Preparation method of high-strength carbon fiber composite material

Abstract

The invention relates to the field of preparation and production of carbon fibers, in particular to a preparation method of a high-strength carbon fiber composite material. Comprising the following steps: S1, raw material preparation, S2, carbon fiber surface graded modification, S21, surface ultrasonic treatment, S22, electrophoretic deposition loading, S23, carbon nanotube in-situ growth, S3, preform weaving, S4, resin matrix modification, S41, resin blending, S42, self-repairing agent doping, and S5, composite material molding. According to the preparation method disclosed by the invention, the surface of the carbon fiber is subjected to graded modification, polar groups are introduced through ultrasonic treatment, then graphene oxide is subjected to electrophoretic deposition, and finally carbon nanotubes grow in situ to form a chemical bonding and physical interlocking synergistic interface, so that the bonding force between the carbon fiber and a resin matrix is greatly enhanced; and the dicyclopentadiene and urea resin microcapsule self-repairing agent is doped into the resin matrix, so that the service life of the material is prolonged, and the material not only has high strength and high toughness, but also has a self-repairing function, so that the maintenance and replacement cost is effectively reduced.

Description

Technical Field

[0001] The present invention relates to the field of carbon fiber preparation and production, and in particular to a method for preparing a high-strength carbon fiber composite material. Background Art

[0002] Carbon fiber is a new type of fiber material with a carbon content of more than 90%. It has many remarkable properties. It is lighter than aluminum, but much stronger than steel. It also has many advantages such as high temperature resistance, friction resistance, corrosion resistance, electrical conductivity and thermal conductivity. In the aerospace field, carbon fiber is an indispensable key material. Aircraft manufacturers use carbon fiber to manufacture wings, fuselages and other components, which greatly reduces the weight of aircraft, improves fuel efficiency and reduces operating costs. In the automotive industry, high-performance sports cars use carbon fiber bodies, which not only reduces vehicle weight, improves acceleration performance and handling, but also increases vehicle range. In the sporting goods industry, high-end bicycle frames, golf clubs, tennis rackets, etc. are made of carbon fiber to provide athletes with better performance and experience. Carbon fiber also plays an important role in building reinforcement, wind power generation, medical equipment and other fields.

[0003] However, traditional carbon fiber composites mainly focus on optimizing the manufacturing processes of autoclave and resin transfer molding (RTM) and material ratios, which leads to insufficient bonding strength at the interface between the carbon fiber and the resin matrix, prone to delamination, low interlaminar shear strength, and after being damaged, these materials are usually unable to self-repair. The expansion of cracks will significantly reduce the mechanical properties of the composite material, shorten its service life, and increase maintenance and replacement costs. Therefore, the present invention proposes a method for preparing a high-strength carbon fiber composite material. The carbon fiber composite material prepared by this method effectively solves the technical difficulties in the traditional preparation process. Summary of the Invention

[0004] In order to overcome the problems of weak interface bonding between carbon fiber and resin matrix, easy delamination, low interlaminar shear strength, and inability to self-repair after damage in traditional carbon fiber composites.

[0005] The technical solution of the present invention is: a method for preparing a high-strength carbon fiber composite material, comprising the following steps:

[0006] S1: Raw material preparation, including carbon fiber, graphene oxide, multi-walled carbon nanotubes, epoxy resin, bismaleimide, dicyclopentadiene@urea-formaldehyde resin microcapsules, nickel-based nanoparticles, nitric acid solution, and imidazole curing accelerator;

[0007] S2: carbon fiber surface graded modification;

[0008] S21: Surface ultrasonic treatment: immerse the carbon fiber in a 3% nitric acid solution and perform ultrasonic treatment at 40 kHz for 30 minutes to remove surface impurities and introduce carboxyl and hydroxyl groups to obtain clean and surface-polarized carbon fiber;

[0009] S22: electrophoretic deposition loading, using electrophoretic deposition method, under the action of a voltage of 50V, immersing the clean carbon fiber in a graphene oxide dispersion for electrophoretic deposition for 5 minutes, utilizing the electrostatic adsorption effect to form a uniform graphene oxide coating layer on the surface of the carbon fiber, thereby obtaining a carbon fiber loaded with graphene oxide;

[0010] S23: In situ growth of carbon nanotubes: hydrogen was first introduced into the chemical vapor deposition furnace to reduce nickel-based nanoparticles for 30 minutes, and then a mixed gas was introduced to catalyze the growth of multi-walled carbon nanotubes using the nickel-based nanoparticles for 10 minutes, resulting in nano-modified carbon fibers with vertical multi-walled carbon nanotube arrays on the surface.

[0011] S3: Weaving a preform, using an automatic weaving machine to weave the modified carbon fiber obtained by pretreatment as a raw material into a 0° / 90° orthogonal three-directional structure to obtain a carbon fiber preform;

[0012] S4: resin matrix modification;

[0013] S41: Resin blending: epoxy resin and bismaleimide are poured into a blender in a mass ratio of 7:3, and then 0.5 wt % of an imidazole curing accelerator is added and uniformly stirred to obtain a blended resin;

[0014] S42: Self-healing agent incorporation: accurately weigh dicyclopentadiene@urea-formaldehyde resin microcapsules according to 2 wt% of the total mass of the resin, and put them into a planetary mixer together with the blended resin to be fully mixed to obtain a modified resin matrix;

[0015] S5: Composite material molding: preheat the mold to 80°C, then place the carbon fiber preform into the mold, and slowly inject the modified resin under a pressure of 0.3MPa to ensure that it fully impregnates the preform. After impregnation, it is cured in stages to obtain a carbon fiber composite material.

[0016] Preferably, the sheet size of graphene oxide in S1 is 1-5 μm, the diameter of multi-walled carbon nanotubes is 20-30 nm, the particle size of dicyclopentadiene@urea-formaldehyde resin microcapsules is 50-100 μm, and the particle size of nickel-based nanoparticles is 50 nm.

[0017] Preferably, dicyclopentadiene@urea-formaldehyde resin microcapsules are prepared using microfluidic technology, and the preparation steps are as follows: urea and formaldehyde are mixed, deionized water is added to dissolve them, the pH is adjusted to 8 with alkaline solution, and the mixture is stirred at 70°C for 2 hours to prepare a urea-formaldehyde resin prepolymer aqueous solution and diluted, dicyclopentadiene and an emulsifier are evenly mixed to obtain an oil phase solution, a microfluidic chip containing two fluid channels is constructed, one channel is for the dicyclopentadiene oil phase solution, and the other channel is for the urea-formaldehyde resin prepolymer aqueous solution, the flow rate ratio is precisely controlled to form stable droplets, a catalyst and a curing agent are added, the pH is adjusted to 3, the temperature is raised to 65°C and the reaction is performed for 4 hours to allow the urea-formaldehyde resin to solidify and coat the dicyclopentadiene, and finally the dicyclopentadiene@urea-formaldehyde resin microcapsules are obtained by filtering, washing, and drying.

[0018] Preferably, the preparation steps of the graphene oxide dispersion in S22 are: adding graphene oxide powder to deionized water to prepare a preliminary solution, then slowly adding dilute hydrochloric acid to adjust the pH value to 4, and continuously stirring the solution, then adding 0.1M potassium chloride electrolyte solution, stirring thoroughly and then ultrasonically treating to uniformly disperse the graphene oxide in the solution to obtain a graphene oxide dispersion with a concentration of 0.5 mg / mL, a pH value of 4 and containing 0.1M potassium chloride electrolyte.

[0019] Preferably, the growth condition of the chemical vapor deposition furnace in S23 is set to 650° C., and the mixed gas used is ethylene and hydrogen in a ratio of 4:1.

[0020] Preferably, the porosity of the carbon fiber preform prepared in S3 is 25%-30%.

[0021] Preferably, the imidazole curing accelerator in S41 includes but is not limited to 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1-vinylimidazole and 1-cyanoethyl-2-methylimidazole.

[0022] Preferably, the speed range of the stirrer in S41 is controlled within 400-600 r / min, the initial stirring time is controlled within 5-10 minutes, and the secondary stirring time is controlled within 20-30 minutes.

[0023] Preferably, the rotation speed range of the planetary mixer in S42 is controlled within 600-1000 r / min, and the stirring time is controlled within 10-15 minutes.

[0024] Beneficial effects of the present invention:

[0025] The high-strength carbon fiber composite material produced by the present invention is modified by graded surface modification of carbon fiber, firstly introducing polar groups by ultrasonic treatment, then electrophoretically depositing graphene oxide, and finally in situ growing carbon nanotubes to form a chemically bonded and physically interlocked synergistic interface, which greatly enhances the bonding force between carbon fiber and resin matrix, effectively solves the problems of easy delamination and low interlaminar shear strength, and enables the composite material to withstand greater external forces without interface failure. In addition, by incorporating dicyclopentadiene@urea-formaldehyde resin microcapsule self-healing agent into the resin matrix, when the material is damaged and cracks are generated, the microcapsules rupture and release the repair agent to achieve local self-healing, significantly delaying the damage of crack propagation to the mechanical properties of the material and extending the service life of the material. In addition, a three-dimensional woven preform is used to control a reasonable porosity, which is conducive to sufficient resin impregnation, further improving the overall performance of the material. Compared with traditional materials, this material not only has high strength and high toughness, but also has a self-healing function, thereby effectively reducing the cost of maintenance and replacement. DETAILED DESCRIPTION

[0026] The present invention will be further described below with reference to the embodiments.

[0027] Example 1

[0028] A method for preparing a high-strength carbon fiber composite material, the preparation steps of which are as follows:

[0029] S1: Raw material preparation, including carbon fiber, graphene oxide, multi-walled carbon nanotubes, epoxy resin, bismaleimide, dicyclopentadiene@urea-formaldehyde resin microcapsules, nickel-based nanoparticles, nitric acid solution, and imidazole curing accelerator;

[0030] S2: carbon fiber surface graded modification;

[0031] S21: Surface ultrasonic treatment: immerse the carbon fiber in a 3% nitric acid solution and perform ultrasonic treatment at 40 kHz for 30 minutes to remove surface impurities and introduce carboxyl and hydroxyl groups to obtain clean and surface-polarized carbon fiber;

[0032] S22: electrophoretic deposition loading, using electrophoretic deposition method, under the action of a voltage of 50V, immersing the clean carbon fiber in a graphene oxide dispersion for electrophoretic deposition for 5 minutes, utilizing the electrostatic adsorption effect to form a uniform graphene oxide coating layer on the surface of the carbon fiber, thereby obtaining a carbon fiber loaded with graphene oxide;

[0033] S23: In situ growth of carbon nanotubes: At 650°C, hydrogen (H2) was first introduced into a chemical vapor deposition furnace to reduce nickel-based nanoparticles for 30 minutes. Subsequently, a gas mixture of ethylene (C2H4) and hydrogen (H2) with a volume ratio of 4:1 was switched to the nickel-based nanoparticles to catalyze the growth of multi-walled carbon nanotubes for 10 minutes, resulting in nano-modified carbon fibers with vertical multi-walled carbon nanotube arrays on the surface.

[0034] S3: Weaving a preform, using an automatic weaving machine to weave the modified carbon fiber obtained by pretreatment into a 0° / 90° orthogonal three-dimensional structure to obtain a carbon fiber preform with a porosity of 25%;

[0035] S4: resin matrix modification;

[0036] S41: Resin blending: epoxy resin and bismaleimide are poured into a blender in a mass ratio of 7:3, the blender speed is controlled at 400 r / min, and the initial stirring is performed for 5 minutes. Then, 0.5 wt% of 2-ethyl-4-methylimidazole is added, and the secondary stirring time is controlled at 20 minutes. After uniform stirring, a blended resin is obtained;

[0037] S42: Self-healing agent incorporation: Dicyclopentadiene@urea-formaldehyde resin microcapsules are accurately weighed according to 2 wt% of the total mass of the resin, and are put into a planetary mixer together with the blended resin. The speed of the planetary mixer is controlled at 600 r / min, and the mixture is fully stirred for 10 minutes to obtain a modified resin matrix;

[0038] S5: Composite material molding: preheat the mold to 80°C, then place the carbon fiber preform into the mold, and slowly inject the modified resin under a pressure of 0.3MPa to ensure that it fully impregnates the preform. After impregnation, it is cured in stages to obtain a carbon fiber composite material.

[0039] Example 2

[0040] A method for preparing a high-strength carbon fiber composite material, the preparation steps of which are as follows:

[0041] S1: Raw material preparation, including carbon fiber, graphene oxide, multi-walled carbon nanotubes, epoxy resin, bismaleimide, dicyclopentadiene@urea-formaldehyde resin microcapsules, nickel-based nanoparticles, nitric acid solution, and imidazole curing accelerator;

[0042] S2: carbon fiber surface graded modification;

[0043] S21: Surface ultrasonic treatment: immerse the carbon fiber in a 3% nitric acid solution and perform ultrasonic treatment at 40 kHz for 30 minutes to remove surface impurities and introduce carboxyl and hydroxyl groups to obtain clean and surface-polarized carbon fiber;

[0044] S22: electrophoretic deposition loading, using electrophoretic deposition method, under the action of a voltage of 50V, immersing the clean carbon fiber in a graphene oxide dispersion for electrophoretic deposition for 5 minutes, utilizing the electrostatic adsorption effect to form a uniform graphene oxide coating layer on the surface of the carbon fiber, thereby obtaining a carbon fiber loaded with graphene oxide;

[0045] S23: In situ growth of carbon nanotubes: At 650°C, hydrogen (H2) was first introduced into a chemical vapor deposition furnace to reduce nickel-based nanoparticles for 30 minutes. Subsequently, a gas mixture of ethylene (C2H4) and hydrogen (H2) with a volume ratio of 4:1 was switched to the nickel-based nanoparticles to catalyze the growth of multi-walled carbon nanotubes for 10 minutes, resulting in nano-modified carbon fibers with vertical multi-walled carbon nanotube arrays on the surface.

[0046] S3: Weaving a preform, using an automatic weaving machine to weave the modified carbon fiber obtained by pretreatment into a 0° / 90° orthogonal three-dimensional structure, to obtain a carbon fiber preform with a porosity of 28%;

[0047] S4: resin matrix modification;

[0048] S41: Resin blending: epoxy resin and bismaleimide are poured into a blender in a mass ratio of 7:3, the blender speed is controlled at 500 r / min, and the initial stirring is performed for 8 minutes. Then, 0.5 wt% of 2-ethyl-4-methylimidazole is added, and the secondary stirring time is controlled at 25 minutes. After uniform stirring, a blended resin is obtained;

[0049] S42: Addition of a self-healing agent: accurately weigh dicyclopentadiene@urea-formaldehyde resin microcapsules according to 2 wt% of the total mass of the resin, and put them into a planetary mixer together with the blended resin. The speed of the planetary mixer is controlled at 800 r / min, and the mixture is stirred for 12 minutes to obtain a modified resin matrix;

[0050] S5: Composite material molding: preheat the mold to 80°C, then place the carbon fiber preform into the mold, and slowly inject the modified resin under a pressure of 0.3MPa to ensure that it fully impregnates the preform. After impregnation, it is cured in stages to obtain a carbon fiber composite material.

[0051] Example 3

[0052] A method for preparing a high-strength carbon fiber composite material, the preparation steps of which are as follows:

[0053] S1: Raw material preparation, including carbon fiber, graphene oxide, multi-walled carbon nanotubes, epoxy resin, bismaleimide, dicyclopentadiene@urea-formaldehyde resin microcapsules, nickel-based nanoparticles, nitric acid solution, and imidazole curing accelerator;

[0054] S2: carbon fiber surface graded modification;

[0055] S21: Surface ultrasonic treatment: immerse the carbon fiber in a 3% nitric acid solution and perform ultrasonic treatment at 40 kHz for 30 minutes to remove surface impurities and introduce carboxyl and hydroxyl groups to obtain clean and surface-polarized carbon fiber;

[0056] S22: electrophoretic deposition loading, using electrophoretic deposition method, under the action of a voltage of 50V, immersing the clean carbon fiber in a graphene oxide dispersion for electrophoretic deposition for 5 minutes, utilizing the electrostatic adsorption effect to form a uniform graphene oxide coating layer on the surface of the carbon fiber, thereby obtaining a carbon fiber loaded with graphene oxide;

[0057] S23: In situ growth of carbon nanotubes: At 650°C, hydrogen (H2) was first introduced into a chemical vapor deposition furnace to reduce nickel-based nanoparticles for 30 minutes. Subsequently, a gas mixture of ethylene (C2H4) and hydrogen (H2) with a volume ratio of 4:1 was switched to the nickel-based nanoparticles to catalyze the growth of multi-walled carbon nanotubes for 10 minutes, resulting in nano-modified carbon fibers with vertical multi-walled carbon nanotube arrays on the surface.

[0058] S3: Weaving a preform, using an automatic weaving machine to weave the modified carbon fiber obtained by pretreatment into a 0° / 90° orthogonal three-dimensional structure to obtain a carbon fiber preform with a porosity of 30%;

[0059] S4: resin matrix modification;

[0060] S41: Resin blending: epoxy resin and bismaleimide are poured into a blender in a mass ratio of 7:3, the blender speed is controlled at 600 r / min, and the initial stirring is carried out for 10 minutes. Then, 0.5 wt% of 2-ethyl-4-methylimidazole is added, and the secondary stirring time is controlled at 30 minutes. After uniform stirring, a blended resin is obtained;

[0061] S42: Addition of a self-healing agent: accurately weigh dicyclopentadiene@urea-formaldehyde resin microcapsules according to 2 wt% of the total mass of the resin, and put them into a planetary mixer together with the blended resin. The speed of the planetary mixer is controlled at 1000 r / min, and the mixture is stirred for 15 minutes to obtain a modified resin matrix;

[0062] S5: Composite material molding: preheat the mold to 80°C, then place the carbon fiber preform into the mold, and slowly inject the modified resin under a pressure of 0.3MPa to ensure that it fully impregnates the preform. After impregnation, it is cured in stages to obtain a carbon fiber composite material.

[0063] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge of those skilled in the art without departing from the spirit of the present invention.

Claims

1. A method for preparing a high-strength carbon fiber composite material, characterized in that: The steps include: S1: Raw material preparation, including carbon fiber, graphene oxide, multi-walled carbon nanotubes, epoxy resin, bismaleimide, dicyclopentadiene@urea-formaldehyde resin microcapsules, nickel-based nanoparticles, nitric acid solution, and imidazole curing accelerator; S2: carbon fiber surface graded modification; S21: Surface ultrasonic treatment: immerse the carbon fiber in a 3% nitric acid solution and perform ultrasonic treatment at 40 kHz for 30 minutes to remove surface impurities and introduce carboxyl and hydroxyl groups to obtain clean and surface-polarized carbon fiber; S22: electrophoretic deposition loading, using electrophoretic deposition method, under the action of a voltage of 50V, immersing the clean carbon fiber in a graphene oxide dispersion for electrophoretic deposition for 5 minutes, utilizing the electrostatic adsorption effect to form a uniform graphene oxide coating layer on the surface of the carbon fiber, thereby obtaining a carbon fiber loaded with graphene oxide; S23: In situ growth of carbon nanotubes: hydrogen was first introduced into the chemical vapor deposition furnace to reduce nickel-based nanoparticles for 30 minutes, and then a mixed gas was introduced to catalyze the growth of multi-walled carbon nanotubes using the nickel-based nanoparticles for 10 minutes, resulting in nano-modified carbon fibers with vertical multi-walled carbon nanotube arrays on the surface. S3: Weaving a preform, using an automatic weaving machine to weave the modified carbon fiber obtained by pretreatment as a raw material into a 0° / 90° orthogonal three-directional structure to obtain a carbon fiber preform; S4: resin matrix modification; S41: Resin blending: epoxy resin and bismaleimide are poured into a blender in a mass ratio of 7:3, and then 0.5 wt % of an imidazole curing accelerator is added and uniformly stirred to obtain a blended resin; S42: Self-healing agent incorporation: accurately weigh dicyclopentadiene@urea-formaldehyde resin microcapsules according to 2 wt% of the total mass of the resin, and put them into a planetary mixer together with the blended resin to be fully mixed to obtain a modified resin matrix; S5: Composite material molding: preheat the mold to 80°C, then place the carbon fiber preform into the mold, and slowly inject the modified resin under a pressure of 0.3MPa to ensure that it fully impregnates the preform. After impregnation, it is cured in stages to obtain a carbon fiber composite material.

2. The method for preparing a high-strength carbon fiber composite material according to claim 1, wherein: The sheet size of graphene oxide in S1 is 1-5 μm, the diameter of multi-walled carbon nanotubes is 20-30 nm, the particle size of dicyclopentadiene@urea-formaldehyde resin microcapsules is 50-100 μm, and the particle size of nickel-based nanoparticles is 50 nm.

3. The method for preparing a high-strength carbon fiber composite material according to claim 2, wherein: Dicyclopentadiene@urea-formaldehyde resin microcapsules are prepared using microfluidic technology. The preparation steps are as follows: urea and formaldehyde are mixed, dissolved in deionized water, adjusted to pH 8 with alkaline solution, stirred at 70°C for 2 hours to prepare a urea-formaldehyde resin prepolymer aqueous solution and diluted, dicyclopentadiene is evenly mixed with an emulsifier to obtain an oil phase solution, and a microfluidic chip containing two fluid channels is constructed, one for the dicyclopentadiene oil phase solution and the other for the urea-formaldehyde resin prepolymer aqueous solution. The flow rate ratio is precisely controlled to form stable droplets, a catalyst and a curing agent are added, the pH is adjusted to 3, the temperature is raised to 65°C, and the reaction is carried out for 4 hours to allow the urea-formaldehyde resin to solidify and coat the dicyclopentadiene. Finally, the dicyclopentadiene@urea-formaldehyde resin microcapsules are obtained by filtration, washing, and drying.

4. The method for preparing a high-strength carbon fiber composite material according to claim 1, wherein: The preparation steps of the graphene oxide dispersion in S22 are as follows: graphene oxide powder is added to deionized water to prepare a preliminary solution, then dilute hydrochloric acid is slowly added to adjust the pH value to 4, and the solution is continuously stirred, and then a 0.1M potassium chloride electrolyte solution is added, and after sufficient stirring, ultrasonic treatment is performed to uniformly disperse the graphene oxide in the solution to obtain a graphene oxide dispersion with a concentration of 0.5 mg / mL, a pH value of 4 and containing 0.1M potassium chloride electrolyte.

5. The method for preparing a high-strength carbon fiber composite material according to claim 1, wherein: The growth condition of the chemical vapor deposition furnace in S23 was set to 650° C., and the mixed gas used was ethylene and hydrogen in a ratio of 4:

1.

6. The method for preparing a high-strength carbon fiber composite material according to claim 1, characterized in that: The porosity of the carbon fiber preform prepared in S3 is 25%-30%.

7. The method for preparing a high-strength carbon fiber composite material according to claim 1, characterized in that: The imidazole curing accelerator in S41 includes but is not limited to 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1-vinylimidazole and 1-cyanoethyl-2-methylimidazole.

8. The method for preparing a high-strength carbon fiber composite material according to claim 1, wherein: The speed range of the mixer in S41 is controlled within 400-600 r / min, the initial stirring time is controlled within 5-10 minutes, and the secondary stirring time is controlled within 20-30 minutes.

9. The method for preparing a high-strength carbon fiber composite material according to claim 1, wherein: The speed range of the S42 planetary mixer is controlled at 600-1000r / min, and the mixing time is controlled at 10-15 minutes.