High-temperature-resistant polyphenylsulfone composite material and preparation method thereof

Abstract

The application discloses a kind of high-temperature-resistant polyphenyl sulfone composite and preparation method thereof, belong to polyphenyl sulfone composite technical field, first by ultrasonic dispersion and complexation reaction preparation tannic acid-iron complex modified molybdenum disulfide, iron-containing carbon-coated molybdenum disulfide is obtained by high-temperature carbonization, so it has good stability and lubricity, then using 6-hydroxy-2-naphthoic acid, 4,4'-diphenyl ether dicarboxylic acid and 4,4'-dihydroxy diphenyl sulfone and other monomers in acetic anhydride system are prepared by melt polycondensation and solid phase condensation reaction, modified aromatic liquid crystal polyester is prepared, and fiber network is formed, finally, iron-containing carbon-coated molybdenum disulfide and modified aromatic liquid crystal polyester and polyphenyl sulfone resin are melt blended in double-screw extruder, and high-temperature-resistant polyphenyl sulfone composite is obtained, effectively solve the problem that the lubricating property of polyphenyl sulfone material is reduced under high temperature and high humidity environment, and the mechanical toughness is attenuated, suitable for high-end medical instrument application needing long-term tolerance multiple sterilization cycle.

Description

Technical Field

[0001] This invention belongs to the field of polyphenylsulfone composite material technology, specifically a high-temperature resistant polyphenylsulfone composite material and its preparation method. Background Technology

[0002] Polyphenylsulfone (PPSU), a high-performance special engineering plastic whose main chain is composed of aryl and sulfone groups, is widely used in the field of reusable medical devices, such as surgical instrument trays and sterilization turnover boxes, due to its excellent intrinsic heat resistance, hydrolysis resistance, and excellent impact toughness. These products need to withstand dozens to hundreds of high-pressure steam sterilizations in clinical use, which places stringent requirements on the material's high-temperature resistance and mechanical stability. However, due to its high surface free energy and large surface friction coefficient, PPSU is prone to surface wear and scratches due to dry friction during actual stacking or cleaning contact. These friction scratches not only affect the appearance, but also easily become stress concentration sources when the material is in a high-temperature, high-humidity and steam impact environment, inducing the initiation and propagation of microcracks, significantly weakening the material's impact resistance and fatigue life, and ultimately leading to embrittlement and cracking of the product, posing a clinical safety risk.

[0003] To address the issue of high surface friction coefficient in polyphenylsulfone (PPS) leading to mechanical failure, existing technologies typically employ a compounding method that introduces low surface tension modifiers into the resin matrix. Chinese patent application CN117229637A discloses a PPS composite material, its preparation method, and its application. By adding low surface tension substances such as fluorinated siloxanes and silane coupling agents to a PPS resin matrix with a specific hydroxyl content, the surface free energy and surface friction coefficient of the composite material are effectively reduced by utilizing the extremely low intermolecular cohesion of fluorinated small molecules and the chemical coupling effect between the modifier and the terminal hydroxyl groups.

[0004] In the above technical solutions, since fluorinated siloxanes are low molecular weight organic compounds, their interfacial bonding with the matrix is ​​highly dependent on the chemical condensation between the silane coupling agent and the terminal hydroxyl groups retained in the PPSU matrix to form silicon-oxygen-carbon bonds. In high-temperature and high-humidity environments, these chemical bonds will undergo irreversible hydrolytic breakage, causing the fluorinated small molecules to easily undergo phase separation and migrate to the material surface at an accelerated rate, volatilize, or be peeled off during cleaning. After these low molecular weight modifiers migrate and are lost, they will leave interfacial debonding gaps and microstructural defects at the micro-phase interface they originally occupied. These pores directly evolve into new stress concentration defects, which will accelerate crack propagation under subsequent high-temperature steam impacts, leading to a decrease in the structural stability of the composite material and making it difficult to meet the core requirements of long-term safe service and maintaining good mechanical properties of medical devices. Summary of the Invention

[0005] The purpose of this invention is to provide a high-temperature resistant polyphenylsulfone composite material and its preparation method. By high-temperature in-situ carbonization of the tannic acid-iron complex layer, a dense iron-based carbon shell coating structure is constructed on the surface of molybdenum disulfide. In addition, an inorganic-organic hybrid interface network is formed in the polyphenylsulfone matrix in synergy with modified aromatic liquid crystal polyester, thereby improving the low-friction performance and mechanical retention of the composite material and meeting the core requirements of high-end medical devices for safe and reliable service under hundreds of sterilization cycles.

[0006] The objective of this invention can be achieved through the following technical solutions: A high-temperature resistant polyphenylsulfone composite material is prepared by the following steps: Step 1: Using tannic acid as a carbon source and polyphenol ligand, it is ultrasonically dispersed with nano-molybdenum disulfide in deionized water. Then, ferric chloride hexahydrate is added to induce a coordination complexation reaction between tannic acid and iron ions to obtain tannic acid-iron complex modified molybdenum disulfide. Subsequently, it is subjected to high-temperature carbonization treatment to obtain iron-carbon coated molybdenum disulfide.

[0007] Step 2: Using 6-hydroxy-2-naphthoic acid, 4,4'-diphenyl ether dicarboxylic acid and 4,4'-dihydroxydiphenyl sulfone as raw materials, acetic anhydride is used to carry out acylation of hydroxyl groups, followed by high-temperature melt polycondensation under the catalysis of sodium acetate to obtain liquid crystal copolyester oligomers. Subsequently, the oligomers are subjected to high-temperature solid-state condensation reaction to achieve chain extension and thickening, resulting in modified aromatic liquid crystal polyester.

[0008] Step 3: Using polyphenylsulfone resin as the matrix, mix it with iron-containing carbon-coated molybdenum disulfide and modified aromatic liquid crystal polyester, and perform melt extrusion and granulation in a twin-screw extruder to obtain a high-temperature resistant polyphenylsulfone composite material.

[0009] This invention also provides a method for preparing a high-temperature resistant polyphenylsulfone composite material, comprising the following steps: Polyphenylsulfone resin, iron-containing carbon-coated molybdenum disulfide, and modified aromatic liquid crystal polyester were placed in a forced-air drying oven and dried at 120-150℃ for 8-12 hours to remove moisture. The dried material was then placed in a high-speed mixer and mixed evenly at a stirring rate of 2000-3000 r / min. The mixed material was then placed in a twin-screw extruder for melt extrusion and granulation to obtain a high-temperature resistant polyphenylsulfone composite material.

[0010] Furthermore, the mass ratio of polyphenylsulfone resin, iron-containing carbon-coated molybdenum disulfide, and modified aromatic liquid crystal polyester is 200-400:5-15:10-30.

[0011] Furthermore, the processing temperatures of each temperature zone of the twin-screw extruder are 320-340℃, 340-360℃, and 360-380℃, respectively, the die temperature is 350-370℃, and the screw speed is 200-300 r / min.

[0012] Furthermore, the preparation process of the modified aromatic liquid crystal polyester is as follows: The liquid crystal copolyester oligomer was placed in a reactor under nitrogen atmosphere protection and reacted at 250-270℃ for 4-6 hours to carry out solid-phase condensation reaction. The product was then ground, washed, and vacuum dried to constant weight to obtain the modified aromatic liquid crystal polyester.

[0013] Furthermore, the preparation process of the liquid crystal copolyester oligomer is as follows: 6-hydroxy-2-naphthoic acid, 4,4'-diphenyl ether dicarboxylic acid, 4,4'-dihydroxydiphenyl sulfone, and acetic anhydride were placed in a reactor under a nitrogen atmosphere and stirred at 25-35°C for 10-20 min. Anhydrous sodium acetate was added, and the reaction was carried out at 140-150°C for 1-3 h. Then, the temperature was increased to 330-350°C at a rate of 1-2°C / min for high-temperature melt polycondensation. After the reaction system reached the set maximum temperature, the reaction vessel was evacuated to a high vacuum state, and the melt was discharged while hot, cooled and solidified, and collected after mechanical crushing to obtain liquid crystal copolyester oligomer.

[0014] Furthermore, the ratio of 6-hydroxy-2-naphthoic acid, 4,4'-diphenyl ether dicarboxylic acid, 4,4'-dihydroxydiphenyl sulfone, anhydrous sodium acetate, and acetic anhydride is 30-40g: 15-20g: 15-20g: 60-100mg: 40-60mL.

[0015] Furthermore, the preparation process of iron-containing carbon-coated molybdenum disulfide is as follows: Tannic acid-iron complex modified molybdenum disulfide was placed in a tube furnace under nitrogen atmosphere protection and heated to 500-600℃ at a rate of 5℃ / min for high-temperature carbonization. The temperature was held for 2-4 hours and then cooled to obtain iron-carbon coated molybdenum disulfide.

[0016] Furthermore, the preparation process of tannic acid-iron complex modified molybdenum disulfide is as follows: Nano-molybdenum disulfide, tannic acid, and deionized water were placed in a reaction vessel and ultrasonically dispersed at 25-35℃ for 1-2 hours. Ferric chloride hexahydrate was added, and the mixture was reacted at the same temperature for 20-40 minutes. The mixture was then centrifuged, washed, and freeze-dried to constant weight to obtain tannic acid-iron complex modified molybdenum disulfide.

[0017] Furthermore, the ratio of nano-molybdenum disulfide, tannic acid, ferric chloride hexahydrate, and deionized water is 20-40g: 30-50g: 6-10g: 3-6L.

[0018] The beneficial effects of this invention are: 1. The high-temperature resistant polyphenylsulfone composite material prepared by the present invention introduces iron-containing carbon-coated molybdenum disulfide as a lubricating dispersed phase. The outer carbon shell protects the integrity of the internal two-dimensional layered slip structure of molybdenum disulfide. At the same time, the iron-based nanonodes generated in situ in the carbon shell serve as highly active Lewis acid sites. During the composite process, they can coordinate with the polar sulfone groups and ether bonds in the polyphenylsulfone matrix and the modified aromatic liquid crystal polyester molecular chain, effectively limiting the phase separation and abnormal migration of the lubricating phase in high temperature and high humidity environments, so that the material can obtain long-lasting low surface friction and stability.

[0019] 2. The high-temperature resistant polyphenylene sulfone composite material prepared by this invention introduces sulfone groups into the modified aromatic liquid crystal polyester, which, based on the principle of similar compatibility, undergoes deep entanglement and interfacial co-solubility of macromolecular chain segments with the polyphenylene sulfone matrix in the polymer melt, thereby improving the interfacial compatibility with the matrix. At the same time, the modified aromatic liquid crystal polyester forms a fiber network in the polyphenylene sulfone matrix, which not only strengthens the mechanical skeleton of the matrix, but also the π-π stacking interaction formed between its macromolecular aromatic ring structure and the surface of iron-containing carbon-coated molybdenum disulfide anchors the iron-containing carbon-coated molybdenum disulfide in the fiber network, improving its dispersion in the matrix and effectively reducing the generation of micro-stress concentration sources, thereby significantly improving the microstructural integrity and long-term service life of the composite material.

[0020] 3. The high-temperature resistant polyphenylsulfone composite material prepared in this invention constructs a multi-scale composite network that combines lubrication and wear resistance with microfiber skeleton reinforcement. The iron-containing carbon-coated molybdenum disulfide is uniformly dispersed under the rheological properties of the modified aromatic liquid crystal polyester. It continuously dissipates external frictional heat energy through interlayer slip mechanism. At the same time, the hydrophobic properties of the carbon shell effectively prevent water molecules from penetrating into the molybdenum disulfide core and polymer interface under high temperature and humid conditions, which significantly delays the initiation of surface micro-scratches. Meanwhile, the modified aromatic liquid crystal polyester forms a rigid microfiber skeleton in the polyphenylsulfone matrix. Under high temperature steam impact conditions, it can effectively buffer and consume interfacial thermal stress and inhibit crack propagation along the interface. Through the multi-scale synergistic mechanism, the safety and high durability of polyphenylsulfone materials in long-term clinical service are significantly improved. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] Example 1: This example provides a high-temperature resistant polyphenylsulfone composite material, which is prepared through the following steps: S1: 20g of nano molybdenum disulfide, 30g of tannic acid and 3L of deionized water were placed in a reaction vessel and ultrasonically dispersed at 25℃ for 1h. 6g of ferric chloride hexahydrate was added and the mixture was stirred at 1000r / min for 20min at the same temperature. After the reaction was completed, the solid was centrifuged, washed twice with deionized water, and freeze-dried to constant weight to obtain tannic acid-iron complex modified molybdenum disulfide.

[0023] S2: 40g of tannic acid-iron complex modified molybdenum disulfide was placed in a tube furnace under nitrogen atmosphere protection and heated to 500℃ at a rate of 5℃ / min for high-temperature carbonization. The temperature was held for 2h and then cooled to room temperature after the reaction was completed to obtain iron-carbon coated molybdenum disulfide.

[0024] S3: 30g of 6-hydroxy-2-naphthoic acid, 15g of 4,4'-diphenyl ether dicarboxylic acid, 15g of 4,4'-dihydroxydiphenyl sulfone, and 40mL of acetic anhydride were placed in a reactor under nitrogen atmosphere protection. The mixture was stirred at 1000r / min for 10min at 25℃. 60mg of anhydrous sodium acetate was added, and the mixture was reacted at 140℃ with the same stirring rate for 1h. Then, the temperature was increased to 330℃ at a rate of 1℃ / min for high-temperature melt polycondensation. After the reaction system reached the set maximum temperature, the reaction vessel was slowly evacuated to a high vacuum state to remove residual trace small molecule by-products. The melt was discharged while hot and allowed to cool and solidify naturally at 20℃. After mechanical crushing, the melt was collected to obtain liquid crystal copolyester oligomer.

[0025] S4: 40g of liquid crystal copolyester oligomer was placed in a reactor under nitrogen atmosphere protection and reacted at 250℃ for 4h to carry out solid-phase condensation reaction. After the reaction was completed, the product was cooled to room temperature, ground, washed twice with anhydrous ethanol and acetone, and vacuum dried at 60℃ to constant weight to obtain modified aromatic liquid crystal polyester.

[0026] S5: Place 200g of polyphenylsulfone resin, 5g of iron-containing carbon-coated molybdenum disulfide, and 10g of modified aromatic liquid crystal polyester in a forced-air drying oven and dry at 120℃ for 8-12h to remove moisture. Then, place the dried material in a high-speed mixer and mix evenly at a stirring rate of 2000r / min. Place the mixed material in a twin-screw extruder for high-temperature melt blending. The processing temperatures of each temperature zone of the twin-screw extruder are set to 320℃, 340℃, and 360℃, respectively, the die temperature is 350℃, and the screw speed is 200r / min. After melt blending and extrusion, the material is cooled in a water tank, stretched, and pelletized using a pelletizer to obtain a high-temperature resistant polyphenylsulfone composite material.

[0027] Example 2: This example provides a high-temperature resistant polyphenylsulfone composite material, which is prepared through the following steps: S1: 30g of nano molybdenum disulfide, 40g of tannic acid and 4.5L of deionized water were placed in a reaction vessel and ultrasonically dispersed at 30℃ for 1.5h. 8g of ferric chloride hexahydrate was added and the mixture was stirred at 1500r / min for 30min at the same temperature. After the reaction was completed, the solid was centrifuged, washed three times with deionized water, and freeze-dried to constant weight to obtain tannic acid-iron complex modified molybdenum disulfide.

[0028] S2: 50g of tannic acid-iron complex modified molybdenum disulfide was placed in a tube furnace under nitrogen atmosphere protection and heated to 550℃ at a rate of 5℃ / min for high-temperature carbonization. The temperature was held for 3h and then cooled to room temperature after the reaction was completed to obtain iron-carbon coated molybdenum disulfide.

[0029] S3: 35g of 6-hydroxy-2-naphthoic acid, 18g of 4,4'-diphenyl ether dicarboxylic acid, 18g of 4,4'-dihydroxydiphenyl sulfone, and 50mL of acetic anhydride were placed in a reactor under nitrogen atmosphere protection. The mixture was stirred at 1500r / min for 15min at 30℃. 80mg of anhydrous sodium acetate was added, and the mixture was reacted at 145℃ with the same stirring rate for 2h. Then, the temperature was increased to 340℃ at a rate of 1.5℃ / min for high-temperature melt polycondensation. After the reaction system reached the set maximum temperature, the reaction vessel was slowly evacuated to a high vacuum state to remove residual trace small molecule by-products. The melt was discharged while hot and allowed to cool and solidify naturally at 25℃. After mechanical crushing, the melt was collected to obtain liquid crystal copolyester oligomer.

[0030] S4: Place 50g of liquid crystal copolyester oligomer in a reactor under nitrogen atmosphere protection and keep it at 260℃ for 5h to carry out solid-phase condensation reaction. After the reaction is completed, cool to room temperature, grind the product, wash it three times with anhydrous ethanol and acetone, and vacuum dry it at 70℃ to constant weight to obtain modified aromatic liquid crystal polyester.

[0031] S5: 300g of polyphenylsulfone resin, 10g of iron-containing carbon-coated molybdenum disulfide, and 20g of modified aromatic liquid crystal polyester were placed in a forced-air drying oven and dried at 140℃ for 10h to remove moisture. Then, the dried material was placed in a high-speed mixer and mixed evenly at a stirring rate of 2500r / min. The mixed material was then placed in a twin-screw extruder for high-temperature melt blending. The processing temperatures of each temperature zone of the twin-screw extruder were set to 330℃, 350℃, and 370℃, respectively, the die temperature was 360℃, and the screw speed was 250r / min. After the material was melt-blended and extruded, it was cooled in a water tank, stretched, and pelletized using a pelletizer to obtain a high-temperature resistant polyphenylsulfone composite material.

[0032] Example 3: This example provides a high-temperature resistant polyphenylsulfone composite material, which is prepared through the following steps: S1: 40g of nano-molybdenum disulfide, 50g of tannic acid and 6L of deionized water were placed in a reaction vessel and ultrasonically dispersed at 35℃ for 2h. 10g of ferric chloride hexahydrate was added and the mixture was stirred at 2000r / min for 40min at the same temperature. After the reaction was completed, the solid was centrifuged, washed 4 times with deionized water, and freeze-dried to constant weight to obtain tannic acid-iron complex modified molybdenum disulfide.

[0033] S2: 60g of tannic acid-iron complex modified molybdenum disulfide was placed in a tube furnace under nitrogen atmosphere protection and heated to 600℃ at a rate of 5℃ / min for high-temperature carbonization. The temperature was held for 4h and then cooled to room temperature after the reaction was completed to obtain iron-carbon coated molybdenum disulfide.

[0034] S3: 40g of 6-hydroxy-2-naphthoic acid, 20g of 4,4'-diphenyl ether dicarboxylic acid, 20g of 4,4'-dihydroxydiphenyl sulfone, and 60mL of acetic anhydride were placed in a reactor under nitrogen atmosphere protection. The mixture was stirred at 2000r / min at 35℃ for 20min. 100mg of anhydrous sodium acetate was added, and the mixture was reacted at 150℃ with the same stirring rate for 3h. Then, the temperature was increased to 350℃ at a rate of 2℃ / min for high-temperature melt polycondensation. After the reaction system reached the set maximum temperature, the reaction vessel was slowly evacuated to a high vacuum state to remove residual trace small molecule by-products. The melt was discharged while hot and allowed to cool and solidify naturally at 30℃. After mechanical crushing, the melt was collected to obtain liquid crystal copolyester oligomer.

[0035] S4: 60g of liquid crystal copolyester oligomer was placed in a reactor under nitrogen atmosphere protection and reacted at 270℃ for 6h to carry out solid-phase condensation reaction. After the reaction was completed, the product was cooled to room temperature, ground, washed 4 times with anhydrous ethanol and acetone, and vacuum dried at 80℃ to constant weight to obtain modified aromatic liquid crystal polyester.

[0036] S5: 400g of polyphenylsulfone resin, 15g of iron-containing carbon-coated molybdenum disulfide, and 30g of modified aromatic liquid crystal polyester were placed in a forced-air drying oven and dried at 150℃ for 12h to remove moisture. Then, the dried material was placed in a high-speed mixer and mixed evenly at a stirring rate of 3000r / min. The mixed material was then placed in a twin-screw extruder for high-temperature melt blending. The processing temperatures of each temperature zone of the twin-screw extruder were set to 340℃, 360℃, and 380℃, respectively, the die temperature was 370℃, and the screw speed was 300r / min. After the material was melt-blended and extruded, it was cooled in a water tank, stretched, and pelletized using a pelletizer to obtain a high-temperature resistant polyphenylsulfone composite material.

[0037] The high-temperature resistant polyphenylsulfone composite materials prepared in Examples 1-3 above were first prepared by dispersing nano-molybdenum disulfide in an aqueous solution of tannic acid. Utilizing the abundant polyphenolic hydroxyl groups in tannic acid, a strong coordination complexation reaction occurred between the introduced iron ions and the nano-polyphenolic hydroxyl groups, resulting in a dense metal-polyphenolic network coating layer formed in situ on the surface of the molybdenum disulfide, thus obtaining tannic acid-iron complex modified molybdenum disulfide. Subsequently, under an inert atmosphere, high-temperature carbonization treatment was performed, transforming the polyphenolic organic framework in situ into a robust iron-based carbon shell, yielding iron-carbon-coated molybdenum disulfide. Then, 6-hydroxy-2-naphthoic acid, 4,4'-diphenyl ether dicarboxylic acid, and 4,4'-dihydroxydiphenyl sulfone were mixed in an acetic anhydride system, where the acetic anhydride first caused the phenolic hydroxyl groups to undergo... Acetylation followed by transesterification and high-temperature deacidification polycondensation with carboxyl groups under sodium acetate catalysis resulted in the implantation of rigid naphthalene rings, flexible ether bonds, and high-temperature resistant sulfone structures into the polymer backbone, yielding a liquid crystal copolyester oligomer. Subsequently, a high-temperature solid-state condensation reaction was carried out, utilizing the thermal motion of the macromolecular chain segments in the amorphous region to promote deep transesterification and condensation of the residual end groups, driving the polymer to continue chain extension while maintaining the integrity of the solid skeleton, further increasing the degree of polymerization, thereby obtaining a modified aromatic liquid crystal polyester. Finally, using polyphenylsulfone resin as the matrix, it was mixed with iron-carbon-coated molybdenum disulfide and the modified aromatic liquid crystal polyester, and melt-extruded and granulated in a twin-screw extruder to obtain a high-temperature resistant polyphenylsulfone composite material.

[0038] Comparative Example 1: The difference from Example 2 is that in step S5, commercially available nano-molybdenum disulfide is used instead of the iron-containing carbon-coated molybdenum disulfide prepared in step S2, while the other steps remain unchanged, and a high-temperature resistant polyphenylsulfone composite material is prepared.

[0039] Comparative Example 2: The difference from Example 2 is that the iron-containing carbon-coated molybdenum disulfide prepared in step S2 is removed in step S5, while the other steps remain unchanged, and a high-temperature resistant polyphenylsulfone composite material is prepared.

[0040] Comparative Example 3: The difference from Example 2 is that the modified aromatic liquid crystal polyester prepared in step S4 is removed in step S5, while the other steps remain unchanged, and a high-temperature resistant polyphenylsulfone composite material is prepared.

[0041] The nano-molybdenum disulfide purchased in the above embodiments and comparative examples was produced by Shanghai McLean Biochemical Technology Co., Ltd., with an average particle size of 50-100nm; the polyphenylsulfone resin was produced by Solvay AG of Belgium, with the brand name Radel R-5000 (medical device grade) and a density of 1.29g / cm³. The high-temperature resistant polyphenylene sulfone composite materials prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests. The test results are shown in Table 1: Sample preparation: After the high-temperature resistant polyphenylsulfone composite materials prepared in the above examples and comparative examples were thoroughly dried, they were injection molded in a high-temperature injection molding machine to prepare dumbbell-shaped tensile specimens conforming to GB / T 1040.2, cantilever beam notched impact specimens conforming to GB / T 1843, and square sheet-shaped friction specimens conforming to GB / T 10006. The above are untreated specimens.

[0042] High-pressure steam treatment: Simulating the scenario of repeated high-temperature sterilization of reusable medical devices, the above standard samples were placed in a medical high-pressure steam sterilizer and treated in a saturated water steam environment at a temperature of 140℃ and a pressure of about 0.2MPa. Each cycle was maintained for 30 minutes, and 100 cycles were performed. After the cycle was completed, the samples were taken out and conditioned for 48 hours in a standard laboratory environment (23±2℃, relative humidity 50±5%) to obtain the treated samples.

[0043] Surface dynamic friction performance test: Referring to standard GB / T 10006-2021, the untreated and treated samples were placed on the friction coefficient meter and tested under dry contact conditions at room temperature. The dynamic friction coefficient of the material surface was recorded. The lower the value of the dynamic friction coefficient, the better the lubrication performance and surface scratch resistance of the material.

[0044] Notched impact strength: Referring to standard GB / T 1843-2008, untreated and treated specimens were placed on a pendulum impact testing machine for cantilever beam notched impact testing, and the notched impact strength (kJ / m²) of the specimens was recorded. The higher the impact strength, the better the material's impact toughness and ability to resist notched stress concentration.

[0045] Elongation at break: Referring to standard GB / T 1040.2-2006, untreated and treated specimens were placed on an electronic universal testing machine for uniaxial tensile testing. The tensile speed was set to 50 mm / min until the specimen broke. The elongation at break (%) of the material was recorded. The higher the elongation at break value, the better the toughness of the material.

[0046] Table 1 Performance Test Table of High Temperature Resistant Polyphenylsulfone Composite Materials

[0047] As shown in Table 1, the high-temperature resistant polyphenylsulfone composite materials prepared in Examples 1-3 all outperformed the comparative examples. After undergoing 100 high-pressure steam treatments, their performance remained good, indicating that the present invention introduces iron-containing carbon-coated molybdenum disulfide and modified aromatic liquid crystal polyester into the polyphenylsulfone matrix to construct a multi-scale synergistic defense system, which may effectively suppress the influence of hygrothermal stress on the material, thereby enabling the composite material to maintain low friction characteristics and mechanical strength and toughness under high temperature and high humidity environments.

[0048] In Comparative Example 1, the composite material showed a significant decline in all properties after high-pressure steam treatment. This may be because commercially available nano-molybdenum disulfide is chemically inert and has poor compatibility with the polyphenylene sulfone matrix and modified aromatic liquid crystal polyester, which makes it prone to agglomeration in the matrix. Under high-temperature steam, the surface of nano-molybdenum disulfide is prone to water absorption and oxidation, further damaging the interfacial bonding. This unstable interfacial connection may not be able to effectively transfer thermal stress and external forces, resulting in a significant decrease in the material's performance when heated.

[0049] The surface dynamic friction coefficient of the material in Comparative Example 2 is significantly higher, which may be because the iron-containing carbon-coated molybdenum disulfide prepared in this invention has a good lubricating effect, and its carbon shell layer may enhance the stability of the material in a high-temperature steam environment. After its absence, the composite material loses its lubricating modification effect, resulting in an increase in the surface friction resistance of the material.

[0050] In Comparative Example 3, the notched impact strength and elongation at break of the composite material decreased significantly after high-pressure steam treatment. This may be because the fiber network provided by the modified aromatic liquid crystal polyester was missing. The iron-carbon coated molybdenum disulfide and polyphenylsulfone matrix are prone to interfacial debonding in high-temperature and humid environments, which makes the material prone to brittle fracture when heated or stressed, resulting in a significant decrease in mechanical properties.

[0051] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A method for preparing a high-temperature resistant polyphenylsulfone composite material, characterized in that, Includes the following steps: Step 1: Using tannic acid as a carbon source and polyphenol ligand, it is ultrasonically dispersed with nano-molybdenum disulfide in deionized water. Then, ferric chloride hexahydrate is added to induce a coordination complexation reaction between tannic acid and iron ions to obtain tannic acid-iron complex modified molybdenum disulfide. Subsequently, it is subjected to high-temperature carbonization treatment to obtain iron-carbon coated molybdenum disulfide. Step 2: Using 6-hydroxy-2-naphthoic acid, 4,4'-diphenyl ether dicarboxylic acid and 4,4'-dihydroxydiphenyl sulfone as raw materials, acetic anhydride is used to carry out acylation of hydroxyl groups, followed by high-temperature melt polycondensation under the catalysis of sodium acetate to obtain liquid crystal copolyester oligomers. Subsequently, the liquid crystal copolyester oligomers are subjected to high-temperature solid-state condensation reaction to achieve chain extension and thickening, resulting in modified aromatic liquid crystal polyester. Step 3: Using polyphenylsulfone resin as the matrix, mix it with iron-containing carbon-coated molybdenum disulfide and modified aromatic liquid crystal polyester, and perform melt extrusion and granulation in a twin-screw extruder to obtain a high-temperature resistant polyphenylsulfone composite material.

2. The method for preparing a high-temperature resistant polyphenylsulfone composite material according to claim 1, characterized in that, The modified aromatic liquid crystal polyester described in step two is prepared through the following steps: The liquid crystal copolyester oligomer was placed in a reactor under nitrogen atmosphere protection and reacted at 250-270℃ for 4-6 hours to carry out solid-phase condensation reaction. The product was then ground, washed, and vacuum dried to constant weight to obtain the modified aromatic liquid crystal polyester.

3. The method for preparing a high-temperature resistant polyphenylsulfone composite material according to claim 2, characterized in that, The liquid crystal copolyester oligomer is prepared by the following steps: 6-hydroxy-2-naphthoic acid, 4,4'-diphenyl ether dicarboxylic acid, 4,4'-dihydroxydiphenyl sulfone, and acetic anhydride were placed in a reactor under a nitrogen atmosphere and stirred at 25-35°C for 10-20 min. Anhydrous sodium acetate was added, and the reaction was carried out at 140-150°C for 1-3 h. Then, the temperature was increased to 330-350°C at a rate of 1-2°C / min for high-temperature melt polycondensation. After the reaction system reached the set maximum temperature, the reaction vessel was evacuated to a high vacuum state, and the melt was discharged while hot, cooled and solidified, and collected after mechanical crushing to obtain liquid crystal copolyester oligomer.

4. The method for preparing a high-temperature resistant polyphenylsulfone composite material according to claim 2, characterized in that, The ratio of 6-hydroxy-2-naphthoic acid, 4,4'-diphenyl ether dicarboxylic acid, 4,4'-dihydroxydiphenyl sulfone, anhydrous sodium acetate, and acetic anhydride is 30-40g: 15-20g: 15-20g: 60-100mg: 40-60mL.

5. The method for preparing a high-temperature resistant polyphenylsulfone composite material according to claim 1, characterized in that, The iron-containing carbon-coated molybdenum disulfide mentioned in step one is prepared through the following steps: Tannic acid-iron complex modified molybdenum disulfide was placed in a tube furnace under nitrogen atmosphere protection and heated to 500-600℃ at a rate of 5℃ / min for high-temperature carbonization. The temperature was held for 2-4 hours and then cooled to obtain iron-carbon coated molybdenum disulfide.

6. The method for preparing a high-temperature resistant polyphenylsulfone composite material according to claim 5, characterized in that, The tannic acid-iron complex modified molybdenum disulfide is prepared by the following steps: Nano-molybdenum disulfide, tannic acid, and deionized water were placed in a reaction vessel and ultrasonically dispersed at 25-35℃ for 1-2 hours. Ferric chloride hexahydrate was added, and the mixture was reacted at the same temperature for 20-40 minutes. The mixture was then centrifuged, washed, and freeze-dried to constant weight to obtain tannic acid-iron complex modified molybdenum disulfide.

7. The method for preparing a high-temperature resistant polyphenylsulfone composite material according to claim 6, characterized in that, The ratio of the amount of nano-molybdenum disulfide, tannic acid, ferric chloride hexahydrate, and deionized water is 20-40g: 30-50g: 6-10g: 3-6L.

8. The method for preparing a high-temperature resistant polyphenylsulfone composite material according to claim 1, characterized in that, The mass ratio of polyphenylene sulfone resin, iron-carbon-coated molybdenum disulfide, and modified aromatic liquid crystal polyester in step three is 200-400: 5-15: 10-30.

9. The method for preparing a high-temperature resistant polyphenylsulfone composite material according to claim 1, characterized in that, The processing temperatures of each temperature zone of the twin-screw extruder described in step three are 320-340℃, 340-360℃, and 360-380℃, respectively; the die temperature is 350-370℃; and the screw speed is 200-300 r / min.

10. A high-temperature resistant polyphenylsulfone composite material, characterized in that, The high-temperature resistant polyphenylsulfone composite material is prepared by any one of the preparation methods of claims 1-9.

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