Hydrophilic polyphenylene sulfide as well as preparation method and application thereof

Abstract

The invention discloses hydrophilic polyphenylene sulfide as well as a preparation method and application thereof, and belongs to the technical field of alkaline electrolytic water hydrogen production, the preparation method of the hydrophilic polyphenylene sulfide comprises the following steps: under the conditions of inert gas and ice-water bath, adding a hydrophilic functional monomer and 2, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1 The preparation method comprises the following steps: adding a dehydrated sulfur source into a prepolymer obtained by mixing and stirring 2, 5-dichlorobenzoyl chloride, and carrying out a copolymerization reaction to obtain the hydrophilic polyphenylene sulfide, wherein the sulfur source is crystalline sodium sulfide. A series of hydrophilic polyphenylene sulfide prepared by the preparation method provided by the invention solves the limitation of the hydrophilicity of commercially available polyphenylene sulfide from the angle of molecular structure, and has the advantages of good hydrophilicity, low surface resistance, acid resistance and alkali resistance.

Description

Technical Field

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

[0002] With the continuous progress of social productivity, human beings have realized that conventional energy sources such as coal, oil, and natural gas are facing the problem of depletion and cannot be regenerated in the short term. Therefore, they place their hopes on new energy sources such as solar energy, wind energy, and tidal energy. However, the electricity converted from natural forces cannot be directly connected to the power grid for delivery to customers. Researchers then use this part of electricity to electrolyze the inexhaustible water resources to obtain hydrogen resources.

[0003] Alkaline water electrolysis is still the mainstream technology for hydrogen production. This technology often uses 30% potassium hydroxide solution as the electrolyte, which is a highly corrosive environment. In the electrolyzer, the membrane that separates oxygen and hydrogen and the cathode and anode plates is called a diaphragm. - Ions should pass through the diaphragm material with the least possible resistance. In this field, asbestos diaphragms were initially used, but were later abandoned due to pollution and other reasons. People then turned their attention to polyphenylene sulfide materials that have high insulation, alkali resistance, and stability at high temperatures. Physical methods were used to manufacture fibers, prepare strands, and subsequently weave the polymer particles. Finally, PPS diaphragms were used in alkaline water electrolysis hydrogen production electrolyzers.

[0004] As PPS diaphragms are put into use, people have found that the energy consumption and air tightness of this material are different from those of obsolete asbestos diaphragms. Through research, it is confirmed that the performance shortcoming is related to the poor hydrophilicity of PPS. In recent years, researchers have tried 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 will destroy the molecular chain structure of PPS, which will directly reduce the service life of the diaphragm or make it no longer suitable for strong alkaline environments. For example, the patent number is CN202311011751.9, and the patent name is: A novel multi-layer alkaline water electrolysis hydrogen production diaphragm, its preparation method and application, which involves a multi-layer alkaline water electrolysis hydrogen production diaphragm. The patent uses a PPS grid as a support and is immersed in a prepared hydrophilic modified liquid, and finally obtains a hydrophilic support network. However, this physical attachment is difficult to ensure that the hydrophilic coating will fall off later; the patent number is: CN201410723796.3, and the patent name is: A method for preparing a modified polyphenylene sulfide composite masterbatch, which involves a method of adding various additives, and then heating, melting, mixing, dispersing, homogenizing, and extruding a twin-screw extruder to produce a modified polyphenylene sulfide composite masterbatch, which enhances the strength, toughness, oxidation resistance, and high temperature resistance of the polyphenylene sulfide material. However, in this physical mixing, the functional additives are prone to phase separation in a series of processing of the masterbatch in the later stage, which ultimately leads to 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 and its preparation method and application. A series of hydrophilic polyphenylene sulfides are prepared by the preparation method provided by the present invention, which solves the limitation of the hydrophilicity of commercially available polyphenylene sulfide from the perspective of molecular structure, and has good hydrophilicity, high OH - The advantages of transmission 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 method for preparing hydrophilic polyphenylene sulfide comprises the following steps:

[0010] Under inert gas and ice water bath conditions, 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 copolymerization;

[0011] Wherein, 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 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'-thiodiphenylamine, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenyl sulfone and benzidine.

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

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

[0019] (2) under inert gas and ice water bath conditions, 2,5-dichlorobenzoyl chloride is added dropwise to the hydrophilic functional monomer dispersed in the organic solvent, and stirred at room temperature to obtain a prepolymer;

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

[0021] Beneficial effects: The present invention uses functional monomers with specific structures to synthesize hydrophilic polyphenylene sulfide prepolymers with different structures through copolymerization, 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 three simple steps.

[0022] Furthermore, on the one hand, compared with the traditional PPS main chain, since there is no hydrophilic group, the present invention fundamentally broadens the application of PPS products. On the other hand, unlike simple physical mixing and the use of harsh chemical modifiers to destroy the benzene ring or sulfur element of PPS for modification, the present invention adjusts the addition ratio and / or type of hydrophilic functional monomers to prepare various hydrophilic modified PPS in a targeted manner, which can selectively avoid the cost increase of certain raw materials caused by the price mechanism of domestic and foreign markets.

[0023] Preferably, the high boiling point 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, the heating process in step (1) is: heating to 150°C-180°C within 1 hour.

[0026] Preferably, the organic solvent in step (2) comprises 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] The suspension after cooling is poured into deionized water, adjusted to neutrality with inorganic acid, and the filter residue is washed with weak alkaline washing solution and deionized water in turn.

[0032] Further, 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 alkaline washing solution is a saturated sodium bicarbonate solution.

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

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

[0036]

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

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

[0039] The hydrophilic polyphenylene sulfide is used in the field of hydrogen production by alkaline water electrolysis.

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

[0041] A polyphenylene sulfide diaphragm used for producing hydrogen by alkaline water electrolysis is prepared by using the hydrophilic polyphenylene sulfide as a raw material.

[0042] Beneficial effect: The polyphenylene sulfide diaphragm used for hydrogen production by alkaline water electrolysis prepared by using the hydrophilic polyphenylene sulfide disclosed in the present invention as a raw material has high OH - Features include high transmission capacity, air tightness 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 in the present invention fundamentally solves the disadvantage 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 product prepared from the hydrophilic PPS masterbatch of the present invention is significantly lower than that of the traditional PPS. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0048] Figure 1 This is a contact angle test diagram of the film product 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 This is a surface resistance test diagram of a film product prepared from hydrophilic polyphenylene sulfide of Examples 1-6 of the present invention;

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

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

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

[0054] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0055] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation 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 associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0056] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0057] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

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

[0059] Wherein, 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'-methylenediphenylamine, c: 4,4'-thiodiphenylamine, d: 4,4'-diaminobenzophenone, e: 4,4'-diaminodiphenyl sulfone, and f: benzidine;

[0061] The sulfur source is sodium sulfide.

[0062] The present invention also discloses a method for preparing a hydrophilic polyphenylene sulfide polymer, comprising the following steps:

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

[0064] Adding crystalline sodium sulfide dispersed in a high-boiling point polar organic solvent and an inorganic strong base equivalent to the sodium sulfide into an autoclave, then filling with inert gas and heating to a target temperature within 1 hour to perform a dehydration reaction to obtain an anhydrous sodium sulfide system;

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

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

[0067] The anhydrous sodium sulfide system was added dropwise to the prepolymer system (hydrophilic PPS prepolymer), stirred at 220°C for 3 hours in an inert gas atmosphere, heated to 260°C and maintained for 2 hours, cooled to room temperature, poured the suspension into deionized water, adjusted to neutrality with inorganic acid, and the filter residue was washed with a weak alkaline washing solution and deionized water in turn, and dried 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 point polar organic solvent is NMP (N-methyl-2-pyrrolidone);

[0069] 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 alkaline washing solution is a saturated sodium bicarbonate solution.

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

[0076] The raw materials used in the present invention are all purchased from the market.

[0077] The technical solution of the present invention is further illustrated by the following embodiments.

[0078] Example 1

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

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

[0081] In a dry 500mL three-necked round-bottom flask equipped with a magnetic stirrer, 16g of p-phenylenediamine (a) dispersed in 200mL of dichloromethane was charged under N2 atmosphere and ice-water bath conditions, and then 25g of 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, and anhydrous sodium sulfide system was added dropwise to the prepolymer system. After stirring at 220°C for 3 hours under N2 atmosphere, the temperature was raised to 260°C and maintained for 2 hours, and then cooled to room temperature. The suspension was poured into deionized water, adjusted to neutrality with dilute hydrochloric acid and filtered, and the filter residue was washed with saturated sodium bicarbonate solution and deionized water in turn, and dried in a vacuum oven at 120°C for 24 hours to obtain hydrophilic modified PPS. Because 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 comprises the following steps:

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

[0087] In an Ar atmosphere and an ice-water bath, a dry 500-mL three-necked round-bottom flask equipped with a magnetic stirrer was charged with 13 g of 4,4'-methylenedianiline (b) dispersed in 200 mL of benzene, and then 25 g of 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, and an anhydrous sodium sulfide system was added dropwise to the prepolymer system. After stirring at 220° C. for 3 hours under an Ar atmosphere, the temperature was raised to 260° C. and maintained for 2 hours, and then cooled to room temperature. The suspension was poured into deionized water, adjusted to neutrality with 5% hydrochloric acid and filtered, and the filter residue was washed with a saturated sodium bicarbonate solution and deionized water in turn, and dried in a vacuum oven at 120° C. for 24 hours to obtain a hydrophilic 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 method for preparing a hydrophilic polyphenylene sulfide polymer comprises the following steps:

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

[0093] In an Ar atmosphere and an ice-water bath, a dry 500-mL three-necked round-bottom flask equipped with a magnetic stirrer was charged with 20 g of 4,4'-thiodiphenylamine (c) dispersed in 200 mL of benzene, and then 18 g of 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, and an anhydrous sodium sulfide system was added dropwise to the prepolymer system. After stirring at 220° C. for 3 hours under an Ar atmosphere, the temperature was raised to 260° C. and maintained for 2 hours, and then cooled to room temperature. The suspension was poured into deionized water, adjusted to neutrality with 8% hydrochloric acid and filtered, and the filter residue was washed with a saturated sodium bicarbonate solution and deionized water in turn, and dried in a vacuum oven at 120° C. for 24 hours to obtain a hydrophilically modified PPS. Since the monomer used was c: 4,4'-thiodiphenylamine, the product was named c-PPS.

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

[0095]

[0096] Example 4

[0097] A method for preparing a hydrophilic polyphenylene sulfide polymer comprises the following steps:

[0098] To the autoclave were added 50 g of crystalline sodium sulfide in NMP (Na2S=50%) and 1.5 g of potassium hydroxide, which was then filled with N2 and heated to 180°C within 1 hour to perform a dehydration reaction to obtain an anhydrous sodium sulfide system.

[0099] In an Ar atmosphere and an ice-water bath, a dry 500 mL three-necked round-bottom flask equipped with a magnetic stirrer was charged with 20 g of 4,4'-diaminobenzophenone (d) dispersed in 200 mL of benzene, and then 18 g of 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, and an anhydrous sodium sulfide system was added dropwise to the prepolymer system. After stirring at 220° C. for 3 hours under an Ar atmosphere, the temperature was raised to 260° C. and maintained for 2 hours, and then cooled to room temperature. The suspension was poured into deionized water, adjusted to neutrality with 8% hydrochloric acid and filtered, and the filter residue was washed with a saturated sodium bicarbonate solution and deionized water in turn, and dried in a vacuum oven at 120° C. for 24 hours to obtain a hydrophilically modified PPS. Because the monomer used was d: 4,4'-diaminobenzophenone, the product was named d-PPS.

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

[0101]

[0102] Example 5

[0103] A method for preparing a hydrophilic polyphenylene sulfide polymer comprises the following steps:

[0104] To the autoclave were added 60 g of crystalline sodium sulfide (Na2S=40%) and 1 g of potassium hydroxide in NMP, which was then filled with N2 and heated to 150°C within 1 hour to perform a dehydration reaction to obtain an anhydrous sodium sulfide system.

[0105] In an Ar atmosphere and an ice-water bath, a dry 500-mL three-necked round-bottom flask equipped with a magnetic stirrer was charged with 12 g of 4,4'-diaminodiphenyl sulfone (e) dispersed in 200 mL of chloroform, and then 30 g of 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, and an anhydrous sodium sulfide system was added dropwise to the prepolymer system. After stirring at 220° C. for 3 hours under an Ar atmosphere, the temperature was increased to 260° C. and maintained for 2 hours, and then cooled to room temperature. The suspension was poured into deionized water, adjusted to neutrality with 10% hydrochloric acid and filtered, and the filter residue was washed with a saturated sodium bicarbonate solution and deionized water in turn, and dried in a vacuum oven at 120° C. for 24 hours to obtain a hydrophilic modified PPS. Because 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 method for preparing a hydrophilic polyphenylene sulfide polymer comprises the following steps:

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

[0111] In an Ar atmosphere and an ice-water bath, a dry 500-mL three-necked round-bottom flask equipped with a magnetic stirrer was charged with 20 g of benzidine (f) dispersed in 200 mL of chloroform, and then 30 g of 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, and an anhydrous sodium sulfide system was added dropwise to the prepolymer system. After stirring at 220° C. for 3 hours under an Ar atmosphere, the temperature was increased to 260° C. and maintained for 2 hours, and then cooled to room temperature. The suspension was poured into deionized water, adjusted to neutrality with 5% hydrochloric acid and filtered, and the filter residue was washed with a saturated sodium bicarbonate solution and deionized water in turn, and dried in a vacuum oven at 120° C. for 24 hours to obtain a hydrophilic modified PPS. Because 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 product prepared from the hydrophilic PPS masterbatch of Examples 1-6 has a preparation process based on the prior art (① Luo 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; ② Marcel 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 PPS membrane was prepared by thermally induced phase separation for physical and chemical property testing. The raw materials were hydrophilic modified PPS polymer, benzophenone and dibutyl phthalate for membrane preparation: first, the hydrophilic modified PPS was placed in a blast drying oven for thorough drying, 35wt% of the polymer, 15wt% of benzophenone and 50wt% of dibutyl phthalate were weighed in a three-necked flask, and the flask was heated in a sand bath to a specific temperature (the specific temperature was determined by the melting and dispersion of the polymer in the solvent), mechanical stirring was turned on to obtain a uniformly dispersed casting liquid, stirring was stopped and the casting liquid was placed at a constant temperature to remove bubbles and then poured onto a pre-heated iron plate, and a 500μm film scraper was used to scrape it into shape, the iron plate was placed in distilled water, solidified into a film, and then the film was soaked in ethanol to extract benzophenone and dibutyl phthalate, and finally the residual ethanol was washed off with distilled water, and the film was dried and tested.

[0117] 2. Contact angle test:

[0118] The hydrophilicity of the membrane product affects the gas purity. In other words, the more hydrophilic the membrane is, the more effective it is in avoiding the mixing of cathode and anode gases, thereby improving the purity of the collected gas. The hydrophilicity of the membrane was tested using the Drop Shape Analyzer-DSA25, and the surface energy of commercially available PPS membranes was compared and analyzed. Five test points were taken for each sample and the average value was calculated.

[0119] like Figure 1As shown, (a) is a commercially available PPS film that is a hydrophobic material with a contact angle of more than 100°, which is not conducive to the infiltration of aqueous solutions, resulting in low air tightness and high contamination. For the hydrophilic PPS series synthesized in Examples 1-6 of the present invention, it can be observed that the contact angle to 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 structure, and f-PPS has a strong hydrophilicity compared to methylene and thio groups due to its small steric hindrance; but the overall three polymers are uniformly hydrophilic due to the presence of strong hydrophilic groups amino groups. For d-PPS (65°), its hydrophilic monomer structure has two benzene rings and a carbonyl group in addition to the amino group, where hydrogen bonds are formed between the carbonyl group and the water molecule, weakening the hydrophobic effect of the "diphenyl ring" system monomer. In a-PPS (58°), the hydrophilic monomer unit has only one benzene ring and two amino groups, which makes the final polymer more hydrophilic. Sulfone group is a well-known group with strong hydrophilicity. In the present invention, e-PPS shows a great potential hydrophilicity of 46°. Although the hydrophilic monomer is also a "diphenyl ring" system, the sulfone group and the amino group work together to make e-PPS more hydrophilic than a-PPS.

[0120] 3. Surface resistance test:

[0121] The surface resistance can reflect the ability of the membrane to transmit 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. The samples to be tested were immersed in a 30wt% KOH solution, and the effective test area was 10cm 2 , the test temperature is 30℃, the surface resistance of the film to be tested is the value obtained by subtracting the value of the KOH solution from the data value of the entrained sample test. Five points are taken for each sample and the average value is taken. The unit is Ω*cm 2 express.

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

[0123] like Figure 2 As shown in Figure 2, due to its hydrophobicity, the surface resistance of the commercially available PPS film reaches 0.487Ω*cm 2 If used in an electrolytic cell, there will be a large loss of electric energy. The surface resistance of the hydrophilic PPS film products prepared in Examples 1-6 of the present invention decreases with the increase of hydrophilicity, so the hydrophilic PPS polymer prepared by the present invention can replace the traditional PPS material and be used in production applications with lower energy consumption and gas purity.

[0124] 4. Differential Scanning Calorimetry Instrument: Glass Transition Temperature (Tg) Test

[0125] The glass transition temperature test was conducted using TA's TA-DSC Q25. The water electrolysis hydrogen production diaphragm is used in 85℃-90℃, 25wt%-30wt% KOH electrolyte, and Tg is a physical property that characterizes the transition of polymers from glassy state to highly elastic state. If the Tg point of the diaphragm material is relatively low, it will directly affect the pore size of the diaphragm from small to large, thus resulting in low gas purity. Figure 3 As shown in Table 1:

[0126] Table 1

[0127] project Tg / ℃ 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 the polarity of the molecules, that is, the higher the polarity, the higher the thermal stability of the polymer.

[0129] The above are only preferred specific implementations 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 a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for preparing hydrophilic polyphenylene sulfide, characterized in that: The following steps are involved: Under inert gas and ice water bath conditions, 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 copolymerization; Wherein, the sulfur source is crystalline sodium sulfide.

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

3. The method for preparing a hydrophilic polyphenylene sulfide according to claim 1 or 2, characterized in that: The hydrophilic functional monomer includes any one of p-phenylenediamine, 4,4'-methylenedianiline, 4,4'-thiodiphenylamine, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenyl sulfone and benzidine.

4. The method for preparing a hydrophilic polyphenylene sulfide according to claim 1, characterized in that: The specific steps of the preparation method are: (1) mixing crystalline sodium sulfide dispersed in a high-boiling point polar organic solvent and an inorganic strong base, and heating under inert gas conditions to obtain a dehydrated sulfur source; (2) under inert gas and ice water bath conditions, 2,5-dichlorobenzoyl chloride is added dropwise to the hydrophilic functional monomer dispersed in the organic solvent, and stirred at room temperature to obtain a prepolymer; (3) dropping the dehydrated sulfur source into the prepolymer, and sequentially performing high-temperature stirring, heating, cooling, washing and drying to obtain the hydrophilic polyphenylene sulfide.

5. The method for preparing a hydrophilic polyphenylene sulfide according to claim 4, characterized in that: The high boiling point polar organic solvent in step (1) is NMP; and / or The inorganic strong base is any one of sodium hydroxide and potassium hydroxide.

6. The method for preparing a hydrophilic polyphenylene sulfide according to claim 4, characterized in that: The heating process in step (1) is: heating to 150° C.-180° C. within 1 hour.

7. The method for preparing a hydrophilic polyphenylene sulfide according to claim 4, characterized in that: The conditions during the high temperature stirring process in step (3) are: stirring at 220° C. for 3 hours; and / or The conditions in the heating process are: heating from 220° C. to 260° C. and keeping the temperature for 2 hours.

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

9. Use of the hydrophilic polyphenylene sulfide as claimed in claim 8 in the field of hydrogen production by alkaline water electrolysis.

10. A polyphenylene sulfide membrane used for hydrogen production by alkaline water electrolysis, characterized in that: Prepared from the hydrophilic polyphenylene sulfide described in claim 8.

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