Sulfonated polysulfone without foam during film formation and its preparation method

Abstract

The present invention discloses a sulfonated polysulfone that is foam-free during film formation and a preparation method thereof, and relates to the technical field of sulfonated polysulfones. The present invention replaces part of DCDPS with a sulfonated monomer SDCDPS, which is copolymerized with bisphenol A, with a sulfonation degree of 1-5%. After polymerization is completed, when chloromethane is used for end-capping, a quaternary ammonium salt catalyst TBAB and an ionic liquid are added to improve the end-capping activity of chloromethane on the sulfonated polysulfone and the small molecule sulfonated polysulfone during the polymerization process, thereby reducing the content of uncapped small molecule sulfonated polysulfone. In the washing process of the sulfonated polysulfone, a mixed system of a polar aprotic solvent and water in an appropriate ratio is used for post-treatment, further reducing the content of small molecules in the sulfonated polysulfone, ultimately reducing the generation of foam, and facilitating the application of the sulfonated polysulfone in downstream film making.

Description

Technical Field

[0001] The invention relates to the technical field of sulfonated polysulfone, in particular to sulfonated polysulfone without foam during film formation and a preparation method thereof. Background Art

[0002] Polysulfone resin (PSU) is a non-crystalline special engineering plastic. Because it contains sulfone groups, isopropyl groups, and benzene rings, it has good antioxidant properties, mechanical properties, and thermal stability. The presence of ether bonds also provides it with a certain degree of toughness. Therefore, due to its excellent properties, polysulfone resin is widely used in high-end medical, electronic products, water treatment, aerospace and other fields.

[0003] Polysulfone is generally hydrophobic. However, hollow fiber ultrafiltration membranes and flat membranes containing hydrophobic polysulfone suffer from poor wettability, easy scaling, and difficulty in cleaning when used for separation and filtration. Therefore, to improve the hydrophilicity of polysulfone, polar groups such as carboxyl, hydroxyl, sulfonic acid, and amino groups can be introduced to improve the hydrophilicity of polysulfone. Sulfonated polysulfone has a long history of research and development and is already commercially produced.

[0004] The sulfonation degree of common sulfonated polysulfones on the market ranges from 5% to 100%. The polymerization process for sulfonated polysulfones is similar to that of conventional polysulfones, namely, bisphenol A, sulfonated 4,4'-dichlorodiphenyl sulfone, and 4,4'-dichlorodiphenyl sulfone monomers undergo salt formation and nucleophilic substitution polycondensation in the presence of an alkaline nucleophile, typically potassium carbonate, and a solvent such as N,N-dimethylacetamide (DMCA) or N-methylpyrrolidone (NMP). After polymerization, the polymer solution is capped with chloroform to obtain a polymer solution, which is then separated, purified, dried, granulated, and packaged to obtain the product. Alternatively, the polymerized polysulfone is directly sulfonated after capping. However, this method makes it difficult to precisely control the sulfonation degree and difficult to produce polysulfone with a low sulfonation degree. The resulting sulfonated polysulfone tends to agglomerate and yellow, and its industrial application prospects are limited.

[0005] Sulfonated polysulfone with a sulfonation degree of over 10% exhibits excessively high hydrophilicity and poor membrane strength, failing to meet performance standards. Therefore, highly sulfonated polysulfone is often mixed with conventional polysulfone as a hydrophilic additive to form membranes. However, with this type of membrane formation method, when the casting solution comes into contact with the coagulation bath (water), the hydrophilic small molecules in the highly sulfonated polysulfone easily escape from the membrane body during the solvent-water exchange process, entering the water to form a large amount of foam, which then adheres to the membrane surface, clogging the membrane pores and reducing membrane flux.

[0006] The hydrophilic small molecules in sulfonated polysulfone mainly come from: the slow polymerization rate of highly sulfonated polysulfone, the wide molecular weight distribution, and the large number of residual small molecules; the sulfonate group, due to its large size and strong polarity, will physically restrict the non-polar chloromethane from approaching the active site of the terminal phenolate group, hindering the nucleophilic attack of chloromethane and causing significant steric hindrance. In a high-sulfonation system, the dense distribution of sulfonate groups will further aggravate the steric hindrance effect, and the terminal hydroxyl groups of small-molecule sulfonated polysulfone will further increase its hydrophilicity. Such uncapped hydrophilic small molecules are easily separated from the membrane body during the solvent exchange process during membrane formation to form foam, affecting membrane quality.

[0007] Therefore, synthesizing low-sulfonation degree polysulfone to form a separate membrane, accelerating the polymerization reaction rate of sulfonated polysulfone, reducing the content of hydrophilic small molecules in sulfonated polysulfone, increasing the end-capping rate of hydrophilic small molecules, and reducing the generation of foam are of great significance for promoting the application of sulfonated polysulfone. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide a sulfonated polysulfone that does not foam during film formation and a preparation method thereof. The synthesized low-sulfonation-degree polysulfone can form a film alone. The sulfonated polysulfone has a low content of hydrophilic small molecules and a high end-capping rate of the hydrophilic small molecules, which can reduce the generation of foam and is conducive to its application in downstream film making.

[0009] The technical solution of the present invention is:

[0010] In one aspect, the present invention provides a method for preparing a sulfonated polysulfone that does not produce foam during film formation, comprising the steps of:

[0011] S1: bisphenol A, dichloromonomer, a salt-forming agent, and a water-separating agent are placed in a polar aprotic solvent, a protective gas is introduced, the temperature is raised to 120-150°C, and the temperature is maintained for 2-8 hours to carry out a salt-forming reaction; after the water extraction reaches the theoretical value and the salt-forming reaction is completed, the temperature is further raised to 160-200°C and the temperature is maintained for 2-10 hours to carry out a nucleophilic polycondensation reaction to obtain a sulfonated polysulfone resin polymer solution; wherein the salt-forming agent is cesium carbonate, potassium carbonate, or sodium carbonate; the water-separating agent is toluene, xylene, trimethylbenzene, ethylbenzene, or ethylidene; the dichloromonomers are 3,3'-sodium disulfonate-4,4'-dichlorodiphenyl sulfone (SDCDPS) and 4,4'-dichlorodiphenyl sulfone (DCDPS), and the molar percentage of 3,3'-sodium disulfonate-4,4'-dichlorodiphenyl sulfone in the dichloromonomer is 1-5%;

[0012] S2: Cooling the sulfonated polysulfone resin polymerization liquid, adding an ionic liquid and a quaternary ammonium salt catalyst tetrabutylammonium bromide (TBAB), and introducing chloromethane for end-capping to obtain an end-capped sulfonated polysulfone resin polymerization liquid; wherein the ionic liquid is 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonylimide), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonylimide), or N-ethylpyridine bis(trifluoromethylsulfonylimide);

[0013] S3: crushing the blocked sulfonated polysulfone resin polymer solution, extracting with a mixed solvent, filtering, and drying to obtain a sulfonated polysulfone without foam during film formation; wherein the mixed solvent is a mixture of a polar aprotic solvent and deionized water.

[0014] Preferably, in step S2, the molar ratio of the quaternary ammonium salt catalyst tetrabutylammonium bromide to 3,3'-sodium disulfonate-4,4'-dichlorodiphenyl sulfone is (1.05-1.2):1.

[0015] Preferably, in step S1, the molar ratio of bisphenol A, dichloromonomer, and salt-forming agent is 1:(0.85-1):(1-3); the mass ratio of the total mass of bisphenol A and dichloromonomer to the polar aprotic solvent is 1:(2.5-5).

[0016] Preferably, in step S1, the mass ratio of the water-separating agent to the polar aprotic solvent is (0.2-0.4):1.

[0017] Preferably, in step S1 and step S3, the polar aprotic solvent is N,N-dimethylacetamide (DMAC) or N-methylpyrrolidone (NMP).

[0018] Preferably, in step S2, the amount of ionic liquid added is 1-5 wt.% of the polar aprotic solvent in step S1.

[0019] Preferably, in step S2, the end-capping process of the sulfonated polysulfone resin polymer solution is as follows: after adding ionic liquid and quaternary ammonium salt catalyst tetrabutylammonium bromide, cooling to 90-150° C., introducing chloromethane, and reacting for 1-4 hours to obtain the end-capped sulfonated polysulfone resin polymer solution.

[0020] Preferably, in step S3, the content of the polar aprotic solvent in the mixed solvent is 5-25 wt.%.

[0021] In another aspect, the present invention provides sulfonated polysulfone that does not produce foam during film formation, which is prepared by the above-mentioned method for preparing sulfonated polysulfone that does not produce foam during film formation.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention reduces the proportion of sulfonated monomers in the dichloromonomer and the proportion of sulfonate groups, thereby increasing the polymerization rate and reducing the production of small molecules in the sulfonated polysulfone. Furthermore, the present invention adds an ionic liquid and a quaternary ammonium salt catalyst, TBAB, during the end-capping stage after polymerization is completed. The quaternary ammonium cations in the TBAB bind to the sulfonate groups through electrostatic attraction, forming ion pairs. This action shields the negative charge of the sulfonate groups, thereby reducing the resistance to nucleophilic attack by methyl chloride, increasing the end-capping rate of the sulfonated polysulfone small molecules, reducing the hydrophilicity of the small molecules, and preventing the formation of foam during film formation. Furthermore, the anion Tf2N in the ionic liquid - With Br - Dynamic exchange occurs, forming a more stable tetrabutylammonium-Tf2N complex with stronger catalytic ability. In addition, during the precipitation process of the polymer solution, the present invention adds 5-25wt.% of a polar aprotic solvent to the washing water, and utilizes the difference in solubility of the polar aprotic solvent for the sulfonated polysulfone macromolecule and small molecules to further remove the sulfonated polysulfone small molecules. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0025] Example 1

[0026] The preparation method of the sulfonated polysulfone without foaming during film formation of the present embodiment comprises the following steps:

[0027] S1: In a 100 L polymerization reactor, 68.96 kg of DMAC, 6084.34 g of bisphenol A, 130.93 g of SDCDPS, 7576.8 g of DCDPS, 3866.67 g of potassium carbonate, and 13.79 kg of xylene were added. After nitrogen replacement three times, nitrogen was introduced to allow the reaction to proceed to normal pressure. Nitrogen protection was applied throughout the polymerization reaction. The temperature was raised to 120° C. and the reaction was maintained at this temperature for 8 h. After the theoretical water production was reached, all the xylene was evaporated, the temperature was raised to 160° C., and the reaction was maintained at this temperature for 10 h to obtain a sulfonated polysulfone resin polymerization solution.

[0028] S2: The sulfonated polysulfone resin polymerization liquid was cooled to 150° C., 689.6 g of 1-butyl-3-methylimidazole bis(trifluoromethylsulfonyl)imide and 90.21 g of TBAB were added, and chloromethane was introduced to cap the mixture for 1 hour to obtain a capped sulfonated polysulfone resin polymerization liquid;

[0029] S3: The blocked sulfonated polysulfone resin polymer solution is poured into cold water to cool and precipitate, and then mechanically crushed into powder. The powder is then boiled several times with a mixed water solvent containing 5 wt.% DMAC, filtered, and dried to obtain a sulfonated polysulfone without foam when forming a film.

[0030] Example 2

[0031] The preparation method of the sulfonated polysulfone without foaming during film formation of the present embodiment comprises the following steps:

[0032] S1: In a 100 L polymerization reactor, 62.31 kg of NMP, 6084.34 g of bisphenol A, 261.85 g of SDCDPS, 7500.27 g of DCDPS, 2965.26 g of sodium carbonate, and 18.69 kg of toluene were added. After nitrogen replacement three times, nitrogen was introduced to allow the reaction to proceed to normal pressure. Nitrogen protection was applied throughout the polymerization reaction. The temperature was raised to 125° C. and the reaction was maintained at this temperature for 4 h. After reaching the theoretical water production rate, all the toluene was evaporated, the temperature was raised to 170° C., and the reaction was maintained at this temperature for 9 h to obtain a sulfonated polysulfone resin polymerization solution.

[0033] S2: Cool the sulfonated polysulfone resin polymerization liquid to 90°C, add 1246.18g of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt and 189.02g of TBAB, introduce chloromethane, and cap the mixture for 2h to obtain a capped sulfonated polysulfone resin polymerization liquid;

[0034] S3: Pour the blocked sulfonated polysulfone resin polymer solution into cold water to cool and precipitate, grind it into powder mechanically, boil it several times with a mixed water solvent containing 10wt.% NMP, filter and dry it to obtain a sulfonated polysulfone without foam when forming a film.

[0035] Example 3

[0036] The preparation method of the sulfonated polysulfone without foaming during film formation of the present embodiment comprises the following steps:

[0037] S1: In a 100 L polymerization reactor, 41.7 kg of NMP, 6084.34 g of bisphenol A, 392.78 g of SDCDPS, 7423.73 g of DCDPS, 9115.38 g of cesium carbonate and 16.68 kg of trimethylbenzene were added. After nitrogen replacement three times, nitrogen was introduced to react at normal pressure. Nitrogen protection was performed throughout the polymerization reaction; the temperature was raised to 130° C. and the temperature was kept for 5 h. After reaching the theoretical water production, all trimethylbenzene was evaporated, the temperature was raised to 185° C. and the temperature was kept for 7 h to obtain a sulfonated polysulfone resin polymerization solution;

[0038] S2: Cool the sulfonated polysulfone resin polymerization liquid to 150°C, add 1668.1g of N-ethylpyridine bis(trifluoromethanesulfonyl)imide salt and 309.3g of TBAB, introduce chloromethane, and cap the mixture for 4h to obtain a capped sulfonated polysulfone resin polymerization liquid;

[0039] S3: Pour the blocked sulfonated polysulfone resin polymer solution into cold water to cool and precipitate, grind it into powder mechanically, boil it several times with a mixed water solvent containing 15wt.% NMP, filter and dry it to obtain a sulfonated polysulfone without foam when forming a film.

[0040] Example 4

[0041] The preparation method of the sulfonated polysulfone without foaming during film formation of the present embodiment comprises the following steps:

[0042] S1: In a 100 L polymerization reactor, 34.89 kg of NMP, 6084.34 g of bisphenol A, 523.71 g of SDCDPS, 7347.2 g of DCDPS, 2801.03 g of potassium carbonate, and 13.96 kg of ethylbenzene were added. After nitrogen replacement three times, nitrogen was introduced to react at normal pressure. Nitrogen protection was performed throughout the polymerization reaction. The temperature was raised to 145° C. and kept at this temperature for 4 hours. After reaching the theoretical water production, all ethylbenzene was evaporated, and the temperature was raised to 190° C. and kept at this temperature for 4 hours to obtain a sulfonated polysulfone resin polymerization solution.

[0043] S2: Cool the sulfonated polysulfone resin polymerization liquid to 150° C., add 1071.12 g of 1-butyl-3-methylimidazole bis(trifluoromethylsulfonyl)imide and 412.4 g of TBAB, introduce chloromethane, and cap the mixture for 2 h to obtain a capped sulfonated polysulfone resin polymerization liquid;

[0044] S3: Pour the blocked sulfonated polysulfone resin polymer solution into cold water to cool and precipitate, grind it into powder mechanically, boil it several times with a mixed water solvent containing 20wt.% NMP, filter and dry it to obtain a sulfonated polysulfone without foam when forming a film.

[0045] Example 5

[0046] The preparation method of the sulfonated polysulfone without foaming during film formation of the present embodiment comprises the following steps:

[0047] S1: In a 100 L polymerization reactor, 70.05 kg of NMP, 6084.34 g of bisphenol A, 654.64 g of SDCDPS, 7270.67 g of DCDPS, 2350.33 g of sodium carbonate, and 21.01 kg of ethylbenzene were added. After nitrogen replacement three times, nitrogen was introduced to react at normal pressure. The entire polymerization reaction was protected by nitrogen. The temperature was raised to 150° C. and kept at this temperature for 2 h. After reaching the theoretical water production, all the ethylbenzene was evaporated, the temperature was raised to 200° C. and kept at this temperature for 2 h to obtain a sulfonated polysulfone resin polymerization solution.

[0048] S2: Cool the sulfonated polysulfone resin polymerization liquid to 120°C, add 3502.41g of 1-butyl-3-methylimidazole bis(trifluoromethylsulfonyl)imide and 515.5g of TBAB, introduce chloromethane, and cap the mixture for 2h to obtain a capped sulfonated polysulfone resin polymerization liquid;

[0049] S3: Pour the blocked sulfonated polysulfone resin polymer solution into cold water to cool and precipitate, grind it into powder mechanically, boil it several times with a mixed water solvent containing 25wt.% NMP, filter and dry it to obtain a sulfonated polysulfone without foam when forming a film.

[0050] Comparative Example 1

[0051] The difference from Example 1 is that in step S1, the amount of SDCDPS added is 1309.27 g, and the amount of DCDPS added is 6888 g.

[0052] Comparative Example 2

[0053] The difference from Example 1 is that in step S2, TBAB is replaced by an equimolar amount of tetraethylammonium chloride (TEAC).

[0054] Comparative Example 3

[0055] The difference from Example 1 is that in step S3, deionized water is used instead of the mixed water solvent containing 5 wt.% DMAC.

[0056] Comparative Example 4

[0057] The difference from Example 1 is that in step S2, 1-butyl-3-methylimidazole bis(trifluoromethylsulfonyl)imide is not added.

[0058] Comparative Example 5

[0059] The difference from Example 1 is that in step S2, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide and TBAB are not added.

[0060] The sulfonated polysulfones prepared in Examples 1-5 and Comparative Examples 1-5 were subjected to pilot-scale continuous film formation, comprising the following steps:

[0061] 1) Dry the sulfonated polysulfone in vacuum at 80°C for 8 hours;

[0062] 2) Dissolve the dried sulfonated polysulfone in DMAC to prepare a casting solution with a solid content of 20 wt.%, and perform vacuum degassing for 4 hours;

[0063] 3) The degassed casting solution passes through the spinneret of the spinning machine to form a spinning stream, which passes through the air gap between the spinneret and the gel tank and enters the coagulation bath in the gel tank to form a sulfonated polysulfone hollow fiber membrane.

[0064] After running continuously in the coagulation bath for 1 hour and 5 hours, the water flux of the obtained sulfonated polysulfone hollow fiber membrane was tested respectively.

[0065] The water flux detection method is as follows:

[0066] Testing instrument: MOIST 3A;

[0067] Testing process: Pre-press at 0.2 MPa for 30 minutes. After the pre-press, measure the volume of pure water passing through the sulfonated polysulfone hollow fiber membrane at 0.1 MPa within a certain period of time. The volume is measured with a graduated cylinder. The water flux of the sulfonated polysulfone hollow fiber membrane is calculated according to the following formula:

[0068] J = V / (S·t);

[0069] Where, J-water flux, L / m 2 h; V-pure water volume, L; S-effective membrane area, m 2 ; t-measurement time, h.

[0070] The tensile strength test method of sulfonated polysulfone hollow fiber membrane is as follows:

[0071] The membrane filaments of the sulfonated polysulfone hollow fiber membrane were clamped on a universal testing machine. The tensile rate was set to 50 mm / min and the mold spacing was 50 mm. The maximum tensile force F when the membrane filaments broke was recorded. The tensile strength was calculated using the following formula:

[0072] δ=F / [π(D 2 -d 2 )];

[0073] Where: δ-tensile strength, MPa; F-maximum tensile force when the membrane breaks F, N; D-outer diameter of the membrane, m; d-inner diameter of the membrane, m.

[0074] The test results of water flux and tensile strength of the sulfonated polysulfone hollow fiber membranes of Examples 1-5 and Comparative Examples 1-5 are shown in Table 1:

[0075] Table 1 Test results of water flux and tensile strength of sulfonated polysulfone hollow fiber membranes of Examples 1-5 and Comparative Examples 1-5

[0076]

[0077] Comparing the data of Comparative Examples 1-5 with Example 1 in Table 1, it can be seen that in Comparative Example 1, due to the excessive addition of the sulfonated monomer SDCDPS in the dichloromonomer, the sulfonation degree of the sulfonated polysulfone increased to 10%. When formed alone, it was too hydrophilic, and it remained in a gel-like state during storage after film formation. After drying, it broke when it touched the fixture, making it difficult to test its mechanical properties. In Comparative Example 2, TEAC was used as the catalyst. Compared with TBAB, TEAC has a shorter ethyl chain length and reduced flexibility. The nucleophilicity of chloride ions is also weaker than that of bromide ions, and the inhibitory effect on steric hindrance is greatly weakened, resulting in a poor end-capping effect of the sulfonated polysulfone. The highly hydrophilic small molecule sulfonated polysulfone still forms foam, causing the water flux of the product to drop to 171.6 L / m after continuous film formation for 5 hours.2 ·h. In Comparative Example 3, deionized water was used instead of the mixed water solvent, which failed to eliminate the residual uncapped sulfonated polysulfone small molecules, resulting in a large attenuation of the water flux of the sulfonated polysulfone hollow fiber membrane. In Comparative Example 4, no ionic liquid was added during the end-capping process, which weakened the TBAB effect and caused a decrease in the water flux during continuous membrane formation for 5 hours. In Comparative Example 5, no ionic liquid and TBAB were added during the end-capping process, and a large amount of uncapped sulfonated polysulfone small molecules were encapsulated in the high molecular weight sulfonated polysulfone product. This part of the encapsulated uncapped sulfonated polysulfone small molecules was difficult to separate only by subsequent mixed water solvent extraction, resulting in a significant decrease in the water flux during continuous membrane formation for 5 hours.

Claims

1. A method for preparing sulfonated polysulfone without foaming during film formation, characterized in that: The following steps are involved: S1: bisphenol A, dichloromonomer, a salt-forming agent, and a water-separating agent are placed in a polar aprotic solvent, a protective gas is introduced, the temperature is raised to 120-150° C., and the temperature is maintained for 2-8 hours to carry out a salt-forming reaction; after the water extraction reaches the theoretical value and the salt-forming reaction is completed, the temperature is further raised to 160-200° C. and the temperature is maintained for 2-10 hours to carry out a nucleophilic polycondensation reaction to obtain a sulfonated polysulfone resin polymer solution; wherein the salt-forming agent is cesium carbonate, potassium carbonate, or sodium carbonate; the water-separating agent is toluene, xylene, trimethylbenzene, or ethylbenzene; the dichloromonomer is 3,3'-sodium disulfonate-4,4'-dichlorodiphenyl sulfone and 4,4'-dichlorodiphenyl sulfone, and the molar percentage of 3,3'-sodium disulfonate-4,4'-dichlorodiphenyl sulfone in the dichloromonomer is 1-5%; S2: Cooling the sulfonated polysulfone resin polymerization liquid, adding an ionic liquid and a quaternary ammonium salt catalyst tetrabutylammonium bromide, and introducing chloromethane for end-capping to obtain an end-capped sulfonated polysulfone resin polymerization liquid; wherein the ionic liquid is 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonylimide), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonylimide), or N-ethylpyridine bis(trifluoromethylsulfonylimide); S3: crushing the blocked sulfonated polysulfone resin polymer solution, extracting it with a mixed solvent, filtering it, and drying it to obtain a sulfonated polysulfone without foaming when forming a membrane; wherein the mixed solvent is a mixture of a polar aprotic solvent and deionized water; In step S1 and step S3, the polar aprotic solvent is N,N-dimethylacetamide or N-methylpyrrolidone; In step S3, the content of the polar aprotic solvent in the mixed solvent is 5-25 wt.%.

2. The method for preparing sulfonated polysulfone without foaming during film formation according to claim 1, wherein: In step S2, the molar ratio of the quaternary ammonium salt catalyst tetrabutylammonium bromide to 3,3'-sodium disulfonate-4,4'-dichlorodiphenyl sulfone is (1.05-1.2):

1.

3. The method for preparing sulfonated polysulfone without foaming during film formation according to claim 1, wherein: In step S1, the molar ratio of bisphenol A, dichloromonomer, and salt-forming agent is 1:(0.85-1):(1-3); the mass ratio of the total mass of bisphenol A and dichloromonomer to the polar aprotic solvent is 1:(2.5-5).

4. The method for preparing sulfonated polysulfone without foaming during film formation according to claim 1, wherein: In step S1, the mass ratio of the water-separating agent to the polar aprotic solvent is (0.2-0.4):

1.

5. The method for preparing sulfonated polysulfone without foaming during film formation according to claim 1, wherein: In step S2, the amount of ionic liquid added is 1-5 wt.% of the polar aprotic solvent in step S1.

6. The method for preparing sulfonated polysulfone without foaming during film formation according to claim 1, wherein: In step S2, the end-capping process of the sulfonated polysulfone resin polymer solution is as follows: after adding ionic liquid and quaternary ammonium salt catalyst tetrabutylammonium bromide, cooling to 90-150° C., introducing chloromethane, and reacting for 1-4 hours to obtain the end-capped sulfonated polysulfone resin polymer solution.

7. Sulfonated polysulfone without foaming during film formation, characterized in that: The polysulfone is prepared by the method for preparing the polysulfone without foaming during film formation as described in any one of claims 1 to 6.

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