Carboxylated carbon nanotube modified porous polyether ether ketone and preparation process and continuous purification process thereof

Abstract

This invention discloses a carboxylated carbon nanotube-modified porous polyether ether ketone (PEEK) and its preparation and continuous purification processes, relating to the field of PEEK technology. This invention constructs a complete technical solution through innovative design of a pore-forming agent system with no inorganic residue, functionalized pore wall interfaces using carboxylated carbon nanotubes, stepwise dynamic pore-forming control technology, and a multi-stage continuous ultrasonic washing process. It can construct interfaces with four functions—adsorption, catalysis, ion exchange, and desorption—within porous crude PEEK, achieving efficient and stable pore structure formation, significantly improving washing and purification efficiency, and significantly reducing solvent and energy consumption. Ultimately, it yields modified PEEK products with both high-purity matrix properties and high-value-added functional characteristics, providing a novel technical solution for the green and continuous preparation and high-value functional applications of high-performance PEEK.

Description

Technical Field

[0001] This invention relates to the field of polyether ether ketone (PEEK) technology, specifically to carboxylated carbon nanotube-modified porous PEEK and its preparation and continuous purification processes. Background Technology

[0002] Polyetheretherketone (PEEK), a semi-crystalline aromatic specialty engineering plastic, possesses excellent high-temperature resistance, chemical corrosion resistance, mechanical properties, insulation, and biocompatibility. Due to its comprehensive performance advantages, it has irreplaceable key applications in strategic high-end fields such as aerospace, high-end medical devices, semiconductor electronic packaging, and new energy equipment, making it one of the world's best-performing specialty engineering plastics. In the industrial nucleophilic substitution polymerization production of PEEK, diphenyl sulfone is commonly used as a high-temperature reaction solvent, and sodium carbonate and potassium carbonate are used as salt-forming agents. After the reaction, the product inevitably contains residual organic solvents such as diphenyl sulfone and inorganic salt byproducts such as sodium fluoride. The presence of these impurities not only severely degrades the mechanical properties, processing flowability, thermal stability, and aging resistance of crude PEEK, but also generates defects such as volatiles and bubbles during high-temperature processing, and may even pose serious risks such as biotoxicity and electrical failure in medical devices and electronic packaging applications. Therefore, efficiently removing residual impurities and achieving deep purification of PEEK are the core processes for preparing high-quality PEEK products for high-end applications, and also the core bottleneck restricting the improvement of PEEK industrial production efficiency, production costs, and energy consumption control.

[0003] To purify and remove impurities from PEEK, traditional industry processes primarily involve multiple rounds of soaking and washing of dense PEEK particles or powder with organic solvents such as acetone and deionized water. However, dense PEEK particles lack internal mass transfer channels. Impurities trapped inside the particles during polymerization can only be removed through slow diffusion of the washing solvent from the particle surface to the interior, resulting in a long mass transfer path, high interfacial resistance, and extremely low mass transfer efficiency. This process not only has a purification cycle of tens of hours and extremely low production efficiency, but also consumes tens of times the mass of PEEK in acetone and deionized water, leading to a significant waste of solvent and water resources. Furthermore, it is difficult to achieve deep removal of impurities, with the final product typically containing impurities at the tens of ppm level, failing to meet the stringent requirements of high-end medical devices and semiconductor packaging fields for PEEK products with impurity residues of <5 ppm.

[0004] To overcome the mass transfer bottleneck of dense PEEK structures, existing technologies are gradually shifting towards a "porous PEEK preparation-washing and purification" approach. This involves introducing porogens into PEEK to create interconnected pores, providing a rapid mass transfer channel for the washing solvent. For example, crude PEEK is melt-blended and granulated with soluble mono- and mono-porogens such as polyethylene glycol. The porogens are then dissolved by water washing, forming a porous structure within the PEEK. Acetone washing removes diphenyl sulfone, and water washing removes inorganic salts. This process significantly shortens the impurity mass transfer path through the porous structure, improving washing efficiency to some extent. Meanwhile, to meet the upgrading requirements of high-end applications for PEEK performance, the industry typically uses nanofillers such as carbon nanotubes to modify and improve PEEK, enhancing its mechanical properties. However, in practical industrial applications, the above-mentioned existing technologies still suffer from several core defects that are difficult to overcome, failing to fundamentally solve the industry pain points of high-purity PEEK preparation and high-value modification. These are specifically reflected in the following aspects: (1) Existing porous PEEK purification technology relies solely on the physical dissolution of a single pore-forming agent to form unfunctionalized pores. The pores can only provide basic physical diffusion channels for solvents and impurities, and cannot actively promote the removal of impurities. For trace amounts of diphenyl sulfone and sodium fluoride impurities trapped deep within the pores, removal can only be achieved through passive dissolution and diffusion of the solvent, which cannot break through the liquid-solid mass transfer equilibrium limit, and the efficiency of deep impurity removal still has a significant bottleneck.

[0005] (2) The existing single-pore agent system forms PEEK pores with wide pore size distribution, poor pore channel connectivity and fragile structure. In subsequent high-temperature washing, mechanical conveying and ultrasonic treatment processes, the pores are prone to collapse and blockage. At the same time, there is no pore structure reinforcement mechanism in the system, and the prepared porous PEEK crude product has low mechanical strength. In the continuous production process of material conveying and stirring, particle breakage and fine powder shedding are easy to occur. This will not only destroy the mass transfer channel, but also contaminate the product and affect batch stability, which seriously limits its application in continuous industrial production.

[0006] (3) In the existing technology, the purification and functionalization modification of PEEK are two completely independent processes, and the process route of "purification first, modification later" is generally adopted: first, high-purity crude PEEK is prepared by washing process, and then modified fillers such as carbon nanotubes are added by melt blending to upgrade the performance. This process not only has the problems of complicated process, long production cycle and high processing cost, but also has two major defects: first, the viscosity of PEEK melt is extremely high, and carbon nanotubes are very easy to agglomerate during melt blending, making it difficult to achieve uniform dispersion at the nanoscale, and the modification effect is greatly reduced; second, new impurities are easily introduced during the modification process, which destroys the high-purity state of the crude PEEK and cannot take into account both the high purity and high performance of the product.

[0007] (4) The existing washing process for porous PEEK still uses the traditional simple two-stage intermittent process of "acetone soaking-water soaking". It does not optimize the process design for the pore structure characteristics of porous PEEK and cannot give full play to the specific surface area advantage of the porous structure. This process is not only slow in washing rhythm and long in single batch production cycle, but also lacks targeted and enhanced removal methods for residual impurities in the pores. It requires a large amount of fresh solvent to be replaced in multiple rounds to achieve a certain purification effect, resulting in a large consumption of acetone and water. At the same time, the high energy consumption caused by long-term heating and stirring significantly increases the cost of industrial production of PEEK.

[0008] (5) Diphenyl sulfone is an organic, poorly soluble impurity, while sodium fluoride is an inorganic, water-soluble impurity. The physicochemical properties and removal characteristics of these two impurities differ significantly, and existing technologies have not designed differentiated removal methods tailored to the characteristics of these two impurities. For trace amounts of sodium fluoride adsorbed on the inner wall of the pores, there is a lack of efficient ion exchange and removal mechanisms, making it difficult to achieve Na… + Deep removal; for poorly soluble trace amounts of diphenyl sulfone, relying solely on the physical dissolution effect of acetone cannot break through the dissolution equilibrium limit, ultimately making it difficult to achieve simultaneous deep removal of the two impurities, and failing to meet the stringent ppm-level requirements for impurity residues in PEEK products in high-end medical devices, semiconductor electronic packaging and other fields.

[0009] Therefore, developing a complete technical solution that can simultaneously achieve stable and controllable PEEK pore structure, efficient removal of impurities, and in-situ upgrading of material properties, while significantly reducing solvent and energy consumption and adapting to continuous industrial production, has become a core technical problem that urgently needs to be solved in the field of high-purity PEEK preparation and high-value application. Summary of the Invention

[0010] The technical problem this invention aims to solve is to overcome the shortcomings of existing technologies and provide a process for preparing and continuously purifying carboxylated carbon nanotube-modified porous polyether ether ketone (PEEK). This is achieved through innovative design of a pore-forming agent system with no inorganic residues, functionalized pore wall interfaces using carboxylated carbon nanotubes, stepwise dynamic pore-forming control technology, and a multi-stage continuous ultrasonic washing process, thus constructing a complete technical solution. This solution enables the construction of interfaces with four functions—adsorption, catalysis, ion exchange, and desorption—within porous PEEK crude products, achieving efficient and stable pore structure formation, significantly improving washing and purification efficiency, and substantially reducing solvent and energy consumption. Ultimately, it yields modified PEEK products with both high-purity matrix properties and high-value-added functional characteristics, providing a novel technical solution for the green and continuous preparation and high-value-added functional applications of high-performance PEEK.

[0011] The technical solution of this invention is as follows: In a first aspect, the present invention provides a process for preparing carboxylated carbon nanotube-modified porous polyether ether ketone, comprising the following steps: S1 Premix: 0.3-1.5 parts by weight of carboxylated carbon nanotubes are premixed with 7.5-11 parts by weight of porogen to obtain a uniform composite powder; wherein the porogen includes 5-8 parts by weight of polyethylene glycol (PEG) and 2.5-3 parts by weight of volatile compounds, wherein the volatile compounds are azodicarbonamide (AC) and ammonium bicarbonate in a mass ratio of 1:(1-3); S2 Melt Blending and Extrusion Granulation: 100 parts of crude polyether ether ketone (PEEK) product and the composite powder are added to a twin-screw extruder. The melt is extruded through the die head, granulated underwater, and then subjected to slow cooling and heat preservation treatment at 120-150℃ for 30-60 minutes to obtain PEEK particles containing porogen and carboxylated carbon nanotubes. S3 removes the pore-forming agent, performs stepwise dynamic pore formation, and completely preserves the carboxylated carbon nanotubes anchored on the inner wall of the pores to prepare porous polyether ether ketone crude product with carboxylated carbon nanotube functionalized pore walls. This process is divided into three stages: S3-1 Hot Water Pre-dissolution: Polyetheretherketone (PEEK) particles are transported to a hot water washing tank containing 60-70°C hot deionized water. Mechanical stirring is applied, and the particles remain for 15-20 minutes. Most of the PEG, which serves as the framework in the pore-forming agent system, is dissolved and washed out, forming basic interconnected channels. Carboxylated carbon nanotubes are completely anchored to the inner wall of the channels through interfacial entanglement and π-π conjugation, and are not dissolved. S3-2 Ultrasonic-Assisted Pore Cleaning: Polyetheretherketone (PEEK) particles pre-dissolved in hot water are transferred to an ultrasonic treatment tank filled with room-temperature deionized water. Ultrasonic waves with a frequency of 15-25kHz and a power of 100-200W are applied for 5-10 minutes. Only residual PEG fragments in the pores are peeled off, completely clearing the pores without damaging the carboxylated carbon nanotubes attached to the pore walls. S3-3 Dehydration and Pre-drying: After centrifugation to dehydrate the cleaned polyether ether ketone particles, they are dried in circulating hot air at 80-100℃ until the moisture content is less than 0.5wt.%, to obtain carboxylated carbon nanotube modified porous polyether ether ketone.

[0012] Preferably, in step S1, during premixing, the mixture is premixed at room temperature for 15-20 minutes, and nitrogen gas is introduced during the premixing process to prevent oxidative aggregation of carboxylated carbon nanotubes; the carboxylated carbon nanotubes have a diameter of 10-20 nm and a length of 10-30 μm, and the surface of the carboxylated carbon nanotubes has a high density of carboxyl functional groups, with a carboxyl content of 1-2 mmol / g; in the porogen, the M of polyethylene glycol is... n =10000-20000.

[0013] Preferably, in step S2, before the crude polyetheretherketone is added to the twin-screw extruder, it is first vacuum dried at 120-150℃ for more than 4 hours to remove moisture. The parameters of each section of the twin-screw extruder are set as follows: zone 1 temperature 260-290℃, zone 2 temperature 280-305℃, zone 3 temperature 300-320℃, zone 4 temperature 310-340℃, die head temperature 310-340℃, and screw speed 200-300 rpm. The vacuum devolatilization section temperature is 320-330℃, the vacuum degree is -0.09~-0.07MPa, and the duration is 1-2 minutes. The gases generated by the decomposition of volatile compounds are removed in this section.

[0014] Preferably, in step S3-1, the mechanical stirring speed is 60-100 rpm.

[0015] Secondly, the present invention provides carboxylated carbon nanotube-modified porous polyether ether ketone, which is prepared by the above-described preparation process of carboxylated carbon nanotube-modified porous polyether ether ketone.

[0016] Thirdly, the present invention provides a continuous purification process for the above-mentioned carboxylated carbon nanotube-modified porous polyether ether ketone, comprising the following steps: (1) Multi-stage continuous ultrasonic washing: Carboxylated carbon nanotubes modified porous polyether ether ketone are put into a continuous washing system. First, diphenyl sulfone is removed by two-stage acetone washing, and then sodium fluoride is removed by two-stage gradient water washing. Simultaneously, the adsorption, catalysis and ion exchange of the pore walls of carboxylated carbon nanotubes are utilized to achieve deep removal of impurities. The continuous washing system includes a primary acetone rough washing tower, a secondary acetone fine washing tower, a water washing and hydrolysis tower, and a water washing enhancement tower, which are connected sequentially by conveyors. Each of the primary acetone rough washing tower, secondary acetone fine washing tower, water washing and hydrolysis tower, and water washing enhancement tower is equipped with a plate conveyor, a spray distributor, and an ultrasonic generator, and has an inlet, outlet, washing liquid inlet, and washing liquid outlet. The material support plate of the plate conveyor uses a perforated sieve plate, and the spray distributor is connected to the washing liquid inlet. The washing liquid inlet of the primary acetone rough washing tower is connected to the washing liquid outlet of the secondary acetone fine washing tower via a pipeline. The washing liquid inlet of the secondary acetone fine washing tower is connected to a fresh acetone feed pipe. The washing liquid inlet of the water washing and hydrolysis tower is connected to the washing liquid outlet of the water washing enhancement tower via a pipeline. The washing liquid inlet of the water washing enhancement tower is connected to a fresh ultrapure water feed pipe. (2) Post-processing and shaping of modified materials: The porous polyetheretherketone particles are subjected to deep drying and vacuum shaping to completely preserve the carboxylated carbon nanotubes in the pores, thereby obtaining a bifunctional porous polyetheretherketone product modified with carboxylated carbon nanotubes. The specific steps are as follows: 1) Deep dehydration and drying: After centrifugation to remove water from the washed polyetheretherketone (PEEK) particles, they are dried in circulating hot air at 100-120℃ until the moisture content is below 0.1 wt.%. 2) Vacuum setting treatment: The dried polyether ether ketone particles are kept at 120-140℃ and -0.08~-0.09MPa for 2-3 hours to remove residual volatile components, eliminate internal stress in the pores, stabilize the pore structure and the interface bonding state with carboxylated carbon nanotubes, and discharge the material after natural cooling to room temperature to obtain the purified carboxylated carbon nanotube modified porous polyether ether ketone product.

[0017] The preferred multi-stage continuous ultrasonic washing process is as follows: a) Primary acetone rough washing tower: The recycled acetone washing liquid discharged from the secondary acetone fine washing tower is used for spraying. The concentration of the recycled acetone washing liquid is 60-70 wt.% and the temperature is 50-60℃. At the same time, ultrasonic waves of 20-25kHz and 150-200W are applied. The porous polyether ether ketone crude product comes into contact with the recycled acetone washing liquid in this section to remove more than 90% of the free state and diphenyl sulfone encapsulated in the PEEK matrix. b) Secondary acetone washing tower: Fresh acetone is sprayed at a concentration ≥99wt.% and a temperature of 60-70℃, while ultrasonic waves of 25-30kHz and 200-300W are applied simultaneously; the discharged recycled acetone washing liquid is sent to the primary acetone coarse washing tower for recycling as spray washing liquid; the material after coarse washing in the primary acetone coarse washing tower comes into contact with fresh acetone in this section to deeply remove residual diphenyl sulfone. c) Water washing and hydrolysis tower: The recycled hot water discharged from the water washing enhancement tower is sprayed at a temperature of 75-85℃, and ultrasonic waves of 30-35kHz and 300-400W are applied simultaneously. The material after two-stage acetone washing comes into contact with the recycled hot water in this section. Through the catalytic effect of carboxylated carbon nanotubes, the trace amount of residual diphenyl sulfone is hydrolyzed into water-soluble products, and sodium fluoride in the PEEK matrix is ​​initially dissolved. d) Water washing enhancement tower: Fresh ultrapure water at 85-95℃ is sprayed, and ultrasonic waves at 30-35kHz and 200-300W are applied simultaneously. The material after hydrolysis is in contact with fresh ultrapure water in this section to deeply remove sodium fluoride, wash off residual acetone and hydrolysis products, and the discharged recycled hot water is sent to the water washing hydrolysis tower for recycling as spray washing liquid.

[0018] The porous polyether ether ketone crude product is sequentially washed through the above four stages to achieve deep removal of diphenyl sulfone and sodium fluoride.

[0019] Preferably, the acetone washing liquid recycled from the secondary acetone washing tower to the primary acetone rough washing tower is filtered to remove solid impurities before being recycled. When the concentration of the recycled acetone washing liquid is below 60 wt.%, recycling is stopped, and it is sent to the solvent distillation system for distillation purification until its concentration is ≥60 wt.%, after which it is recycled to the primary acetone rough washing tower.

[0020] Preferably, the hot water recycled from the water washing enhancement tower to the water washing hydrolysis tower is filtered and treated with ion exchange resin to remove metal ions before being recycled.

[0021] This invention achieves deep synergy between carboxylated carbon nanotube modification and PEEK purification processes through innovative design of a pore-forming agent system with no inorganic residue, functionalized pore wall interfaces of carboxylated carbon nanotubes, stepwise dynamic pore-forming control technology, and multi-stage continuous ultrasonic washing process. It completely solves the core problems of existing technologies, such as single pore function, poor structural stability, low washing efficiency, high solvent consumption, and separation of modification and purification processes. Compared with existing technologies, it has significant technical advantages and practical value, with specific beneficial effects as follows: 1. This invention utilizes a quadruple functional interface constructed from carboxylated carbon nanotubes to achieve targeted and deep removal of diphenyl sulfone and sodium fluoride. The resulting modified PEEK product exhibits residual diphenyl sulfone levels of <5 ppm, residual sodium fluoride levels of <2 ppm, and Na... + With a residual content of <1ppm and no porogen residue, it far exceeds the purification level of existing technologies and can meet the stringent requirements for ultra-high purity PEEK in aerospace, high-end medical devices, precision electronic packaging and other fields.

[0022] 2. This invention breaks away from the traditional step-by-step process of "purification first, modification later" for PEEK. Carboxylated carbon nanotubes not only play a core role in removing impurities during the purification process, but also serve as functional fillers permanently anchored in the inner wall of PEEK pores, significantly improving the tensile strength and flexural strength of the material. Without adding any extra steps, this invention upgrades PEEK from general-purpose grade to high-value-added functional products.

[0023] 3. The inorganic residue-free pore-forming agent system designed in this invention achieves precise control of three-dimensional interconnected multi-level channels through the synergistic effect of PEG pore-forming framework and volatile compound foaming pore formation; at the same time, carboxylated carbon nanotubes provide effective support for the channels, preventing collapse and blockage of the channels during high-temperature washing, mechanical conveying, and ultrasonic treatment. The mechanical strength and structural integrity of porous PEEK crude product are significantly improved, and there is no obvious particle breakage or fine powder generation in continuous production, providing a stable and reliable carrier for the industrial continuous production of PEEK.

[0024] 4. The multi-stage continuous ultrasonic washing process designed in this invention is highly compatible with the functionalized pore structure of carboxylated carbon nanotubes. Two-stage acetone gradient washing achieves stepwise deep removal of diphenyl sulfone, two-stage hot water gradient washing achieves efficient removal of sodium fluoride, and multi-frequency ultrasound enhances the mass transfer process within the pores. Combined with the stepwise recycling of the washing solution, solvent utilization is significantly improved. Compared with traditional batch processes, the acetone consumption of this invention is reduced by more than 60%, water consumption by more than 50%, and heating and ultrasonic energy consumption are reduced simultaneously, significantly reducing the production cost of PEEK purification and modification.

[0025] 5. The stepwise dynamic pore-forming process of the present invention can be seamlessly integrated with existing PEEK production equipment such as twin-screw extrusion and underwater pelletizing to achieve continuous preparation of porous crude products; the continuous washing system can realize continuous feeding, segmented washing and continuous discharge of crude products, replacing the traditional intermittent soaking process, greatly shortening the production cycle and improving production efficiency, and constructing a green, continuous and high-value preparation process technology solution for high-performance PEEK.

[0026] In summary, this invention, through the deep integration of material design and process optimization, not only achieves deep removal of PEEK impurities and a significant improvement in product purity, but also solves problems such as poor structural stability, low washing efficiency, high solvent energy consumption, and difficulty in continuous production in existing technologies. It provides a brand-new technical solution for the green, low-cost, and continuous industrial production of high-performance PEEK, with significant economic and social benefits, and has broad prospects for promotion in PEEK application fields such as aerospace, medical devices, and high-end manufacturing. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the continuous washing system of the present invention.

[0028] In the diagram, 1. Primary acetone coarse washing tower; 2. Secondary acetone fine washing tower; 3. Water washing and hydrolysis tower; 4. Water washing enhancement tower; 5. Plate conveyor; 6. Spray distributor; 7. Ultrasonic generator; 8. Valve 1; 9. Filter 1; 10. Online acetone concentration detector 1; 11. Recycled acetone washing liquid pipeline; 12. Online acetone concentration detector 2; 13. Distillation column; 14. Reboiler; 15. Condenser; 16. Reflux tank; 17. Acetone washing liquid storage tank; 18. Fresh acetone feed pipe; 19. Valve 2; 20. Filter 2; 21. Ion exchange resin; 22. Fresh ultrapure water feed pipe. Detailed Implementation

[0029] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention.

[0030] like Figure 1 As shown, the continuous washing system used in the following embodiments has the following structure: The continuous washing system includes a primary acetone rough washing tower 1, a secondary acetone fine washing tower 2, a water washing and hydrolysis tower 3, and a water washing enhancement tower 4, which are connected sequentially by conveyors. Each of the primary acetone rough washing tower 1, secondary acetone fine washing tower 2, water washing and hydrolysis tower 3, and water washing enhancement tower 4 is equipped with a plate conveyor 5, a spray distributor 6, and an ultrasonic generator 7, and is equipped with a feed inlet, a discharge outlet, a washing liquid inlet, and a washing liquid outlet. The material support plate of the plate conveyor 5 uses a perforated sieve plate, and the spray distributor 6 is connected to the washing liquid inlet. The inlet of the primary acetone rough washing tower 1 is connected to the outlet of the secondary acetone fine washing tower 2 via a pipeline. This pipeline is equipped with valve 8, filter 9, and an online acetone concentration detector 10. The outlet of the secondary acetone fine washing tower 2 is connected to a solvent distillation system. The solvent distillation system is connected to the inlet of the primary acetone rough washing tower 1 via a recycled acetone washing pipeline 11, which is equipped with an online acetone concentration detector 12. Specifically, the solvent distillation system includes a distillation tower 13, which is connected to a reboiler 14 and a condenser 15. The condenser 15 is connected to a reflux tank 16, which is connected to the distillation tower 13 and also connected to an acetone washing liquid storage tank 17.

[0031] The acetone washing liquid recycled from the primary acetone rough washing tower 1 in the secondary acetone washing tower 2 is filtered to remove solid impurities before being recycled. Recycling stops when the concentration of the recycled acetone washing liquid is below 60 wt.%, and it is then transported to the middle of the distillation tower 13. The reboiler 14 heats the bottom liquid to generate steam. The steam from the top of the tower is condensed by the condenser 15 and enters the reflux tank 16. Part of the steam is recycled back to the distillation tower 13, and the rest is collected as acetone washing liquid with a concentration ≥60 wt.% and sent to the acetone washing liquid storage tank 17. The outlet of the acetone washing liquid storage tank 17 is connected to the washing liquid inlet of the primary acetone rough washing tower 1. After purification by the solvent distillation system, the acetone washing liquid is tested by the online acetone concentration detector 12 and its concentration is ≥60 wt.% before being recycled back to the primary acetone rough washing tower 1.

[0032] The washing liquid inlet of the secondary acetone washing tower 2 is connected to a fresh acetone feed pipe 18. The washing liquid inlet of the water washing and hydrolysis tower 3 is connected to the washing liquid outlet of the water washing enhancement tower 4 via a pipeline equipped with a valve 19, a filter 20, and an ion exchange resin 21. The washing liquid inlet of the water washing enhancement tower 4 is connected to a fresh ultrapure water feed pipe 22. The hot water recycled from the water washing and hydrolysis tower 3 to the water washing enhancement tower 4 is filtered and treated with ion exchange resin 21 to remove metal ions before being recycled.

[0033] Example 1 The preparation process of carboxylated carbon nanotube-modified porous polyether ether ketone in this embodiment includes the following steps: S1 premix 0.3 parts by weight of carboxylated carbon nanotubes (10 nm in diameter, 10 μm in length, and 1 mmol / g of carboxyl group content) and 7.5 parts by weight of a porogen were premixed in a high-speed mixer at room temperature for 15 min. Nitrogen gas was introduced during the premixing process to obtain a uniform composite powder. The porogen included 5 parts by weight of PEG-10000 and 2.5 parts by weight of volatile compounds, which included AC and ammonium bicarbonate in a 1:1 mass ratio.

[0034] S2 melt blending and extrusion granulation 100 parts of crude PEEK were vacuum dried at 120℃ for 4 hours to remove moisture. The resulting product was then added to a twin-screw extruder along with the aforementioned composite powder. The parameters for each section of the twin-screw extruder were set as follows: Zone 1 temperature 260℃, Zone 2 temperature 280℃, Zone 3 temperature 300℃, Zone 4 temperature 310℃, Die head temperature 310℃, screw speed 200 rpm; Vacuum devolatilization section temperature 320℃, vacuum degree -0.08 MPa, duration 1 min; the melt was extruded through the die head, underwater pelletized, and then slowly cooled and held at 120℃ for 30 min to obtain PEEK particles containing pore-forming agents and carboxylated carbon nanotubes.

[0035] S3 was used to remove the pore-forming agent and prepare porous crude PEEK with carboxylated carbon nanotube functionalized pore walls. S3-1 Hot Water Pre-dissolution: PEEK particles are transported to a hot water washing tank containing 60°C hot deionized water. Mechanical stirring at 60 rpm is applied, and the particles are held for 15 minutes to dissolve most of the PEG-10000, forming basic interconnected channels. Carboxylated carbon nanotubes are completely anchored to the inner wall of the channels.

[0036] S3-2 Ultrasonic-Assisted Pore Cleaning: PEEK particles pre-dissolved in hot water are transferred to an ultrasonic treatment tank. The medium in the tank is room temperature deionized water. Ultrasonic waves with a frequency of 15kHz and a power of 100W are applied for 5 minutes to clear the pores without damaging the carboxylated carbon nanotubes.

[0037] S3-3 Dehydration and Pre-drying: After centrifugation and dehydration, PEEK particles are dried in circulating hot air at 80°C until the moisture content is less than 0.5 wt.%, to obtain porous crude PEEK with carboxylated carbon nanotube functionalized pore walls.

[0038] S4 Multi-stage Continuous Ultrasonic Washing The above-mentioned porous PEEK crude product is fed into a continuous washing system and undergoes four washing stages sequentially, as follows: a) Primary acetone coarse washing tower 1: Spray with 60wt.% recycled acetone washing liquid discharged from secondary acetone fine washing tower 2 at a temperature of 50℃, and simultaneously apply 20kHz, 150W ultrasonic waves to remove more than 90% of diphenyl sulfone, and discharge the waste liquid.

[0039] b) Secondary acetone washing tower 2: 99wt.% fresh acetone is sprayed at a temperature of 60℃, and 25kHz, 200W ultrasonic waves are applied simultaneously to deeply remove diphenyl sulfone. The discharged recycled acetone washing liquid is sent to the primary acetone coarse washing tower 1.

[0040] c) Water washing and hydrolysis tower 3: The recycled hot water discharged from the water washing enhancement tower 4 is sprayed at a temperature of 75℃, and ultrasonic waves of 30kHz and 300W are applied simultaneously to catalyze the hydrolysis of trace amounts of diphenyl sulfone, initially dissolving sodium fluoride, and the waste liquid is discharged.

[0041] d) Water washing enhancement tower 4: It uses 85℃ fresh ultrapure water spray and simultaneously applies 30kHz, 200W ultrasonic waves to deeply remove sodium fluoride. The discharged recycled hot water is sent to water washing hydrolysis tower 3.

[0042] S5 Post-treatment and Modified Material Finalization 1) Deep dehydration and drying: The washed PEEK particles are centrifuged to remove water and dried in 100°C circulating hot air until the moisture content is less than 0.1 wt.%.

[0043] 2) Vacuum shaping treatment: The dried PEEK particles are placed in a vacuum oven and kept at 120℃ and -0.09MPa for 2 hours. After naturally cooling to room temperature, the material is discharged to obtain the purified carboxylated carbon nanotube modified porous PEEK product.

[0044] Example 2 The preparation process of carboxylated carbon nanotube-modified porous polyether ether ketone in this embodiment includes the following steps: S1 premix 0.9 parts by weight of carboxylated carbon nanotubes (15 nm diameter, 20 μm length, carboxyl content 1.5 mmol / g) and 9.2 parts by weight of a porogen were premixed in a high-speed mixer at room temperature for 17.5 min. Nitrogen gas was introduced during the premixing process to obtain a uniform composite powder. The porogen included 6.5 parts by weight of PEG-15000 and 2.7 parts by weight of volatile compounds, which included AC and ammonium bicarbonate in a mass ratio of 1:2.

[0045] S2 melt blending and extrusion granulation 100 parts of crude PEEK were vacuum dried at 135℃ for 5 hours to remove moisture. The resulting product was then added to a twin-screw extruder along with the aforementioned composite powder. The parameters for each section of the twin-screw extruder were set as follows: zone 1 temperature 275℃, zone 2 temperature 292℃, zone 3 temperature 310℃, zone 4 temperature 325℃, die head temperature 325℃, screw speed 250 rpm; vacuum devolatilization zone temperature 325℃, vacuum degree -0.09 MPa, duration 1.5 min; the melt was extruded through the die head, underwater pelletized, and then slowly cooled and held at 135℃ for 45 min to obtain PEEK particles containing pore-forming agents and carboxylated carbon nanotubes.

[0046] S3 was used to remove the pore-forming agent and prepare porous crude PEEK with carboxylated carbon nanotube functionalized pore walls. S3-1 Hot Water Pre-dissolution: PEEK particles are transported to a hot water washing tank containing 65°C hot deionized water. Mechanical stirring at 80 rpm is applied, and the particles are held for 18 minutes to dissolve most of the PEG-15000, forming basic interconnected channels. Carboxylated carbon nanotubes are completely anchored to the inner wall of the channels.

[0047] S3-2 Ultrasonic-Assisted Pore Cleaning: PEEK particles pre-dissolved in hot water are transferred to an ultrasonic treatment tank. The medium in the tank is room temperature deionized water. Ultrasonic waves with a frequency of 20kHz and a power of 150W are applied for 8 minutes to clear the pores without damaging the carboxylated carbon nanotubes.

[0048] S3-3 Dehydration and Pre-drying: After centrifugation and dehydration, PEEK particles are dried in circulating hot air at 90°C until the moisture content is less than 0.5 wt.%, to obtain porous crude PEEK with carboxylated carbon nanotube functionalized pore walls.

[0049] S4 Multi-stage Continuous Ultrasonic Washing The above-mentioned porous PEEK crude product is fed into a continuous washing system and undergoes four washing stages sequentially, as follows: a) Primary acetone coarse washing tower 1: Spray with 65wt.% recycled acetone washing liquid discharged from secondary acetone fine washing tower 2 at a temperature of 55℃, and simultaneously apply 22kHz, 175W ultrasonic waves to remove more than 90% of diphenyl sulfone, and the waste liquid is discharged.

[0050] b) Secondary acetone washing tower 2: 99wt.% fresh acetone is sprayed at a temperature of 65℃, and 28kHz, 250W ultrasonic waves are applied simultaneously to deeply remove diphenyl sulfone. The discharged recycled acetone washing liquid is sent to the primary acetone coarse washing tower 1.

[0051] c) Water washing and hydrolysis tower 3: The recycled hot water discharged from the water washing enhancement tower 4 is sprayed at a temperature of 80℃, and ultrasonic waves of 32kHz and 350W are applied simultaneously to catalyze the hydrolysis of trace amounts of diphenyl sulfone, initially dissolving sodium fluoride, and the waste liquid is discharged.

[0052] d) Water washing enhancement tower 4: It uses 90℃ fresh ultrapure water spray and simultaneously applies 32kHz, 250W ultrasonic waves to deeply remove sodium fluoride. The discharged recycled hot water is sent to water washing hydrolysis tower 3.

[0053] S5 Post-treatment and Modified Material Finalization 1) Deep dehydration and drying: The washed PEEK particles are centrifuged to remove water and dried in circulating hot air at 110℃ until the moisture content is less than 0.1wt.%.

[0054] 2) Vacuum shaping treatment: The dried particles are placed in a vacuum oven and kept at 130℃ and -0.09MPa for 2.5h. After naturally cooling to room temperature, the material is discharged to obtain the purified carboxylated carbon nanotube modified porous PEEK product.

[0055] Example 3 The preparation process of carboxylated carbon nanotube-modified porous polyether ether ketone in this embodiment includes the following steps: S1 premix 1.5 parts by weight of carboxylated carbon nanotubes (20 nm diameter, 30 μm length, carboxyl content 2 mmol / g) and 11 parts by weight of a porogen were premixed in a high-speed mixer at room temperature for 20 min. Nitrogen gas was introduced during the premixing process to obtain a uniform composite powder. The porogen included 8 parts by weight of PEG-20000 and 3 parts by weight of volatile compounds, which included AC and ammonium bicarbonate in a mass ratio of 1:3.

[0056] S2 melt blending and extrusion granulation 100 parts of crude PEEK were vacuum dried at 150℃ for 6 hours to remove moisture. The resulting product was then added to a twin-screw extruder along with the aforementioned composite powder. The parameters for each section of the twin-screw extruder were set as follows: Zone 1 temperature 290℃, Zone 2 temperature 305℃, Zone 3 temperature 320℃, Zone 4 temperature 340℃, Die head temperature 340℃, screw speed 300 rpm; Vacuum devolatilization section temperature 330℃, vacuum degree -0.07 MPa, duration 2 min; the melt was extruded through the die head, underwater pelletized, and then slowly cooled and held at 150℃ for 60 min to obtain PEEK particles containing porogens and carboxylated carbon nanotubes.

[0057] S3 was used to remove the pore-forming agent and prepare porous crude PEEK with carboxylated carbon nanotube functionalized pore walls. S3-1 Hot Water Pre-dissolution: PEEK particles are transported to a hot water washing tank containing 70°C hot deionized water. Mechanical stirring at 100 rpm is applied, and the particles are held for 20 minutes to dissolve most of the PEG-20000, forming basic interconnected channels. Carboxylated carbon nanotubes are completely anchored to the inner wall of the channels.

[0058] S3-2 Ultrasonic-Assisted Pore Cleaning: PEEK particles pre-dissolved in hot water are transferred to an ultrasonic treatment tank. The medium in the tank is room temperature deionized water. Ultrasonic waves with a frequency of 25kHz and a power of 200W are applied for 10 minutes to clear the pores without damaging the carboxylated carbon nanotubes.

[0059] S3-3 Dehydration and Pre-drying: After centrifugation and dehydration, PEEK particles are dried in circulating hot air at 100℃ until the moisture content is less than 0.5wt.%, to obtain porous crude PEEK with carboxylated carbon nanotube functionalized pore walls.

[0060] S4 Multi-stage Continuous Ultrasonic Washing The above-mentioned porous PEEK crude product is fed into a continuous washing system and undergoes four washing stages sequentially, as follows: a) Primary acetone coarse washing tower 1: Spray with 70wt.% recycled acetone washing liquid discharged from secondary acetone fine washing tower 2 at a temperature of 60℃, and simultaneously apply 25kHz, 200W ultrasonic waves to remove more than 90% of diphenyl sulfone, and discharge the waste liquid.

[0061] b) Secondary acetone washing tower 2: 99wt.% fresh acetone is sprayed at a temperature of 70℃, and ultrasonic waves of 30kHz and 300W are applied simultaneously to deeply remove diphenyl sulfone. The discharged recycled acetone washing liquid is sent to the primary acetone coarse washing tower 1.

[0062] c) Water washing and hydrolysis tower 3: The recycled hot water discharged from the water washing enhancement tower 4 is sprayed at a temperature of 85℃, and ultrasonic waves of 35kHz and 400W are applied simultaneously to catalyze the hydrolysis of trace amounts of diphenyl sulfone, initially dissolve sodium fluoride, and discharge the waste liquid.

[0063] d) Water washing enhancement tower 4: It uses 95℃ fresh ultrapure water spray and simultaneously applies 35kHz, 300W ultrasonic waves to deeply remove sodium fluoride. The discharged recycled hot water is sent to water washing hydrolysis tower 3.

[0064] S5 Post-treatment and Modified Material Finalization 1) Deep dehydration and drying: The washed PEEK particles are centrifuged to remove water and dried in circulating hot air at 120℃ until the moisture content is less than 0.1 wt.%.

[0065] 2) Vacuum shaping treatment: The dried particles are placed in a vacuum oven and kept at 140℃ and -0.08MPa for 3 hours. After naturally cooling to room temperature, the particles are discharged to obtain purified carboxylated carbon nanotube modified porous PEEK products.

[0066] Comparative Example 1 The difference from Example 1 is that carboxylated carbon nanotubes are not added in step S1; at the same time, 7.5 parts by weight of PEG-10000 is used instead of the pore-forming agent in Example 1.

[0067] Comparative Example 2 The difference from Example 1 is that in step S1, no pore-forming agent or carboxylated carbon nanotubes are added, and the final product obtained is a dense PEEK product.

[0068] Comparative Example 3 The difference from Example 1 is that in step S1, uncarboxylated pure carbon nanotubes are used to replace carboxylated carbon nanotubes by the same mass.

[0069] Comparative Example 4 The difference from Example 1 is that the porogen used in step S1 does not include volatile compounds.

[0070] Comparative Example 5 The difference from Example 1 is that in step S1, ammonium bicarbonate is used instead of AC in the volatile compounds of the pore-forming agent.

[0071] Comparative Example 6 The difference from Example 1 is that step S3-2 is not performed.

[0072] Comparative Example 7 The difference from Example 1 is that in step S4, the washing process adopts the traditional "acetone soaking-water soaking" intermittent process: the porous PEEK crude product is cooled, crushed, and ground and then sent to the intermittent extractor to complete acetone extraction and pressure filtration to remove diphenyl sulfone; then, the filter cake after pressure filtration is first put into the extractor, acetone is added for soaking, and stirring is used to dissolve the residual diphenyl sulfone and organic impurities. The solvent is recovered by pressure filtration and separation of filtrate. The filter cake is then returned to the reactor and demineralized water is added for constant temperature soaking, standing and stirring to dissolve the alkali metal inorganic salts wrapped in the material. The solid-liquid separation is performed again by the filter press.

[0073] Performance Testing and Results Analysis The PEEK products prepared in Examples 1-3 and Comparative Examples 1-7 were tested for residual impurities, solvent consumption, and mechanical properties. The test methods are as follows: Diphenyl sulfone residue: determined by high performance liquid chromatography (HPLC); Sodium fluoride / Na + Residual amount: determined by ion chromatography; Solvent consumption: The total consumption of fresh acetone and water for processing 1 kg of PEEK product was statistically analyzed, and the consumption reduction rate was calculated (based on the traditional batch process). Mechanical properties: Tensile strength and flexural strength were tested using a universal testing machine, and the improvement rate compared with PEEK crude product was calculated.

[0074] The test results are shown in Table 1: Table 1. Test results of impurity residue, solvent consumption, and mechanical properties of PEEK products in Examples 1-3 and Comparative Examples 1-7.

[0075] As shown in Table 1, the carboxylated carbon nanotube-modified porous PEEK products prepared using the process of this invention have residual diphenyl sulfone levels of <5 ppm, sodium fluoride levels of <2 ppm, and Na... + The residual amounts were all <1ppm; at the same time, the acetone consumption was reduced by more than 60%, the water consumption was reduced by more than 50%, and the mechanical properties of the material were significantly improved. That is, the porous PEEK product prepared by this invention is significantly better than the comparative example in terms of deep removal of diphenyl sulfone and sodium fluoride, solvent saving, and improvement of mechanical properties.

[0076] Comparative Example 1 used PEG-10000 as a porogen and did not add carboxylated carbon nanotubes. It could not form a functionalized pore wall interface and a stable hierarchical channel. The impurity removal effect was extremely poor, the solvent consumption increased significantly, and there was no modification effect.

[0077] Comparative Example 2 yielded a dense PEEK structure, which prevented the washing solvent from penetrating the particle interior, resulting in the highest amount of impurities and the greatest solvent consumption, completely failing to meet the requirements for preparing high-purity PEEK.

[0078] Comparative Example 3 uses uncarboxylated carbon nanotubes, which lack carboxyl active sites and cannot achieve the four-fold mechanism of adsorption-catalysis-ion exchange-desorption. As a result, the impurity removal effect is significantly reduced, and the binding force with the PEEK matrix is ​​weak, with some of it being lost during the washing process, thus greatly reducing the modification effect.

[0079] The pore-forming agent in Comparative Example 4 did not contain any volatile compounds and relied solely on the dissolution of PEG to form pores. It could not construct a three-dimensional interconnected hierarchical pore structure and could only form closed-pore and semi-closed-pore structures. The pore connectivity was extremely poor, and the washing solvent could not penetrate deep into the pores to remove impurities, resulting in a significant increase in the amount of impurities remaining. At the same time, the closed-pore structure led to a sharp increase in solvent mass transfer resistance, requiring more acetone and water to achieve a basic washing effect, resulting in a significant increase in solvent consumption. Furthermore, the lack of foaming and pore-forming effects of volatile compounds resulted in poor pore structure support, and the reinforcing effect of carboxylated carbon nanotubes on the pores could not be fully utilized, thus significantly reducing the improvement rate of mechanical properties.

[0080] Comparative Example 5 used only ammonium bicarbonate as a volatile compound without adding azodicarbonamide. Ammonium bicarbonate has a low decomposition temperature and a fast decomposition rate, causing it to decompose prematurely during the PEEK melt blending process. A large amount of gas escapes from the melt, making it impossible to form a uniform microporous structure inside the PEEK matrix. The resulting pores have a wide pore size distribution and poor connectivity, failing to provide an effective mass transfer channel for the washing solvent. This leads to a significant decrease in impurity removal efficiency and an increase in solvent consumption. At the same time, the poor uniformity of the pore structure prevents the reinforcing effect of carboxylated carbon nanotubes from being uniformly exerted, resulting in a lower mechanical property improvement rate than the examples.

[0081] Comparative Example 6 did not undergo an ultrasonic-assisted pore-forming and cleaning process. After hot water pre-dissolving, a large number of PEG fragments remained in the pores, causing pore blockage, pore size reduction, and even the formation of closed pores. This severely hindered the entry of the washing solvent and the escaping of impurities, resulting in a significant increase in the amount of residual impurities and a substantial increase in solvent consumption. At the same time, the PEG residues in the pores affected the interfacial bonding between carboxylated carbon nanotubes and PEEK pore walls, leading to a decrease in the improvement rate of material mechanical properties.

[0082] Comparative Example 7 uses a traditional intermittent washing process, which cannot be adapted to the porous structure of PEEK products. It lacks ultrasonic enhancement and graded reuse of washing liquid, resulting in low washing efficiency, high solvent consumption, and impurity removal effect far lower than the multi-stage continuous ultrasonic washing process of this invention.

Claims

1. A preparation process for carboxylated carbon nanotube-modified porous polyetheretherketone, characterized in that, Includes the following steps: S1 Premixing: 0.3-1.5 parts by weight of carboxylated carbon nanotubes are premixed with 7.5-11 parts by weight of pore-forming agent to obtain a uniform composite powder; wherein, the pore-forming agent includes 5-8 parts by weight of polyethylene glycol and 2.5-3 parts by weight of volatile compound, wherein the volatile compound is azodicarbonamide and ammonium bicarbonate in a mass ratio of 1:(1-3); S2 Melt Blending and Extrusion Granulation: 100 parts of crude polyether ether ketone (PEEK) product and the composite powder are added to a twin-screw extruder. The melt is extruded through the die head, granulated underwater, and then subjected to slow cooling and heat preservation treatment at 120-150℃ for 30-60 minutes to obtain PEEK particles containing porogen and carboxylated carbon nanotubes. S3 removes porogen: S3-1 Hot water pre-dissolution: Polyetheretherketone (PEEK) particles are transported to a hot water washing tank containing hot deionized water at 60-70°C. Mechanical stirring is applied, and the particles remain for 15-20 minutes. S3-2 Ultrasonic-assisted pore-forming cleaning: Polyetheretherketone (PEEK) particles pre-dissolved in hot water are transferred to an ultrasonic treatment tank containing room-temperature deionized water. Ultrasonic waves with a frequency of 15-25kHz and a power of 100-200W are applied for 5-10 minutes. S3-3 Dehydration and Pre-drying: After centrifugation to dehydrate the cleaned polyether ether ketone particles, they are dried in circulating hot air at 80-100℃ until the moisture content is less than 0.5wt.%, to obtain carboxylated carbon nanotube modified porous polyether ether ketone.

2. The preparation process of carboxylated carbon nanotube-modified porous polyetheretherketone as described in claim 1, characterized in that, In step S1, during premixing, the mixture is premixed at room temperature for 15-20 minutes, and nitrogen gas is introduced during the premixing process; the carboxylated carbon nanotubes have a diameter of 10-20 nm, a length of 10-30 μm, and a carboxyl content of 1-2 mmol / g; in the porogen, the M of polyethylene glycol is... n =10000-20000.

3. The preparation process of carboxylated carbon nanotube-modified porous polyetheretherketone as described in claim 1, characterized in that, In step S2, before the crude polyetheretherketone (PEEK) is added to the twin-screw extruder, it is first vacuum dried at 120-150℃ for more than 4 hours to remove moisture. The parameters of each section of the twin-screw extruder are set as follows: Zone 1 temperature 260-290℃, Zone 2 temperature 280-305℃, Zone 3 temperature 300-320℃, Zone 4 temperature 310-340℃, Die head temperature 310-340℃, screw speed 200-300rpm; Vacuum devolatilization section temperature 320-330℃, vacuum degree -0.09~-0.07MPa, duration 1-2min.

4. The preparation process of carboxylated carbon nanotube-modified porous polyether ether ketone as described in claim 1, characterized in that, In step S3-1, the mechanical stirring speed is 60-100 rpm.

5. A porous polyetheretherketone modified with carboxylated carbon nanotubes, characterized in that, It was prepared by the preparation process of carboxylated carbon nanotube modified porous polyether ether ketone as described in any one of claims 1-3.

6. The continuous purification process for carboxylated carbon nanotube-modified porous polyether ether ketone as described in claim 5, characterized in that, Includes the following steps: (1) Multi-stage continuous ultrasonic washing: Carboxylated carbon nanotubes modified porous polyether ether ketone are put into a continuous washing system. First, diphenyl sulfone is removed by two-stage acetone washing, and then sodium fluoride is removed by two-stage gradient water washing. Simultaneously, the adsorption, catalysis and ion exchange of the pore walls of carboxylated carbon nanotubes are utilized to achieve deep removal of impurities. The continuous washing system includes a primary acetone rough washing tower (1), a secondary acetone fine washing tower (2), a water washing and hydrolysis tower (3), and a water washing enhancement tower (4) connected sequentially by conveyors. Each of the primary acetone rough washing tower (1), secondary acetone fine washing tower (2), water washing and hydrolysis tower (3), and water washing enhancement tower (4) is equipped with a plate conveyor (5), a spray distributor (6), and an ultrasonic generator (7), and is also equipped with a feed inlet, a discharge outlet, a washing liquid inlet, and a washing liquid outlet. 5) The material tray adopts a porous sieve plate, and the spray distributor (6) is connected to the washing liquid inlet; the washing liquid inlet of the primary acetone coarse washing tower (1) is connected to the washing liquid outlet of the secondary acetone fine washing tower (2) through a pipeline, the washing liquid inlet of the secondary acetone fine washing tower (2) is connected to a fresh acetone feed pipe (18), the washing liquid inlet of the water washing and hydrolysis tower (3) is connected to the washing liquid outlet of the water washing enhancement tower (4) through a pipeline, and the washing liquid inlet of the water washing enhancement tower (4) is connected to a fresh ultrapure water feed pipe (22). (2) Post-processing and modification of materials: 1) Deep dehydration and drying: After centrifugation to remove water from the washed polyetheretherketone (PEEK) particles, they are dried in circulating hot air at 100-120℃ until the moisture content is below 0.1 wt.%. 2) Vacuum shaping treatment: The dried polyether ether ketone particles are kept at 120-140℃ and -0.08~-0.09MPa for 2-3 hours, and then discharged after natural cooling to room temperature to obtain the purified carboxylated carbon nanotube modified porous polyether ether ketone product.

7. The continuous purification process for carboxylated carbon nanotube-modified porous polyether ether ketone as described in claim 6, characterized in that, The specific process of multi-stage continuous ultrasonic washing is as follows: a) Primary acetone coarse washing tower (1): The recycled acetone washing liquid discharged from the secondary acetone fine washing tower (2) is used for spraying. The concentration of the recycled acetone washing liquid is 60-70wt.% and the temperature is 50-60℃. Ultrasonic waves of 20-25kHz and 150-200W are applied simultaneously. b) Secondary acetone washing tower (2): Fresh acetone is sprayed, with a concentration of ≥99wt.% and a temperature of 60-70℃. Ultrasonic waves of 25-30kHz and 200-300W are applied simultaneously. The discharged recycled acetone washing liquid is sent to the primary acetone coarse washing tower (1) for recycling as the spray washing liquid. c) Water washing hydrolysis tower (3): The recycled hot water discharged from the water washing enhancement tower (4) is sprayed with water at a temperature of 75-85℃, and ultrasonic waves of 30-35kHz and 300-400W are applied simultaneously. d) Water washing enhancement tower (4): Fresh ultrapure water at 85-95℃ is sprayed and ultrasonic waves at 30-35kHz and 200-300W are applied simultaneously; the discharged recycled hot water is sent to the water washing hydrolysis tower (3) as a spray washing liquid for recycling.

8. The continuous purification process for carboxylated carbon nanotube-modified porous polyether ether ketone as described in claim 7, characterized in that, The acetone washing liquid recycled from the secondary acetone washing tower (2) to the primary acetone rough washing tower (1) is filtered to remove solid impurities and then recycled. When the concentration of the recycled acetone washing liquid is less than 60 wt.%, the recycling is stopped and it is sent to the solvent distillation system for distillation purification until its concentration is ≥60 wt.%, and then recycled to the primary acetone rough washing tower (1).

9. The continuous purification process for carboxylated carbon nanotube-modified porous polyether ether ketone as described in claim 7, characterized in that, The hot water from the water washing enhancement tower (4) is recycled to the water washing hydrolysis tower (3), and after the metal ions are removed by filtration and ion exchange resin (21), it is recycled again.

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