A hydrophilic modified polyphenylene sulfide fabric diaphragm and preparation method thereof

Abstract

The present invention provides a hydrophilically modified polyphenylene sulfide fabric diaphragm and a preparation method thereof, comprising the following steps: adding a solvent to a container containing a brominated alkane, polyoxyethylene diamine, and a strong base under a nitrogen flow, heating the container, cooling the container to room temperature after the reaction is completed, adding the obtained polymer solution to hydrochloric acid for precipitation, soaking the obtained precipitate in anhydrous ethanol, washing with deionized water, and drying to obtain a triblock amphiphilic polymer; washing the polyphenylene sulfide fabric diaphragm with the mixed solution, drying it for later use; swelling the polyphenylene sulfide fabric diaphragm, adding the triblock amphiphilic polymer thereto, and performing a primary drying, secondary orientation arrangement, and secondary drying after the reaction is completed. The preparation method of the present invention improves the hydrophilicity of the polyphenylene sulfide fabric diaphragm by inducing the intercalation of the amphiphilic polymer through swelling, and can effectively improve the hydrophilicity of the PPS fabric diaphragm without damaging the mechanical properties of the PPS fabric.

Description

Technical Field

[0001] The invention belongs to the field of materials, and in particular relates to a hydrophilic modified polyphenylene sulfide fabric diaphragm and a preparation method thereof. Background Art

[0002] In today's energy sector, water electrolysis hydrogen production technology is attracting much attention for its sustainability. It primarily falls into four technology categories: alkaline water electrolysis (ALK), proton exchange membrane electrolysis (PEM), high-temperature solid oxide electrolysis (SOEC), and solid polymer anion exchange membrane electrolysis (AEM). ALK operates by using electricity to decompose water in an alkaline electrolyte environment, producing hydrogen and oxygen. ALK utilizes relatively inexpensive non-precious metals (such as iron, cobalt, and nickel) as catalysts, while avoiding the use of expensive titanium-based components, offering greater potential for cost control. Therefore, the large-scale development of alkaline water electrolysis hydrogen production technology is of strategic importance for reducing the cost of large-scale hydrogen production and can provide strong support for future energy transitions and sustainable development.

[0003] During the entire alkaline water electrolysis process, the diaphragm is a key factor in ensuring the efficient and safe operation of the entire electrolysis process. Therefore, the alkaline water electrolysis diaphragm has become an important technical branch in the alkaline water electrolysis hydrogen production technology. The main functions of the diaphragm in the electrolysis process are reflected in the following aspects: 1. The diaphragm can clearly separate the positive and negative poles of the electrolytic cell to form independent cathode and anode chambers, preventing short circuits caused by direct contact between the two poles, ensuring that the electrolysis reaction can proceed in an orderly manner according to the predetermined path, and providing a stable spatial environment for the separate generation of hydrogen and oxygen; 2. The diaphragm needs to effectively prevent hydrogen and oxygen from permeating each other, ensuring the safety and reliability of the electrolysis process and the production environment, and eliminating the potential safety risks caused by the mixing of hydrogen and oxygen generated by electrolysis; 3. The diaphragm needs to have a high porosity while ensuring airtightness so that hydroxide ions can be smoothly transferred from the cathode to the anode. These pores are like "fast channels" tailored for ions, allowing hydroxide ions to move freely through them, greatly reducing the resistance during ion transmission, thereby ensuring the continuous and stable progress of the electrolysis reaction and improving the efficiency of the entire electrolysis process.

[0004] It can be seen that for alkaline water electrolysis diaphragm materials, it needs to meet a series of strict and multi-dimensional requirements such as high porosity, high gas barrier properties, high hydrophilicity, high corrosion resistance, high mechanical strength, low resistivity and dimensional stability, in order to adapt to the complex working conditions and high performance requirements in the alkaline water electrolysis hydrogen production process.

[0005] Throughout the development of alkaline water electrolysis diaphragm materials, asbestos diaphragms met most of the aforementioned requirements and were widely used as early commercial alkaline diaphragm materials. However, with the continuous advancement of science and technology and growing concern for health and environmental issues, asbestos has been gradually phased out of the market due to its serious carcinogenicity. In search of a suitable alternative, researchers, after extensive research and exploration, discovered polyphenylene sulfide (PPS), a high-performance engineering material with many excellent properties, making it an ideal asbestos replacement.

[0006] The main chain of PPS is composed of alternating benzene rings and sulfur atoms. The introduction of benzene rings gives its molecular chain a certain degree of rigidity; the structurally symmetrical and regularly distributed molecular chains can partially condense into a crystalline state. These structures give PPS excellent high-temperature resistance, good mechanical strength, outstanding thermal stability, outstanding chemical corrosion resistance, antioxidant properties and other properties, enabling it to exist stably in the harsh environment of alkaline electrolyzed water, and become a rising star in the field of alkaline water electrolysis diaphragms.

[0007] However, despite the many advantages mentioned above, PPS has gradually become a problem of weak hydrophilicity when used as an alkaline water electrolysis membrane. Due to its insufficient hydrophilicity, using only PPS fabric as an alkaline water electrolysis membrane will result in excessive internal resistance of the electrolyzer. This is because water molecules have difficulty fully diffusing and penetrating the hydrophobic PPS surface, which hinders the transport of ions at the interface between the membrane and the electrolyte, thereby increasing energy loss during the electrolysis process and reducing electrolysis efficiency. At the same time, the insufficient hydrophilicity of PPS also leads to insufficient binding ability with water molecules, resulting in a decrease in its airtightness and posing a safety hazard. Therefore, in order to improve the application performance of PPS fabric in alkaline water electrolysis hydrogen production, improving its hydrophilicity has become the focus and key direction of current research. Currently, common surface modification methods include: coating treatment, chemical oxidation treatment, plasma treatment, irradiation grafting treatment and corona discharge treatment.

[0008] For example, the Chinese invention patent application number CN202410599971.6 discloses a polyphenylene sulfide fiber composite NH2-UiO 66 The membrane and preparation method thereof are as follows: NH2-UiO is added to the polyphenylene sulfide fiber membrane after sulfonation treatment. 66 The composite solution is subjected to hydrothermal reaction to obtain the polyphenylene sulfide fiber composite NH2-UiO 66 The method can effectively improve the hydrophilicity of polyphenylene sulfide fiber. However, in the patent, the hydrophilic NH2-UiO 66 The sulfonic acid group reacts with the sulfonic acid group to form a sulfonamide bond fixed on the fiber surface, and the sulfonic acid group itself will gradually be reacted with the base, eventually resulting in NH2-UiO 66The hydrophilicity of the fibers will also decrease as they gradually fall off the surface of the substrate. At the same time, the hydrothermal reaction temperature during the preparation process is 120°C, which is too high and may destroy the crystalline part of the PPS fibers, resulting in a decrease in mechanical properties.

[0009] Chinese invention patent application number CN202410087625.X discloses a method for preparing a hydrophilic PPS membrane for water electrolysis. Zirconia and polyphenylene sulfide are mixed and melt-spun to form a surface membrane. Polyphenylene sulfide and aramid materials are then mixed and melt-spun to form a core membrane. The surface membrane is sandwiched between the core membrane and hot-rolled to form a composite membrane. This is then hydroentangled to form a hydrophilic PPS membrane for water electrolysis. However, in this patented method, the physical blending of PPS resin and inorganic zirconium oxide nanoparticles can easily lead to poor fusion and phase separation, ultimately resulting in uneven hydrophilicity on the surface of the PPS membrane.

[0010] The Chinese invention patent with application number CN202011524159.5 discloses a polyphenylene sulfide fabric for a water electrolyzer. The polyphenylene sulfide fabric is sulfonated using sulfuric acid and chromic acid. Chromic acid can decompose the polyphenylene sulfide macromolecular segments into small molecular segments, and concentrated sulfuric acid can enter the interior of the PPS for sulfonation, thereby introducing hydrophilic sulfoxide groups on the surface and inside of the PPS fiber, allowing long-term use and improving the stability and life of the PPS diaphragm. However, in this patented method, the highly oxidizing chromic acid decomposes the polyphenylene sulfide macromolecular segments into several small molecular segments, which will change the original physical and chemical properties of PPS and reduce the mechanical strength of the PPS diaphragm. In addition, the internal sulfoxide functional groups still need to be exposed to alkaline solution to exert their hydrophilic effect, which means that the internal functional groups will also be corroded by the alkaline solution over time.

[0011] It can be seen that the above-mentioned modification methods have problems such as damage to fibers, uneven modification and being greatly affected by environmental conditions. In addition, the introduced hydrophilic groups cannot ensure whether they have lasting hydrophilicity, whether they can withstand the harsh electrolysis conditions of high temperature and alkalinity, and whether the mechanical properties meet the standards, which ultimately leads to limited improvement in the overall hydrophilic performance.

[0012] In the existing PPS fabric hydrophilic modification technology, there are problems such as inability to use for a long time in a high-temperature alkaline environment and damage to the mechanical properties of the diaphragm itself, resulting in a shortened service life of the diaphragm. Summary of the Invention

[0013] In view of this, the present invention aims to overcome the defects in the prior art and proposes a hydrophilic modified polyphenylene sulfide fabric diaphragm and a preparation method thereof.

[0014] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0015] A method for preparing a hydrophilically modified polyphenylene sulfide fabric diaphragm comprises the following steps:

[0016] Step 1 is to add a brominated alkane, polyoxyethylene diamine and a strong base into a container, add a solvent into the container under a nitrogen flow, heat the container, cool to room temperature after the reaction is completed, add the obtained polymer solution into hydrochloric acid for precipitation, soak the obtained precipitate in anhydrous ethanol, wash with deionized water, and dry to obtain a triblock amphiphilic polymer;

[0017] Step 2 is to use the mixed solution to wash the polyphenylene sulfide fabric diaphragm, and then dry it for standby use;

[0018] Step 3 is to perform swelling treatment on the polyphenylene sulfide fabric diaphragm treated in step 2, add the triblock amphiphilic polymer obtained in step 1 thereto, and after the reaction is completed, perform primary drying, secondary orientation arrangement, and secondary drying to obtain the hydrophilically modified polyphenylene sulfide fabric diaphragm.

[0019] Furthermore, the mass ratio of the brominated alkane, polyoxyethylene diamine and strong base in step 1 is 1:0.78:0.25-0.35; and the strong base is K2CO3.

[0020] Furthermore, the temperature of the heating step in step 1 is 50-100° C., and the reaction time is 12-24 hours.

[0021] Furthermore, the brominated alkane in step 1 is at least one of 1-bromohexadecane, 1-bromooctadecane, 1-bromoeicosane or 1-bromodocosane; and the solvent in step 1 is DMAC and / or toluene.

[0022] Furthermore, the molecular weight of the polyoxyethylene diamine in step 1 is 500-5000; and the concentration of the hydrochloric acid is 0.05-0.5 mol / L.

[0023] Furthermore, the mixed solution in step 2 is formed by mixing at least two of deionized water, ethanol or acetone.

[0024] Furthermore, the thickness of the polyphenylene sulfide fabric diaphragm in step 2 is 0.7-1.0 mm, and the weight is 450-550 g / m 2 , the diameter of polyphenylene sulfide fiber is 8-18 μm.

[0025] Furthermore, the swelling agent in the swelling step of step 3 is 3,3'-dichlorobiphenyl and petroleum ether in a mass ratio of 7-9:1-3; the amount of the triblock amphiphilic polymer added in step 3 is 0.5-5% of the mass of the polyphenylene sulfide fabric diaphragm.

[0026] Furthermore, the swelling step in step 3 is performed by heating in an oil bath at a temperature of 80-150°C for 12-24 hours; and the primary drying step in step 3 is performed at a temperature of 50-100°C for 4-12 hours.

[0027] A hydrophilic modified polyphenylene sulfide fabric diaphragm prepared by using the preparation method.

[0028] The reaction process in step 1 is shown in formula (I):

[0029]

[0030] Formula (I)

[0031] Among them, the hydrophobic part is selected from a polyethylene chain segment with small steric hindrance, and its precursor is a brominated alkane (m=16, 18, 20, 22); the hydrophilic part is selected from a polyether polymer with good alkali resistance, and its precursor is polyoxyethylene diamine (molecular weight of 1000).

[0032] The alkyl segments on both sides of the triblock amphiphilic polymer in step 1 and the PPS main chain are both oil-soluble structures. According to the principle of like dissolves like, the alkyl segments are more likely to enter between the PPS molecular chains. The aminoalkoxy segment in the middle of the amphiphilic polymer is a water-soluble segment that repels the PPS molecular chain, which allows it to be exposed outside the PPS molecular chain, thereby providing hydrophilicity to the PPS.

[0033] After the PPS fabric surface is swollen with the swelling agent in step 3, the agent penetrates the surface and interior of the PPS fibers. This weakens the intermolecular forces between the molecular chains in the amorphous regions of the PPS fibers, causing them to untangle and widen the gaps between them. This creates ample space for the hydrophobic segments of the amphiphilic polymer PE-NH-PEO-NH-PE to enter the PPS interior. 3,3'-Dichlorobiphenyl, the primary swelling agent, penetrates the PPS interior, weakening the van der Waals forces between the molecular chains in the amorphous regions and allowing petroleum ether to enter more easily, further swelling the PPS. According to the principle of like dissolves like, the hydrophobic segments at both ends of PE-NH-PEO-NH-PE have a structure closer to that of petroleum ether. With the help of petroleum ether, the hydrophobic segments will approach the polymer surface and gradually insert into the gaps created by the swelling of the molecular chains in the amorphous region of the PPS fiber. At the same time, the hydrophilic segments in the middle of the amphiphilic polymer are insoluble in 3,3'-dichlorobiphenyl and petroleum ether. Therefore, under the repulsive effect of the two swelling agents, the hydrophobic segments will further move between the PSS molecular chains, providing a driving force for the hydrophobic segments to enter the gaps between the molecular chains in the amorphous region of the PPS.

[0034] As the swelling agent evaporates and is removed, the molecular chains in the amorphous PPS region release their swelling state. Under the action of van der Waals forces, the PPS molecular chains approach each other again and become entangled together. In this process, the hydrophobic segments of PE-NH-PEO-NH-PE are firmly fixed and embedded between the PPS molecular chains.

[0035] Soaking in anhydrous ethanol reorients and arranges the hydrophilic segments in PE-NH-PEO-NH-PE and removes the residual un-embedded amphiphilic polymer. Finally, the membrane is washed with deionized water and dried to obtain the final product of the hydrophilically modified PPS alkaline water electrolysis membrane.

[0036] Compared with the prior art, the present invention has the following advantages:

[0037] The method for preparing a hydrophilically modified polyphenylene sulfide fabric diaphragm described in the present invention enhances the hydrophilicity of the polyphenylene sulfide fabric diaphragm by inducing the intercalation of an amphiphilic polymer through swelling. This method can effectively improve the hydrophilicity of the PPS fabric diaphragm and reduce its internal resistance in electrolytic cell applications without nearly damaging the mechanical properties of the PPS fabric. Furthermore, it can continue to function stably during long-term electrolysis of water, greatly extending its service life and meeting industrial production needs. The method for preparing a hydrophilically modified polyphenylene sulfide fabric diaphragm described in the present invention is simple to operate, has a significant modification effect, is unaffected by environmental conditions, does not affect the mechanical properties of the PPS itself, and retains its hydrophilicity for a long time. Furthermore, it has broad application prospects in other high-performance fiber surface modification fields.

[0038] The hydrophilically modified polyphenylene sulfide fabric membrane of the present invention utilizes a swelling agent to swell the amorphous region of the fiber surface, and simultaneously adds an amphiphilic polymer. The spontaneous orientation of the amphiphilic polymer is utilized to cause the hydrophobic chain segments to tend to be inserted into the interior of the fiber. Simultaneously, the entanglement between the PPS molecular chains provides a strong anchoring force for the embedding of the hydrophobic chain segments of the amphiphilic polymer, thereby exposing the hydrophilic chain segments on the fiber surface and enhancing the hydrophilic properties of the PPS fabric. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The scanning electron microscope images of the PPS fabric separator embedded with the amphiphilic polymer according to the embodiment of the present invention are shown: Figure A shows the original PPS fabric separator, and Figure B shows the embedded PPS fabric separator;

[0040] Figure 2 This is an optical physical picture of the chimeric amphiphilic polymer PPS fabric diaphragm described in an embodiment of the present invention at the moment of dripping water: Figure A is the original PPS fabric diaphragm, and Figure B is the chimeric PPS fabric diaphragm. DETAILED DESCRIPTION

[0041] Unless otherwise defined, the technical terms used in the following examples have the same meanings as commonly understood by those skilled in the art to which this invention belongs. The experimental reagents used in the following examples, unless otherwise specified, are conventional biochemical reagents; the experimental methods described, unless otherwise specified, are conventional methods.

[0042] Example 1

[0043] A method for preparing a hydrophilically modified polyphenylene sulfide fabric diaphragm comprises the following steps:

[0044] (1) 10 g of bromodocosane, 7.8 g of polyoxyethylene diamine, and 3.5 g of K2CO3 were added to a 500 mL three-necked round-bottom flask. Subsequently, 133.5 g of DMAC and 44.5 g of toluene were added as solvents under a nitrogen flow. The above reagent mixture was heated to 70°C and reacted for 24 hours. After cooling to room temperature, the polymerization was stopped. The polymer solution was precipitated in 0.1 mol / L hydrochloric acid. The precipitated polymer was thoroughly washed with water and ethanol and dried to constant weight.

[0045] (2) The PPS fabric sheet was first ultrasonically washed in anhydrous ethanol for 0.5 h, then ultrasonically washed in deionized water for 0.5 h, and then dried for use;

[0046] (3) The PPS fabric dried in step (1) was immersed in a swelling agent (the mass ratio of petroleum ether and 3,3'-dichlorobiphenyl was 1:9), 1.5 g of the amphiphilic polymer PE-NH-PEO-NH-PE was added, and then heated in an oil bath at 100°C for 12 h;

[0047] (4) The PPS fabric in step (3) was removed from the swelling agent, the excess swelling agent on the surface was lightly wiped off, and then vacuum dried at 60°C and -0.1 MPa;

[0048] (5) The PPS fabric dried in step (4) was soaked in anhydrous ethanol for 5 minutes, washed with deionized water, and dried to obtain a hydrophilically modified PPS fabric membrane.

[0049] Example 2

[0050] The only difference from Example 1 is that the brominated alkane is 1-bromooctadecane.

[0051] Example 3

[0052] The only difference from Example 1 is that the swelling temperature is 60°C.

[0053] Comparative Example 1

[0054] The only difference from Example 1 is that the polymer is PE-COO-PEG-COO-PE.

[0055] Comparative Example 2

[0056] The only difference from Example 1 is that the polymer is polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene-graft-maleic anhydride, CAS No. 124578-11-6.

[0057] Comparative Example 3

[0058] The only difference from Example 1 is that the swelling agent is petroleum ether.

[0059] Comparative Example 4

[0060] The only difference from Example 1 is that the swelling agent is 3,3'-dichlorobiphenyl.

[0061] Comparative Example 5

[0062] The only difference from Example 1 is that the swelling agent is dimethyl sulfoxide.

[0063] The PPS diaphragms of the above embodiments and comparative examples were subjected to performance tests, and the test items and methods were as follows:

[0064] Characterization of micromorphological changes: Scanning electron microscopy (SEM) was used to characterize the morphology of the PPS separator before and after modification.

[0065] Surface resistance: tested according to the electronic industry standard SJ / T 10171.5-1991 of the People's Republic of China for the test standard of surface resistance of alkaline battery separators.

[0066] Water diffusion time: The water absorption rate and water absorption time before and after hydrophilic treatment are tested according to GB / T 21655.1-2008 standard.

[0067] Alkaline electrolyzed water resistance test: The PPS fabric separators from the above examples and comparative examples were immersed in a 30 wt% KOH solution at 90°C for 360 hours. The surface resistance and water drop diffusion time were then measured. The results are shown in Table 1 below.

[0068] Table 1 Test data

[0069]

[0070] like Figure 1 As shown in Figure 2, it can be seen that the surface roughness of the PPS fabric fiber embedded with PE-NH-PEO-NH-PE is significantly increased; Figure 2As shown in the figure, it can be seen that the water contact angle of the PPS fabric membrane embedded with PE-NH-PEO-NH-PE is significantly smaller than that of the PPS fabric membrane without PE-NH-PEO-NH-PE, indicating that PE-NH-PEO-NH-PE significantly improves the hydrophilicity of PPS.

[0071] As shown in Table 1, from the comparison of Examples 1 and 2, it can be seen that the length of the hydrophobic segment has little effect on the entry of the amphiphilic polymer into the interior of PPS, and the surface resistance and hydrophilic time are at the same level; from the comparison of Examples 1 and 3, it can be seen that the temperature has a greater effect on the swelling degree of PPS. When the temperature of Example 1 is significantly higher than that of Example 3, the swelling degree of PPS in Example 1 is higher than that of Example 3, so that the amphiphilic polymer in Example 1 can be more embedded between the PPS molecular chains, so that its hydrophilic effect is the best.

[0072] By comparing Comparative Example 1 with Example 1, it can be seen that the surface resistance of the diaphragm in Comparative Example 1 increases significantly after alkali boiling, which indicates that the amphiphilic polymer in Comparative Example 1 is almost completely destroyed under the action of strong alkali and cannot tolerate strong alkali.

[0073] By comparing Comparative Example 2 with Example 1, it can be seen that the hydrophilic effect of the diaphragm in Comparative Example 1 is not obvious, but the mechanical properties of the two are at the same level, which shows that the swelling degrees of the two are at the same level, but the hydrophobic chain segment of the amphiphilic polymer in Comparative Example 2 has too large a steric hindrance and cannot enter between the molecular chains of PPS. Therefore, the hydrophilic ability of the diaphragm in Comparative Example 2 is not significantly improved.

[0074] By comparing Comparative Examples 3-4 with Example 1, it can be seen that the membrane surface resistance and hydrophilic time in Comparative Examples 3 and 4 are not as good as those in Example 1. This shows that the effect of using a mixed swelling agent is worse than using a single swelling agent, which can better increase the swelling degree of PPS and enable more amphiphilic polymers to enter between the PPS molecular chains, bringing better hydrophilic effect.

[0075] By comparing Comparative Example 5 with Example 3, it can be seen that the mechanical properties of the two membranes are similar, but the swelling temperature in Comparative Example 5 is 100°C, which shows that the dimethyl sulfoxide in Comparative Example 5 is not a good swelling agent for PPS and the amphiphilic polymer cannot enter PPS; therefore, the hydrophilic time and surface resistance of the membrane in Comparative Example 5 are close to those in Example 3, and the hydrophilic effect of the membrane is not good.

[0076] After the amphiphilic polymer PE-NH-PEO-NH-PE is embedded in the surface of the hydrophilically modified PPS fabric membrane of the present invention, the hydrophilic property of the PPS membrane is significantly improved, its surface resistance is effectively reduced, and its hydrophilic property can still be stably maintained in a high-temperature alkaline electrolyte environment for a long time. However, the hydrophilic modified PPS membrane of the comparative example has the problem of insufficient hydrophilic modification, resulting in serious energy loss and affecting production efficiency.

[0077] The present invention modifies the surface of a PPS membrane by inducing an amphiphilic polymer to enter and immobilize the PPS by swelling the PPS fibers. Under the action of interfacial tension, the hydrophobic segments at both ends of the PE-NH-PEO-NH-PE structure spontaneously insert into the swollen PPS fibers, while the hydrophilic segments remain on the fiber surface. This enhances the interaction between the PPS fiber surface and water molecules, allowing the water molecules to be more evenly distributed on the fiber surface, forming a continuous hydration layer, thereby improving the hydrophilicity of the PPS fabric. The presence of the hydrophilic layer improves the transmission environment of hydroxide ions in the alkaline water electrolysis membrane, making it easier for hydroxide ions to migrate within the membrane, reducing resistance and energy loss during hydroxide transmission, thereby significantly reducing membrane resistance and greatly improving energy efficiency.

[0078] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a hydrophilically modified polyphenylene sulfide fabric diaphragm, characterized in that: The steps include: Step 1 is to add a brominated alkane, polyoxyethylene diamine and a strong base into a container, add a solvent into the container under a nitrogen flow, heat the container, cool to room temperature after the reaction is completed, add the obtained polymer solution into hydrochloric acid for precipitation, soak the obtained precipitate in anhydrous ethanol, wash with deionized water, and dry to obtain a triblock amphiphilic polymer; Step 2 is to use the mixed solution to wash the polyphenylene sulfide fabric diaphragm, and then dry it for standby use; Step 3 is to perform swelling treatment on the polyphenylene sulfide fabric diaphragm treated in step 2, add the triblock amphiphilic polymer obtained in step 1 thereto, and after the reaction is completed, perform primary drying, secondary orientation arrangement, and secondary drying to obtain the hydrophilically modified polyphenylene sulfide fabric diaphragm; The swelling agent in the swelling step of step 3 is 3,3'-dichlorobiphenyl and petroleum ether in a mass ratio of 7-9:1-3; The swelling step in step 3 is performed by heating in an oil bath at a temperature of 80-150° C. for 12-24 hours; The molecular weight of the polyoxyethylene diamine in step 1 is 500-5000.

2. The method for preparing the hydrophilic modified polyphenylene sulfide fabric diaphragm according to claim 1, characterized in that: The mass ratio of the brominated alkane, polyoxyethylene diamine and strong base in step 1 is 1:0.78:0.25-0.35; the strong base is K2CO3.

3. The method for preparing the hydrophilic modified polyphenylene sulfide fabric diaphragm according to claim 1, wherein: The temperature of the heating step in step 1 is 50-100° C., and the reaction time is 12-24 hours.

4. The method for preparing the hydrophilically modified polyphenylene sulfide fabric diaphragm according to claim 1, wherein: The brominated alkane in step 1 is at least one of 1-bromohexadecane, 1-bromooctadecane, 1-bromoeicosane or 1-bromodocosane; and the solvent in step 1 is DMAC and / or toluene.

5. The method for preparing the hydrophilic modified polyphenylene sulfide fabric diaphragm according to claim 1, characterized in that: The concentration of the hydrochloric acid is 0.05-0.5 mol / L.

6. The method for preparing the hydrophilic modified polyphenylene sulfide fabric diaphragm according to claim 1, characterized in that: The mixed solution in step 2 is formed by mixing at least two of deionized water, ethanol or acetone.

7. The method for preparing the hydrophilic modified polyphenylene sulfide fabric diaphragm according to claim 1, characterized in that: The thickness of the polyphenylene sulfide fabric diaphragm in step 2 is 0.7-1.0 mm and the weight is 450-550 g / m 2 , the diameter of polyphenylene sulfide fiber is 8-18 μm.

8. The method for preparing the hydrophilic modified polyphenylene sulfide fabric diaphragm according to claim 1, characterized in that: The amount of the triblock amphiphilic polymer added in step 3 is 0.5-5% of the mass of the polyphenylene sulfide fabric diaphragm.

9. The method for preparing the hydrophilic modified polyphenylene sulfide fabric diaphragm according to claim 1, characterized in that: The time of the primary drying step in step 3 is 4-12 hours and the temperature is 50-100°C.

10. A hydrophilic modified polyphenylene sulfide fabric diaphragm prepared using the preparation method according to claim 1.

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