the substituted thienyl group is 1 to 20, the carbon number of the substituted pyrrolyl group is 1 to 20, and the carbon number of the substituted morpholinyl group is 1 to 20.

[0011] In addition, the present application also provides a method for preparing a modified polybenzimidazole, the method comprising the following steps:

[0012] Dissolve p-aminophenol, triethylamine and formaldehyde solution in an organic solvent, and stir in nitrogen at 5-10°C for 30-120 minutes to obtain solution A;

[0013] Dissolving polybenzimidazole in an organic solvent and mixing well to obtain a solution B;

[0014] Adding a formaldehyde solution accounting for 1 / 3 of the amount of the formaldehyde solution and the solution B to the solution A, heating to 90° C. within 40 minutes, then adding the remaining formaldehyde solution, continuing to stir for 1 hour to 4 hours in nitrogen, and then pouring into deionized water, precipitating, filtering, and repeatedly washing with water to obtain a polymer;

[0015] dissolving the polymer in an organic solvent to obtain a solution C;

[0016] Add halogenated hydrocarbon, potassium carbonate and potassium iodide to the solution C, stir in nitrogen at 20°C to 70°C for 12h to 72h, then pour into deionized water, precipitate, filter, and repeatedly wash with ethanol to obtain modified polybenzimidazole.

[0017] Furthermore, the organic solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and N-methylpyrrolidone.

[0018] Furthermore, in the solution A, the ratio of the p-aminophenol, the triethylamine, the formaldehyde solution and the organic solvent is 98:4:35:480 in parts by weight.

[0019] Furthermore, in the solution B, the ratio of the polybenzimidazole to the formaldehyde solution is (52-125):70 in terms of weight.

[0020] Furthermore, the mass percentage concentration of the formaldehyde solution is 37%.

[0021] Furthermore, the amount of the polymer added in the solution C is 0.05 g / mL to 0.5 g / mL.

[0022] Furthermore, the mass ratio of the halogenated hydrocarbon, the potassium carbonate and the potassium iodide is 1:(1-3):(0.02-0.06).

[0023] Furthermore, the halogenated hydrocarbon is a halogenated alkane having 1 to 30 carbon atoms and having a substituent, a halogenated alkoxy compound having 1 to 30 carbon atoms and having a substituent, a halogenated aromatic hydrocarbon having 6 to 30 carbon atoms and having a substituent, a halogenated aromatic hydrocarbon having 7 to 40 carbon atoms and having a substituent, a halogenated olefin having 2 to 30 carbon atoms and having a substituent, a halogenated alkyne having 2 to 30 carbon atoms and having a substituent, a halogenated alkylphosphonic acid having 1 to 20 carbon atoms and having a substituent, a halogenated alkylphosphonic acid ester having 1 to 20 carbon atoms and having a substituent, a halogenated alkylsulfonic acid having 1 to 20 carbon atoms and a halogenated alkylcarboxylic acid having 1 to 20 carbon atoms and having a substituent. Acid, a substituted halogenated alkylcarboxylic acid ester having 1 to 20 carbon atoms, a substituted halogenated alkylimidazole having 1 to 20 carbon atoms, a substituted halogenated alkylpyridine having 1 to 20 carbon atoms, a substituted halogenated alkylpyran having 1 to 20 carbon atoms, a substituted halogenated alkylfuran having 1 to 20 carbon atoms, a substituted halogenated alkyltriazole having 1 to 20 carbon atoms, a substituted halogenated alkyltetrazole having 1 to 20 carbon atoms, a substituted halogenated alkylthiophene having 1 to 20 carbon atoms, a substituted halogenated alkylpyrrole having 1 to 20 carbon atoms, and a substituted halogenated alkylmorpholine having 1 to 20 carbon atoms.

[0024] The modified polybenzimidazole prepared in the above scheme can be cross-linked and cured under heating conditions without the need for an external cross-linking agent, which simplifies the preparation process of the cross-linked polybenzimidazole and allows it to be mixed evenly in the state of solution or powder, which helps to improve the uniformity of the cross-linking density of the cured product, thereby helping to improve the quality stability of the product. In addition, the functional groups on the side chains of the prepared modified polybenzimidazole can help improve its compatibility, solubility and crystallinity, and can also increase proton conductivity, thereby reducing its dependence on the amount of acid added and thus alleviating the acid leakage problem. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with its embodiments. It should be understood that the specific implementation methods described herein are only used to explain the present invention and do not limit the protection scope of the present invention.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0027] A modified polybenzimidazole in one embodiment of the present invention has a chemical structural formula of:

[0028] or or ;

[0029] Where R1 is: , , , , as well as R2 is a hydrogen atom or a substituent T, and the same molecular chain contains at least one R2 that is a substituent T.

[0030] In one embodiment, it is characterized in that the structural formula of the substituent T is as follows:

[0031] ;

[0032] wherein R3 is a hydrogen atom or a substituent M, and the substituent M is an alkyl group having 1 to 30 carbon atoms and having a substituent, an alkoxy group having 1 to 30 carbon atoms and having a substituent, an aryl group having 6 to 30 carbon atoms and having a substituent, an aralkyl group having 7 to 40 carbon atoms and having a substituent, an alkenyl group having 2 to 30 carbon atoms and having a substituent, an alkynyl group having 2 to 30 carbon atoms and having a substituent, a phosphonic acid group having 1 to 20 carbon atoms and having a substituent, a phosphonate group having 1 to 20 carbon atoms and having a substituent, a sulfonic acid group having 1 to 20 carbon atoms and having a substituent The carbon number of the substituted carboxylic acid group is 1 to 20, the carbon number of the substituted carboxylate group is 1 to 20, the carbon number of the substituted imidazolyl group is 1 to 20, the carbon number of the substituted pyridyl group is 1 to 20, the carbon number of the substituted pyranyl group is 1 to 20, the carbon number of the substituted furanyl group is 1 to 20, the carbon number of the substituted triazolyl group is 1 to 20, the carbon number of the substituted tetrazolyl group is 1 to 20, the carbon number of the substituted thienyl group is 1 to 20, the carbon number of the substituted pyrrolyl group is 1 to 20, and the carbon number of the substituted morpholinyl group is 1 to 20.

[0033] In addition, the present application also provides a method for preparing a modified polybenzimidazole, the method comprising the following steps:

[0034] Dissolve p-aminophenol, triethylamine and formaldehyde solution in an organic solvent, and stir in nitrogen at 5-10°C for 30-120 minutes to obtain solution A;

[0035] Dissolving polybenzimidazole in an organic solvent and mixing well to obtain a solution B;

[0036] Adding a formaldehyde solution accounting for 1 / 3 of the amount of the formaldehyde solution and the solution B to the solution A, heating to 90° C. within 40 minutes, then adding the remaining formaldehyde solution, continuing to stir for 1 hour to 4 hours in nitrogen, and then pouring into deionized water, precipitating, filtering, and repeatedly washing with water to obtain a polymer;

[0037] dissolving the polymer in an organic solvent to obtain a solution C;

[0038] Add halogenated hydrocarbon, potassium carbonate and potassium iodide to the solution C, stir in nitrogen at 20°C to 70°C for 12h to 72h, then pour into deionized water, precipitate, filter, and repeatedly wash with ethanol to obtain modified polybenzimidazole.

[0039] In one embodiment, the organic solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and N-methylpyrrolidone.

[0040] In one embodiment, in the solution A, the ratio of the p-aminophenol, the triethylamine, the formaldehyde solution and the organic solvent is 98:4:35:480 by weight.

[0041] In one embodiment, in the solution B, the ratio of the polybenzimidazole to the formaldehyde solution is (52-125):70 in terms of weight.

[0042] In one embodiment, the mass percentage concentration of the formaldehyde solution is 37%.

[0043] In one embodiment, the amount of the polymer added to the solution C is 0.05 g / mL to 0.5 g / mL.

[0044] In one embodiment, the mass ratio of the halogenated hydrocarbon, the potassium carbonate and the potassium iodide is 1:(1-3):(0.02-0.06).

[0045] In one embodiment, the halogenated hydrocarbon is a halogenated alkane having 1 to 30 carbon atoms and having a substituent, a halogenated alkoxy compound having 1 to 30 carbon atoms and having a substituent, a halogenated aromatic hydrocarbon having 6 to 30 carbon atoms and having a substituent, a halogenated aromatic hydrocarbon having 7 to 40 carbon atoms and having a substituent, a halogenated olefin having 2 to 30 carbon atoms and having a substituent, a halogenated alkyne having 2 to 30 carbon atoms and having a substituent, a halogenated alkylphosphonic acid having 1 to 20 carbon atoms and having a substituent, a halogenated alkylphosphonic acid ester having 1 to 20 carbon atoms and having a substituent, a halogenated alkylsulfonic acid having 1 to 20 carbon atoms and a halogenated alkane having 1 to 20 carbon atoms and a substituent. The invention further comprises a halogenated alkyl carboxylic acid having 1 to 20 carbon atoms and having a substituent, a halogenated alkyl imidazole having 1 to 20 carbon atoms and having a substituent, a halogenated alkyl pyridine having 1 to 20 carbon atoms and having a substituent, a halogenated alkyl pyran having 1 to 20 carbon atoms and having a substituent, a halogenated alkyl furan having 1 to 20 carbon atoms and having a substituent, a halogenated alkyl triazole having 1 to 20 carbon atoms and having a substituent, a halogenated alkyl tetrazole having 1 to 20 carbon atoms and having a substituent, a halogenated alkyl thiophene having 1 to 20 carbon atoms and having a substituent, a halogenated alkyl pyrrole having 1 to 20 carbon atoms and a halogenated alkyl morpholine having 1 to 20 carbon atoms and having a substituent.

[0046] In one embodiment, the thermal crosslinking temperature of the modified polybenzimidazole is 100°C to 180°C.

[0047] In one embodiment, the modified polybenzimidazole is thermally cross-linked to obtain a polybenzimidazole cross-linked polymer.

[0048] The modified polybenzimidazole prepared in the above scheme can be cross-linked and cured under heating conditions without the need for an external cross-linking agent, which simplifies the preparation process of the cross-linked polybenzimidazole and allows it to be mixed evenly in the state of solution or powder, which helps to improve the uniformity of the cross-linking density of the cured product, thereby helping to improve the quality stability of the product. In addition, the functional groups on the side chains of the prepared modified polybenzimidazole can help improve its compatibility, solubility and crystallinity, and can also increase proton conductivity, thereby reducing its dependence on the amount of acid added and thus alleviating the acid leakage problem.

[0049] The embodiments of the present invention will be described in detail below with reference to specific examples.

[0050] Embodiment 1:

[0051] A method for preparing a modified polybenzimidazole comprises the following steps:

[0052] 98 parts of p-aminophenol, 4 parts of triethylamine and 35 parts of formaldehyde solution were dissolved in N,N-dimethylformamide and stirred in nitrogen at 10°C for 60 minutes to obtain solution A;

[0053] Dissolve 70 parts of polybenzimidazole in N,N-dimethylformamide and mix well to obtain 0.1 g / mL solution B;

[0054] 35 parts of formaldehyde solution and solution B are added to solution A, heated to 90° C. within 40 minutes, and then 35 parts of formaldehyde solution are added, and stirring is continued for 2 hours in nitrogen, and then poured into deionized water, precipitated, filtered, and repeatedly washed with water to obtain a polymer;

[0055] Dissolving the polymer in N,N-dimethylformamide to obtain a 0.1 g / mL solution C;

[0056] To the solution C, halogenated hydrocarbon, potassium carbonate and potassium iodide in a molar ratio of 1:1:1:0.02 were added, and the mixture was stirred in nitrogen at 25° C. for 72 hours. The mixture was then poured into deionized water, precipitated, filtered and repeatedly washed with ethanol to obtain modified polybenzimidazole.

[0057] The structural formula of the modified polybenzimidazole in Example 1 is as follows:

[0058] ;

[0059] In Example 1, R2 is a hydrogen atom or a substituent T, and the structure of the substituent T is:

[0060] ;

[0061] In Example 1, R3 is a hydrogen atom or a substituent M, and the structure of the substituent M is:

[0062] .

[0063] Embodiment 2:

[0064] A method for preparing a modified polybenzimidazole comprises the following steps:

[0065] 98 parts of p-aminophenol, 4 parts of triethylamine and 35 parts of formaldehyde solution were dissolved in N,N-dimethylformamide and stirred in nitrogen at 8°C for 120 minutes to obtain solution A;

[0066] Dissolve 90 parts of polybenzimidazole in N,N-dimethylformamide and mix well to obtain 0.05 g / mL solution B;

[0067] 35 parts of formaldehyde solution and solution B are added to solution A, heated to 90° C. within 40 minutes, then 35 parts of formaldehyde solution are added, stirring is continued for 4 hours in nitrogen, and then poured into deionized water, precipitated, filtered, and repeatedly washed with water to obtain a polymer;

[0068] Dissolving the polymer in N,N-dimethylformamide to obtain a 0.05 g / mL solution C;

[0069] To the solution C, 1-bromohexane, potassium carbonate and potassium iodide in a molar ratio of 1:2:2:0.04 were added, stirred in nitrogen at 70° C. for 12 hours, then poured into deionized water, precipitated, filtered, and repeatedly washed with ethanol to obtain modified polybenzimidazole.

[0070] The structural formula of the modified polybenzimidazole in Example 2 is as follows:

[0071] ;

[0072] In Example 2, R2 is a hydrogen atom or a substituent T, and the structure of the substituent T is:

[0073] ;

[0074] In Example 2, R3 is a hydrogen atom or a substituent M, and the structure of the substituent M is:

[0075] .

[0076] Embodiment 3:

[0077] A method for preparing a modified polybenzimidazole comprises the following steps:

[0078] 98 parts of p-aminophenol, 4 parts of triethylamine and 35 parts of formaldehyde solution were dissolved in N-methylpyrrolidone and stirred in nitrogen at 8°C for 120 minutes to obtain solution A;

[0079] Dissolve 60 parts of polybenzimidazole in N-methylpyrrolidone and mix well to obtain 0.3 g / mL solution B;

[0080] 35 parts of formaldehyde solution and solution B are added to solution A, heated to 90° C. within 40 minutes, then 35 parts of formaldehyde solution are added, stirring is continued for 1 hour in nitrogen, and then poured into deionized water, precipitated, filtered, and repeatedly washed with water to obtain a polymer;

[0081] The polymer was dissolved in N-methylpyrrolidone to obtain a 0.3 g / mL solution C;

[0082] 4-Chloromethylimidazole, potassium carbonate and potassium iodide in a molar ratio of 1:3:3:0.06 were added to the solution C, stirred in nitrogen at 50° C. for 24 hours, then poured into deionized water, precipitated, filtered, and repeatedly washed with ethanol to obtain modified polybenzimidazole.

[0083] The structural formula of the modified polybenzimidazole in Example 3 is as follows:

[0084] ;

[0085] In Example 3, R2 is a hydrogen atom or a substituent T, and the structure of the substituent T is:

[0086] ;

[0087] R3 is a hydrogen atom or a substituent M, and the structure of the substituent M is:

[0088] .

[0089] Application Example 1:

[0090] The modified polybenzimidazole obtained in Example 1 was cured at 120° C. for 24 hours to obtain a cross-linked modified polybenzimidazole film.

[0091] Application Example 2:

[0092] The modified polybenzimidazole obtained in Example 2 was cured at 180° C. for 24 hours to obtain a cross-linked modified polybenzimidazole film.

[0093] Application Example 3:

[0094] The modified polybenzimidazole obtained in Example 3 was cured at 150° C. for 24 h to obtain a cross-linked modified polybenzimidazole film.

[0095] Conventional linear polybenzimidazole, modified polybenzimidazole of Example 1 and cross-linked modified polybenzimidazole membrane of Application Example 1 were tested, and the results of tensile strength and anhydrous proton conductivity at 150° C. are shown in Table 1 below.

[0096] Table 1:

[0097]

[0098] The modified polybenzimidazole of Example 2 and the cross-linked modified polybenzimidazole film of Application Example 2 were tested, and the tensile strengths were shown in Table 2 below.

[0099] Table 2:

[0100]

[0101] Conventional linear polybenzimidazole, modified polybenzimidazole of Example 3 and cross-linked modified polybenzimidazole membrane of Application Example 3 were tested, and the tensile strength and proton conductivity results are shown in Table 3 below, wherein the proton conductivity test method is to immerse the cross-linked modified polybenzimidazole membrane in 15 mol / L phosphoric acid at room temperature for 48 hours, wipe the surface dry, and measure at 180°C.

[0102] Table 3:

[0103]

[0104] From the analysis of Tables 1 to 3, it can be seen that the modified polybenzimidazole of the present application still has an excellent cross-linking effect without adding a cross-linking agent, cross-links into a membrane at 100 to 180° C., can be used as a proton exchange membrane, and has excellent tensile strength and conductivity.

[0105] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0106] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A modified polybenzimidazole, characterized in that: The chemical structural formula of the modified polybenzimidazole is: or or ; Where R1 is: , , , , as well as R2 is a hydrogen atom or a substituent T, and the same molecular chain contains at least one R2 that is a substituent T; The structural formula of the substituent T is as follows: ； wherein R3 is a hydrogen atom or a substituent M, and the substituent M is an alkyl group having 1 to 30 carbon atoms and having a substituent, an alkoxy group having 1 to 30 carbon atoms and having a substituent, an aryl group having 6 to 30 carbon atoms and having a substituent, an aralkyl group having 7 to 40 carbon atoms and having a substituent, an alkenyl group having 2 to 30 carbon atoms and having a substituent, an alkynyl group having 2 to 30 carbon atoms and having a substituent, a phosphonic acid group having 1 to 20 carbon atoms and having a substituent, a phosphonate group having 1 to 20 carbon atoms and having a substituent, a sulfonic acid group having 1 to 20 carbon atoms and having a substituent The carbon number of the substituted carboxylic acid group is 1 to 20, the carbon number of the substituted carboxylate group is 1 to 20, the carbon number of the substituted imidazolyl group is 1 to 20, the carbon number of the substituted pyridyl group is 1 to 20, the carbon number of the substituted pyranyl group is 1 to 20, the carbon number of the substituted furanyl group is 1 to 20, the carbon number of the substituted triazolyl group is 1 to 20, the carbon number of the substituted tetrazolyl group is 1 to 20, the carbon number of the substituted thienyl group is 1 to 20, the carbon number of the substituted pyrrolyl group is 1 to 20, and the carbon number of the substituted morpholinyl group is 1 to 20.

2. A method for preparing a modified polybenzimidazole, characterized in that: The preparation method is used to prepare the modified polybenzimidazole according to claim 1, and the preparation method comprises the following steps: Dissolve p-aminophenol, triethylamine and formaldehyde solution in an organic solvent, and stir in nitrogen at 5-10°C for 30-120 minutes to obtain solution A; Dissolving polybenzimidazole in an organic solvent and mixing well to obtain a solution B; Adding a formaldehyde solution accounting for 1 / 3 of the amount of the formaldehyde solution and the solution B to the solution A, heating to 90° C. within 40 minutes, then adding the remaining formaldehyde solution, continuing to stir for 1 hour to 4 hours in nitrogen, and then pouring into deionized water, precipitating, filtering, and repeatedly washing with water to obtain a polymer; dissolving the polymer in an organic solvent to obtain a solution C; Add halogenated hydrocarbon, potassium carbonate and potassium iodide to the solution C, stir in nitrogen at 20°C to 70°C for 12h to 72h, then pour into deionized water, precipitate, filter, and repeatedly wash with ethanol to obtain modified polybenzimidazole.

3. The preparation method according to claim 2, characterized in that: The organic solvent is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and N-methylpyrrolidone.

4. The preparation method according to claim 2, characterized in that: In the solution A, the ratio of the p-aminophenol, the triethylamine, the formaldehyde solution and the organic solvent is 98:4:35:480 in parts by weight.

5. The preparation method according to claim 2, characterized in that: In the solution B, the ratio of the polybenzimidazole to the formaldehyde solution is (52-125):70 in terms of weight.

6. The preparation method according to claim 2, characterized in that: The mass percentage concentration of the formaldehyde solution is 37%.

7. The preparation method according to claim 2, characterized in that: The amount of the polymer added in the solution C is 0.05 g / mL to 0.5 g / mL.

8. The preparation method according to claim 2, characterized in that: The mass ratio of the halogenated hydrocarbon, the potassium carbonate and the potassium iodide is 1:(1-3):(0.02-0.06).

9. The preparation method according to claim 8, characterized in that: The halogenated hydrocarbon is a halogenated alkane having 1 to 30 carbon atoms and having a substituent, a halogenated alkoxy compound having 1 to 30 carbon atoms and having a substituent, a halogenated aromatic hydrocarbon having 6 to 30 carbon atoms and having a substituent, a halogenated arylalkane having 7 to 40 carbon atoms and having a substituent, a halogenated olefin having 2 to 30 carbon atoms and having a substituent, a halogenated alkyne having 2 to 30 carbon atoms and having a substituent, a halogenated alkylphosphonic acid having 1 to 20 carbon atoms and having a substituent, a halogenated alkylphosphonic acid ester having 1 to 20 carbon atoms and having a substituent, a halogenated alkylsulfonic acid having 1 to 20 carbon atoms and having a substituent, a halogenated alkylcarboxylic acid having 1 to 20 carbon atoms and having a substituent. A substituted halogenated alkyl carboxylate having 1 to 20 carbon atoms, a substituted halogenated alkyl imidazole having 1 to 20 carbon atoms, a substituted halogenated alkyl pyridine having 1 to 20 carbon atoms, a substituted halogenated alkyl pyran having 1 to 20 carbon atoms, a substituted halogenated alkyl furan having 1 to 20 carbon atoms, a substituted halogenated alkyl triazole having 1 to 20 carbon atoms, a substituted halogenated alkyl tetrazole having 1 to 20 carbon atoms, a substituted halogenated alkyl thiophene having 1 to 20 carbon atoms, a substituted halogenated alkyl pyrrole having 1 to 20 carbon atoms, and a substituted halogenated alkyl morpholine having 1 to 20 carbon atoms.

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