Preparation method and application of polyether-ether-ketone and sulfonated polyether-ether-ketone

Abstract

The invention discloses a preparation method and application of polyether-ether-ketone and sulfonated polyether-ether-ketone, and belongs to the technical field of proton exchange membranes. The preparation method of the polyether-ether-ketone comprises the following steps: uniformly mixing a difluorobenzophenone monomer, a bisphenol monomer, sulfonated graphene and a catalyst in diphenyl sulfone, completely dissolving, heating to react, separating out in water, and sequentially extracting, pickling, cleaning and drying to obtain the polyether-ether-ketone, the mass ratio of the difluorobenzophenone monomer to the bisphenol monomer to the sulfonated graphene to the catalyst to the diphenyl sulfone is (55-65): (25-30): (3-8): (45-55): (140-160). The sulfonated polyether-ether-ketone is obtained by sulfonating polyether-ether-ketone with a sulfonating agent. The sulfonated polyetheretherketone obtained by the method has good machinability, moderate viscosity and better solution film-forming property, and the proton exchange membrane obtained by the solution film-forming method is smooth in appearance, free of pores and bulges and excellent in ion exchange capacity, mechanical strength, thermal stability and durability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of proton exchange membrane, and particularly relates to a preparation method of polyether ether ketone and sulfonated polyether ether ketone and application thereof. BACKGROUND

[0002] With the development of clean energy technologies such as fuel cells, hydrogen energy and water electrolysis hydrogen production, the performance of proton exchange membrane (PEM) as a core component of fuel cells directly determines the overall efficiency and service life of fuel cells. The most widely used proton exchange membrane on the market is mainly represented by perfluorosulfonic acid resin (such as Nafion). However, perfluorosulfonic acid resin has been one of the main factors hindering the commercialization of fuel cells due to its high cost. In recent years, sulfonated polyether ether ketone (SPEEK) as a low-cost proton exchange membrane material can achieve high proton conductivity in a hydrated state, but also has some problems, for example, direct sulfonation method uses concentrated sulfuric acid to treat polyether ether ketone to obtain sulfonated polyether ether ketone, the distribution of sulfonic acid groups is random and uneven, and it is difficult to form continuous and optimized proton conduction channels like perfluorosulfonic acid resin. The microphase separation structure formed by SPEEK is not continuous, which leads to a decrease in conductivity under low humidity or high temperature conditions. In addition, sulfonated polyether ether ketone is also synthesized by monomer polymerization reaction, which can solve the problem of uneven distribution of sulfonic acid groups to a certain extent, but also has the problem of narrow adjustment range of sulfonation degree, which makes it difficult to improve the sulfonation degree, causing local excessive water absorption of the membrane body, high swelling rate, and other problems such as mechanical property decline and size instability. Therefore, how to control the sulfonation degree and uniformity of sulfonated polyether ether ketone is a major problem in the field. SUMMARY

[0003] In view of the problems in the background art, the purpose of the present application is to provide a preparation method of polyether ether ketone. The method introduces sulfonated graphene in the synthesis process of polyether ether ketone, finds that the high specific surface area characteristics of sulfonic acid groups are beneficial to the polymerization reaction, and can reduce the reaction temperature. And according to the needs, subsequent resulfonation treatment can be carried out, and problems such as insufficient sulfonation uniformity caused by resulfonation treatment can be avoided. The sulfonated polyether ether ketone prepared from the polyether ether ketone has good processability, and the proton exchange membrane prepared therefrom has excellent ion exchange capacity and thermal stability, and the mechanical strength is increased significantly.

[0004] In order to achieve the above-mentioned purpose, the present application further provides a preparation method of polyether ether ketone, comprising the following steps: uniformly mixing and completely dissolving difluorobenzophenone monomer, bisphenol monomer, sulfonated graphene and catalyst in diphenyl sulfone, heating and reacting, precipitating in water, and then sequentially performing extraction, pickling, cleaning and drying to obtain polyether ether ketone; the mass ratio of the difluorobenzophenone monomer, bisphenol monomer, sulfonated graphene, catalyst and diphenyl sulfone is 55-65:25-30:3-8:45-55:140-160.

[0005] Optionally, the catalyst is one or a combination of potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide and tetrabutylammonium bromide.

[0006] Optionally, the difluorobenzophenone monomer is one or a combination of 4,4'-difluorobenzophenone and 4,4'-difluorotriphenyl ketone.

[0007] Optionally, the bisphenol monomer is one or a combination of hydroquinone, 4,4'-dihydroxybenzophenone and tert-butyl hydroquinone.

[0008] Optionally, the particle size of the sulfonated graphene is 1.2-4.0 μm, the thickness is 0.8-6.6 nm, the number of layers is <5, and the S content is 2.2-6.4 wt%.

[0009] The application also provides a preparation method of sulfonated polyether ether ketone.

[0010] Optionally, the sulfonating agent is one or a combination of concentrated sulfuric acid, fuming sulfuric acid, chlorosulfonic acid and sulfur trioxide-triethyl phosphate; and the concentration of the concentrated sulfuric acid ranges from 96 wt% to 98 wt%.

[0011] Optionally, the method comprises the following steps: (1) drying the polyether ether ketone, grinding it into powder, dissolving it in concentrated sulfuric acid, heating to 60℃, adding a catalyst FeCl3, and heating to 80℃, and continuing to react for 10 h to obtain a sulfonated solution; (2) placing a pure ice-water mixture in a beaker, so that the water temperature is lower than 5℃, continuously stirring the ice-water mixture with a glass rod to form a vortex and slowly pouring it into the sulfonated solution in a linear shape, so that the sulfonated polyether ether ketone primary material is precipitated in the ice-water mixture; (3) separating the sulfonated polyether ether ketone primary material from the ice-water mixture, repeatedly immersing and washing it with 3% dilute hydrochloric acid for 3-5 times, washing it with deionized water until the pH value reaches 7, draining it, and then placing it in a blast drying oven, setting the temperature to 60℃, and drying it for 12 h to obtain the sulfonated polyether ether ketone.

[0012] The application also provides a sulfonated polyether ether ketone prepared by the above preparation method.

[0013] The application also provides an application of the above sulfonated polyether ether ketone, which is used for preparing a proton exchange membrane of a hydrogen fuel cell.

[0014] The application has the following beneficial effects: 1. By introducing the sulfonated graphene in the synthesis process of the polyether ether ketone, it is found that the sulfonated graphene has a high specific surface area characteristic of sulfonic acid groups, which is beneficial to the polymerization reaction and can reduce the reaction temperature; and the subsequent resulfonation treatment can be performed according to the needs, and the problem of insufficient sulfonation uniformity in the resulfonation treatment process can be avoided.

[0015] 2. The sulfonated polyether ether ketone obtained by the above method has good processability, moderate viscosity, and better solution film forming property. The proton exchange membrane obtained by the solution film forming method has a smooth appearance, no pores and protrusions, and excellent ion exchange capacity, mechanical strength, thermal stability and durability. DETAILED DESCRIPTION

[0016] To make the above objectives, features and advantages of the application more obvious and easy to understand, the specific embodiments of the application are described in detail below.

[0017] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the concept of the present application, therefore the present application is not limited to the specific embodiments disclosed below.

[0018] The preparation method of the polyether ether ketone according to the present application comprises the following steps: mixing and uniformly dissolving difluorobenzophenone monomer, bisphenol monomer, sulfonated graphene and catalyst in diphenyl sulfone, heating and reacting, precipitating in water, and then sequentially performing extraction, acid washing, cleaning and drying to obtain polyether ether ketone; the mass ratio of the difluorobenzophenone monomer, bisphenol monomer, sulfonated graphene, catalyst and diphenyl sulfone is 55-65:25-30:3-8:45-55:140-160. The catalyst can be one or a combination of potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide and tetrabutylammonium bromide. The difluorobenzophenone monomer can be one or a combination of 4,4'-difluorobenzophenone and 4,4'-difluorotriphenyl ketone. The bisphenol monomer can be one or a combination of hydroquinone, 4,4'-dihydroxybenzophenone and tert-butyl hydroquinone. The particle size of the sulfonated graphene can be 1.2-4.0 μm, the thickness can be 0.8-6.6 nm, the number of layers can be <5, and the S content can be 2.2-6.4 wt%.

[0019] The preparation method of the sulfonated polyether ether ketone according to the present application is obtained by sulfonating the polyether ether ketone obtained by the above preparation method with a sulfonating agent. The sulfonating agent can be one or a combination of concentrated sulfuric acid, fuming sulfuric acid, chlorosulfonic acid and sulfur trioxide-phosphorus triethyl ester; the concentration of the concentrated sulfuric acid ranges from 96 to 98 wt%.

[0020] The preparation method of the sulfonated polyether ether ketone according to the application can comprise the following steps: (1) drying the polyether ether ketone, grinding it into powder, dissolving it in concentrated sulfuric acid, heating to 60 DEG C, adding a catalyst FeCl3, raising the temperature to 80 DEG C, and continuing to react for 10 hours to obtain a sulfonated solution; (2) putting a pure ice-water mixture into a beaker, making the water temperature lower than 5 DEG C, continuously stirring the ice-water mixture with a glass rod to form a vortex and slowly pouring it into the sulfonated solution in a linear shape, so that the sulfonated polyether ether ketone primary material is precipitated in the ice-water mixture; (3) separating the sulfonated polyether ether ketone primary material from the ice-water mixture, repeatedly immersing and cleaning it with dilute hydrochloric acid with a concentration of 3% for 3-5 times, cleaning it with deionized water until the pH value reaches 7, draining, and then putting it into a blast drying oven, setting the temperature to 60 DEG C, and drying for 12 hours to obtain the sulfonated polyether ether ketone.

[0021] The sulfonated polyether ether ketone prepared by the preparation method according to the application can be used to prepare a proton exchange membrane of a hydrogen fuel cell.

[0022] The preparation method of the sulfonated polyether ether ketone according to the application and its application are specifically described below by examples. The main raw materials and equipment used are as follows: in the absence of specific indications, the raw materials and equipment of each example and the comparative example are the same; the materials without specific models or types are common models purchased from the market, and are not specifically limited. The sulfonated graphene is from Shandong Jincheng Graphene Technology Co., Ltd.

[0023] Example 1 Synthesis of the polyether ether ketone: adding diphenyl sulfone, 4,4'-difluorobenzophenone, t-butyl hydroquinone, sulfonated graphene and anhydrous sodium carbonate into a reaction container, sequentially raising the temperature to 160 DEG C under nitrogen protection for 0.5 hours, 180 DEG C for 0.5 hours, 230 DEG C for 0.5 hours, 260 DEG C for 0.5 hours, 300 DEG C for 1 hour, lowering the temperature, sequentially extracting with acetone, washing with hydrochloric acid, washing with deionized water and drying in a vacuum box to obtain the polyether ether ketone; the mass ratio of the 4,4'-difluorobenzophenone, t-butyl hydroquinone, sulfonated graphene, anhydrous sodium carbonate and diphenyl sulfone is 55:25:3:45:140.

[0024] Sulfonation of the polyether ether ketone: (1) After drying the polyether ether ketone, it is ground into powder, dissolved in concentrated sulfuric acid with a concentration of 96wt%, heated to 60℃, a catalyst FeCl3 is added, the temperature is raised to 80℃, and the reaction is continued for 10h to obtain a sulfonated solution; (2) A pure ice-water mixture is placed in a beaker, the water temperature is kept below 5℃, the ice-water mixture is continuously stirred with a glass rod to form a vortex and slowly poured into the sulfonated solution in a linear shape, and the sulfonated polyether ether ketone primary material is precipitated from the ice-water mixture; (3) The sulfonated polyether ether ketone primary material is separated from the ice-water mixture, repeatedly immersed and washed with dilute hydrochloric acid with a concentration of 3wt% for 3 times, washed with deionized water until the pH value reaches 7, drained, and then placed in a blast drying oven, set to 60℃, and dried for 12h to obtain sulfonated polyether ether ketone.

[0025] Example 2 Synthesis of polyether ether ketone: Diphenyl sulfone, 4,4'-difluorotriphenyl ketone, hydroquinone, sulfonated graphene, and anhydrous potassium carbonate are added to a reaction container, and under nitrogen protection, the temperature is sequentially raised to 160℃ for 0.5h, 180℃ for 0.5h, 230℃ for 0.5h, 265℃ for 0.5h, 295℃ for 1h, and then cooled, sequentially extracted with acetone, washed with hydrochloric acid, washed with deionized water, and dried in a vacuum box to obtain polyether ether ketone; the mass ratio of 4,4'-difluorotriphenyl ketone, hydroquinone, sulfonated graphene, anhydrous potassium carbonate, and diphenyl sulfone is 65:30:8:55:160.

[0026] Sulfonation of the polyether ether ketone: (1) After drying the polyether ether ketone, it is ground into powder, dissolved in concentrated sulfuric acid with a concentration of 96wt%, heated to 60℃, a catalyst FeCl3 is added, the temperature is raised to 80℃, and the reaction is continued for 10h to obtain a sulfonated solution; (2) A pure ice-water mixture is placed in a beaker, the water temperature is kept below 5℃, the ice-water mixture is continuously stirred with a glass rod to form a vortex and slowly poured into the sulfonated solution in a linear shape, and the sulfonated polyether ether ketone primary material is precipitated from the ice-water mixture; (3) The sulfonated polyether ether ketone primary material is separated from the ice-water mixture, repeatedly immersed and washed with dilute hydrochloric acid with a concentration of 3wt% for 3 times, washed with deionized water until the pH value reaches 7, drained, and then placed in a blast drying oven, set to 60℃, and dried for 12h to obtain sulfonated polyether ether ketone.

[0027] Example 3 Synthesis of polyether ether ketone: diphenyl sulfone, 4,4'-difluorobenzophenone, tert-butyl hydroquinone, sulfonated graphene and anhydrous sodium carbonate were added in a reaction vessel, and sequentially heated to 160°C for 0.5h, 180°C for 0.5h, 230°C for 0.5h, 265°C for 0.5h, 290°C for 1h under nitrogen protection, and then cooled down, sequentially extracted with acetone, washed with hydrochloric acid, washed with deionized water and dried in a vacuum box to obtain polyether ether ketone; the mass ratio of 4,4'-difluorobenzophenone, tert-butyl hydroquinone, sulfonated graphene, anhydrous sodium carbonate and diphenyl sulfone is 60:28:5:50:150.

[0028] Sulfonation of polyether ether ketone: (1) the polyether ether ketone was dried and ground into powder, dissolved in concentrated sulfuric acid with a concentration of 97wt%, heated to 60°C, added with a catalyst FeCl3, and heated to 80°C for continuous reaction for 10h to obtain a sulfonated solution; (2) a beaker was placed with a pure ice-water mixture, the water temperature was lower than 5°C, the ice-water mixture was continuously stirred with a glass rod to form a vortex and slowly poured into the sulfonated solution in a linear shape, so that the sulfonated polyether ether ketone primary material was precipitated in the ice-water mixture; (3) the sulfonated polyether ether ketone primary material was separated from the ice-water mixture, sequentially immersed in 3wt% dilute hydrochloric acid for repeated cleaning for 5 times, washed with deionized water until the pH value reached 7, then drained and placed in a blast drying oven, set the temperature to 60°C, and dried for 12h to obtain sulfonated polyether ether ketone.

[0029] Comparative Example 1 Synthesis of polyether ether ketone: diphenyl sulfone, 4,4'-difluorobenzophenone, tert-butyl hydroquinone and anhydrous sodium carbonate were added in a reaction vessel, and sequentially heated to 180°C for 0.5h, 200°C for 0.5h, 250°C for 0.5h, 275°C for 0.5h, 305°C for 1h under nitrogen protection, and then cooled down, sequentially extracted with acetone, washed with hydrochloric acid, washed with deionized water and dried in a vacuum box to obtain polyether ether ketone; the mass ratio of 4,4'-difluorobenzophenone, tert-butyl hydroquinone, anhydrous sodium carbonate and diphenyl sulfone is 60:28:50:150.

[0030] Sulfonation of polyether ether ketone: (1) after drying the polyether ether ketone, grinding into powder, dissolving in concentrated sulfuric acid with a concentration of 97wt%, heating to 60℃, adding catalyst FeCl3, increasing the temperature to 80℃, continuing to react for 10h, obtaining sulfonated liquor; (2) putting pure ice water mixture into beaker, making the water temperature lower than 5℃, continuously stirring the ice water mixture with glass rod to form vortex and slowly pouring into the sulfonated liquor in line shape, making the liquor precipitate sulfonated polyether ether ketone primary material in the ice water mixture; (3) separating the sulfonated polyether ether ketone primary material from the ice water mixture, repeatedly immersing and washing with dilute hydrochloric acid with a concentration of 3wt% for 5 times, washing with deionized water until the pH value reaches 7, then draining and putting into the air drying oven, setting the temperature to 60℃, drying for 12h, obtaining sulfonated polyether ether ketone.

[0031] Performance test 1, using point titration method, the sulfonation degree of sulfonated polyether ether ketone is tested, 10 groups of samples are taken from different parts of each example, the test results are counted, the average value and deviation are calculated, and the specific data are shown in Table 1.

[0032] Table 1 2, the sulfonated polyether ether ketone of examples 1-3 and comparative example 1 is configured into a solution according to the ratio of 15g:150ml, the solution is uniformly coated on the surface of the glass plate, the film thickness is controlled to 60μm by scraper, and the oven is sequentially subjected to stage type temperature rising drying of 50℃ / 6h and 80℃ / 5h, obtaining sulfonated polyether ether ketone film; at the same time, comparative example 2 is provided: the sulfonated polyether ether ketone of comparative example 1, sulfonated graphene and DMF are configured into a solution according to the ratio of 15g:0.85g:150ml, the solution is uniformly coated on the surface of the glass plate, the film thickness is controlled to 60μm by scraper, and the oven is sequentially subjected to stage type temperature rising drying of 50℃ / 6h and 80℃ / 5h, obtaining sulfonated polyether ether ketone film; the obtained film is tested as follows, and the specific data are shown in Table 2.

[0033] Table 2 From the example and comparative example data, it can be seen that by adding sulfonated graphene in the synthesis process of polyether ether ketone, the reaction temperature can be reduced, and after subsequent sulfonation treatment, sulfonated polyether ether ketone with good sulfonation uniformity and sulfonation degree can be obtained; the prepared sulfonated polyether ether ketone has good processability, moderate viscosity, better solution film forming property, smooth and flat appearance without pores and protrusions, excellent ion exchange capacity, mechanical strength and thermal stability, and better durability.

[0034] The above embodiments are merely exemplary but not limiting on the implementation. Based on the above description, those skilled in the art can make further changes or modifications to the embodiments in different forms. Here, it is not necessary or possible to enumerate all the embodiments. The obvious changes or modifications derived from the above description are still within the scope of the present application.

Claims

1. A method for preparing polyetheretherketone, characterized in that, The process includes the following steps: mixing difluorobenzophenone monomer, bisphenol monomer, sulfonated graphene and catalyst in diphenyl sulfone until uniform and completely dissolved, heating to react, precipitating in water, and then sequentially extracting, acid washing, cleaning and drying to obtain polyetheretherketone; the mass ratio of difluorobenzophenone monomer, bisphenol monomer, sulfonated graphene, catalyst and diphenyl sulfone is 55-65:25-30:3-8:45-55:140-160.

2. The method for preparing polyetheretherketone as described in claim 1, characterized in that, The catalyst is one or a combination of potassium carbonate, sodium carbonate, potassium hydroxide, sodium hydroxide, and tetrabutylammonium bromide.

3. The method for preparing polyetheretherketone as described in claim 1 or 2, characterized in that, The difluorobenzophenone monomer is one or a combination of 4,4'-difluorobenzophenone and 4,4'-difluorotribenzophenone.

4. The method for preparing polyetheretherketone as described in claim 1 or 2, characterized in that, The bisphenol monomer is one or a combination of hydroquinone, 4,4'-dihydroxybenzophenone and tert-butylhydroquinone.

5. The method for preparing polyetheretherketone as described in claim 1 or 2, characterized in that, The sulfonated graphene has a particle size of 1.2-4.0 μm, a thickness of 0.8-6.6 nm, a number of layers of <5, and an S content of 2.2-6.4 wt%.

6. A method for preparing sulfonated polyether ether ketone, characterized in that, The polyether ether ketone obtained by any one of the preparation methods of claims 1-5 is obtained by sulfonation with a sulfonating agent.

7. The method for preparing sulfonated polyether ether ketone as described in claim 6, characterized in that, The sulfonating agent is one or a combination of concentrated sulfuric acid, fuming sulfuric acid, chlorosulfonic acid, and sulfur trioxide-triethyl phosphate; the concentration of the concentrated sulfuric acid is in the range of 96-98 wt%.

8. The method for preparing sulfonated polyether ether ketone as described in claim 6 or 7, characterized in that, Includes the following steps: (1) After drying the polyether ether ketone, grind it into powder, dissolve it in concentrated sulfuric acid, heat it to 60°C, add catalyst FeCl3, raise the temperature to 80°C, and continue the reaction for 10 hours to obtain sulfonated liquid. (2) Place a pure ice-water mixture in a beaker to make the water temperature lower than 5°C. Stir the ice-water mixture continuously with a glass rod to form a vortex and slowly pour it into the sulfonated liquid in a line so that the sulfonated polyether ether ketone primary material is precipitated in the ice-water mixture. (3) Separate the sulfonated polyether ether ketone primary material from the ice-water mixture, and repeatedly soak and wash it with 3% dilute hydrochloric acid 3-5 times. After washing with deionized water until the pH value reaches 7, drain it and put it into a forced-air drying oven. Set the temperature to 60℃ and dry for 12 hours to obtain sulfonated polyether ether ketone.

9. A sulfonated polyether ether ketone prepared by the preparation method according to any one of claims 6-8.

10. An application of the sulfonated polyether ether ketone as described in claim 9, characterized in that, Proton exchange membranes used in the preparation of hydrogen fuel cells.

Images