Preparation method and application of polyetheretherketone polymer in presence of heavy sodium carbonate

Abstract

The invention discloses a preparation method and application of a polyether-ether-ketone polymer in the presence of heavy sodium carbonate. The preparation method of the polyether-ether-ketone polymer comprises the following steps: 1) preparing a mixture; 2) under the protection of inert gas, adding the mixture in the step 1) into aromatic sulfone and organic dihalide to obtain a reaction system, and then heating and reacting; (3) adding organic halide into the reaction system in the step (2), and carrying out end capping treatment to obtain a reaction product; and 4) cooling, crushing, purifying and drying the reaction product obtained in the step 3) to obtain the polyether-ether-ketone polymer. The mixture is prepared from the heavy sodium carbonate, and compared with a conventional process, the polyetheretherketone prepared by the method is lower in gel content, lower in crystallinity and more beneficial to being applied to processing of film products.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and particularly relates to a polyether ether ketone polymer, a preparation method thereof, and an application thereof. Background Art

[0002] Polyether ether ketone is a high-performance thermoplastic. It has excellent mechanical properties and high crystallinity, and has a glass transition temperature (Tg) of 143 °C and a melting point (Tm) of 343 °C. Current conventional production requires the use of alkali metal carbonates, among which light sodium carbonate is mostly used. However, the market price of light sodium carbonate fluctuates greatly, it occupies a large storage space and is prone to moisture absorption. There is a lot of dust in operations such as feeding and weighing, and it is light in weight and easy to stick to the wall. And due to its relatively large density, when heavy sodium carbonate is used in the preparation of polyether ether ketone, it deposits at the bottom of the reaction kettle after being added to the diphenyl sulfone solvent and cannot be fully mixed in the entire reaction system, resulting in the inability to carry out the polymerization reaction normally.

[0003] Therefore, there is an urgent need to develop a new process for preparing polyether ether ketone using heavy sodium carbonate. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides the following technical solutions:

[0005] A mixture, the mixture comprising heavy sodium carbonate and bisphenol.

[0006] According to an embodiment of the present invention, the heavy sodium carbonate may be selected from heavy sodium carbonate known in the art.

[0007] According to an embodiment of the present invention, the bisphenol is selected from at least one or a mixture of two or more of hydroquinone, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenyl ether, 1,4-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, preferably hydroquinone.

[0008] According to an embodiment of the present invention, the molar ratio of the sodium carbonate to the bisphenol is 1.01 to 1.15; for example, 1.1.

[0009] According to an embodiment of the present invention, the mixture may further comprise potassium carbonate.

[0010] According to an embodiment of the present invention, the mixture is a solid powder.

[0011] The present invention also provides a method for preparing a polyether ether ketone polymer, the preparation method comprising the following steps:

[0012] 1) Prepare the above mixture;

[0013] 2) Under the protection of an inert gas, add the mixture obtained in step 1) to an aromatic sulfone and an organic dihalide to obtain a reaction system, and then raise the temperature and react;

[0014] 3) After adding an organic halide to the reaction system in step 2) for end-capping treatment, a reaction product is obtained;

[0015] 4) After cooling, pulverizing, purifying, and drying the reaction product obtained in step 3), the polyetheretherketone polymer is obtained.

[0016] According to an embodiment of the present invention, the aromatic sulfone may be at least one or a mixture of two or more of diphenyl sulfone, dibenzothiophene dioxide, phenoxathiin dioxide, and 4-phenylsulfonyl biphenyl, preferably diphenyl sulfone.

[0017] According to an embodiment of the present invention, the organic dihalide is at least one or a mixture of two or more of 4,4'-difluorobenzophenone, 2,4'-difluorobenzophenone, 4-chloro-4'-fluorobenzophenone, 4,4'-dichlorobenzophenone, and 1,4-bis(4'-fluorobenzoyl)benzene, preferably 4,4'-difluorobenzophenone.

[0018] According to an embodiment of the present invention, in step 1), the method for preparing the mixture includes: under the protection of an inert gas, add sodium bicarbonate and bisphenol to ultrapure water, and stir at 20-50 °C to obtain a solution; continue heating and stirring, and evaporate the water in the solution to obtain a solid, which is the mixture. Preferably, after obtaining the solid, it can also be crushed.

[0019] According to an embodiment of the present invention, in step 2), raising the temperature means controlling the temperature of the reaction system at 220-320 °C (for example, 250 °C, 300 °C), and then reacting.

[0020] According to an embodiment of the present invention, the organic halide is selected from monofluoro-substituted aromatic halides. Preferably, the aromatic halide includes at least 2 aryl groups, wherein the substituent on one aryl group includes -F, and the substituent on the other aryl group is selected from at least one of a hydrogen atom, -SO3, -NO2, -NH3, -Cl, -Br, and -I; for example, selected from 4-fluorobenzophenone, 4-fluoro-4-bromobenzophenone, 4-fluoro-4-iodobenzophenone, 4-fluoro-4-chlorobenzophenone, 4-fluoro-4-nitrobenzophenone, 2-chloro-4-fluorobenzophenone, 4-fluoro-4-chlorobenzophenone, preferably 4-fluorobenzophenone.

[0021] According to an embodiment of the present invention, in step 3), the conditions for the end-capping treatment include: the temperature is 295-320 °C; the time is 15-45 min.

[0022] According to an embodiment of the present invention, in step 4), the cooling can be carried out by a method known in the art. For example, the reaction product is placed on a metal plate (such as a stainless steel plate) for cooling.

[0023] According to an embodiment of the present invention, in step 4), the cooled reaction product is ground into powder particles. Preferably, the size of the powder particles is less than 1.3 mm and greater than 0.22 mm.

[0024] According to an embodiment of the present invention, in step 4), the purification includes first washing the powder particles with an organic solvent and then performing multiple water washes.

[0025] Preferably, the washing of the powder particles with the organic solvent specifically includes: mixing the powder particles with the organic solvent, removing impurities in the powder particles, and then removing the organic solvent. Preferably, a suitable separation device is used to remove the organic solvent. For example, a Soxhlet extractor is used for separation. Further, during washing, the organic solvent is selected from organic solvents miscible with water, such as acetone.

[0026] Preferably, the water wash specifically includes: performing a first water wash on the powder particles with ultrapure water and / or deionized water to remove the organic solvent, and then performing a rinse with deionized water or pure water under heating conditions. The heating temperature is 50 - 60 °C.

[0027] Preferably, the number of times of the water wash is not specifically limited, as long as the conductivity of the filtered water after rinsing is less than 10 μS / cm.

[0028] According to an embodiment of the present invention, in step 4), the drying can be carried out by a method known in the art, as long as the washed polyetheretherketone can be dried.

[0029] The present invention also provides a polyetheretherketone polymer obtained by the above preparation method.

[0030] According to an embodiment of the present invention, the polyetheretherketone polymer has at least one of the following properties:

[0031] 1) The gel content is not more than 0.7%, preferably not less than 0.1%, such as 0.47%, 0.62%, 0.32%, 0.37%;

[0032] 2) The melt index is not more than 20 g / 10 min, preferably not less than 1 g / 10 min, such as 10 g / 10 min, 14.35 g / 10 min, 15.68 g / 10 min;

[0033] 3) The viscosity is not less than 300 Pa·s, preferably not more than 500 Pa·s, such as 361.1 Pa·s, 113.1 Pa·s, 312.2 Pa·s;

[0034] 4) The glass transition temperature Tg is at least 143 °C, for example 145 °C;

[0035] 5) The melting point Tm is at least 330 °C, for example 334 °C.

[0036] According to an embodiment of the present invention, the crystallization temperature of the polyetheretherketone polymer is not greater than 300 °C, for example 280 - 300 °C, for example 299.8 °C.

[0037] According to an embodiment of the present invention, the crystallinity of the polyetheretherketone polymer is less than 25%, for example 10%, 19.2%, 20%.

[0038] The present invention also provides the application of the above polyetheretherketone polymer in the fields of aerospace, medical, electronic and electrical appliances, automobile manufacturing, petrochemical industry, etc., for example, the application in membrane products.

[0039] Beneficial effects

[0040] The present invention uses heavy sodium carbonate to prepare a mixture, and then reacts the mixture with raw materials such as aromatic sulfone and organic dihalide to prepare polyetheretherketone. Compared with the conventional process, the polyetheretherketone prepared by the present invention has less gel content (less than 0.7%) and lower crystallinity (less than 20%), which is more conducive to the processing of membrane products. Specific embodiments

[0041] The technical solutions of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only used to illustrate and explain the present invention exemplarily, and should not be construed as limiting the protection scope of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0042] Unless otherwise specified, the raw materials and reagents used in the following examples are all commercially available products, or can be prepared by known methods.

[0043] The following test methods in the following examples are as follows:

[0044] 1. Test method for viscosity

[0045] In the present invention, the viscosity is the ratio of shear stress to shear rate, and the unit is Pa·s.

[0046] In the present invention, the method for measuring the fluidity of plastics by using a capillary rheometer, which can also be called the test method for apparent viscosity, is tested using a Dynisco laboratory capillary rheometer LCR7001 according to the GB / T 25278-2010 standard.

[0047] The dimensions of the capillary die of the equipment used for testing are as follows: a diameter of 1 mm and a length of 20 mm, and the length-to-diameter ratio (L / D) of the die is 20.

[0048] In the present invention, the specific steps of the viscosity testing method are as follows:

[0049] (1) Before measurement, the test sample (polyetheretherketone) is pretreated according to the provisions of GB / T 2918-1998, that is, the test sample is placed in an environment with a temperature of 23 ± 2 °C and a humidity of 50 ± 10% for 24 ± 0.5 hours and then reserved for use.

[0050] (2) Before testing, each component of the testing instrument reaches thermal equilibrium at the test temperature (the test temperature is 400 °C), and then charging starts: 10 - 15 g of the test sample in step (1) is added to the barrel in small portions and sub-portions (charged to about 12.5 mm from the top of the barrel), and immediately compacted with a plunger to prevent air from being introduced, and the charging is completed within 2 minutes.

[0051] (3) Immediately after the charging is completed, the preheating timing starts, and preheating is carried out for 5 minutes. Subsequently, the melt of the test sample is extruded through a capillary die of known dimensions, and under the condition of a certain volume flow rate, the test pressure (i.e., shear stress) is measured; the test conditions are a test temperature of 400 °C, and the shear rates are 100 s -1 、200 s -1 、500 s -1 、1000 s -1 、2000 s -1 、5000 s -1 、10000 s -1 .

[0052] 2. The method for gel testing is as follows:

[0053] For gel testing, a sintered glass funnel is used. A 40 ml G4 sintered glass funnel is placed in an oven and kept at a constant temperature of 150 °C for 8 hours. After cooling, it is taken out and left to stand. The weight W1 of the sintered glass funnel is weighed using an analytical balance; 0.1 g of PEEK sample is taken with an analytical balance and placed in a reagent bottle, 5 ml of 4-chlorophenol is added, and then it is placed in a shaker and shaken at a constant temperature of 180 °C for 2 h. After complete dissolution without residues, it is placed on the operating table and cooled to room temperature, and then 1,2,4-trichlorobenzene is added and left to stand for 5 min; Five groups of solutions of the same batch are poured into the sintered glass funnel for suction filtration, and then 10 ml of 4-chlorophenol is used to wash the reagent bottle and the sintered glass funnel, followed by suction filtration. Next, 25 ml of absolute ethanol is used to wash the sintered glass funnel and then suction filtration is carried out. Finally, it is placed in an oven and dried for 2 h. After cooling, the funnel is taken out and weighed with an analytical balance as W2; the percentage content of PEEK gel is calculated according to the formula (W2 - W1) / 0.5 g × 100%.

[0054] 3. Crystallization Test Method

[0055] The crystallization test is carried out by differential scanning calorimetry (DSC).

[0056] The DSC measurement is carried out on a NETZSCH DSC 200F3 instrument with nitrogen as the carrier gas (purity of 99.999%, 50 ml / min) according to GB / T 19466.1 - 2004. Temperature and heat flow calibration are carried out using indium. The sample weight is 8 - 12 mg, accurate to ±0.01 mg.

[0057] The sample is placed in the test instrument and the following heating or cooling cycles are carried out in sequence:

[0058] The first heating cycle: from 30.0 °C to 400.0 °C at 10.0 °C / min and hold at 400.0 °C for 5 min;

[0059] The first cooling cycle: from 400.0 °C to 80.0 °C at 10.0 °C / min;

[0060] The second heating cycle: from 80.0 °C to 400.0 °C at 10.0 °C / min;

[0061] After the end of the second heating cycle, the melting enthalpy of the sample is measured by scanning. The melting of PEEK is selected as the area above a linear baseline extending from 220 °C to a temperature higher than the last endotherm (typically, the temperature range of 270 °C - 380 °C is selected).

[0062] 4. Test Method for Melt Index

[0063] The melt mass flow rate is based on the standard of GB / T3682.1 - 2018, and the mass extruded in a specified time (such as 10 min) is used as the melt mass flow rate, with the unit of g / 10min. It is measured using an SRZ - 400E melt flow rate tester from Changchun Intelligent Instrument and Equipment Co., Ltd. The die of the equipment used has the following dimensions: 2.095 ± 0.005 mm in diameter and 8.000 ± 0.025 mm in length.

[0064] The test method for the melt index of the present invention specifically includes:

[0065] (1) Before the test, the barrel and the piston are kept at a constant temperature for at least 15 minutes at the test temperature;

[0066] (2) The amount of the material added to the barrel is 3 - 8 g of polymer. The loading is completed within 1 minute. After the loading is completed, preheating is started immediately. The preheating time is 5 minutes, and during the preheating, it is necessary to confirm that the temperature of the equipment returns to the set test temperature value.

[0067] (3) Subsequently, the test is carried out under the conditions of a test temperature of 380 °C and a load of 5 kg. The melt of the test sample is extruded from the die within the specified time. When the specified time is reached, the melt strip is cut off. The length of the cut strip is 10 - 20 mm. Discard all strips with visible bubbles and cool them.

[0068] (4) Repeat the above steps (1)-(3) N times (N is not less than 3). When at least N strips are obtained, weigh each one accurately to 1 mg, calculate the average mass M of the strips, and input it into the machine to obtain the melt index, with the unit g / 10min.

[0069] Example 1

[0070] The preparation method of polyetheretherketone includes the following steps:

[0071] In a 5L stainless steel reactor, add 1500 ml of deoxygenated ultrapure water, introduce nitrogen for 1 h. Subsequently, add 367.82 g (3.47 mol, density 900 kg / m 3 ) of sodium bicarbonate and 9.67 g (0.07 mol) of potassium carbonate, heat to 35.4 °C, add 335 g (3.04 mol) of hydroquinone while stirring and stir at a constant temperature for 2 h. Then randomly raise the temperature to boiling, evaporate the water component to obtain a solid. Then add 2135 g (9.78 mol) of diphenyl sulfone and 696.06 g (3.19 mol) of 4,4'-difluorobenzophenone, raise the temperature to 220 °C at a rate of 2 °C / min and keep it at a constant temperature for 1 h. Subsequently, raise the temperature to 270 °C at a rate of 1 °C / min and keep it at a constant temperature for 1 h. Then raise the temperature to 312 °C at a rate of 2 °C / min and keep it at a constant temperature for 1.5 h. Immediately add 4-fluorobenzophenone to the reactor for end-capping treatment and continuously stir for 30 min to obtain the product, which is the crude polyetheretherketone product.

[0072] After that, spread the obtained product flat on a stainless steel plate and let it solidify and cool to room temperature under normal temperature conditions to obtain the solidified product. Subsequently, use a pulverizer to crush the solidified product, sieve it, and select the powder particles with a mesh number between 15 and 60, which are the powder particles of the crude polyetheretherketone product.

[0073] (2) Purification

[0074] Purify the above powder particles: Add the powder particles to an acetone solvent to dissolve the reaction solvent diphenyl sulfone and other remaining organic impurities in the powder particles in the solvent, and use a Soxhlet extractor to extract repeatedly for 1 hour to obtain the filtered powder particles.

[0075] (3) Washing with water

[0076] Then, the above-filtered powder particles are washed with water: The above-filtered powder particles are added to purified water and stirred for washing, then heated to 60 °C, and the deionized water is filtered out. After that, it is rinsed with ultrapure water (with a conductivity of 1 μS / cm) and then heated and stirred again. It is repeatedly washed more than 4 times until the conductivity of the ultrapure water after rinsing is between 2 and 10 μS / cm. The powder particles after water washing are placed in a vacuum drying oven and dried at a constant temperature of 150 °C for 8 h to obtain polyether ether ketone.

[0077] Comparative Example 1

[0078] A 5L stainless steel reactor is used, equipped with a nitrogen protection device, a feed inlet, a thermocouple temperature detection device, a stirrer, and a stirring paddle. 2135 g (9.78 mol) of diphenyl sulfone, 367.82 g (3.47 mol, with a density of 900 kg / m 3 ) of heavy sodium carbonate, 9.67 g (0.07 mol) of potassium carbonate, 335 g (3.04 mol) of hydroquinone, and 696.06 g (3.19 mol) of 4,4'-difluorobenzophenone are added thereto. Nitrogen is introduced for protection for 1 h, and then the temperature is raised. The heating rate is 4 °C / min. After the temperature rises to 140 °C, stirring is started, and the stirring rate is 90 rpm. The temperature is raised to 180 °C at a heating rate of 2 °C / min and kept at a constant temperature for 60 min; then the temperature is raised to 190 °C at a heating rate of 1 °C / min and kept at a constant temperature for 30 min; then the temperature is raised to 200 °C at a heating rate of 0.5 °C and kept at a constant temperature for 30 min; immediately afterwards, the temperature is raised to 280 °C at a heating rate of 1 °C / min and kept at this temperature for 60 min. Finally, the temperature is raised to 300 °C at a heating rate of 1 °C / min. After keeping at this temperature for 60 min, 4-fluorobenzophenone is added to the reaction kettle for end-capping. Stirring is continued for 30 min.

[0079] Afterwards, the obtained product is poured and flattened on a stainless steel plate and waited to solidify and cool to room temperature. The obtained reactants are crushed with a crusher, sieved, and the powder with a particle size between 15 and 60 mesh is selected from the mixture particles. A Soxhlet extractor is used, and acetone is used as the solvent to extract the reaction solvent diphenyl sulfone and other remaining organic impurities in the powder particles, and the extraction is repeated for 1 hour. Then, the filtered particles are stirred and washed with purified water. When heated, the temperature is raised to 60 °C and then the deionized water is poured out. After rinsing with ultrapure water, it is heated and stirred again. This is repeated more than 4 times until the conductivity is between 2 and 10 μS. The product after water washing is placed in a vacuum drying oven, and the temperature inside the cavity is set to 150 °C and dried at a constant temperature for 8 h.

[0080] Comparative Example 2

[0081] The preparation method of polyether ether ketone in this comparative example is basically the same as that in Comparative Example 1, except that: the stirring rate is increased to 220 rpm.

[0082] Comparative Example 3

[0083] A 5L stainless steel reactor was used, equipped with a nitrogen protection device, a feed inlet, a thermocouple temperature detection device, a stirrer, and a stirring paddle. 2135 g (9.78 mol) of diphenyl sulfone, 367.82 g (3.47 mol, density 700 kg / m 3 ) of light sodium carbonate, 9.67 g (0.07 mol) of potassium carbonate, 335 g (3.04 mol) of hydroquinone, and 696.06 g (3.19 mol) of 4,4'-difluorobenzophenone were added thereto. Nitrogen was introduced for protection for 1 h, then the temperature was raised at a rate of 4 °C / min. After the temperature reached 140 °C, stirring was started, and the temperature was raised to 180 °C at a rate of 2 °C / min and kept constant for 60 min; then the temperature was raised to 190 °C at a rate of 1 °C / min and kept constant for 30 min; then the temperature was raised to 200 °C at a rate of 0.5 °C and kept constant for 30 min; then the temperature was raised to 280 °C at a rate of 1 °C / min and kept at this temperature for 60 min. Finally, the temperature was raised to 300 °C at a rate of 1 °C / min and kept for 60 min, and then 4-fluorobenzophenone was added to the reaction kettle for end-capping. Stirring was continued for 30 min.

[0084] Afterwards, the obtained product was poured and spread flat on a stainless steel plate and waited to solidify and cool to room temperature. The obtained reactant was crushed with a pulverizer, sieved, and the powder with particle size between 15 and 60 mesh of the mixture was selected. Using a Soxhlet extractor, acetone was used as the solvent to extract the reaction solvent diphenyl sulfone and other remaining organic impurities in the powder particles, and extraction was repeated for 1 hour. Then the filtered particles were stirred and washed with purified water. When heated, the temperature was raised to 60 °C and then the deionized water was poured out. After rinsing with ultrapure water, heating and stirring were carried out again, and this was repeated more than 4 times until the conductivity was between 2 and 10 μS. The product after water washing was put into a vacuum drying oven, the temperature in the cavity was set to 150 °C, and drying was carried out at a constant temperature for 8 h.

[0085] Test Example 1

[0086] 1. The polyether ether ketone obtained from the example and the comparative example was respectively taken, and the melt index (abbreviated as melt index) and viscosity were tested according to the above method, and the results were summarized in Table 1.

[0087] 2. The polyether ether ketone obtained from the example and the comparative example was respectively taken, and the crystallinity and gel content were tested according to the above method, and the results were summarized in Table 2.

[0088] Table 1 Test results of melt index and viscosity

[0089] Melt Index (10 g / min) Viscosity (Pa·s) Example 1 11.23 398.2 Comparative Example 1 - - Comparative Example 2 121.31 135.4 Comparative Example 3 12.34 387.9

[0090] Table 2 Crystallinity and Gel Test Results

[0091] Crystallinity (%) Crystallization Temperature (°C) Gel Content (%) Example 1 19.2 299.8 0.40 Comparative Example 1 - - - Comparative Example 2 32.4 304.2 0.11 Comparative Example 3 27.3 300.2 0.67

[0092] From the test results in Table 1 and Table 2, it can be seen that for the polyether ether ketone obtained by the preparation method of the present invention, compared with the polyether ether ketone prepared by the conventional process in Comparative Example 3, the melt index and viscosity are close, so the fluidity of the polyether ether ketone is basically the same; and by using the preparation method of Example 1 (reacting with a mixture containing sodium sesquicarbonate), the gel content in the prepared polyether ether ketone is less (less than 0.7%). Moreover, the inventor also unexpectedly found that the polyether ether ketone of Example 1 has a lower crystallinity (less than 20%) than that of Comparative Example 3, which is beneficial to the processing of membrane products. When Comparative Examples 2 and 3 adopt the conventional feeding process, the melt index and viscosity of the prepared polyether ether ketone cannot meet the requirements of membrane product processing.

[0093] Since sodium sesquicarbonate cannot be used to prepare polyether ether ketone under normal circumstances, in the present invention, different solvents are used to first mix sodium sesquicarbonate and hydroquinone, and then it can be further used to prepare polyether ether ketone. The use of sodium sesquicarbonate in the present invention can save storage space, reduce dust generation during the preliminary weighing of materials, and the market price of sodium sesquicarbonate is relatively stable, which is beneficial to stable production.

[0094] The above has described the exemplary embodiments of the present invention. However, the protection scope of this application is not limited to the above embodiments. Any modifications, equivalent replacements, improvements, etc. made by those skilled in the art within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a polyetheretherketone polymer, characterized in that, The preparation method comprises the following steps: 1) Prepare a mixture; 2) Under the protection of an inert gas, add the mixture obtained in step 1) to an aromatic sulfone and an organic dihalide to obtain a reaction system, and then raise the temperature and react; 3) Add an organic halide to the reaction system obtained in step 2) for end-capping treatment to obtain a reaction product; 4) After cooling, pulverizing, purifying, and drying the reaction product obtained in step 3), the polyether ether ketone polymer is obtained.

2. The preparation method according to claim 1, characterized in that, The mixture comprises sodium sesquicarbonate and bisphenol; the molar ratio of the sodium carbonate to the bisphenol is 1.01-1.15; and / or, the bisphenol is selected from at least one or a mixture of two or more of hydroquinone, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenyl ether, 1,4-dihydroxynaphthalene, and 2,3-dihydroxynaphthalene; and / or, the mixture further comprises potassium carbonate; and / or, the mixture is a solid powder.

3. The preparation method according to claim 1, wherein, In step 1), the method for preparing the mixture comprises: under the protection of an inert gas, add sodium sesquicarbonate and bisphenol to ultrapure water, and stir at 20-50°C to obtain a solution; continue heating and stirring, and evaporate the water in the solution to obtain a solid, which is the mixture.

4. The preparation method according to claim 1, characterized in that, The aromatic sulfone is at least one or a mixture of two or more of diphenyl sulfone, dibenzothiophene dioxide, phenoxathiin dioxide, and 4-phenylsulfonylbiphenyl; and / or, the organic dihalide is at least one or a mixture of two or more of 4,4'-difluorobenzophenone, 2,4'-difluorobenzophenone, 4-chloro-4'-fluorobenzophenone, 4,4'-dichlorobenzophenone, and 1,4-bis(4'-fluorobenzoyl)benzene.

5. The preparation method according to claim 1, characterized in that In step 2), raising the temperature means controlling the temperature of the reaction system at 220-320°C, and then reacting; and / or, the organic halide is selected from monofluoro-substituted aromatic halides; the aromatic halide comprises at least 2 aryl groups, wherein the substituent on one aryl group comprises -F, and the substituent on the other aryl group is selected from at least one of a hydrogen atom, -SO3, -NO2, -NH3, -Cl, -Br, and -I.

6. The preparation method according to claim 1, characterized in that, In step 3), the conditions for the end-capping treatment comprise: the temperature is 295-320°C; the time is 15-45 min; and / or, in step 4), grind the cooled reaction product into powder particles, and the size of the powder particles is less than 1.3 mm and greater than 0.22 mm.

7. The polyether ether ketone polymer obtained by the preparation method according to any one of claims 1-6.

8. The polyetheretherketone polymer according to claim 7, characterized in that, The polyether ether ketone polymer has at least one of the following properties: 1) The gel content is not more than 0.7%; 2) The melt index is not more than 20 g / 10 min; 3) The viscosity is not less than 300 Pa·s; 4) The glass transition temperature Tg is at least 143°C; 5) The melting point Tm is at least 330°C.

9. The polyetheretherketone polymer according to claim 7, characterized in that, The crystallization temperature of the polyether ether ketone polymer is not more than 300°C; and / or, the crystallinity of the polyether ether ketone polymer is less than 25%.

10. Use of the polyetheretherketone polymer according to any one of claims 7-9 in aerospace, medical, electronic and electrical appliances, automotive manufacturing, petrochemical industry.