Sulfonated polyarane, sulfonated polyarane proton exchange membrane and preparation methods of sulfonated polyarane and sulfonated polyarane proton exchange membrane

Abstract

The invention relates to the technical field of proton exchange membranes, and provides sulfonated polyarylalkane, a sulfonated polyarylalkane proton exchange membrane and a preparation method of the sulfonated polyarylalkane proton exchange membrane. On the basis of not destroying the main chain structure of the polyarane, a sulfonic acid side chain is introduced at a fixed point, and the obtained sulfonated polyarane shows excellent proton conduction performance and structural stability; according to the invention, polyarane with a side chain containing a bromine substituent group is adopted as a raw material, and a sulfonic acid group is introduced into the side chain through the sulfydryl-terminated alkyl sodium sulfonate, so that a new polyarane sulfonation strategy is developed, the operation is simple and efficient, and the development of a polyarane side chain grafting method and a polyarane proton exchange membrane is widened.

Description

Technical Field

[0001] The present invention relates to the technical field of proton exchange membranes, and in particular to a sulfonated polyarylalkane, a sulfonated polyarylalkane proton exchange membrane and a preparation method thereof. Background Art

[0002] Proton exchange membranes (PEMs) are core components of energy storage devices such as fuel cells, flow batteries, and water electrolysis for hydrogen production. Their performance determines the energy conversion efficiency and service life of these devices. Perfluorosulfonic acid membranes, represented by Nafion, are used as benchmarks for PEMs due to their excellent mechanical stability and proton conductivity. However, Nafion has disadvantages such as high cost, difficulty in synthesis, limited conductivity under high temperature and low humidity conditions, and the presence of a large number of non-degradable fluorine atoms in the system, which restricts its scope of use. Developing new polymer systems to replace Nafion as PEMs remains a hot topic among researchers.

[0003] In recent years, aromatic polymers with an all-carbon backbone have been recognized as a promising alternative material for proton exchange membranes due to their excellent chemical, thermal, and mechanical properties. Polyarane, a type of all-carbon backbone polymer prepared using superacid catalysis, exhibits high oxidative stability. However, current polyarane polymers exhibit poor proton conductivity.

[0004] Sulfonic acid groups are excellent proton-conducting groups and play a key role in accelerating proton transport in PEMs. However, polyarane structures have limited reactive sites. How to introduce sulfonic acid groups into polyarane structures while improving their proton conductivity and maintaining structural stability remains an urgent challenge in this field. Summary of the Invention

[0005] In view of this, the present invention provides a sulfonated polyarylalkane, a sulfonated polyarylalkane proton exchange membrane, and a preparation method. The present invention introduces sulfonic acid side chains at specific locations without destroying the polyarylalkane main chain structure. The resulting sulfonated polyarylalkane exhibits excellent proton conductivity and structural stability.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] A sulfonated polyarylalkane, the structural formula of which is shown in Formula I:

[0008]

[0009] In formula I, a is 1 to 10, b is 1 to 10, n represents the degree of polymerization, and Ar is any one or more of the following structures:

[0010]

[0011] R is any of the following structures: R1 is H or Na.

[0012] The present invention also provides a method for preparing the sulfonated polyarylalkane described in the above scheme. When R1 in Formula I is Na, the preparation method comprises the following steps:

[0013] Mixing polyarylalkane, a base, sodium terminal mercaptoalkyl sulfonate and a polar organic solvent to carry out a substitution reaction to obtain the sulfonated polyarylalkane wherein R1 is Na;

[0014] The structural formula of the polyarylalkane is shown in Formula II:

[0015]

[0016] In formula II: the types of Ar and R are the same as those in formula I, a is 1 to 10, and n represents the degree of polymerization;

[0017] The structure of the sodium sulfonate terminated with mercapto groups is shown in Formula III:

[0018]

[0019] In formula III, the value of b is 1 to 10;

[0020] When R1 in formula I is H, the preparation method comprises the following steps:

[0021] The sulfonated polyarylalkane wherein R1 is Na is acidified to obtain the sulfonated polyarylalkane wherein R1 is H.

[0022] Preferably, the preparation method of the polyarylalkane comprises the following steps:

[0023] Aromatic hydrocarbons, carbonyl compounds, organic acids and polar organic solvents are mixed and subjected to condensation reaction to obtain polyarylalkane having a structure shown in Formula II;

[0024] The structure of the carbonyl compound is shown in Formula IV;

[0025]

[0026] The type of R in formula IV is the same as that in formula I, and the value of a is 1-10.

[0027] Preferably, the molar ratio of the aromatic hydrocarbon to the carbonyl compound is 1:(1-2);

[0028] The organic acid includes one or more of trifluoromethanesulfonic acid, trifluoroacetic acid and methanesulfonic acid; the molar ratio of the aromatic hydrocarbon to the organic acid is 1:(4-50);

[0029] The temperature of the condensation reaction is -20 to 80° C., and the reaction time is 24 to 72 hours.

[0030] Preferably, the sodium terminal mercaptoalkyl sulfonate is sodium mercaptoethanesulfonate or sodium 3-mercapto-1-propanesulfonate; the molar ratio of the polyarylalkane to the sodium terminal mercaptoalkyl sulfonate is 1:(1-5);

[0031] The base includes one or more of sodium hydride, sodium hydroxide, potassium hydroxide and potassium carbonate; the molar ratio of the polyarylalkane to the base is 1:(1-5);

[0032] The temperature of the sulfonation reaction is 50-120° C., and the reaction time is 3-8 days.

[0033] The present invention also provides a sulfonated polyarylalkyl proton exchange membrane, wherein the material of the sulfonated polyarylalkyl proton exchange membrane is sulfonated polyarylalkyl, the sulfonated polyarylalkyl is the sulfonated polyarylalkyl described in the above scheme or the sulfonated polyarylalkyl prepared by the preparation method described in the above scheme, and R1 in the sulfonated polyarylalkyl is H.

[0034] The present invention also provides a method for preparing the sulfonated polyarylalkane proton exchange membrane described in the above scheme. When R1 in Formula I is Na, the preparation method comprises the following steps:

[0035] dissolving the sulfonated polyarylalkane in a polar organic solvent to obtain a casting solution;

[0036] casting the casting solution into a film to obtain a sodium-type thin film;

[0037] Acidifying the sodium-type membrane to obtain the sulfonated polyarylalkyl proton exchange membrane;

[0038] When R1 in Formula I is H, the preparation method comprises the following steps:

[0039] dissolving the sulfonated polyarylalkane in a polar organic solvent to obtain a casting solution;

[0040] The casting solution is cast into a membrane to obtain the sulfonated polyarylalkyl proton exchange membrane.

[0041] Preferably, the polar organic solvent includes one or more of dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylformamide and N,N-dimethylacetamide; the concentration of the sulfonated polyarylalkane in the casting solution is 50-100 mg mL -1 .

[0042] Preferably, the casting membrane comprises: casting the casting liquid and then drying it; the drying temperature is 50-120°C.

[0043] Preferably, the reagent used for the acidification is a sulfuric acid solution, and the concentration of the sulfuric acid solution is 0.5 to 3 mol L -1 The acidification temperature is 60-100° C. and the time is 12-72 hours.

[0044] The present invention provides a sulfonated polyarylalkane, the structural formula of which is shown in Formula I (see above). The present invention introduces sulfonic acid side chains at specific points without destroying the main chain structure of the polyarylalkane. The sulfonic acid group has a high proton dissociation ability and is an excellent proton donor. It can also participate in the construction of the hydrogen bond network of the system and accelerate proton transfer. By introducing the sulfonic acid group, the present invention can bring about excellent proton conduction performance while ensuring the mechanical properties of the membrane material; at the same time, the main chain structure of the sulfonated polyarylalkane provided by the present invention contains phenyl-phenyl bonds and phenyl-alkyl bonds with higher bond energy, and its chemical properties are much more stable than polymers containing heteroatom bonds, and it has excellent stability. In summary, the sulfonated polyarylalkane provided by the present invention exhibits excellent proton conduction performance and structural stability, and has broad application prospects.

[0045] The present invention also provides a method for preparing the sulfonated polyarylalkane described in the above scheme, comprising the steps of: mixing a polyarylalkane having a structure represented by Formula II, a base, a sodium-terminated mercaptoalkylsulfonate, and a polar organic solvent to carry out a substitution reaction to obtain the sulfonated polyarylalkane. The present invention utilizes a polyarylalkane having a bromine substituent in its side chain (Formula II) as a raw material, and introduces a sulfonic acid group into the side chain via the sodium-terminated mercaptoalkylsulfonate, thereby developing a new polyarylalkane sulfonation strategy that is simple to operate and highly efficient, broadening the development of polyarylalkane side chain grafting methods and polyarylalkane proton exchange membranes.

[0046] The present invention also provides a sulfonated polyarylalkyl proton exchange membrane and a preparation method thereof. The sulfonated polyarylalkyl proton exchange membrane provided by the present invention has excellent proton conductivity, and does not require the addition of other additives to the membrane, does not cause the problem of additive precipitation, has good structural stability, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 1 is the H NMR spectrum of the product before and after sulfonation in Example 1;

[0048] Figure 2 1H NMR spectra of the products before and after sulfonation in Example 2;

[0049] Figure 3 1H NMR spectra of the products before and after sulfonation in Example 3;

[0050] Figure 4 1H NMR spectra of the products before and after sulfonation in Example 4;

[0051] Figure 5 1H NMR spectra of the products before and after sulfonation in Example 5;

[0052] Figure 6 1 is the H NMR spectrum of the product before and after sulfonation in Example 6. DETAILED DESCRIPTION

[0053] The present invention provides a sulfonated polyarylalkane, the structural formula of which is shown in Formula I:

[0054]

[0055] In formula I, a is 1 to 10, b is 1 to 10, n represents the degree of polymerization, and Ar is any one or more of the following structures:

[0056]

[0057]

[0058] R is any of the following structures: R1 is H or Na.

[0059] In the present invention, in the structure of Ar, Ar with two broken bonds indicates two reaction sites, and the polymer is a linear polymer; Ar with three broken bonds indicates three reaction sites, and the polymer is a bulk polymer.

[0060] In the present invention, when Ar is two or more of the above structures, the Ar portion of the sulfonated polyarylalkane is a copolymer of two or more aromatic hydrocarbons. Specifically, when Ar is two, the structure of the sulfonated polyarylalkane is represented as follows (wherein m and n represent the degree of polymerization):

[0061]

[0062] In the present invention, the value of a in Formula I can be specifically 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, and the value of b can be specifically 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.

[0063] In the present invention, the weight average molecular weight of the sulfonated polyarylalkane is preferably 40 kDa-200 kDa.

[0064] In a specific embodiment of the present invention, the sulfonated polyarylalkane is preferably any one of the following structures:

[0065]

[0066]

[0067] In formula I-5, m and n represent the degree of polymerization, wherein the value of n / (m+n) is preferably 50 to 70%.

[0068] The present invention also provides a method for preparing the sulfonated polyarylalkane described in the above scheme. When R1 in Formula I is Na, the preparation method (denoted as Method 1) comprises the following steps:

[0069] Mixing polyarylalkane, a base, sodium terminal mercaptoalkyl sulfonate and a polar organic solvent to carry out a substitution reaction to obtain the sulfonated polyarylalkane;

[0070] The structural formula of the polyarylalkane is shown in Formula II:

[0071]

[0072] In formula II: the types of Ar and R are the same as those in formula I, a is 1 to 10, and n represents the degree of polymerization;

[0073] The structure of the sodium sulfonate terminated with mercapto groups is shown in Formula III:

[0074]

[0075] In formula III, the value of b is 1 to 10;

[0076] When R1 in Formula I is H, the preparation method (denoted as Method 2) comprises the following steps:

[0077] The sulfonated polyarylalkane wherein R1 is Na is acidified to obtain the sulfonated polyarylalkane wherein R1 is H.

[0078] First, the method for preparing polyarene will be described.

[0079] In the present invention, the preparation method of the polyarylalkane preferably comprises the following steps:

[0080] Aromatic hydrocarbons, carbonyl compounds, organic acids and polar organic solvents (referred to as the first polar organic solvent) are mixed and subjected to condensation reaction to obtain polyarylalkane having a structure shown in Formula II;

[0081] The structure of the carbonyl compound is shown in Formula IV:

[0082]

[0083] The type of R in formula IV is the same as that in formula I, and the value of a is 1-10.

[0084] In the present invention, the structure of the aromatic hydrocarbon is H-Ar-H, wherein the type of Ar is the same as that in Formula I; specifically, the aromatic hydrocarbon is preferably any one or more of the following structures:

[0085]

[0086] In the present invention, the carbonyl compound is preferably any one of the following structures:

[0087]

[0088] In the present invention, the molar ratio of the aromatic hydrocarbon to the carbonyl compound is preferably 1:(1-2), specifically 1:1, 1:1.1, 1:1.5 or 1:2; the organic acid preferably includes one or more of trifluoromethanesulfonic acid, trifluoroacetic acid and methanesulfonic acid; the molar ratio of the aromatic hydrocarbon to the organic acid is preferably 1:(4-50), specifically 1:5, 1:7, 1:10, 1:20, 1:30 or 1:50; the first polar solvent is preferably one or more of dichloromethane and bromoform. In the present invention, the mass ratio of the first polar solvent to the aromatic hydrocarbon is preferably (10-60):1; the temperature of the condensation reaction is preferably -20-80°C, specifically -20°C, 0°C, 25°C, 50°C or 80°C, and the time of the condensation reaction is preferably 24-72h, specifically 24h, 36h, 48h or 72h. In a specific embodiment of the present invention, it is preferred to first mix the aromatic hydrocarbon and the first organic solvent, and then add the organic acid dropwise at 0°C under stirring conditions, and after the addition is complete, react at the condensation reaction temperature. During the condensation reaction, the carbonyl group in the carbonyl compound forms a carbon cation under the action of the organic acid, and undergoes a classic condensation reaction with the aromatic hydrocarbon to achieve chain growth and thus polymerization. After the condensation reaction is completed, the present invention preferably adds the product liquid to a second polar solvent to precipitate the solid product, and then separates the solid product and washes and dries it to obtain a polyarylalkane having a structure shown in Formula II; the second polar solvent is preferably one or more of ethanol, methanol and acetone; the precipitation of the solid product is carried out under stirring conditions, and the stirring time is preferably 1 to 4 hours.

[0089] In the present invention, the polyarylalkane may specifically be a biphenyl-3-bromo-1,1,1-trifluoroacetone copolymer or a terphenyl-biphenyl-3-bromo-1,1,1-trifluoroacetone terpolymer.

[0090] The following is an explanation of the first method for preparing sulfonated polyarylalkane.

[0091] When R1 in Formula I is Na, the present invention mixes a polyarylalkane, a base, a sodium terminal mercaptoalkyl sulfonate, and a polar organic solvent (referred to as a third organic solvent) to carry out a substitution reaction to obtain the sulfonated polyarylalkane. In the present invention, the sodium terminal mercaptoalkyl sulfonate is preferably sodium mercaptoethanesulfonate or sodium 3-mercapto-1-propanesulfonate; the molar ratio of the polyarylalkane to the sodium terminal mercaptoalkyl sulfonate is preferably 1:(1-5), specifically 1:1, 1:2, 1:3, 1:4, or 1:5; the base preferably includes one or more of sodium hydride, sodium hydroxide, potassium hydroxide, and potassium carbonate; the molar ratio of the polyarylalkane to the base is preferably 1:(1-5), specifically 1:1, 1:2, 1:3, 1:4, or 1:5; the third organic solvent is preferably one or more of dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide; the mass ratio of the third organic solvent to the polyarylalkane is preferably (20-60):1.

[0092] In the present invention, the temperature of the sulfonation reaction is preferably 50-120°C, specifically 80°C, 100°C, or 120°C; the duration of the sulfonation reaction is preferably 3-8 days, specifically 3 days, 5 days, 7 days, or 8 days. In a specific embodiment of the present invention, the polyarylalkane is preferably first dissolved in a third polar organic solvent, and then a base and sodium-terminated mercaptoalkylsulfonate are added, followed by the reaction at the sulfonation reaction temperature. During the sulfonation reaction, the sodium-terminated mercaptoalkylsulfonate undergoes a substitution reaction with the polyarylalkane containing a bromine substituent in the side chain under alkaline conditions to produce a sulfonated polyarylalkane. After the reaction, the present invention preferably adds the product liquid to acetone to precipitate the solid product, and then separates the solid product, washes, and dries it to obtain a sulfonated polyarylalkane wherein R1 is Na.

[0093] The second method for preparing sulfonated polyarylalkane is described below.

[0094] When R1 in formula I is H, the sulfonated polyarylalkane wherein R1 is Na is acidified to obtain the sulfonated polyarylalkane wherein R1 is H. In the present invention, the reagent used for the acidification is preferably a sulfuric acid solution, and the concentration of the sulfuric acid solution is preferably 0.5 to 3 mol L -1 , specifically 1 mol L -1 , 1.5 mol L -1 , 2 mol L -1 or 3 mol L -1 The acidification temperature is preferably 60 to 100°C, specifically 60°C, 80°C or 100°C, and the acidification time is preferably 12 to 72h, specifically 24h.

[0095] The present invention also provides a sulfonated polyarylalkyl proton exchange membrane, wherein the material of the sulfonated polyarylalkyl proton exchange membrane is sulfonated polyarylalkyl, and the sulfonated polyarylalkyl is the sulfonated polyarylalkyl described in the above scheme or the sulfonated polyarylalkyl prepared by the preparation method described in the above scheme; R1 in the sulfonated polyarylalkyl is H.

[0096] The present invention also provides a method for preparing the sulfonated polyarylalkyl proton exchange membrane described in the above scheme. The preparation methods are described below according to the type of R1 in Formula I.

[0097] When R1 in Formula I is Na, the preparation method of the sulfonated polyarylalkane proton exchange membrane comprises the following steps:

[0098] dissolving the sulfonated polyarylalkane in a polar organic solvent (denoted as the fourth polar organic solvent) to obtain a casting solution;

[0099] casting the casting solution into a film to obtain a sodium-type thin film;

[0100] The sodium-type membrane is acidified with sulfuric acid to obtain the sulfonated polyarylalkane proton exchange membrane.

[0101] In the present invention, the fourth polar organic solvent preferably includes one or more of dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylformamide and N,N-dimethylacetamide; the concentration of the sulfonated polyarylalkane in the casting solution is preferably 50 to 100 mg mL -1 , specifically 60 mg mL -1 , 80mg mL -1 or 100 mg mL -1 The casting film includes: casting the casting liquid and then drying it to obtain a sodium-type thin film; the drying temperature is preferably 50 to 120°C, and the drying time is preferably 24 hours.

[0102] In the present invention, the acidification reagent is preferably a sulfuric acid solution, and the concentration of the sulfuric acid solution is preferably 0.5 to 3 mol L -1 , specifically 1 mol L -1 , 1.5 mol L -1 , 2 mol L -1 or 3 mol L -1 The acidification temperature is preferably 60 to 100°C, specifically 60°C, 80°C or 100°C, and the acidification time is preferably 12 to 72h, specifically 24h.

[0103] In the present invention, when R1 in Formula I is H, the method for preparing the sulfonated polyarylalkane proton exchange membrane comprises the following steps:

[0104] dissolving the sulfonated polyarylalkane in a polar organic solvent to obtain a casting solution;

[0105] The casting solution is cast into a membrane to obtain the sulfonated polyarylalkyl proton exchange membrane.

[0106] In the present invention, when R1 in Formula I is H, the preparation method of the sulfonated polyarylalkane proton exchange membrane is the same as the preparation method when R1 in Formula I is Na, except that the acidification step is omitted.

[0107] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0108] Example 1

[0109] Add 15 mL of dichloromethane and 1 g of biphenyl (CAS No. 92-52-4) to a three-necked flask. Add 800 μL of 3-bromo-1,1,1-trifluoroacetone (CAS No. 431-35-6) with stirring. After stirring for 5 minutes, slowly add 4 mL of trifluoromethanesulfonic acid (CAS No. 1493-13-6) dropwise at 0°C. After the addition is complete, return the mixture to room temperature and allow to react for 24 hours. After the reaction is complete, precipitate the product in ethanol and stir until precipitation is complete. Then, wash it three times with hot ethanol under reflux. The washed product is a biphenyl-3-bromo-1,1,1-trifluoroacetone copolymer, which is then air-dried at room temperature for later use.

[0110] Take 1g of diphenyl-3-bromo-1,1,1-trifluoroacetone copolymer in a round-bottom flask, add 40mL of DMSO, and after complete dissolution at 60°C, add 0.5g of sodium hydroxide and 1g of sodium 3-mercapto-1-propanesulfonate (CAS No.: 17636-10-1) to the system. After the addition is completed, the temperature is raised to 80°C and reacted for 5 days. After the reaction is completed, the product is precipitated in acetone and washed three times. The washed sulfonated polyarylalkane is placed at 60°C and dried for 24 hours.

[0111] 0.18g of the sulfonated polyarylamine prepared in the previous step was dissolved in 3mL of DMSO and stirred to dissolve. The resulting casting solution was cast at 80°C and then dried at 80°C for 24 hours to obtain a sulfonated propyl polybiphenyl-trifluoroacetone proton exchange membrane (Na-type) with a thickness of 50±3μm. The resulting proton exchange membrane was soaked in 1MH2SO4 for 24 hours to replace the sodium ions in the membrane with hydrogen ions. The membrane was then washed with deionized water until neutral, removing excess acid ions in the system, and obtaining a hydrogen-type sulfonated propyl polybiphenyl-trifluoroacetone proton exchange membrane.

[0112] Figure 1 The NMR hydrogen spectra of the products before and after sulfonation are shown in Figure 2. Figure 1 It can be seen that this example successfully introduced sulfonic acid groups into the polyarylalkane.

[0113] Example 2

[0114] The aromatic hydrocarbon was replaced with p-terphenyl (CAS No.: 92-94-4), 3-bromo-1,1,1-trifluoroacetone was selected as the carbonyl compound, and sodium 3-mercapto-1-propanesulfonate was selected as the sulfonating reagent to prepare the sulfonated propyl polyterphenyl-trifluoroacetone proton exchange membrane. The other steps were the same as in Example 1. Figure 2 1 is the H NMR spectrum of the product before and after sulfonation.

[0115] Example 3

[0116] The aromatic hydrocarbon was replaced with biphenyl (CAS No.: 92-94-4), 3-bromo-1,1,1-trifluoroacetone was selected as the carbonyl compound, and sodium 2-mercaptoethanesulfonate (CAS No.: 19767-45-4) was selected as the sulfonating reagent to prepare the sulfonated ethyl polybiphenyl-trifluoroacetone proton exchange membrane. The other steps were the same as in Example 1. Figure 3 1 is the H NMR spectrum of the product before and after sulfonation.

[0117] Example 4

[0118] The aromatic hydrocarbon was replaced by terphenyl, the carbonyl compound was selected as 3-bromo-1,1,1-trifluoroacetone, and the sulfonating reagent was selected as sodium 2-mercaptoethane sulfonate to prepare the sulfonated ethyl polyterphenyl-trifluoroacetone proton exchange membrane. The other steps were the same as those in Example 1. Figure 4 H NMR spectra of the products before and after sulfonation.

[0119] Example 5

[0120] To a three-necked flask, add 20 mL of dichloromethane, 1 g of biphenyl, and 1.4 g of terphenyl. Add 1.6 mL of 3-bromo-1,1,1-trifluoroacetone while stirring. After stirring for 5 minutes, slowly add 7 mL of trifluoromethanesulfonic acid dropwise at 0°C. After the addition is complete, return the mixture to room temperature and allow to react for 24 hours. After the reaction is complete, precipitate the product in ethanol and stir until precipitation is complete. Then, wash it three times with hot ethanol under reflux. The washed product, a terphenyl-biphenyl-3-bromo-1,1,1-trifluoroacetone terpolymer, is left to air-dry at room temperature for later use.

[0121] Take 1g of the above-mentioned terphenyl-biphenyl-3-bromo-1,1,1-trifluoroacetone terpolymer in a round-bottom flask, add 40mL DMSO, and after complete dissolution at 60°C, add 0.5g sodium hydroxide and 1g 3-mercapto-1-propanesulfonic acid sodium to the system. After the addition is completed, the temperature is raised to 80°C and reacted for 5 days. After the reaction is completed, the product is precipitated into acetone and washed three times. The washed sulfonated polyarylalkane is placed at 60°C and dried for 24 hours.

[0122] 0.18g of the sulfonated polyarylalkane prepared in the previous step was dissolved in 3mL of DMSO and stirred to dissolve. The resulting casting solution was cast into a membrane at 80°C and dried at 80°C for 24 hours to obtain a sulfonated propyl poly(terphenyl-biphenyl-trifluoroacetone) proton exchange membrane (sodium form) with a thickness of 50±3μm. The resulting proton exchange membrane was soaked in 1M H2SO4 for 24 hours to replace the sodium ions in the membrane with hydrogen ions. The membrane was then washed with deionized water until neutral, removing excess acid ions in the system, and obtaining a hydrogen-type sulfonated propyl poly(biphenyl-trifluoroacetone) proton exchange membrane. Figure 5 H NMR spectra of the products before and after sulfonation.

[0123] Example 6

[0124] To a three-necked flask, add 20 mL of dichloromethane, 1.4 g of biphenyl, and 0.9 g of terphenyl. Add 1.6 mL of 3-bromo-1,1,1-trifluoroacetone with stirring. After stirring for 5 minutes, slowly add 7 mL of trifluoromethanesulfonic acid dropwise at 0°C. After the addition is complete, return the mixture to room temperature and allow to react for 24 hours. After the reaction, precipitate the product in ethanol and stir until complete. Then, wash it three times with hot ethanol under reflux. The washed product, a terphenyl-biphenyl-3-bromo-1,1,1-trifluoroacetone terpolymer, is allowed to air-dry at room temperature.

[0125] Take 1g of the above-mentioned terphenyl-biphenyl-3-bromo-1,1,1-trifluoroacetone terpolymer in a round-bottom flask, add 40mL DMSO, and after complete dissolution at 60°C, add 0.5g sodium hydroxide and 1g 3-mercapto-1-propanesulfonic acid sodium to the system. After the addition is completed, the temperature is raised to 80°C and reacted for 5 days. After the reaction is completed, the product is precipitated into acetone and washed three times. The washed sulfonated polyarylalkane is placed at 60°C and dried for 24 hours.

[0126] 0.18g of the sulfonated polyarylalkane prepared in the previous step was dissolved in 3mL of DMSO and stirred to dissolve. The resulting casting solution was cast into a membrane at 80°C and dried at 80°C for 24 hours to obtain a sulfonated propyl poly(terphenyl-biphenyl-trifluoroacetone) proton exchange membrane (Na-type) with a thickness of 50±3μm. The resulting proton exchange membrane was soaked in 1M H2SO4 for 24 hours to replace the sodium ions in the membrane with hydrogen ions. The membrane was then washed with deionized water until neutral, removing excess acid ions in the system, and obtaining a hydrogen-type sulfonated propyl poly(biphenyl-trifluoroacetone) proton exchange membrane. Figure 6 H NMR spectra of the products before and after sulfonation.

[0127] Test example:

[0128] 1. Proton conductivity test

[0129] The proton conductivity of the proton exchange membranes prepared in Examples 1 to 6 was tested using an AC impedance meter. All membranes were immersed in water at different temperatures (30 to 80° C.) and the conductivity was measured in a fully wet state in the water. The test results are shown in Table 1.

[0130] Table 1 Proton conductivity under different temperature conditions of Examples 1 to 6

[0131]

[0132] As can be seen from Table 1, the sulfonated polyarylalkyl proton exchange membrane of the present invention has excellent proton conductivity. Furthermore, the sulfonated polyarylalkyl proton exchange membrane of the present invention does not require any other additives, does not have the problem of additive precipitation, and has good structural stability.

[0133] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A sulfonated polyarylalkane, characterized in that The structural formula is shown in Formula I: In formula I, a is 1 to 10, b is 1 to 10, n represents the degree of polymerization, and Ar is any one or more of the following structures: R is any of the following structures: R1 is H or Na.

2. The method for preparing the sulfonated polyarylalkane according to claim 1, characterized in that: When R1 in formula I is Na, the preparation method comprises the following steps: Mixing polyarylalkane, a base, sodium terminal mercaptoalkyl sulfonate and a polar organic solvent to carry out a substitution reaction to obtain the sulfonated polyarylalkane wherein R1 is Na; The structural formula of the polyarylalkane is shown in Formula II: In formula II: the types of Ar and R are the same as those in formula I, a is 1 to 10, and n represents the degree of polymerization; The structure of the sodium sulfonate terminated with mercapto groups is shown in Formula III: In formula III, the value of b is 1 to 10; When R1 in formula I is H, the preparation method comprises the following steps: The sulfonated polyarylalkane wherein R1 is Na is acidified to obtain the sulfonated polyarylalkane wherein R1 is H.

3. The preparation method according to claim 2, characterized in that The preparation method of the polyarylalkane comprises the following steps: Aromatic hydrocarbons, carbonyl compounds, organic acids and polar organic solvents are mixed and subjected to condensation reaction to obtain polyarylalkane having a structure shown in Formula II; The structure of the carbonyl compound is shown in Formula IV; The type of R in formula IV is the same as that in formula I, and the value of a is 1-10.

4. The preparation method according to claim 3, characterized in that The molar ratio of the aromatic hydrocarbon to the carbonyl compound is 1:(1-2); The organic acid includes one or more of trifluoromethanesulfonic acid, trifluoroacetic acid and methanesulfonic acid; the molar ratio of the aromatic hydrocarbon to the organic acid is 1:(4-50); The temperature of the condensation reaction is -20 to 80° C., and the reaction time is 24 to 72 hours.

5. The preparation method according to claim 2, characterized in that The sodium sulfonate terminated with mercaptoalkyl is sodium mercaptoethanesulfonate or sodium 3-mercapto-1-propanesulfonate; the molar ratio of the polyarylalkane to the sodium sulfonate terminated with mercaptoalkyl is 1:(1-5); The base includes one or more of sodium hydride, sodium hydroxide, potassium hydroxide and potassium carbonate; the molar ratio of the polyarylalkane to the base is 1:(1-5); The temperature of the sulfonation reaction is 50-120° C., and the reaction time is 3-8 days.

6. A sulfonated polyarylalkane proton exchange membrane, characterized in that: The material of the sulfonated polyarylalkane proton exchange membrane is sulfonated polyarylalkane, which is the sulfonated polyarylalkane according to claim 1 or the sulfonated polyarylalkane prepared by the preparation method according to any one of claims 2 to 5, and R1 in the sulfonated polyarylalkane is H.

7. The method for preparing the sulfonated polyarylalkane proton exchange membrane according to claim 6, characterized in that: When R1 in Formula I is Na, the preparation method comprises the following steps: dissolving the sulfonated polyarylalkane in a polar organic solvent to obtain a casting solution; casting the casting solution into a film to obtain a sodium-type thin film; Acidifying the sodium-type membrane to obtain the sulfonated polyarylalkyl proton exchange membrane; When R1 in Formula I is H, the preparation method comprises the following steps: dissolving the sulfonated polyarylalkane in a polar organic solvent to obtain a casting solution; The casting solution is cast into a membrane to obtain the sulfonated polyarylalkyl proton exchange membrane.

8. The preparation method according to claim 7, characterized in that The polar organic solvent includes one or more of dimethyl sulfoxide, N-methylpyrrolidone, N,N-dimethylformamide and N,N-dimethylacetamide; the concentration of sulfonated polyarylalkane in the casting solution is 50-100 mg mL -1 .

9. The preparation method according to claim 7, characterized in that The casting and forming of the membrane comprises: casting the membrane liquid and then drying it; the drying temperature is 50-120°C.

10. The preparation method according to claim 7, characterized in that The acidification reagent used is sulfuric acid solution, and the concentration of the sulfuric acid solution is 0.5-3 mol L -1 The acidification temperature is 60-100° C. and the time is 12-72 hours.

Images