A hydrophilic polyphenylene sulfide and its preparation method and application

Abstract

The present invention discloses a hydrophilic polyphenylene sulfide and its preparation method and application, belonging to the technical field of alkaline electrolytic water hydrogen production. The preparation method of the hydrophilic polyphenylene sulfide includes the following steps: under the conditions of inert gas and ice-water bath, adding a dehydrated sulfur source to a prepolymer obtained by mixing and stirring a hydrophilic functional monomer and 2,5-dichlorobenzoyl chloride, and preparing the hydrophilic polyphenylene sulfide through a copolymerization reaction; wherein, the sulfur source is crystalline sodium sulfide. A series of hydrophilic polyphenylene sulfides prepared by the preparation method provided by the present invention solve the limitation of the hydrophilicity of commercially available polyphenylene sulfide from the perspective of molecular structure, and have the advantages of good hydrophilicity, low surface resistance, acid resistance and alkali resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen production by alkaline electrolysis of water, and particularly relates to a hydrophilic polyphenylene sulfide and a preparation method and application thereof. Background Art

[0002] With the continuous progress of social productivity, humans have realized that conventional energy sources such as coal, oil, and natural gas on which they depend for survival are facing the problems of gradual depletion and non-renewability in the short term. Therefore, hopes are placed on new energy fields such as solar energy, wind energy, and tidal energy. However, the electric energy converted from natural forces cannot be directly incorporated into the power grid for delivery to customers. Researchers then use this part of the electric energy to electrolyze the inexhaustible water resources to obtain hydrogen resources.

[0003] The alkaline electrolysis water hydrogen production technology is still the mainstream technology at present. This technology often uses a 30% potassium hydroxide solution as the electrolyte, belonging to an extremely corrosive environment. In the electrolytic cell, the component that separates oxygen and hydrogen and separates the cathode and anode plates is called a diaphragm, and during the electrolysis process, OH - ions should pass through the diaphragm material with as little resistance as possible. In this field, at first, asbestos diaphragms were used, but later they were abandoned due to pollution and other reasons. People then turned their attention to polyphenylene sulfide materials with high insulation, alkali resistance, and stability at high temperatures. Physical methods were used to manufacture fibers from polymer particles, prepare strands, and perform subsequent textile weaving. Finally, PPS diaphragms were used in alkaline electrolysis water hydrogen production electrolytic cells.

[0004] With the application of PPS diaphragms, it has been found that there are gaps in the energy consumption and airtightness of this material compared to the asbestos diaphragms that have been phased out. Through research, it has been confirmed that the shortcoming in performance is related to the extremely poor hydrophilicity of PPS. In recent years, some researchers have attempted to improve the hydrophilicity of PPS through a series of methods, but there are problems such as the instability of the hydrophilic coating or the modification method damaging the molecular chain structure of PPS. The latter directly reduces the service life of the diaphragm or makes it no longer suitable for strong alkaline environments. For example, the patent number is CN202311011751.9, and the patent name is: A new type of multi-layer alkaline water electrolysis hydrogen production diaphragm, its preparation method and application, which involves a multi-layer alkaline water electrolysis hydrogen production diaphragm. This patent uses a PPS grid as a support and soaks it in the prepared hydrophilic modification liquid, and finally obtains a hydrophilic support network. However, it is very difficult to ensure that the hydrophilic coating does not fall off later with this physical attachment; the patent number is: CN201410723796.3, and the patent name is: A preparation method of a modified polyphenylene sulfide composite masterbatch, which involves adding various additives and then heating, melting, mixing, dispersing, homogenizing, and extruding through a twin-screw extruder to produce a modified polyphenylene sulfide composite masterbatch, enhancing the strength, toughness, antioxidant property, and high-temperature resistance of the polyphenylene sulfide material. However, in a series of subsequent processing of this physical mixture, the various functional additives are prone to phase separation, ultimately resulting in unstable product performance.

[0005] Therefore, starting from the molecular structure, developing a series of PPS materials with high chemical stability and improved hydrophilicity will still be the key research direction in the field of alkaline water electrolysis. Summary of the Invention

[0006] In view of the above technical problems, the present invention proposes a hydrophilic polyphenylene sulfide, its preparation method and application. Through the preparation method provided by the present invention, a series of hydrophilic polyphenylene sulfides are prepared, which solve the limitation of the hydrophilicity of commercially available polyphenylene sulfide from the perspective of molecular structure, and have good hydrophilicity, high OH - transport efficiency and stability.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] One of the technical solutions of the present invention:

[0009] A preparation method of a hydrophilic polyphenylene sulfide, comprising the following steps:

[0010] Under the conditions of inert gas and ice-water bath, add a dehydrated sulfur source to the prepolymer obtained by mixing and stirring a hydrophilic functional monomer and 2,5-dichlorobenzoyl chloride, and prepare the hydrophilic polyphenylene sulfide through a copolymerization reaction;

[0011] Among them, the sulfur source is crystalline sodium sulfide; the specific synthesis process is as follows:

[0012]

[0013] Beneficial effects: The hydrophilic polyphenylene sulfide prepared by the above method has many advantages such as stable performance, low price, environmental friendliness, high heat transfer efficiency, easy availability of raw materials and high utilization rate.

[0014] Preferably, the mass ratio of the hydrophilic functional monomer, 2,5-dichlorobenzoyl chloride and the sulfur source is: (18-27):(29-45):(33-40).

[0015] Preferably, the inert gas is any one of argon and nitrogen.

[0016] Preferably, the hydrophilic functional monomer includes any one of p-phenylenediamine, 4,4'-methylenedianiline, 4,4'-thiodianiline, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenyl sulfone, and benzidine.

[0017] Preferably, the specific steps of the preparation method are as follows:

[0018] (1) Mix crystalline sodium sulfide and inorganic strong base dispersed in a high-boiling polar organic solvent, and heat under an inert gas condition to obtain a dehydrated sulfur source;

[0019] (2) Under an inert gas and ice-water bath condition, drop 2,5-dichlorobenzoyl chloride into the hydrophilic functional monomer dispersed in an organic solvent, and stir at room temperature to obtain a prepolymer;

[0020] (3) Drop the dehydrated sulfur source into the prepolymer, and successively carry out high-temperature stirring, heating, cooling, washing and drying to obtain the hydrophilic polyphenylene sulfide.

[0021] Beneficial effects: The present invention uses a functional monomer with a specific structure to synthesize hydrophilic polyphenylene sulfide prepolymers with different structures through copolymerization reaction, and then introduces a sulfur source to prepare hydrophilic polyphenylene sulfide. That is, the present invention can prepare polyphenylene sulfide with good hydrophilicity and stability through simple three steps.

[0022] Furthermore, on the one hand, compared with the traditional PPS main chain without hydrophilic groups, the present invention fundamentally broadens the application of PPS products. On the other hand, different from simple physical mixing and using harsh chemical modifiers to damage the benzene ring or sulfur element of PPS for modification, the present invention prepares various hydrophilic modified PPSs by adjusting the addition ratio and / or type of hydrophilic functional monomers, and can selectively avoid the cost increase caused by the price mechanism of some raw materials in the domestic and international markets.

[0023] Preferably, the high-boiling polar organic solvent in step (1) is NMP; and / or

[0024] The inorganic strong base is any one of sodium hydroxide and potassium hydroxide.

[0025] Preferably, in step (1), the heating process is: heating to 150°C - 180°C within 1 hour.

[0026] Preferably, the organic solvent in step (2) includes at least one of benzene, dichloromethane, and chloroform.

[0027] Preferably, the stirring time at room temperature in step (2) is 24 h.

[0028] Preferably, the parameters in the high-temperature stirring process in step (3) are: stirring at 220°C for 3 hours.

[0029] Preferably, the conditions in the heating process in step (3) are: heating from 220°C to 260°C and maintaining for 2 hours.

[0030] Preferably, the washing process in step (3) is:

[0031] Pour the cooled suspension into deionized water, adjust it to neutral with inorganic acid, and wash the filter residue with a weak base washing solution and deionized water in sequence.

[0032] Furthermore, the inorganic dilute acid is at least one of 5% - 10% dilute hydrochloric acid and 5% - 10% dilute sulfuric acid; and / or

[0033] The weak base washing solution is a saturated sodium bicarbonate solution.

[0034] The second technical solution of the present invention:

[0035] A hydrophilic polyphenylene sulfide prepared by the above preparation method, wherein the structural general formula of the hydrophilic polyphenylene sulfide is:

[0036]

[0037] In the above formula, R is selected from any one of.

[0038] The third technical solution of the present invention:

[0039] The application of the hydrophilic polyphenylene sulfide in the field of alkaline electrolytic water hydrogen production.

[0040] The fourth technical solution of the present invention:

[0041] A polyphenylene sulfide diaphragm applied to alkaline electrolytic water hydrogen production, prepared from the hydrophilic polyphenylene sulfide as a raw material.

[0042] Beneficial effects: The polyphenylene sulfide separator for alkaline water electrolysis hydrogen production prepared from the hydrophilic polyphenylene sulfide disclosed by the present invention has high OH - transmission ability, high airtightness and chemical corrosion resistance.

[0043] Compared with the prior art, the present invention has the following advantages and technical effects:

[0044] (1) The hydrophilic PPS prepared by the preparation method disclosed by the present invention fundamentally solves the drawback of poor hydrophilicity of PPS;

[0045] (2) The main chain of the hydrophilic PPS prepared by the present invention will not phase-separate from the hydrophilic functional end;

[0046] (3) The surface resistance of the film products prepared from the hydrophilic PPS masterbatch of the present invention is significantly reduced compared with traditional PPS. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The drawings constituting a part of this application are used to provide a further understanding of this application. The schematic embodiments and descriptions thereof of this application are used to explain this application and do not constitute an improper limitation of this application. In the drawings:

[0048] Figure 1 is the contact angle test chart of the film products prepared from the hydrophilic polyphenylene sulfide of Examples 1-6 of the present invention;

[0049] Among them, a is a commercially available PPS film; b is a b-PPS film; c is a c-PPS film; d is an f-PPS film; e is a d-PPS film; f is an a-PPS film; g is an e-PPS film;

[0050] Figure 2 is the surface resistance test chart of the film products prepared from the hydrophilic polyphenylene sulfide of Examples 1-6 of the present invention;

[0051] Figure 3 The DSC test chart of the film products prepared from the hydrophilic polyphenylene sulfide of Examples 1-6 of the present invention;

[0052] Among them, a is a b-PPS film; b is a c-PPS film; c is an f-PPS film; d is a d-PPS film; e is an a-PPS film; f is an e-PPS film. DETAILED DESCRIPTION OF THE INVENTION

[0053] The various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present invention.

[0054] It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0055] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0056] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific embodiments of the present invention specification, which are obvious to those skilled in the art. Other embodiments obtained from the specification of the present invention are obvious to those skilled in the art. The specification and examples of the present invention are merely exemplary.

[0057] Regarding the use of "comprising", "including", "having", "containing", etc. herein, they are all open-ended terms, meaning including but not limited to.

[0058] The present invention discloses a hydrophilic polyphenylene sulfide (masterbatch), and the raw material composition of the material includes: an organic main chain material, a hydrophilic functional monomer, and a sulfur source;

[0059] Among them, the organic main chain material is 2,5-dichlorobenzoyl chloride;

[0060] The hydrophilic functional monomer includes any one of a: p-phenylenediamine, b: 4,4'-methylenedianiline, c: 4,4'-thiodianiline, d: 4,4'-diaminobenzophenone, e: 4,4'-diaminodiphenyl sulfone, f: benzidine;

[0061] The sulfur source is sodium sulfide.

[0062] The present invention also discloses a preparation method of a hydrophilic polyphenylene sulfide polymer, including the following steps:

[0063] Step (1), anhydrous treatment of the sulfur source:

[0064] Add crystalline sodium sulfide dispersed in a high-boiling polar organic solvent and an inorganic strong base equivalent to the sodium sulfide equivalent to an autoclave, then fill with inert gas and heat to the target temperature within 1 hour to carry out a dehydration reaction to obtain an anhydrous sodium sulfide system;

[0065] Step (ii), preparation of hydrophilic PPS prepolymer and hydrophilic modified PPS:

[0066] Under an inert gas atmosphere and in an ice-water bath, load p-phenylenediamine dispersed in an organic solvent into a dry three-necked round-bottom flask equipped with a magnetic stirrer, and then add a 2,5-dichlorobenzoyl chloride solution dropwise to the mixture through a dropping funnel within half an hour. Stir the reaction mixture at room temperature for 24 hours to obtain a hydrophilic PPS prepolymer;

[0067] Drop the anhydrous sodium sulfide system into the prepolymer system (hydrophilic PPS prepolymer), stir at 220 °C for 3 hours under an inert gas atmosphere, then raise the temperature to 260 °C and hold for 2 hours. Cool to room temperature, pour the suspension into deionized water, adjust to neutral with inorganic acid, wash the filter residue successively with a weak base washing solution and deionized water, and dry in a vacuum oven at 120 °C for 24 hours to obtain hydrophilic modified PPS.

[0068] In some preferred embodiments, in step (i), the high-boiling polar organic solvent is NMP (N-methyl-2-pyrrolidone);

[0069] The inert gas refers to nitrogen or argon;

[0070] The inorganic strong base is potassium hydroxide or sodium hydroxide; the target temperature range is 150 °C - 180 °C.

[0071] In some preferred embodiments, in step (ii), the inert gas refers to nitrogen or argon;

[0072] The organic solvent refers to at least one of benzene, dichloromethane, and chloroform;

[0073] The inorganic acid is at least one of 5% - 10% dilute hydrochloric acid and 5% - 10% dilute sulfuric acid;

[0074] The weak base washing solution is a saturated sodium bicarbonate solution.

[0075] In the present invention, the "room temperature" refers to 20 - 30 °C unless otherwise specified.

[0076] All raw materials used in the present invention are obtained by purchasing on the market.

[0077] The technical solution of the present invention is further described below through examples.

[0078] Example 1

[0079] A method for preparing a hydrophilic polyphenylene sulfide polymer, comprising the following steps:

[0080] 90 g of crystalline sodium sulfide (Na2S = 30%) and 2 g of sodium hydroxide dispersed in NMP were added to an autoclave, and then N2 was filled and heated to 150 °C within 1 hour to carry out a dehydration reaction to obtain an anhydrous sodium sulfide system.

[0081] Under the conditions of an N2 atmosphere and an ice-water bath, 16 g of p-phenylenediamine (a) dispersed in 200 mL of dichloromethane was charged into a dry 500 mL three-necked round-bottom flask equipped with a magnetic stirrer. Then, 25 g of a 2,5-dichlorobenzoyl chloride solution was added dropwise to the mixture through a dropping funnel within half an hour. Then, the reaction mixture was stirred at room temperature for 24 hours to obtain a prepolymer. The anhydrous sodium sulfide system was added dropwise to the prepolymer system. After stirring at 220 °C for 3 hours under an N2 atmosphere, the temperature was raised to 260 °C and maintained for 2 hours. After cooling to room temperature, the suspension was poured into deionized water, adjusted to neutral with dilute hydrochloric acid and filtered. The filter cake was washed successively with a saturated sodium bicarbonate solution and deionized water, and dried in a vacuum oven at 120 °C for 24 hours to obtain hydrophilic modified PPS. Since the monomer used was a: p-phenylenediamine, the product was named a-PPS.

[0082] The structural formula of a-PPS is:

[0083]

[0084] Example 2

[0085] A method for preparing a hydrophilic polyphenylene sulfide polymer, comprising the following steps:

[0086] 45 g of crystalline sodium sulfide (Na2S = 50%) and 1 g of potassium hydroxide in NMP were added to an autoclave, and then N2 was filled and heated to 180 °C within 1 hour to carry out a dehydration reaction to obtain an anhydrous sodium sulfide system.

[0087] Under the conditions of an Ar atmosphere and an ice-water bath, 13 g of 4,4'-methylenedianiline (b) dispersed in 200 mL of benzene was charged into a dry 500 mL three-necked round-bottom flask equipped with a magnetic stirrer. Then, 25 g of 2,5-dichlorobenzoyl chloride solution was added dropwise to this mixture through a dropping funnel within half an hour. Subsequently, the reaction mixture was stirred at room temperature for 24 hours to obtain a prepolymer. An anhydrous sodium sulfide system was added dropwise to the prepolymer system, stirred at 220 °C for 3 hours under an Ar atmosphere, then heated to 260 °C and maintained for 2 hours, cooled to room temperature, the suspension was poured into deionized water, adjusted to neutral with 5% hydrochloric acid and filtered. The filter cake was washed successively with saturated sodium bicarbonate solution and deionized water, and dried in a vacuum oven at 120 °C for 24 hours to obtain hydrophilically modified PPS. Since the monomer used was b: 4,4'-methylenedianiline, the product was named b-PPS.

[0088] The structural formula of b-PPS is:

[0089]

[0090] Example 3

[0091] A preparation method of a hydrophilically modified polyphenylene sulfide polymer, comprising the following steps:

[0092] 50 g of crystalline sodium sulfide (Na2S = 50%) and 1.5 g of potassium hydroxide in NMP were added to an autoclave, then filled with N2 and heated to 180 °C within 1 hour for a dehydration reaction to obtain an anhydrous sodium sulfide system.

[0093] Under the conditions of an Ar atmosphere and an ice-water bath, 20 g of 4,4'-thiodianiline (c) dispersed in 200 mL of benzene was charged into a dry 500 mL three-necked round-bottom flask equipped with a magnetic stirrer. Then, 18 g of 2,5-dichlorobenzoyl chloride solution was added dropwise to this mixture through a dropping funnel within half an hour. Subsequently, the reaction mixture was stirred at room temperature for 24 hours to obtain a prepolymer. An anhydrous sodium sulfide system was added dropwise to the prepolymer system, stirred at 220 °C for 3 hours under an Ar atmosphere, then heated to 260 °C and maintained for 2 hours, cooled to room temperature, the suspension was poured into deionized water, adjusted to neutral with 8% hydrochloric acid and filtered. The filter cake was washed successively with saturated sodium bicarbonate solution and deionized water, and dried in a vacuum oven at 120 °C for 24 hours to obtain hydrophilically modified PPS. Since the monomer used was c: 4,4'-thiodianiline, the product was named c-PPS.

[0094] The structural formula of c-PPS is:

[0095]

[0096] Example 4

[0097] A preparation method of a hydrophilic polyphenylene sulfide polymer, comprising the following steps:

[0098] Add 50 g of crystalline sodium sulfide (Na2S = 50%) and 1.5 g of potassium hydroxide in NMP to an autoclave, then fill with N2 and heat to 180 °C within 1 hour for dehydration reaction to obtain an anhydrous sodium sulfide system.

[0099] Under the conditions of an Ar atmosphere and an ice-water bath, charge 20 g of 4,4'-diaminobenzophenone (d) dispersed in 200 mL of benzene into a dry 500 mL three-necked round-bottom flask equipped with a magnetic stirrer. Then, dropwise add 18 g of 2,5-dichlorobenzoyl chloride solution to the mixture within half an hour. Then, stir the reaction mixture at room temperature for 24 hours to obtain a prepolymer. Drop the anhydrous sodium sulfide system into the prepolymer system, stir at 220 °C for 3 hours under an Ar atmosphere, then raise the temperature to 260 °C and hold for 2 hours. Cool to room temperature, pour the suspension into deionized water, adjust to neutral with 8% hydrochloric acid and filter. Wash the filter cake successively with saturated sodium bicarbonate solution and deionized water, and dry in a vacuum oven at 120 °C for 24 hours to obtain hydrophilic modified PPS. Since the monomer used is d: 4,4'-diaminobenzophenone, the product is named d-PPS.

[0100] The structural formula of d-PPS is:

[0101]

[0102] Example 5

[0103] A preparation method of a hydrophilic polyphenylene sulfide polymer, comprising the following steps:

[0104] Add 60 g of crystalline sodium sulfide (Na2S = 40%) and 1 g of potassium hydroxide in NMP to an autoclave, then fill with N2 and heat to 150 °C within 1 hour for dehydration reaction to obtain an anhydrous sodium sulfide system.

[0105] Under the conditions of an Ar atmosphere and an ice-water bath, 12 g of 4,4'-diaminodiphenyl sulfone (e) dispersed in 200 mL of chloroform was charged into a dry 500 mL three-necked round-bottom flask equipped with a magnetic stirrer. Then, 30 g of a 2,5-dichlorobenzoyl chloride solution was added dropwise to the mixture through a dropping funnel within half an hour. Subsequently, the reaction mixture was stirred at room temperature for 24 hours to obtain a prepolymer. An anhydrous sodium sulfide system was added dropwise to the prepolymer system, stirred at 220 °C for 3 hours under an Ar atmosphere, then heated to 260 °C and maintained for 2 hours, cooled to room temperature, the suspension was poured into deionized water, adjusted to neutral with 10% hydrochloric acid and filtered. The filter cake was washed successively with saturated sodium bicarbonate solution and deionized water, and dried in a vacuum oven at 120 °C for 24 hours to obtain hydrophilically modified PPS. Since the monomer used was e: 4,4'-diaminodiphenyl sulfone, the product was named e-PPS.

[0106] The structural formula of e-PPS is:

[0107]

[0108] Example 6

[0109] A preparation method of a hydrophilically modified polyphenylene sulfide polymer, comprising the following steps:

[0110] 55 g of crystalline sodium sulfide (Na2S = 45%) and 2 g of potassium hydroxide in NMP were added to an autoclave, then filled with N2 and heated to 130 °C within 1 hour for a dehydration reaction to obtain an anhydrous sodium sulfide system.

[0111] Under the conditions of an Ar atmosphere and an ice-water bath, 20 g of benzidine (f) dispersed in 200 mL of chloroform was charged into a dry 500 mL three-necked round-bottom flask equipped with a magnetic stirrer. Then, 30 g of a 2,5-dichlorobenzoyl chloride solution was added dropwise to the mixture through a dropping funnel within half an hour. Subsequently, the reaction mixture was stirred at room temperature for 24 hours to obtain a prepolymer. An anhydrous sodium sulfide system was added dropwise to the prepolymer system, stirred at 220 °C for 3 hours under an Ar atmosphere, then heated to 260 °C and maintained for 2 hours, cooled to room temperature, the suspension was poured into deionized water, adjusted to neutral with 5% hydrochloric acid and filtered. The filter cake was washed successively with saturated sodium bicarbonate solution and deionized water, and dried in a vacuum oven at 120 °C for 24 hours to obtain hydrophilically modified PPS. Since the monomer used was f: benzidine, the product was named f-PPS.

[0112] The structural formula of f-PPS is:

[0113]

[0114] Effect verification:

[0115] 1. The membrane products prepared from the hydrophilic PPS masterbatch of Examples 1-6 are prepared with reference to the prior art (①Luo Feng, Zhang Jun, Wang Xiaolin, Xu Zhongzi. Principles and Progress of Preparing Polymer Microporous Membranes by Thermally Induced Phase Separation. Journal of Nanjing University of Chemical Technology. 2001, 23(4): 91-100; ②Marcel Mulder. Basic Principles of Membrane Technology [M]. Translated by Li Lin. Beijing, Tsinghua University Press, 1999). The specific membrane preparation process is as follows:

[0116] The thermally induced phase separation method is used to prepare PPS membranes for physical and chemical property tests. The raw materials are hydrophilic modified PPS polymers, benzophenone and dibutyl phthalate for film preparation: First, place the hydrophilic modified PPS in a forced-air drying oven for thorough drying. Weigh 35 wt% of the polymer, 15 wt% of benzophenone and 50 wt% of dibutyl phthalate into a three-necked flask, and heat the flask in a sand bath to a specific temperature (the specific temperature depends on the melting and dispersion of the polymer in the solvent). Turn on the mechanical stirrer to obtain a uniformly dispersed casting solution. Stop stirring and keep it at a constant temperature until the casting solution de-bubbles, then pour it onto a pre-heated iron plate, and use a 500-μm film scraper to scrape it into shape. Place the iron plate in distilled water to solidify into a film, then soak the film in ethanol to extract benzophenone and dibutyl phthalate, and finally wash away the residual ethanol with distilled water, and then the film can be dried and tested.

[0117] 2. Contact angle test:

[0118] The hydrophilicity of the membrane products affects the gas purity. In other words, the stronger the hydrophilicity of the membrane, the more effectively it can avoid the mixing of cathode and anode gases, thereby improving the purity of the collected gas. Therefore, in this invention, the Drop Shape Analyzer-DSA25 from Germany is used to test the hydrophilicity of the membrane, and a surface energy comparison analysis is carried out on the commercially available PPS membranes. Five test points are taken for each sample and the average value is calculated.

[0119] Figure 1 As Figure 1As shown, (a) The commercially available PPS film is a hydrophobic material, and the contact angle reaches more than 100°, which is not conducive to the infiltration of aqueous solutions, resulting in low airtightness and high pollution. For the hydrophilic PPS series synthesized in Examples 1-6 of the present invention, it can be observed that the contact angle with water is between 46°-78°. For b-PPS (78°), c-PPS (75°) and f-PPS (73°), it can be observed that the hydrophilicity is very similar because there are two benzene rings in the corresponding hydrophilic monomer molecular structures, and f-PPS has stronger hydrophilicity than methylene and thio groups due to small steric hindrance; but overall, the three polymers show certain hydrophilicity due to the presence of the strong hydrophilic group amino. For d-PPS (65°), in addition to the amino group, its hydrophilic monomer structure also has two benzene rings and a carbonyl group. Here, a hydrogen bond is formed between the carbonyl group and water molecules, weakening the hydrophobic effect of the "diphenyl ring" system monomer. For a-PPS (58°), the hydrophilic monomer unit has only one benzene ring and two amino groups, making the final polymer have stronger hydrophilicity. The sulfone group is a group well-known for its strong hydrophilicity. In the present invention, e-PPS shows great potential hydrophilicity of 46°. Although the hydrophilic monomer is also a "diphenyl ring" system, the sulfone group and the amino group cooperate, making e-PPS more hydrophilic than a-PPS.

[0120] III. Surface resistance test:

[0121] The surface resistance can reflect the ability of the membrane to transport ions. Under the same test conditions, the stronger the affinity of the membrane product for water, the easier it is for ions to pass through. Referring to SJ / T 10171.5-1991, the surface resistance of different membranes was tested. Among them, the samples to be tested were all immersed in a 30wt% KOH solution, and the effective test area was 10 cm 2 , the test temperature was 30 °C. The data value of the sample with the entrained sample minus the data value of the KOH solution was regarded as the surface resistance value of the membrane to be tested. Five points were taken for each sample and the average value was taken, with the unit of Ω*cm 2 indicated.

[0122] As Figure 2 shown are the surface resistance test results of the membrane products prepared from the hydrophilic PPS masterbatch of Examples 1-6 of the present invention and the commercially available PPS membrane.

[0123] As Figure 2 shown, due to the hydrophobicity, the surface resistance of the commercially available PPS membrane reached 0.487 Ω*cm 2 , and if applied in an electrolytic cell, there will be a large power loss. For the surface resistance of the membrane products of the hydrophilic PPS prepared in Examples 1-6 of the present invention, it shows a decreasing pattern with the improvement of hydrophilicity. Therefore, the hydrophilic PPS polymer prepared in the present invention can replace the traditional PPS material and be used in production applications with lower energy consumption and gas purity.

[0124] IV. Differential Scanning Calorimetry Instrument: Glass Transition Temperature (Tg) Test

[0125] The glass transition temperature test was carried out using TA-DSC Q25 of TA Company. The electrolytic water hydrogen production diaphragm is applied in KOH electrolyte at 85°C - 90°C and 25wt% - 30wt%. And Tg is a physical property that characterizes the transition of a polymer from a glassy state to a highly elastic state. If the Tg point of the diaphragm material is relatively low, it will directly affect the increase in the pore size of the diaphragm, thereby resulting in low gas purity. As Figure 3 shown in Table 1:

[0126] Table 1

[0127] Item Tg / °C a-PPS 99.23 b-PPS 98.41 c-PPS 99.25 d-PPS 99.36 e-PPS 162.15 f-PPS 100.35

[0128] Conclusion: A series of hydrophilic PPS prepared in Examples 1 - 6 of the present invention all have a Tg above 98°C. The reason is that the heat resistance of polymer materials is affected by molecular polarity, that is, the higher the polarity, the higher the thermal stability of the polymer.

[0129] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A preparation method of hydrophilic polyphenylene sulfide, characterized in that, It includes the following steps: Under the conditions of inert gas and ice-water bath, add the dehydrated sulfur source to the prepolymer obtained by mixing and stirring a hydrophilic functional monomer and 2,5-dichlorobenzoyl chloride, and prepare the hydrophilic polyphenylene sulfide through copolymerization reaction; Wherein, the sulfur source is crystalline sodium sulfide; The hydrophilic functional monomer includes any one of p-phenylenediamine, 4,4'-methylenedianiline, 4,4'-thiodianiline, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenyl sulfone, benzidine.

2. The preparation method of a hydrophilic polyphenylene sulfide according to claim 1, characterized in that, The mass ratio of the hydrophilic functional monomer, 2,5-dichlorobenzoyl chloride and sulfur source is: (18-27):(29-45):(33-40).

3. The preparation method of a hydrophilic polyphenylene sulfide according to claim 1, characterized in that, The specific steps of the preparation method are as follows: (1) Mix crystalline sodium sulfide dispersed in a high-boiling polar organic solvent and inorganic strong base, and heat under inert gas conditions to obtain a dehydrated sulfur source; (2) Under the conditions of inert gas and ice-water bath, drop 2,5-dichlorobenzoyl chloride into the hydrophilic functional monomer dispersed in an organic solvent, and stir at room temperature to obtain a prepolymer; (3) Drop the dehydrated sulfur source into the prepolymer, and successively carry out high-temperature stirring, heating, cooling, washing and drying to obtain the hydrophilic polyphenylene sulfide.

4. The preparation method of a hydrophilic polyphenylene sulfide according to claim 3, characterized in that, In step (1), the high-boiling polar organic solvent is NMP; and / or The inorganic strong base is any one of sodium hydroxide and potassium hydroxide.

5. The preparation method of a hydrophilic polyphenylene sulfide according to claim 3, characterized in that, The heating process in step (1) is: heat to 150°C - 180°C within 1 hour.

6. The preparation method of a hydrophilic polyphenylene sulfide according to claim 3, wherein The conditions in the high-temperature stirring process in step (3) are: stir at 220°C for 3 hours; and / or The conditions in the heating process are: heat from 220°C to 260°C and keep the temperature for 2 hours.

7. A hydrophilic polyphenylene sulfide, characterized in that, Prepared according to the preparation method described in any one of claims 1-6.

8. Application of the hydrophilic polyphenylene sulfide according to claim 7 in the field of alkaline electrolytic water hydrogen production.

9. A polyphenylene sulfide diaphragm applied to alkaline electrolytic water hydrogen production, characterized in that, Prepared from the hydrophilic polyphenylene sulfide described in claim 7.

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