Carbon fiber reinforced PEEK composite material as well as preparation method and application thereof

Abstract

The invention discloses a carbon fiber reinforced PEEK composite material as well as a preparation method and application thereof, and relates to the technical field of composite materials. The carbon fiber reinforced PEEK composite material is mainly prepared by mixing modified carbon fiber and PEEK resin according to a weight ratio of (15-20): 82; the modified carbon fiber is obtained by cleaning and drying carbon fiber, immersing the carbon fiber into a KH550 hydrolysis solution, stirring and reacting, and drying. The prepared carbon fiber reinforced PEEK composite material has the advantages of small density, high specific strength and small fiber orientation error, and can be used for preparing orthopedic implant stent raw materials or CT equipment supporting arm raw materials through 3D printing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite materials, in particular to a carbon fiber reinforced PEEK composite material and a preparation method and application thereof. BACKGROUND

[0002] Carbon fiber reinforced polyether ether ketone (CF / PEEK) composite material is a high-performance thermoplastic composite material with great potential. Because of its excellent high-temperature resistance, flame resistance, wear resistance, chemical corrosion resistance and biocompatibility, CF / PEEK has attracted great attention in the fields of aerospace, rail transportation, high-end medical treatment and the like at home and abroad. Although CF / PEEK thermoplastic composite material has excellent performance, the chemical inertness of the surface of carbon fiber and the hydrophobicity of PEEK lead to difficult bonding of the fiber and the matrix interface, and the poor interface performance affects the performance of the overall composite material, which needs to be modified.

[0003] In the prior art, patent CN 113322678 A discloses a surface modified carbon fiber and a modification method thereof. The method uses oxidized carbon fiber as a cathode, and a mixed solution containing imidazole ionic liquid, organic solvent, condensing agent and conductive agent as an electrolyte to perform electrochemical reaction. Under the action of the condensing agent, imidazole ions are covalently grafted on the surface of the carbon fiber. The interfacial shear strength of the carbon fiber grafted with imidazole ionic liquid is greatly improved compared with that of the unmodified carbon fiber. Patent CN 113501982 A discloses a preparation method of a carbon fiber reinforced PEEK composite material. The acyl chloride groups of the acyl chloride carbon fiber react with the terminal hydroxyl groups of PEEK to form chemical bonds, which strengthens the interfacial bonding strength between PEEK and carbon fiber and improves the wettability between carbon fiber and PEEK, i.e. enhances the interfacial compatibility of the carbon fiber PEEK composite material. Although the above patents can well solve the problems of strength, wettability and interfacial compatibility of the carbon fiber PEEK composite material, the strength, stability and durability of the composite material still need to be further improved. At the same time, in 3D printing, the performance of the raw material will affect the strength, stability and durability of the printed part.

[0004] Therefore, it is currently an urgent problem to be solved to prepare a carbon fiber reinforced PEEK composite material with high strength, high stability and high durability suitable for 3D printing. SUMMARY

[0005] In view of the above problems, the present application provides a carbon fiber reinforced PEEK composite material and a preparation method and application thereof. The carbon fiber reinforced PEEK composite material prepared by the present application has the advantages of small density, high specific strength and small fiber orientation error, and can be used for 3D printing to prepare orthopedic implant support raw materials or CT device support arm raw materials. The specific technical scheme is as follows: A carbon fiber reinforced PEEK composite material, which is mainly prepared by mixing modified carbon fiber and PEEK resin in a weight ratio of (15-20):82; the PEEK resin has a particle size of 150-200 μm and a melt flow rate of 30-40 g / 10 min at 380 ℃ / 5 kg; The preparation method of the modified carbon fiber is as follows: Step S1, wash the carbon fiber, dry in vacuum, and reserve; Step S2, mix anhydrous ethanol and deionized water in a volume ratio of (94-96):(4-6), stir uniformly, adjust the pH value to 4-4.5 with 0.1 mol / L hydrochloric acid solution, then add KH550 (γ-aminopropyl triethoxysilane) to prepare a KH550 hydrolysis solution with a mass concentration of 1.5-2.5%, and stand for 15-20 min, and reserve; Step S3, completely immerse the carbon fiber dried in step S1 in the KH550 hydrolysis solution and stir to react; Step S4, dry the carbon fiber obtained in step S3 by two-stage drying treatment, and the modified carbon fiber is obtained.

[0006] Further, the step S1 is as follows: place a carbon fiber bundle with a single fiber diameter of 7-10 μm and a length-diameter ratio of 500-1000 in anhydrous ethanol, and ultrasonically clean for 28-32 min at a power of 280-320 W, replace the anhydrous ethanol every 10 min during the cleaning, until the residual amount of oil stains and release agent on the surface of the carbon fiber bundle is ≤0.1 wt%, then dry to constant weight under the conditions of a vacuum degree of ≤-0.09 MPa and a temperature of 78-82 ℃, and reserve.

[0007] Further, in step S2, the stirring rate is 300-500 r / min, and the stirring time is 5-8 min.

[0008] Further, the step S3 is as follows: completely immerse the carbon fiber dried in step S1 in the KH550 hydrolysis solution, with the liquid surface being higher than the top end of the fiber by ≥5 cm, then stir to react in a constant-temperature water bath at 33-37 ℃ at a rate of 200-300 r / min for 1.2-1.8 h, after the reaction, hang the carbon fiber at an inclination angle of 30° to drain for 3-5 min, so that the thickness of the excess liquid film on the surface is ≤50 μm.

[0009] Further, in step S4, the two-stage drying treatment is as follows: First stage: place the carbon fiber obtained in step S3 in a forced air drying oven, dry at a temperature of 58-62 ℃ and a wind speed of 1.0-1.5 m / s for 55-65 min to evaporate the surface free solvent; The second stage is to increase to 125-135 DEG C at a heating rate of 3-6 DEG C / min, and to keep the temperature for 1.8-2.2 h, so that the condensation reaction between the molecules of KH550 occurs, and a continuous siloxane film is formed.

[0010] The application further provides a preparation method of the carbon fiber reinforced PEEK composite material, which comprises the following steps: short-cut modified carbon fibers with a diameter of 7±0.5 μm and a length of 5±0.5 mm and PEEK resin are dried respectively, then uniformly mixed and stirred, and then extrusion molding is performed to obtain the carbon fiber reinforced PEEK composite material.

[0011] Further, the drying is that the modified carbon fibers are air-dried at 78-82 DEG C until the water content is less than or equal to 0.05 wt%, and the PEEK resin is dried in a vacuum drying oven under the conditions of 120±5 DEG C and a vacuum degree less than or equal to-0.09 MPa until the water content is less than or equal to 0.02 wt%.

[0012] Further, the rotating speed of the mixing and stirring is 200-300 r / min, and the mixing time is 15-20 min.

[0013] Further, the extrusion molding is performed in the mode of double-screw extrusion. The screw structure is that a built-in double screw (with a diameter of 12-15 mm and a length-diameter ratio of 25:1) is adopted, and a three-section thread combination is adopted: a feeding section (with a pitch of 30 mm and a lead of 25 mm), a melting and mixing section (with a pitch of 20 mm and containing three groups of reverse kneading blocks), and a metering and extruding section (with a pitch of 15 mm and a compression ratio of 3:1); The extrusion temperature gradient is that five temperature control zones are arranged along the axial direction of the screw, and the temperature control zones from the feeding port to the nozzle are 280±5 DEG C (resin preheating)→320±5 DEG C (initial melting)→360±5 DEG C (complete melting)→380±5 DEG C (mixing and homogenization)→390±5 DEG C (nozzle discharge); The rotating speed of the screw and the extrusion rate are that the rotating speed of the screw is 80-120 r / min, and the corresponding extrusion rate is 1.5-3.0 g / min.

[0014] The application further provides an application of the carbon fiber reinforced PEEK composite material as a raw material of an orthopedic implant support or a CT equipment support arm.

[0015] The method for preparing the CT equipment support arm by taking the carbon fiber reinforced PEEK composite material as a raw material through 3D printing is as follows: (1) the carbon fiber reinforced PEEK composite material is prepared into 3D printing material through a double-screw extruder; (2) Design the 3D model of the CT device support arm by modeling software and convert it into a layered path file, then import it into the 3D printer, and the layered path planning is as follows: the layer thickness is 0.1-0.2 mm, the scanning path of each layer is a bidirectional cross grid (the angle is alternately 45° / 135°), the path spacing is 0.4-0.6 mm (which is 1.2-1.5 times the nozzle diameter), and the edge contour adopts a single closed loop path (the line width is increased by 10% compared with the internal path), so as to reduce the stress concentration between layers; (3) Set the printer parameters: the nozzle moving speed is 30-60 mm / s, which is linked with the extrusion rate (the speed / rate ratio is kept at 20-25 mm·min / g); the forming chamber temperature is controlled at 180±5℃; the printer is driven by the program control motion platform to print the material according to the layered path file; (4) Put the printed part prepared in step (3) into a vacuum annealing furnace, heat it to 200±5℃ at a rate of 5℃ / min, keep it at this temperature for 2h, then cool it to below 80℃ at a rate of 3℃ / min, and eliminate the internal stress; then slightly polish the edge of the printed part with a diamond grinding wheel (particle size 120 mesh) (remove ≤0.1mm surface layer), and ensure that the surface roughness Ra≤1.6μm, so as to obtain the CT device support arm.

[0016] Compared with the prior art, the beneficial effects of the present application are: 1. The carbon fiber reinforced PEEK composite material of the present application is prepared by modifying the carbon fiber with KH550 as a coupling agent, and then extruding the modified carbon fiber and PEEK, which has the advantages of small density (density≤1.5g / cm³), high specific strength (specific strength≥200MPa / (g / cm³)), and small fiber orientation error (fiber orientation error≤5°), which is superior to the carbon fiber reinforced PEEK composite material prepared by traditional process (the specific strength of traditional material is <150MPa / g / cm³, and the fiber orientation error is >10°), and can be used for 3D printing to prepare orthopedic implant support raw materials or CT device support arm raw materials.

[0017] 2. The carbon fiber reinforced PEEK composite material prepared by the present application is used for 3D printing to prepare a CT device support arm, and since the carbon fiber reinforced PEEK composite material has good matching with the layered path, the dispersion ratio of the carbon fiber monofilament of the prepared printed part is ≥90%, the size of the agglomerate is ≤50μm (each agglomerate contains ≤10 fibers), the tensile strength of the printed part along the deposition direction is ≥180MPa (ASTM D638 standard), the bending strength is ≥220MPa (ASTM D790 standard), and the elongation at break is ≥2.5%, which meets the mechanical requirements of the lightweight structure of medical devices. BRIEF DESCRIPTION OF DRAWINGS

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0019] Figure 1 This is a physical image of the Y-shaped support frame of the CT device prepared in Example 4. Detailed Implementation

[0020] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0021] Example 1 A carbon fiber reinforced PEEK composite material is mainly composed of modified carbon fiber and PEEK resin mixed in a weight ratio of 15:82; the particle size of the PEEK resin is 150μm, and the melt flow rate at 380℃ / 5kg is 30g / 10min. The preparation method of carbon fiber reinforced PEEK composite material includes the following steps: (1) First, chopped modified carbon fibers with a diameter of 6.5 μm and a length of 4.5 mm were dried at 78 °C with forced air drying until the moisture content was 0.05 wt%; PEEK resin was placed in a vacuum drying oven and dried at 115 °C and a vacuum of -0.09 MPa until the moisture content was 0.02 wt%; (2) The dried chopped modified carbon fibers and PEEK resin were mixed and stirred at 200 r / min for 15 min, and then extruded to obtain carbon fiber reinforced PEEK composite material. The extrusion molding was carried out by twin-screw extrusion, and the specific parameters are as follows: Screw structure: The nozzle has a built-in twin screw (12mm diameter, 25:1 length-to-diameter ratio), which adopts a three-section screw combination: feeding section (30mm pitch, 25mm lead), melt mixing section (20mm pitch, including 3 sets of reverse kneading blocks), and metering extrusion section (15mm pitch, 3:1 compression ratio). The extrusion temperature gradient is as follows: five temperature control zones are set along the screw axis, from the feed port to the nozzle: 275℃ (resin preheating) → 315℃ (initial melting) → 355℃ (complete melting) → 375℃ (mixing and homogenization) → 385℃ (nozzle discharge); the screw speed and extrusion rate are as follows: screw speed 80r / min, corresponding to an extrusion rate of 1.5g / min.

[0022] The preparation method of modified carbon fiber is as follows: Step S1: Place the carbon fiber bundle with a single filament diameter of 7μm and an aspect ratio of 500 in anhydrous ethanol and ultrasonically clean it at a power of 280W for 28 minutes, replacing the anhydrous ethanol every 10 minutes until the oil and release agent residue on the surface of the carbon fiber bundle is 0.1wt%. Then dry it to constant weight under a vacuum of -0.09MPa and a temperature of 78℃ for later use. Step S2: Mix anhydrous ethanol and deionized water at a volume ratio of 94:6 at a rate of 300 r / min for 5 min, adjust the pH value to 4 with 0.1 mol / L hydrochloric acid solution, then add KH550 (γ-aminopropyltriethoxysilane) to prepare a KH550 hydrolysis solution with a mass concentration of 1.5%, let stand for 15 min, and set aside for later use. Step S3: Immerse the dried carbon fiber from step S1 completely in the KH550 hydrolysis solution, with the liquid level 5 cm above the top of the fiber. Then, stir the reaction at a rate of 200 r / min in a constant temperature water bath at 33°C for 1.2 h. After the reaction is completed, hang the carbon fiber at a 30° angle to drain for 3 min, so that the excess liquid film thickness on the surface is 50 μm. Step S4: The carbon fiber obtained from the reaction in step S3 is subjected to a two-stage drying process to obtain the modified carbon fiber.

[0023] The two-stage drying process is as follows: First stage: The carbon fiber obtained from step S3 is placed in a forced-air drying oven and dried at 58°C and 1.0 m / s wind speed for 55 min to evaporate the free solvent on the surface. Second stage: The temperature is increased to 125℃ at a rate of 3℃ / min and held for 1.8h to allow the KH550 molecules to undergo a condensation reaction and form a continuous siloxane film.

[0024] Example 2 A carbon fiber reinforced PEEK composite material is mainly composed of modified carbon fiber and PEEK resin mixed in a weight ratio of 20:82; the particle size of the PEEK resin is 200 μm, and the melt flow rate at 380℃ / 5kg is 40 g / 10 min. The preparation method of carbon fiber reinforced PEEK composite material includes the following steps: (1) First, chopped modified carbon fibers with a diameter of 7.5 μm and a length of 5.5 mm were dried at 82 °C with forced air drying until the moisture content was 0.05 wt%; then, PEEK resin was placed in a vacuum drying oven and dried at 125 °C and a vacuum of -0.09 MPa until the moisture content was 0.02 wt%. (2) The dried chopped modified carbon fibers and PEEK resin were mixed and stirred at 300 r / min for 20 min, and then extruded to obtain carbon fiber reinforced PEEK composite material. The extrusion molding was carried out by twin-screw extrusion, and the specific parameters are as follows: Screw structure: The nozzle has a built-in twin screw (15mm diameter, 25:1 length-to-diameter ratio), which adopts a three-section screw combination: feeding section (30mm pitch, 25mm lead), melt mixing section (20mm pitch, including 3 sets of reverse kneading blocks), and metering extrusion section (15mm pitch, 3:1 compression ratio). The extrusion temperature gradient is as follows: five temperature control zones are set along the screw axis, from the feed port to the nozzle, in the following order: 285℃ (resin preheating) → 325℃ (initial melting) → 365℃ (complete melting) → 385℃ (mixing and homogenization) → 395℃ (nozzle discharge); the screw speed and extrusion rate are as follows: screw speed 120r / min, corresponding to an extrusion rate of 3.0g / min.

[0025] The preparation method of modified carbon fiber is as follows: Step S1: Place the carbon fiber bundle with a single filament diameter of 10μm and an aspect ratio of 1000 in anhydrous ethanol and ultrasonically clean it at a power of 320W for 32 minutes, replacing the anhydrous ethanol every 10 minutes until the oil and release agent residue on the surface of the carbon fiber bundle is 0.1wt%. Then dry it to constant weight under a vacuum of -0.09MPa and a temperature of 82℃ for later use. Step S2: Mix anhydrous ethanol and deionized water at a volume ratio of 96:4 at a speed of 500 r / min for 8 min, and adjust the pH value to 4.5 with 0.1 mol / L hydrochloric acid solution. Then add KH550 (γ-aminopropyltriethoxysilane) to prepare a KH550 hydrolysis solution with a mass concentration of 2.5%, let it stand for 20 min, and set aside for later use. Step S3: Immerse the dried carbon fiber from step S1 completely in the KH550 hydrolysis solution, with the liquid level 5 cm above the top of the fiber. Then, stir the reaction at a rate of 300 r / min for 1.8 h in a constant temperature water bath at 37 °C. After the reaction is complete, hang the carbon fiber at a 30° angle to drain for 5 min, so that the excess liquid film thickness on the surface is 50 μm. Step S4: The carbon fiber obtained from the reaction in step S3 is subjected to a two-stage drying process to obtain the modified carbon fiber.

[0026] The two-stage drying process is as follows: First stage: The carbon fiber obtained from step S3 is placed in a forced-air drying oven and dried at 62°C and 1.5 m / s wind speed for 65 min to evaporate the free solvent on the surface. Second stage: The temperature is increased to 135℃ at a rate of 6℃ / min and held for 2.2h to allow the KH550 molecules to undergo a condensation reaction and form a continuous siloxane film.

[0027] Example 3 A carbon fiber reinforced PEEK composite material is mainly composed of modified carbon fiber and PEEK resin mixed in a weight ratio of 18:82; the particle size of the PEEK resin is 170 μm, and the melt flow rate at 380℃ / 5 kg is 35 g / 10 min. The preparation method of carbon fiber reinforced PEEK composite material includes the following steps: (1) First, chopped modified carbon fibers with a diameter of 7 μm and a length of 5 mm were dried at 80 °C with forced air until the moisture content was 0.05 wt%; then, PEEK resin was placed in a vacuum drying oven and dried at 120 °C and a vacuum of -0.09 MPa until the moisture content was 0.02 wt%. (2) The dried chopped modified carbon fibers and PEEK resin were mixed and stirred at 250 r / min for 18 min, and then extruded to obtain carbon fiber reinforced PEEK composite material. The extrusion molding was carried out by twin-screw extrusion, and the specific parameters are as follows: Screw structure: The nozzle has a built-in twin screw (15mm diameter, 25:1 length-to-diameter ratio), which adopts a three-section screw combination: feeding section (30mm pitch, 25mm lead), melt mixing section (20mm pitch, including 3 sets of reverse kneading blocks), and metering extrusion section (15mm pitch, 3:1 compression ratio). The extrusion temperature gradient is as follows: five temperature control zones are set along the screw axis, from the feed port to the nozzle: 280℃ (resin preheating) → 320℃ (initial melting) → 360℃ (complete melting) → 380℃ (mixing and homogenization) → 390℃ (nozzle discharge); the screw speed and extrusion rate are as follows: the screw speed is 100 r / min, and the corresponding extrusion rate is 2 g / min.

[0028] The preparation method of modified carbon fiber is as follows: Step S1: Place the carbon fiber bundle with a single filament diameter of 8μm and an aspect ratio of 800 in anhydrous ethanol and ultrasonically clean it at a power of 300W for 30 minutes, replacing the anhydrous ethanol every 10 minutes until the oil and release agent residue on the surface of the carbon fiber bundle is 0.1wt%. Then dry it to constant weight under a vacuum of -0.09MPa and a temperature of 80℃ for later use. Step S2: Mix anhydrous ethanol and deionized water at a volume ratio of 95:5 at a speed of 400 r / min for 6 min, adjust the pH value to 4.2 with 0.1 mol / L hydrochloric acid solution, then add KH550 (γ-aminopropyltriethoxysilane) to prepare a 2% KH550 hydrolysis solution, let it stand for 18 min, and set aside for later use. Step S3: Immerse the dried carbon fiber from step S1 completely in the KH550 hydrolysis solution, with the liquid level 5 cm above the top of the fiber. Then, stir the reaction at a rate of 250 r / min in a constant temperature water bath at 35°C for 1.6 h. After the reaction is completed, hang the carbon fiber at a 30° angle to drain for 4 min, so that the excess liquid film thickness on the surface is 50 μm. Step S4: The carbon fiber obtained from the reaction in step S3 is subjected to a two-stage drying process to obtain the modified carbon fiber.

[0029] The two-stage drying process is as follows: First stage: The carbon fiber obtained from step S3 is placed in a forced-air drying oven and dried at 60°C and 1.2 m / s wind speed for 60 min to evaporate the free solvent on the surface; Second stage: Increase the temperature to 130℃ at a rate of 4℃ / min and hold for 2 hours to allow the KH550 molecules to undergo a condensation reaction and form a continuous siloxane film.

[0030] Example 4 The method for 3D printing to fabricate the Y-shaped support frame for CT equipment is as follows: (1) The carbon fiber reinforced PEEK composite material (with added color masterbatch for color matching) prepared in Example 3 was processed into 3D printing material by twin-screw extrusion. (2) Design the Y-shaped support frame 3D model of the CT equipment using modeling software and convert it into a layered path file, and then import it into the 3D printer; the layered path is planned as follows: the layer thickness is 0.1mm, the scanning path of each layer is a bidirectional cross grid (45° / 135° angle alternating), the path spacing is 0.4mm (1.2 times the nozzle diameter), and the edge contour adopts a single closed loop path (the line width is 10% greater than the internal path) to reduce interlayer stress concentration; (3) Set printer parameters: nozzle moving speed 30mm / s, which is adjusted in conjunction with the extrusion rate (speed / rate ratio is kept at 20mm·min / g); the forming chamber temperature is controlled at 180℃; the printer prints the material according to the layer path file under the drive of the program-controlled motion platform. (4) Place the printed part obtained in step (3) in a vacuum annealing furnace, heat it to 200℃ at 5℃ / min, hold it for 2 hours, and then cool it down to 75℃ at 3℃ / min to eliminate internal stress; then use a diamond grinding wheel (120 mesh) to lightly grind the edge of the printed part (remove ≤0.1mm surface layer) to ensure that the surface roughness Ra≤1.6μm, thus obtaining the Y-shaped support frame of the CT equipment. Its physical picture is as follows. Figure 1 As shown, the overall appearance is white because color masterbatch was added for color matching.

[0031] Performance testing: The density, specific strength, fiber orientation error, fiber orientation angle, proportion of oriented arrangement area, and thickness of the interfacial bonding layer of the carbon fiber reinforced PEEK composite materials prepared in Examples 1 and 2 were tested. The results are shown in Table 1. Table 1 Material properties of each embodiment Table 1 shows that the carbon fiber reinforced PEEK composite material prepared by this invention has a density ≤1.5g / cm³, a specific strength ≥200MPa / (g / cm³), a fiber orientation error ≤5°, a fiber orientation angle of about 45°, an oriented arrangement area of ​​about 92%, and an interface bonding layer thickness of about 5μm. It is superior to the carbon fiber reinforced PEEK composite material prepared by traditional processes and can be used for 3D printing to prepare raw materials for orthopedic implant stents or CT equipment support arms.

[0032] Comparative Example 1: The method for 3D printing to prepare a Y-shaped support frame for a CT device is the same as in Example 4, except that the layer path planning is as follows: the layer thickness is 0.5 mm, the scanning path of each layer is a bidirectional cross grid (interleaving angles of 50° / 145°), the path spacing is 0.7 mm (1.2 times the nozzle diameter), and the edge contour adopts a single-loop closed path (the line width is increased by 10% compared with the internal path).

[0033] The performance of the Y-shaped support frame for the CT equipment prepared in Example 4 and Comparative Example 1 was tested: carbon fiber monofilament dispersion ratio, agglomerate size (each agglomerate contains ≤10 fibers), tensile strength along the deposition direction (ASTM D638 standard), flexural strength (ASTM D790 standard), and elongation at break. The results are shown in Table 2. Table 2. Performance comparison of the Y-shaped support frame of the CT equipment prepared in Example 4 and Comparative Example 1 Table 2 shows that the carbon fiber reinforced PEEK composite material prepared by this invention has a good match with the layering path, which makes the printed parts have excellent mechanical properties and meet the mechanical requirements of lightweight medical equipment structures.

[0034] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A carbon fiber reinforced PEEK composite material, characterized in that, The composite material is mainly made of modified carbon fiber and PEEK resin mixed in a weight ratio of (15-20):82; The method for preparing the modified carbon fiber is as follows: Step S1: Wash the carbon fiber, vacuum dry it, and set it aside. Step S2: Mix anhydrous ethanol and deionized water at a volume ratio of (94-96):(4-6) and stir until homogeneous. Adjust the pH value to 4-4.5, and then add KH550 to prepare a KH550 hydrolysis solution with a mass concentration of 1.5-2.5%. Step S3: Immerse the dried carbon fiber from step S1 completely in the KH550 hydrolysis solution and stir to react. Step S4: The carbon fiber obtained from the reaction in step S3 is subjected to a two-stage drying process to obtain the modified carbon fiber.

2. The carbon fiber reinforced PEEK composite material according to claim 1, characterized in that, Step S1 is as follows: Place the carbon fiber bundle in anhydrous ethanol and ultrasonically clean it at a power of 280-320W for 28-32 minutes, replacing the anhydrous ethanol every 10 minutes until the oil and release agent residue on the surface of the carbon fiber bundle is ≤0.1wt%. Then dry it to constant weight under a vacuum of ≤-0.09MPa and a temperature of 78-82℃ for later use.

3. The carbon fiber reinforced PEEK composite material according to claim 1, characterized in that, In step S2, the stirring rate is 300-500 r / min and the stirring time is 5-8 min.

4. The carbon fiber reinforced PEEK composite material according to claim 1, characterized in that, Step S3 is as follows: The carbon fibers dried in step S1 are completely immersed in the KH550 hydrolysis solution, with the liquid level ≥5cm above the top of the fiber. Then, the mixture is stirred in a constant temperature water bath at 33-37℃ at a rate of 200-300r / min for 1.2-1.8h. After the reaction is completed, the carbon fibers are hung to drain.

5. The carbon fiber reinforced PEEK composite material according to claim 1, characterized in that, In step S4, the two stages of drying are as follows: First stage: Place the carbon fiber obtained from step S3 in a forced-air drying oven and dry it at 58-62℃ and 1.0-1.5m / s wind speed for 55-65 minutes; Second stage: Increase the temperature to 125-135℃ at a rate of 3-6℃ / min, and hold for 1.8-2.2 hours.

6. A method for preparing a carbon fiber reinforced PEEK composite material as described in any one of claims 1-5, characterized in that, The process includes the following steps: first, the modified carbon fiber and PEEK resin are dried separately, then mixed and stirred evenly, and then extruded to obtain carbon fiber reinforced PEEK composite material.

7. The method for preparing a carbon fiber reinforced PEEK composite material according to claim 6, characterized in that, The drying process involves drying the modified carbon fiber to a moisture content of ≤0.05wt% and drying the PEEK resin to a moisture content of ≤0.02wt%.

8. The method for preparing a carbon fiber reinforced PEEK composite material according to claim 6, characterized in that, The mixing speed is 200-300 r / min, and the mixing time is 15-20 min.

9. The method for preparing a carbon fiber reinforced PEEK composite material according to claim 6, characterized in that, The extrusion molding is carried out using a twin-screw extrusion method. The extrusion temperature gradient is as follows: five temperature control zones are set along the screw axis, from the feed port to the nozzle, in the following order: 280±5℃→320±5℃→360±5℃→380±5℃→390±5℃; the screw speed and extrusion rate are: screw speed 80-120 r / min, corresponding to an extrusion rate of 1.5-3.0 g / min.

10. The use of the carbon fiber reinforced PEEK composite material as described in any one of claims 1-5 or the composite material prepared by the preparation method as described in any one of claims 6-9 as a raw material for orthopedic implant stents / CT equipment support arms.

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