Polyphenylene sulfone resin and preparation method thereof

Abstract

The invention belongs to the technical field of polymer synthesis, and particularly relates to polyphenylene sulfone resin and a preparation method thereof. Comprising the following steps: S1, salt forming reaction; s2, polymerization reaction; s3, carrying out supercritical CO2 extraction; s4, membrane-method water washing and resource recovery; and S5, microwave-assisted drying and chain extension. Aiming at the problems of low solvent efficiency, harsh reaction conditions, large environmental protection load and insufficient product performance in the prior art, the invention provides a PPSU preparation method based on a compound solvent system, efficient catalytic reaction, green post-treatment and molecular chain regulation. Through innovative compounding of a solvent system (blending of choline chloride-urea-based DES and sulfolane), an efficient mesoporous silica supported palladium catalysis technology and green process integration, the bottleneck of traditional PPSU preparation is remarkably broken through, and industrial production with high efficiency, low consumption, high purity and high performance is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer synthesis, and particularly relates to a polyphenylene sulfone resin and a preparation method thereof. Background Art

[0002] Polyphenylene sulfone resin (PPSU) is a special engineering plastic with excellent high-temperature resistance, chemical corrosion resistance and mechanical properties. Since PPSU is a safe material, it does not contain carcinogenic chemical substances (environmental hormone: bisphenol A) that disrupt the endocrine system, and as a material with extremely excellent heat resistance, the heat resistance temperature is as high as 207 degrees. It can be boiled repeatedly at high temperature and sterilized by steam. It has extremely excellent drug resistance and acid and alkali resistance, can withstand the cleaning of general potions and detergents, and will not produce chemical changes. It is light and drop-resistant, and is the best in terms of safety, heat resistance, hydrolysis resistance and impact resistance. It is widely used in high-end fields such as medical devices (such as baby bottles, hemodialysis membranes), electronic appliances (such as LED lamp covers) and aerospace. Its preparation is usually based on nucleophilic substitution polycondensation reaction, using biphenol and 4,4'-dichlorodiphenyl sulfone as monomers, and realizing through steps such as salt formation, polymerization, and post-treatment.

[0003] However, the existing industrial production process has the following problems: (1) Low reaction efficiency: The salt formation and polymerization reactions require 12 - 16 hours, with high energy consumption; (2) Large solvent pollution: Using VOCs solvents such as acetone for washing is prone to cause residues and air pollution; (3) Difficult by-product treatment: The treatment cost of high-salt wastewater is high, and the recovery rate of inorganic salts is less than 70%; (4) Limited product performance: The molecular weight distribution is wide (Mw / Mn > 2.5), and the thermal stability is insufficient (Tg = 220 °C).

[0004] Based on this, the present invention proposes a polyphenylene sulfone resin and a preparation method thereof, hoping to solve the deficiencies in the existing technology. Summary of the Invention

[0005] The purpose of the present invention is to provide a polyphenylene sulfone resin and a preparation method thereof for the existing problems.

[0006] The present invention is achieved through the following technical solutions:

[0007] A preparation method of a polyphenylene sulfone resin, comprising the following steps:

[0008] S1. Salt formation reaction:

[0009] Add biphenol, potassium hydroxide, a solvent and a catalyst into a microchannel continuous flow reactor to carry out a salt formation reaction to obtain a salt formation product;

[0010] S2. Polymerization reaction:

[0011] The salt-forming product and 4,4'-dichlorodiphenyl sulfone are introduced into a tubular continuous flow reactor to carry out nucleophilic substitution polycondensation reaction to obtain a polymer;

[0012] S3. Supercritical CO2 extraction:

[0013] Use supercritical CO2 fluid to remove the residual solvent in the polymer;

[0014] S4. Membrane washing and resource recovery:

[0015] Adopt reverse-flow washing combined with nanofiltration membrane circulation technology to remove inorganic salts, and recover the alkali reagent by MVR evaporation;

[0016] S5. Microwave-assisted drying and chain extension:

[0017] Use microwave drying technology to reduce the moisture content, and realize molecular chain extension through twin-screw reactive extrusion.

[0018] Furthermore, the dosage of potassium hydroxide described in step S1 is 0.65 - 0.75 times the mass of biphenol.

[0019] Furthermore, the dosage of the solvent described in step S1 is 1.7 - 2 times the mass of biphenol;

[0020] The preparation of the solvent includes the following steps:

[0021] (1) Weigh choline chloride and urea according to a molar ratio of 1:2, add them to a reaction kettle, under nitrogen protection, heat up to 80 - 100 °C, and stir at 200 - 300 r / min for 1 - 3 h to obtain choline chloride-urea-based DES;

[0022] (2) Stir and mix the choline chloride-urea-based DES and sulfolane evenly according to a mass ratio of 3:7.

[0023] Furthermore, the catalyst described in step S1 is palladium supported on mesoporous silica, and the dosage of the catalyst is 0.2 - 0.3% of the mass of palladium agent based on biphenol;

[0024] The preparation of the palladium supported on mesoporous silica includes the following steps:

[0025] 1) Drop tetraethyl orthosilicate (TEOS) into a CTAB (cetyltrimethylammonium bromide) solution, stir to make TEOS evenly dispersed, then drop ammonia water to adjust the pH to 9 - 11, and stir at room temperature at 100 - 300 r / min for 30 - 36 h to obtain a gel-like substance;

[0026] 2) Transfer the above gel-like substance to a high-pressure reactor, carry out hydrothermal reaction at 110 - 130 °C for 16 - 20 h. After the hydrothermal reaction is completed, cool to room temperature, carry out centrifugal separation, wash with ethanol and deionized water until no CTAB can be detected in the washing liquid, and then carry out drying to obtain mesoporous silica powder;

[0027] 3) Add the above-obtained mesoporous silica powder to a palladium salt solution with a concentration of 0.3 - 0.5 mol / L. After ultrasonic treatment for 40 - 60 min, under the stirring condition of 100 - 300 r / min, dropwise add a sodium borate solution with a mass fraction of 3 - 5%. After the dropping is complete, continue stirring for 1 - 2 h. After the reaction is completed, carry out centrifugal separation, wash with ethanol and deionized water until no chloride ions can be detected in the washing liquid, and then carry out drying.

[0028] Furthermore, in step 1), the concentration of the CTAB solution is 0.01 - 0.02 mol / L, the mass of CTAB is controlled to be 6 - 10% of that of tetraethyl orthosilicate, and the dropping rate of TEOS is 1 - 2 mL / min;

[0029] Furthermore, in step 3), the palladium loading amount is 5 - 6%.

[0030] Furthermore, in step S1, the material flow rate of the microchannel reactor is 4 - 6 L / min, the salt-forming reaction is 20 - 30 min, and the temperature is controlled at 100 - 110 °C.

[0031] Furthermore, in step S2, the dosage of 4,4'-dichlorodiphenyl sulfone is 1.8 - 2 times the mass of biphenol.

[0032] Furthermore, in step S2, during the nucleophilic substitution polycondensation reaction, the temperature is controlled at 160 - 180 °C, the pressure is 0.4 - 0.6 MPa, and the time is 3 - 4 h.

[0033] Furthermore, in step S3, the pressure of the supercritical CO2 extraction is 20 - 30 MPa, the temperature is 50 - 70 °C, the circulation flow rate is 400 - 600 L / h, and the extraction time is 1 - 3 h.

[0034] Furthermore, in step S4, the cut-off molecular weight of the nanofiltration membrane is 100 - 300 Da.

[0035] Furthermore, in step S5, the power of the microwave drying is 40 - 60 kW, and the final moisture content of the material is controlled at 0.2 - 0.5%;

[0036] During the twin-screw reaction, 0.5 - 1% of 1,6-hexamethylene diisocyanate is added.

[0037] The present invention has the following advantages compared with the prior art:

[0038] In view of the problems of low solvent efficiency, harsh reaction conditions, high environmental protection load and insufficient product performance in the existing processes, the present invention provides a method for preparing PPSU based on a compound solvent system, efficient catalytic reaction, green post-treatment and molecular chain regulation, so as to realize industrial production of "high efficiency, low consumption, high purity and high performance". Specifically:

[0039] (1) The present invention uses a compound solvent to replace single sulfolane. The choline chloride-urea-based DES in the compound solvent has good solubility and ionic conductivity, which can promote the reaction. At the same time, sulfolane can improve the stability of the reaction system. The choline chloride in DES can form a dynamic hydrogen bond network with potassium hydroxide to enhance the dissociation efficiency of phenolic hydroxyl groups; sulfolane promotes ion migration through a high dielectric constant (ε = 43.3), thereby increasing the conversion rate of the salt-forming reaction.

[0040] (2) The present invention introduces mesoporous silica-supported palladium (Pd@SiO2) as a catalyst, which can reduce the activation energy of the reaction and accelerate the reaction rate. Moreover, the catalyst of the present invention adopts a hydrothermal synthesis method combined with a template agent removal process, which can precisely control the formation of the mesoporous structure, improve the specific surface area and pore volume of silica, and is beneficial to the loading of palladium and the improvement of catalytic activity. During the preparation process, an ultrasonic dispersion method and a reducing agent reduction method are also combined to uniformly load palladium on the surface of mesoporous silica, improving the activity and stability of the catalyst.

[0041] (3) By using a microchannel continuous flow reactor and a tubular continuous flow reactor in combination, the present invention can precisely control the reaction temperature, pressure and reaction time, enabling the reaction to proceed efficiently and helping to reduce the occurrence of side reactions.

[0042] (4) The present invention utilizes the good solubility and diffusivity of supercritical CO2 fluid in the residual solvent in the polymer to extract the residual solvent from the polymer under specific pressure and temperature conditions, realizing the efficient separation of the solvent and the polymer. By means of countercurrent water washing combined with a nanofiltration membrane recycling technology, the content of inorganic salts in the polymer is gradually reduced. The forward osmosis membrane is used to concentrate the high-salt wastewater, and MVR evaporation realizes the recycling of potassium hydroxide, reducing resource waste and environmental pollution. By using the thermal effect and non-thermal effect of microwave, the water molecules inside the material vibrate rapidly to generate heat, thereby realizing rapid drying. During the twin-screw reactive extrusion process, the chain extender reacts with the polymer molecular chain to realize the chain extension of the molecular chain, improving the molecular weight and performance of the polymer. Specific Embodiments

[0043] In order to further explain the present invention, the following specific embodiments are described below.

[0044] Experimental Equipment and Reagents

[0045] Table 1 Instruments and Equipment

[0046] Instrument Name Manufacturer Model Microchannel Continuous Flow Reactor Microfluidic Technology (Changzhou) Co., Ltd. MF-V6M Tube-Type Continuous Flow Reactor Zhongshan Zhian Chemical Technology Co., Ltd. DMR-0800 <![CDATA[Supercritical CO2 extraction kettle]]> Beijing Jinyang Wanda Technology Co., Ltd. HA220-40-11 Twin-Screw Reaction Extruder Guangzhou Potop Experimental Analysis Instrument Co., Ltd. POTOP Module Edition

[0047] Table 2 Reagents

[0048] Reagent Name Manufacturer Properties Biphenol Jinzhou Sanfeng Technology Co., Ltd. Purity ≥ 99.5% 4,4'-Dichlorodiphenyl Sulfone Wuhan Jiangxin Biotechnology Co., Ltd. Purity ≥ 99% Potassium Hydroxide Sinopharm Chemical Reagent Co., Ltd. Analytical Reagent, Purity ≥ 85% Choline Chloride Langfang Qianyao Technology Co., Ltd. Purity ≥ 99% Urea Sinopharm Chemical Reagent Co., Ltd. Analytical Reagent Sulfolane Sigma-Aldrich Purity ≥ 99%

[0049] Note: Unless otherwise specified, the reagents and equipment used in the present invention are all conventional products purchased from the market.

[0050] Example 1

[0051] A preparation method of polyphenylene sulfone resin, comprising the following steps:

[0052] S1. Salt formation reaction:

[0053] Add biphenol, potassium hydroxide, solvent and palladium supported on mesoporous silica into a microchannel continuous flow reactor for reaction. The flow rate of the material is 4 L / min, control the temperature at 100 °C, and react for 20 min to obtain a salt formation product;

[0054] The dosage of potassium hydroxide is 0.65 times the mass of biphenol;

[0055] The dosage of the solvent is 1.7 times the mass of biphenol;

[0056] The preparation of the solvent comprises the following steps:

[0057] (1) Weigh choline chloride and urea according to a molar ratio of 1:2, add them into a reaction kettle, under nitrogen protection, heat up to 80 °C, and stir at 200 r / min for 1 h to obtain choline chloride-urea-based DES;

[0058] (2) Stir and mix choline chloride-urea-based DES and sulfolane evenly according to a mass ratio of 3:7;

[0059] The catalyst is, and the dosage of the catalyst is based on the palladium agent, accounting for 0.2% of the mass of biphenol;

[0060] The preparation of palladium supported on mesoporous silica comprises the following steps:

[0061] 1) Drop TEOS into a CTAB (cetyltrimethylammonium bromide 0.01 mol / L) solution, control the mass of CTAB to be 6% of tetraethyl orthosilicate, the dropping rate of TEOS is 1 mL / min, stir to make TEOS evenly dispersed, then drop ammonia water to adjust the pH to 9, and stir at room temperature at 100 r / min for 30 h to obtain a gel-like substance;

[0062] 2) Transfer the above gel-like substance to a high-pressure reactor, carry out hydrothermal reaction at 110 °C for 16 h. After the hydrothermal reaction is completed, cool it to room temperature, perform centrifugal separation, wash with ethanol and deionized water until no CTAB can be detected in the washing liquid, and then dry to obtain mesoporous silica powder;

[0063] 3) Add the obtained mesoporous silica powder above to a palladium salt solution with a concentration of 0.3 mol / L. After ultrasonic treatment for 40 min, under the stirring condition of 100 r / min, add a sodium borate solution with a mass fraction of 3%. After the addition is complete, continue stirring for 1 h. After the reaction is completed, perform centrifugal separation, wash with ethanol and deionized water until no chloride ions can be detected in the washing liquid, and then dry. Control the palladium loading amount to be 5%;

[0064] S2. Polymerization reaction:

[0065] Pass the salt-forming product and 4,4'-dichlorodiphenyl sulfone into a tubular continuous flow reactor to carry out nucleophilic substitution polycondensation reaction. Control the temperature to be 160 °C, the pressure to be 0.4 MPa, and react for 3 h to obtain a polymer;

[0066] The dosage of 4,4'-dichlorodiphenyl sulfone is 1.8 times the mass of biphenol;

[0067] S3. Supercritical CO2 extraction:

[0068] Use supercritical CO2 fluid to remove the residual solvent in the polymer;

[0069] The pressure of supercritical CO2 extraction is 20 MPa, the temperature is 50 °C, the circulation flow rate is 400 L / h, and the extraction time is 1 h;

[0070] S4. Membrane washing and resource recovery:

[0071] Adopt countercurrent washing combined with nanofiltration membrane (molecular weight cut-off is 100 - 300 Da) recycling technology to remove inorganic salts, and recover the alkali reagent by MVR evaporation;

[0072] S5. Microwave-assisted drying and chain extension:

[0073] Use microwave drying technology to reduce the moisture content. The power of microwave drying is 40 kW, and the final moisture content of the material is controlled at 0.2%. And realize molecular chain extension through twin-screw reactive extrusion;

[0074] Add 0.5% of 1,6-hexamethylene diisocyanate during twin-screw reaction.

[0075] Example 2

[0076] A preparation method of polyphenylene sulfone resin, comprising the following steps:

[0077] S1. Salt formation reaction:

[0078] Biphenol, potassium hydroxide, solvent and palladium supported on mesoporous silica were added to a microchannel continuous flow reactor for reaction. The flow rate of the materials was 5 L / min, the temperature was controlled at 105 °C, and the reaction was carried out for 25 min to obtain a salt formation product;

[0079] The amount of potassium hydroxide used was 0.7 times the mass of biphenol;

[0080] The amount of solvent used was 1.8 times the mass of biphenol;

[0081] The preparation of the solvent includes the following steps:

[0082] (1) Choline chloride and urea were weighed according to a molar ratio of 1:2, added to a reaction kettle, and under nitrogen protection, the temperature was raised to 90 °C, and stirred at 250 r / min for 2 h to obtain choline chloride-urea-based DES;

[0083] (2) The choline chloride-urea-based DES and sulfolane were stirred and mixed evenly according to a mass ratio of 3:7;

[0084] The catalyst was, and the amount of the catalyst was based on the palladium agent, accounting for 0.25% of the mass of biphenol;

[0085] The preparation of palladium supported on mesoporous silica includes the following steps:

[0086] 1) TEOS was dropped into a CTAB (cetyltrimethylammonium bromide 0.015 mol / L) solution, controlling the mass of CTAB to be 8% of tetraethyl orthosilicate, and the dropping rate of TEOS was 1.5 mL / min. Stir to make TEOS evenly dispersed, and then dropwise add ammonia water to adjust the pH to 10, and stir at room temperature at 200 r / min for 33 h to obtain a gel-like substance;

[0087] 2) The above gel-like substance was transferred to a high-pressure reaction kettle, and hydrothermal reaction was carried out at 110-130 °C for 16-20 h. After the hydrothermal reaction was completed, it was cooled to room temperature, centrifuged, and washed with ethanol and deionized water until CTAB could not be detected in the washing liquid, and then dried to obtain mesoporous silica powder;

[0088] 3) The above-obtained mesoporous silica powder was added to a palladium salt solution with a concentration of 0.4 mol / L. After ultrasonic treatment for 50 min, under the stirring condition of 200 r / min, a sodium borate solution with a mass fraction of 4% was dropwise added. After the dropping was complete, continue to stir for 1.5 h. After the reaction was completed, centrifuged, and washed with ethanol and deionized water until chloride ions could not be detected in the washing liquid, and then dried to obtain the product, controlling the palladium loading amount to be 5.5%;

[0089] S2. Polymerization reaction:

[0090] The salt-forming product and 4,4'-dichlorodiphenyl sulfone are introduced into a tubular continuous flow reactor for nucleophilic substitution polycondensation reaction. The temperature is controlled at 170 °C, the pressure is 0.5 MPa, and the reaction is carried out for 3.5 h to obtain the polymer.

[0091] The dosage of 4,4'-dichlorodiphenyl sulfone is 1.9 times the mass of biphenol.

[0092] S3. Supercritical CO2 extraction:

[0093] Use supercritical CO2 fluid to remove the residual solvent in the polymer.

[0094] The pressure of supercritical CO2 extraction is 25 MPa, the temperature is 60 °C, the circulation flow rate is 500 L / h, and the extraction time is 2 h.

[0095] S4. Membrane washing and resource recovery:

[0096] Adopt countercurrent washing combined with nanofiltration membrane (molecular weight cut-off is 100 - 300 Da) circulation technology to remove inorganic salts, and recover the alkali reagent by MVR evaporation.

[0097] S5. Microwave-assisted drying and chain extension:

[0098] Use microwave drying technology to reduce the moisture content. The power of microwave drying is 50 kW, and the final moisture content of the material is controlled at 0.35%. Molecular chain extension is achieved by twin-screw reactive extrusion.

[0099] Add 0.75% of 1,6-hexamethylene diisocyanate during twin-screw reaction.

[0100] Example 3

[0101] A preparation method of polyphenylene sulfone resin, comprising the following steps:

[0102] S1. Salt-forming reaction:

[0103] Biphenol, potassium hydroxide, solvent and palladium supported on mesoporous silica are added to a microchannel continuous flow reactor for reaction. The material flow rate is 6 L / min, the temperature is controlled at 110 °C, and the reaction is carried out for 30 min to obtain the salt-forming product.

[0104] The dosage of potassium hydroxide is 0.75 times the mass of biphenol.

[0105] The dosage of the solvent is 2 times the mass of biphenol.

[0106] The preparation of the solvent comprises the following steps:

[0107] (1)Weigh choline chloride and urea according to a molar ratio of 1:2, add them to a reaction kettle, and under nitrogen protection, heat up to 100 °C and stir at 300 r / min for 3 h to obtain choline chloride-urea-based DES;

[0108] (2)Mix the choline chloride-urea-based DES and sulfolane evenly by stirring according to a mass ratio of 3:7;

[0109] The catalyst is palladium agent, and the dosage of the catalyst accounts for 0.3% of the mass of biphenol;

[0110] The preparation of palladium supported on mesoporous silica includes the following steps:

[0111] 1) Drop TEOS into a CTAB (cetyltrimethylammonium bromide 0.02 mol / L) solution, control the mass of CTAB to be 10% of tetraethyl orthosilicate, the dropping rate of TEOS is 2 mL / min, stir to make TEOS evenly dispersed, then drop ammonia water to adjust the pH to 11, and stir at room temperature at 300 r / min for 36 h to obtain a gel-like substance;

[0112] 2) Transfer the above gel-like substance to a high-pressure reaction kettle, carry out hydrothermal reaction at 130 °C for 20 h. After the hydrothermal reaction is completed, cool to room temperature, carry out centrifugal separation, wash with ethanol and deionized water until CTAB cannot be detected in the washing liquid, and then carry out drying to obtain mesoporous silica powder;

[0113] 3) Add the obtained mesoporous silica powder to a palladium salt solution with a concentration of 0.5 mol / L, carry out ultrasonic treatment for 60 min, then under the stirring condition of 300 r / min, dropwise add a sodium borate solution with a mass fraction of 5%. After the dropping is complete, continue stirring for 2 h. After the reaction is completed, carry out centrifugal separation, wash with ethanol and deionized water until chloride ions cannot be detected in the washing liquid, and then carry out drying. Control the palladium loading amount to be 6%;

[0114] S2. Polymerization reaction:

[0115] Feed the salt-forming product and 4,4'-dichlorodiphenyl sulfone into a tubular continuous flow reactor to carry out nucleophilic substitution polycondensation reaction, control the temperature to be 180 °C, the pressure to be 0.6 MPa, and react for 4 h to obtain a polymer;

[0116] The dosage of 4,4'-dichlorodiphenyl sulfone is 2 times the mass of biphenol;

[0117] S3. Supercritical CO2 extraction:

[0118] Use supercritical CO2 fluid to remove the residual solvent in the polymer;

[0119] The pressure of supercritical CO2 extraction is 30 MPa, the temperature is 70 °C, the circulation flow rate is 600 L / h, and the extraction time is 3 h;

[0120] S4. Membrane washing with water and resource recovery:

[0121] The reverse water washing combined with the nanofiltration membrane (the molecular weight cut-off is 100 - 300 Da) circulation technology is adopted to remove inorganic salts, and the alkaline reagent is recovered by MVR evaporation;

[0122] S5. Microwave-assisted drying and chain extension:

[0123] The microwave drying technology is used to reduce the moisture content. The power of microwave drying is 60 kW, the final moisture content of the material is controlled at 0.5%, and the molecular chain is extended by twin-screw reactive extrusion;

[0124] 1% of 1,6-hexamethylene diisocyanate is added during the twin-screw reaction.

[0125] Comparative Example 1

[0126] Compared with Example 2, in this Comparative Example 1, the solvent in Step S1 is replaced with sulfolane, and the other steps are the same as those in Example 2.

[0127] Comparative Example 2

[0128] Compared with Example 2, in this Comparative Example 2, potassium hydroxide in Step S1 is replaced with sodium carbonate, and the remaining steps are the same as those in Example 2.

[0129] Comparative Example 3

[0130] Compared with Example 2, in this Comparative Example 3, the palladium supported on mesoporous silica in Step S1 is omitted, and the other steps are the same as those in Example 2.

[0131] Comparative Example 4

[0132] Compared with Example 2, in this Comparative Example 4, the microwave-assisted drying in Step S5 is replaced with vacuum drying, and the temperature of vacuum drying is 80 °C, and the other steps are the same as those in Example 2.

[0133] Performance test

[0134] The polyphenylene sulfone resins are respectively prepared by the methods of the above Examples 1 - 3 and Comparative Examples 1 - 4, and then the performance tests are carried out.

[0135] 1. Mechanical property test

[0136] The polyphenylene sulfone resin is made into a standard specimen, and then the tensile property test is carried out using a universal material testing machine. The test speed is 5 mm / min, and the tensile strength and elongation at break of each group of samples are recorded. Three repeated tests are carried out for each group of tests, and the average value is taken as the final test result.

[0137] The test results are shown in Table 3 below.

[0138] Table 3

[0139] Sample Tensile Strength (MPa) Elongation at Break (%) Example 1 86 10 Example 2 89 10 Example 3 88 10 Comparative Example 1 76 8 Comparative Example 2 80 9 Comparative Example 3 72 6 Comparative Example 4 85 9

[0140] As can be seen from Table 3 above, the tensile strength and elongation at break of Examples 1 to 3 are better than those of Comparative Examples 1 to 4, indicating that the preparation method of the polyphenylene sulfone resin provided by the present invention helps to improve the mechanical properties of the polyphenylene sulfone resin.

[0141] 2. Thermal property test

[0142] The thermal properties of the samples were tested using a differential scanning calorimeter (DSC). The samples were heated from room temperature to 300 °C at a heating rate of 10 °C / min under a nitrogen atmosphere, and their glass transition temperatures (Tg) were recorded. Three replicate tests were performed for each group of tests, and the average value was taken as the final test result.

[0143] The test results are shown in Table 4 below.

[0144] Table 4

[0145] Sample Glass Transition Temperature (Tg, °C) Example 1 236 Example 2 239 Example 3 235 Comparative Example 1 231 Comparative Example 2 233 Comparative Example 3 230 Comparative Example 4 234

[0146] As can be seen from Table 4 above, Example 2 has the highest glass transition temperature, indicating the best thermal stability, which shows that the use of the compounded dissolution, potassium hydroxide, palladium supported on mesoporous silica, and the improvement of the process in the present invention help to improve the thermal properties of the polyphenylene sulfone resin.

[0147] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes should be covered within the protection scope of the present invention.

Claims

1. A method for preparing a polyphenylene sulfone resin, characterized in that, It includes the following steps: S1. Salt formation reaction: Add biphenol, potassium hydroxide, solvent and catalyst into a microchannel continuous flow reactor to carry out the salt formation reaction to obtain a salt formation product; S2. Polymerization reaction: Feed the salt formation product and 4,4'-dichlorodiphenyl sulfone into a tubular continuous flow reactor to carry out a nucleophilic substitution polycondensation reaction to obtain a polymer; S3. Supercritical CO2 extraction: Use supercritical CO2 fluid to remove the residual solvent in the polymer; S4. Membrane washing and resource recovery: Adopt countercurrent washing combined with nanofiltration membrane recycling technology to remove inorganic salts, and recover the alkali reagent by MVR evaporation; S5. Microwave-assisted drying and chain extension: Utilize microwave drying technology to reduce the moisture content, and realize molecular chain extension through twin-screw reactive extrusion.

2. The preparation method of a polyphenylene sulfone resin according to claim 1, characterized in that, The dosage of potassium hydroxide described in step S1 is 0.65 - 0.75 times the mass of biphenol.

3. The preparation method of a polyphenylene sulfone resin according to claim 1, wherein, The dosage of the solvent described in step S1 is 1.7 - 2 times the mass of biphenol; The preparation of the solvent includes the following steps: (1) Weigh choline chloride and urea according to a molar ratio of 1:2, add them into a reaction kettle, under nitrogen protection, heat up to 80 - 100 °C, and stir at 200 - 300 r / min for 1 - 3 h to obtain choline chloride-urea-based DES; (2) Stir and mix the choline chloride-urea-based DES and sulfolane evenly according to a mass ratio of 3:

7.

4. The preparation method of a polyphenylene sulfone resin according to claim 1, characterized in that, The catalyst described in step S1 is palladium supported on mesoporous silica, and the dosage of the catalyst is based on the palladium agent, accounting for 0.2 - 0.3% of the mass of biphenol; The preparation of the palladium supported on mesoporous silica includes the following steps: 1) Drop tetraethyl orthosilicate into the CTAB solution, stir to make TEOS evenly dispersed, then drop ammonia water to adjust the pH to 9 - 11, and stir at room temperature at 100 - 300 r / min for 30 - 36 h to obtain a gel-like substance; 2) Transfer the above gel-like substance to a high-pressure reaction kettle, carry out hydrothermal reaction at 110 - 130 °C for 16 - 20 h. After the hydrothermal reaction is completed, cool to room temperature, carry out centrifugal separation, wash with ethanol and deionized water until CTAB cannot be detected in the washing solution, and then carry out drying to obtain mesoporous silica powder; 3) Add the above-obtained mesoporous silica powder into a palladium salt solution with a concentration of 0.3 - 0.5 mol / L, carry out ultrasonic treatment for 40 - 60 min, then under the stirring condition of 100 - 300 r / min, drop a sodium borate solution with a mass fraction of 3 - 5%. After the dropping is complete, continue to stir for 1 - 2 h. After the reaction is completed, carry out centrifugal separation, wash with ethanol and deionized water until chloride ions cannot be detected in the washing solution, and then carry out drying.

5. The preparation method of a polyphenylene sulfone resin according to claim 1, characterized in that, The material flow rate of the microchannel reactor described in step S1 is 4 - 6 L / min, the salt formation reaction is carried out for 20 - 30 min, and the temperature is controlled at 100 - 110 °C.

6. The preparation method of a polyphenylene sulfone resin according to claim 1, characterized in that, The dosage of 4,4'-dichlorodiphenyl sulfone described in step S2 is 1.8 - 2 times the mass of biphenol; During the nucleophilic substitution polycondensation reaction, the temperature is controlled at 160 - 180 °C, the pressure is 0.4 - 0.6 MPa, and the time is 3 - 4 h.

7. The preparation method of a polyphenylene sulfone resin according to claim 1, characterized in that, In step S3, the pressure of the supercritical CO2 extraction is 20 - 30 MPa, the temperature is 50 - 70 °C, the circulation flow rate is 400 - 600 L / h, and the extraction time is 1 - 3 h.

8. The preparation method of a polyphenylene sulfone resin according to claim 1, characterized in that, In step S4, the molecular weight cut-off of the nanofiltration membrane is 100 - 300 Da.

9. The preparation method of a polyphenylene sulfone resin according to claim 1, wherein In step S5, the power of the microwave drying is 40 - 60 kW, and the final moisture content of the material is controlled at 0.2 - 0.5%; 0.5 - 1% of 1,6 - hexamethylene diisocyanate is added during the twin-screw reaction.

10. A polyphenylene sulfone resin, characterized in that, It is prepared by the preparation method of the polyphenylene sulfone resin according to any one of claims 1 - 9.