Graphene / carbon fiber / epoxy resin composite material and preparation method thereof

Abstract

The invention discloses a graphene / carbon fiber / epoxy resin composite material and a preparation method thereof. The preparation method comprises the steps of preparing graphene / carbon fibers and compounding the graphene / carbon fibers and epoxy resin. The graphene / carbon fiber material is obtained through an in-situ polymerization method, the graphene oxide material is adopted, the characteristic that the graphene oxide material is added with functional groups is utilized, graphene can be deposited on the carbon fiber material, the bonding strength of the graphene and the carbon fiber material is improved, and the prepared material has better electric conduction and heat conduction performance and also has better mechanical performance; then the graphene / carbon fiber material is added into an epoxy resin system as an additive, and the mechanical property of the epoxy resin is enhanced by adding the additive. Meanwhile, through mixed use of the nano-carbon tubes and the graphene / carbon fiber material, an interconnected three-dimensional network structure can be formed, and an efficient heat conduction channel is constructed in an epoxy resin matrix, so that a heat conduction synergistic effect is generated, and the heat conductivity of the composite material is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and in particular to a graphene / carbon fiber / epoxy resin composite material and a preparation method thereof. Background Art

[0002] Epoxy resin is a general term for a class of polymers containing more than two epoxy groups in the molecule. Due to the chemical activity of the epoxy group, it can be opened with a variety of compounds containing active hydrogen, cured and cross-linked to form a network structure. It is a thermosetting resin. Epoxy resin has excellent mechanical properties, high adhesion properties, good chemical stability, good heat resistance and electrical insulation, and is therefore widely used in coatings, composite materials, casting materials, and electronic packaging materials. However, after the epoxy resin is cured, it has more cross-linking points and greater internal stress, making the overall material brittle, and the impact resistance and bending properties are poor, which directly affects its application as a structural material or load-bearing parts.

[0003] At present, epoxy resin toughening is mainly achieved by adding inorganic fillers for blending and modification. After surface modification of the fillers, they are dispersed in the epoxy resin matrix and cured to obtain epoxy resin modified composite materials. For example, graphene, nano-silicon dioxide, etc. are added to epoxy resin. However, the existing additives have poor synergy on the mechanical strength of epoxy resin, and the uniformity of dispersion of each additive in epoxy resin is poor, resulting in that the toughness of epoxy resin with added additives cannot meet the demand. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a graphene / carbon fiber / epoxy resin composite material and a preparation method thereof, which solves the problem of poor toughness of epoxy resin materials in the prior art.

[0005] To achieve the above object, the present invention adopts the following technical solution: a method for preparing a graphene / carbon fiber / epoxy resin composite material, comprising the following steps:

[0006] (1) ultrasonically dispersing graphene oxide into an organic solvent to form a suspension to obtain a dispersion A;

[0007] (2) dispersing polyacrylonitrile (PAN) in an organic solvent, swelling at 5°C-20°C for 2.5h-3h, then heating to 60°C-80°C, and mechanically stirring for 1h-3h to obtain dispersion B;

[0008] (3) uniformly blending the dispersion A in step (1) and the dispersion B in step (2), filtering and degassing after thermal reaction to obtain a spinning precursor solution;

[0009] (4) spinning the spinning precursor solution in step (3) by dry-jet wet spinning to obtain graphene / carbon fiber precursor, and then subjecting the precursor solution to pre-oxidation treatment and carbonization treatment to obtain graphene / carbon fiber;

[0010] (5) After adding the graphene / carbon fiber in step (4) to epoxy resin and heating to 80-90° C., cyanate resin, antioxidant, and carbon nanotubes are added and stirred, and then vacuum is applied to allow the epoxy resin to completely infiltrate the graphene / carbon fiber, and then the temperature is continued to be raised to 160-200° C. and cured for 4-8 hours to obtain a graphene / carbon fiber / epoxy resin composite material.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] The present application first utilizes an in-situ polymerization method to obtain a graphene / carbon fiber material. At the same time, an oxide graphene material is used, and its increased functional group characteristics are utilized to facilitate the deposition of graphene on the carbon fiber material, thereby increasing the bonding strength between the two, so that the prepared material has better electrical and thermal conductivity while also having better mechanical properties. The graphene / carbon fiber material is then added as an additive to an epoxy resin system, and the mechanical properties of the epoxy resin are enhanced by adding the additive.

[0013] At the same time, nano-scale carbon nanotubes are added. The mixed use of carbon nanotubes and graphene / carbon fiber materials can also form an interconnected three-dimensional network structure, build an efficient heat conduction channel in the epoxy resin matrix, thereby producing a heat conduction synergistic effect and greatly improving the thermal conductivity of the composite material.

[0014] Furthermore, the graphene oxide in step (1) is prepared by the following steps:

[0015] 1) Weighing graphite, sodium nitrate and potassium permanganate respectively, and mixing them thoroughly in an ice bath to obtain a mixture, wherein the added mass ratio of graphite, sodium nitrate and potassium permanganate is 2:1:6;

[0016] 2) Place the mixture in concentrated sulfuric acid at a solid-liquid ratio of 0.02 g / ml-0.03 g / ml, react in a beaker for 12 hours, and stir until a slurry-like substance appears;

[0017] 3) Add deionized water to the beaker while stirring, the amount of deionized water added is 3-4 times the volume of concentrated sulfuric acid, then transfer the beaker to a 90° C. constant temperature water bath and continue stirring for 7 hours, then add hydrogen peroxide and continue stirring for 30 minutes, the amount of hydrogen peroxide added is 1.2-1.4 times the volume of concentrated sulfuric acid, to obtain a solution;

[0018] 4) filtering the solution through dialysis to remove a large amount of sulfate ions present in the solution, and storing the solution after multiple centrifugation treatments, at a centrifugal speed of 9000 rpm-13500 rpm, measuring the concentration of graphene oxide, and obtaining purified graphene oxide;

[0019] 5) The purified graphene oxide is ultrasonically treated by a constant temperature ultrasonic device, and a single layer of graphene oxide is screened out. The constant temperature ultrasonic device is constructed by a low-temperature coolant circulating pump with a submersible pump inside and an ultrasonic cleaner. The submersible pump inside the low-temperature coolant circulating pump is connected to the ultrasonic cleaner through a pipeline. The maximum flow rate of the submersible pump is 1800L / h, the stirring speed is 500rpm, and the water temperature inside the low-temperature coolant circulating pump is maintained at 7°C-9°C.

[0020] Furthermore, the organic solvent in steps (1) and (2) includes any one of dimethylformamide, N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide.

[0021] Furthermore, in step (3), the thermal reaction is carried out under nitrogen protection with mechanical stirring, the temperature is 50°C-65°C, and the reaction time is 6h-10h.

[0022] Furthermore, in step (4), the spinning temperature of the dry-jet wet spinning method is set to 35°C-50°C, the diameter of the spinneret hole is 0.03mm-0.5mm, the temperature of the coagulation bath is 25°C-50°C, the stretching speed is 5m / min-20m / min, and the stretching multiple is 2 times-5 times.

[0023] Furthermore, the coagulation bath is a mixed solution of the organic solvent and deionized water, the ratio thereof is 20-50:10, and the temperature is 25°C-40°C.

[0024] Furthermore, in step (4), the pre-oxidation treatment is to heat the graphene / carbon fiber precursor to 200° C.-300° C. and perform pre-oxidation in an air atmosphere for 0.5 h-1.5 h.

[0025] Furthermore, in step (4), the carbonization treatment is performed by heating the temperature to 1000°C-1200°C, passing nitrogen for protection, and the treatment time is 1h-4h.

[0026] Furthermore, in step (5), the antioxidant includes any one of antioxidant 168, antioxidant 1076, antioxidant 1010, dilauryl thiodipropionate (DLTP), and 2,6-di-tert-butyl-4-methylphenol.

[0027] The present application also provides a graphene / carbon fiber / epoxy resin composite material, which is prepared by the above-mentioned preparation method. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0029] A method for preparing a graphene / carbon fiber / epoxy resin composite material comprises the following steps:

[0030] (1) ultrasonically dispersing graphene oxide into an organic solvent to form a suspension to obtain a dispersion A;

[0031] (2) dispersing polyacrylonitrile (PAN) in an organic solvent, swelling at 5°C-20°C for 2.5h-3h, then heating to 60°C-80°C, and mechanically stirring for 1h-3h to obtain dispersion B;

[0032] (3) uniformly blending the dispersion A in step (1) and the dispersion B in step (2), filtering and degassing after thermal reaction to obtain a spinning precursor solution;

[0033] (4) spinning the spinning precursor solution in step (3) by dry-jet wet spinning to obtain graphene / carbon fiber precursor, and then subjecting the precursor solution to pre-oxidation treatment and carbonization treatment to obtain graphene / carbon fiber;

[0034] (5) After adding the graphene / carbon fiber in step (4) to epoxy resin and heating to 80-90° C., cyanate resin, antioxidant, and carbon nanotubes are added and stirred, and then vacuum is applied to allow the epoxy resin to completely infiltrate the graphene / carbon fiber, and then the temperature is continued to be raised to 160-200° C. and cured for 4-8 hours to obtain a graphene / carbon fiber / epoxy resin composite material.

[0035] The graphene oxide in this application is prepared by the Hummers method, and the specific steps are as follows:

[0036] 1) Weigh graphite, sodium nitrate and potassium permanganate respectively, and mix them thoroughly under ice bath conditions to obtain a mixture, wherein the added mass ratio of graphite, sodium nitrate and potassium permanganate is 2:1:6; 2) Place the mixture in concentrated sulfuric acid at a solid-liquid ratio of 0.02g / ml-0.03g / ml, react in a beaker for 12 hours, and stir until a muddy substance appears; 3) Add deionized water to the beaker while stirring, the amount of deionized water added is 3-4 times the volume of concentrated sulfuric acid, then transfer the beaker to a 90°C constant temperature water bath and continue stirring for 7 hours, then add hydrogen peroxide and continue stirring for 30 minutes, the amount of hydrogen peroxide added is 1.2-1.4 times the volume of concentrated sulfuric acid, to obtain a solution; 4) Add the solution A large amount of sulfate ions present in the dialysis filtration solution are stored after multiple centrifugation treatments, the centrifugation speed is 9000rpm-13500rpm, the concentration of graphene oxide is measured, and purified graphene oxide is obtained; 5) the purified graphene oxide is ultrasonically treated by a constant temperature ultrasonic device, and a single layer of graphene oxide is screened out. The constant temperature ultrasonic device is constructed by a low-temperature coolant circulating pump with a submersible pump inside and an ultrasonic cleaner, wherein the submersible pump inside the low-temperature coolant circulating pump is connected to the ultrasonic cleaner through a pipeline, the maximum flow of the submersible pump is 1800L / h, the stirring speed is 500rpm, and the water temperature inside the low-temperature coolant circulating pump is maintained at 7°C-9°C.

[0037] The surface of graphene oxide contains a large number of oxygen-containing functional groups, such as carboxyl, hydroxyl, epoxy, etc., which can provide a large specific surface area when compounded with carbon fiber materials, effectively disperse the attached materials, prevent agglomeration, and facilitate the preparation of high-performance composite materials. Therefore, graphene oxide and carbon fiber materials are used for composite production.

[0038] The epoxy resin of the present application can be any one of bisphenol A epoxy resin and bisphenol F epoxy resin.

[0039] The organic solvent includes any one of dimethylformamide, N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide.

[0040] Furthermore, in step (3), the thermal reaction is carried out under nitrogen protection with mechanical stirring, the temperature is 50°C-65°C, and the reaction time is 6h-10h.

[0041] Furthermore, in step (4), the spinning temperature of the dry-jet wet spinning method is set to 35°C-50°C, the diameter of the spinneret hole is 0.03mm-0.5mm, the temperature of the coagulation bath is 25°C-50°C, the stretching speed is 5m / min-20m / min, and the stretching multiple is 2 times-5 times.

[0042] Furthermore, the coagulation bath is a mixed solution of the organic solvent and deionized water, the ratio thereof is 20-50:10, and the temperature is 25°C-40°C.

[0043] Furthermore, in step (4), the pre-oxidation treatment is to heat the graphene / carbon fiber precursor to 200° C.-300° C. and perform pre-oxidation in an air atmosphere for 0.5 h-1.5 h.

[0044] Furthermore, in step (4), the carbonization treatment is performed by heating the temperature to 1000°C-1200°C, passing nitrogen for protection, and the treatment time is 1h-4h.

[0045] Furthermore, in step (5), the antioxidant includes any one of antioxidant 168, antioxidant 1076, antioxidant 1010, dilauryl thiodipropionate (DLTP), and 2,6-di-tert-butyl-4-methylphenol.

[0046] The present application also provides a graphene / carbon fiber / epoxy resin composite material, which is prepared by the above-mentioned preparation method.

[0047] Example 1

[0048] A method for preparing a graphene / carbon fiber / epoxy resin composite material comprises the following steps:

[0049] 1. Take 1 part of graphene and disperse it in 100 parts of dimethylformamide solvent, heat it to 50°C, and stir it for 1 hour by mechanical stirring to obtain dispersion A.

[0050] 2. Take 100 parts of polyacrylonitrile (PAN) and disperse them in 300 parts of dimethylformamide solvent. The temperature is controlled at 5°C. PAN is swollen for 2.5 hours. Then the temperature is raised to 60°C and mechanically stirred for 1 hour to fully disperse and obtain dispersion B.

[0051] 3. The first dispersion and the second dispersion are uniformly blended under nitrogen protection by mechanical stirring, the temperature is controlled at 55° C., the reaction time is 6 h, and then the mixed solution is filtered and degassed to obtain a spinning precursor solution.

[0052] 4. The spinning precursor solution is subjected to dry-jet wet spinning, the spinning temperature is set to 35°C, the spinneret hole diameter is 0.03mm, and the spinning is immersed in a coagulation bath mixed with dimethylformamide solvent and deionized water, the volume ratio of dimethylformamide solvent and deionized water is 20:10, the temperature is set to 40°C, and the coagulation bath is stretched at a stretching rate of 5m / min and a stretching multiple of 5 times to obtain graphene / carbon fiber precursor. The prepared precursor is first pre-oxidized in an air atmosphere at a pre-oxidation temperature of 200°C and a pre-oxidation time of 1h, and then high-purity nitrogen is introduced, the temperature is raised to 1100°C for carbonization treatment, and the carbonization time is 3h to obtain a graphene / carbon fiber product.

[0053] 5. Add 3 parts of graphene / carbon fiber to 55 parts of bisphenol A epoxy resin (E44) and raise the temperature to 80°C. Then add 5 parts of cyanate resin, 0.5 parts of antioxidant 1010 and 0.5 parts of carbon nanotubes. Stir thoroughly for 0.5 hours, then vacuum to allow the epoxy resin to completely infiltrate the graphene / carbon fiber. Then continue to heat to 160°C and cure for 4 hours to obtain a graphene / carbon fiber / epoxy resin composite material.

[0054] Example 2

[0055] 1. Take 1.5 parts of graphene and disperse it in 120 parts of N,N-dimethylformamide solvent, heat it to 60°C, and stir it for 2 hours by mechanical stirring to obtain dispersion A.

[0056] 2. Take 100 parts of polyacrylonitrile (PAN) and disperse them in 300 parts of N,N-dimethylformamide solvent. The temperature is controlled at 15°C. PAN is swollen for 3 hours. Then the temperature is raised to 70°C and mechanically stirred for 2 hours to fully disperse and obtain dispersion B.

[0057] 3. The first dispersion and the second dispersion are uniformly blended under nitrogen protection by mechanical stirring, the temperature is controlled at 60° C., the reaction time is 8 h, and then the mixed solution is filtered and degassed to obtain a spinning precursor solution.

[0058] 4. The spinning precursor solution is subjected to dry-jet wet spinning, the spinning temperature is set to 40°C, the spinneret hole diameter is 0.04mm, and the spinning is immersed in a coagulation bath mixed with N,N-dimethylformamide solvent and deionized water, the volume ratio of N,N-dimethylformamide solvent and deionized water is 30:10, the temperature is set to 30°C, and the coagulation bath is stretched at a stretching rate of 10m / min and a stretching multiple of 2 times to obtain graphene / carbon fiber precursor. The prepared precursor is first pre-oxidized in an air atmosphere at a pre-oxidation temperature of 300°C and a pre-oxidation time of 1.5h, and then high-purity nitrogen is introduced, the temperature is raised to 1000°C for carbonization treatment, and the carbonization time is 2h to obtain a graphene / carbon fiber product.

[0059] 5. Add 4 parts of graphene / carbon fiber to 60 parts of bisphenol F epoxy resin and raise the temperature to 80°C (80-90), then add 4 parts of cyanate resin, 0.5 parts of antioxidant 1076, and 0.6 parts of carbon nanotubes. After stirring for 1 hour, vacuum the mixture to allow the epoxy resin to completely soak the graphene / carbon fiber. Then continue to heat to 180°C and cure for 6 hours to obtain a graphene / carbon fiber / epoxy resin composite material.

[0060] Example 3

[0061] 1. Take 1 part of graphene and disperse it in 100 parts of N,N-dimethylacetamide solvent, heat it to 55°C, and stir it for 1.5 hours by mechanical stirring to obtain dispersion A.

[0062] 2. Take 100 parts of polyacrylonitrile (PAN) and disperse them in 300 parts of N,N-dimethylacetamide solvent. The temperature is controlled at 20°C. PAN is swollen for 2.5 hours. Then the temperature is raised to 80°C and mechanically stirred for 3 hours to fully disperse and obtain dispersion B.

[0063] 3. The first dispersion and the second dispersion are uniformly blended under nitrogen protection by mechanical stirring, the temperature is controlled at 50° C., the reaction time is 10 h, and then the mixed solution is filtered and degassed to obtain a spinning precursor solution.

[0064] 4. The spinning precursor solution is subjected to dry-jet wet spinning, the spinning temperature is set to 45°C, the spinneret hole diameter is 0.04mm, and the spinning is immersed in a coagulation bath mixed with N, N-dimethylacetamide solvent and deionized water, the volume ratio of N, N-dimethylacetamide solvent and deionized water is 50:10, the temperature is set to 25°C, and the coagulation bath is stretched at a stretching rate of 20m / min and a stretching multiple of 4 times to obtain graphene / carbon fiber precursor. The prepared precursor is first pre-oxidized in an air atmosphere, the pre-oxidation temperature is 250°C, the pre-oxidation time is 1h, and then high-purity nitrogen is introduced, the temperature is raised to 1200°C for carbonization treatment, and the carbonization time is 4h to obtain a graphene / carbon fiber product.

[0065] 5. Add 3.5 parts of graphene / carbon fiber to 60 parts of bisphenol A epoxy resin (E44) and raise the temperature to 85°C, then add 3.5 parts of cyanate resin, 0.8 parts of antioxidant 168, and 0.6 parts of carbon nanotubes. Stir thoroughly for 1 hour, then vacuumize to allow the epoxy resin to completely infiltrate the graphene / carbon fiber, then continue to heat to 1.70°C and cure for 6 hours to obtain a graphene / carbon fiber / epoxy resin composite material.

[0066] Example 4

[0067] 1. Take 1.5 parts of graphene and disperse it in 130 parts of dimethyl sulfoxide solvent, heat it to 50°C, and stir it for 1 hour by mechanical stirring to obtain dispersion A.

[0068] 2. Take 100 parts of polyacrylonitrile (PAN) and disperse them in 300 parts of dimethyl sulfoxide solvent. The temperature is controlled at 15°C. PAN is swollen for 2.5 hours. Then the temperature is raised to 65°C and mechanically stirred for 3 hours to fully disperse and obtain dispersion B.

[0069] 3. The first dispersion and the second dispersion are uniformly blended under nitrogen protection by mechanical stirring, the temperature is controlled at 65° C., the reaction time is 8 h, and then the mixed solution is filtered and degassed to obtain a spinning precursor solution.

[0070] 4. The spinning precursor solution is subjected to dry-jet wet spinning, the spinning temperature is set to 40°C, the spinneret hole diameter is 0.03mm, and the spinning is immersed in a coagulation bath mixed with dimethyl sulfoxide solvent and deionized water, the volume ratio of dimethyl sulfoxide solvent and deionized water is 50:10, the temperature is set to 40°C, and the coagulation bath is stretched, the stretching rate is 5m / min, and the stretching multiple is 4 times to obtain graphene / carbon fiber precursor. The prepared precursor is first pre-oxidized in an air atmosphere, the pre-oxidation temperature is 250°C, the pre-oxidation time is 1.5h, and then high-purity nitrogen is introduced, the temperature is raised to 1100°C for carbonization treatment, and the carbonization time is 3h to obtain a graphene / carbon fiber product.

[0071] 5. Add 4 parts of graphene / carbon fiber to 65 parts of bisphenol A epoxy resin (E44) and raise the temperature to 80°C, then add 6 parts of cyanate resin, 0.5 parts of 2,6-di-tert-butyl-4-methylphenol, and 0.5 parts of carbon nanotubes. Stir thoroughly for 0.5 hours, then evacuate to allow the epoxy resin to completely infiltrate the graphene / carbon fiber, then continue to heat to 160°C and cure for 6 hours to obtain a graphene / carbon fiber / epoxy resin composite material.

[0072] Comparative Example 1

[0073] The difference between this comparative example and Example 1 is that in step 5, no carbon nanotubes are added.

[0074] Comparative Example 2

[0075] The difference between this comparative example and Example 1 is that in step 5, no cyanate resin is added.

[0076] Comparative Example 3

[0077] The difference between this comparative example and Example 1 is that in step 5, the graphene / carbon fiber is replaced by an equal amount of nano-silicon dioxide material.

[0078] Effect verification

[0079] The tensile strength of the composite materials obtained in the above Examples 1-4 and Comparative Examples 1-3 was tested according to ASTM D638, and the resistivity was tested according to GB / T 31838.3-2019, and the results shown in Table 1 were obtained.

[0080] Table 1:

[0081]

[0082] From the data in Table 1, it can be seen that the addition of carbon nanotubes and cyanate resin is conducive to the dispersion of additives in the epoxy resin system, reduces the resistivity, and increases the electrical and thermal conductivity of the material. The graphene / carbon fiber material can significantly improve the mechanical strength of the epoxy resin material, and the tensile strength is significantly increased compared to the nano-silicon dioxide in the prior art. Therefore, it can be concluded that the graphene / carbon fiber / epoxy resin composite material prepared in this application has good electrical and thermal conductivity, as well as good mechanical properties.

[0083] In summary, the present application first utilizes an in-situ polymerization method to obtain a graphene / carbon fiber material. At the same time, an oxide graphene material is used, and its increased functional group characteristics are utilized to facilitate the deposition of graphene on the carbon fiber material, thereby increasing the bonding strength between the two, so that the prepared material has better electrical and thermal conductivity while also having better mechanical properties; the graphene / carbon fiber material is then added as an additive to the epoxy resin system, and the mechanical properties of the epoxy resin are enhanced by adding the additive.

[0084] At the same time, nano-scale carbon nanotubes are added. The mixed use of carbon nanotubes and graphene / carbon fiber materials can also form an interconnected three-dimensional network structure, build an efficient heat conduction channel in the epoxy resin matrix, thereby producing a heat conduction synergistic effect and greatly improving the thermal conductivity of the composite material.

[0085] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and scope of the equivalent elements of the claims be included in the invention. Any marking in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A method for preparing a graphene / carbon fiber / epoxy resin composite material, characterized in that: The steps include: (1) ultrasonically dispersing graphene oxide into an organic solvent to form a suspension to obtain a dispersion A; (2) dispersing polyacrylonitrile (PAN) in an organic solvent, swelling at 5°C-20°C for 2.5h-3h, then heating to 60°C-80°C, and mechanically stirring for 1h-3h to obtain dispersion B; (3) uniformly blending the dispersion A in step (1) and the dispersion B in step (2), filtering and degassing after thermal reaction to obtain a spinning precursor solution; (4) spinning the spinning precursor solution in step (3) by dry-jet wet spinning to obtain graphene / carbon fiber precursor, and then subjecting the precursor solution to pre-oxidation treatment and carbonization treatment to obtain graphene / carbon fiber; (5) After adding the graphene / carbon fiber in step (4) to epoxy resin and heating to 80-90° C., cyanate resin, antioxidant, and carbon nanotubes are added and stirred, and then vacuum is applied to allow the epoxy resin to completely infiltrate the graphene / carbon fiber, and then the temperature is continued to be raised to 160-200° C. and cured for 4-8 hours to obtain a graphene / carbon fiber / epoxy resin composite material.

2. The method for preparing the graphene / carbon fiber / epoxy resin composite material according to claim 1, characterized in that: The graphene oxide in step (1) is prepared by the following steps: 1) Weighing graphite, sodium nitrate and potassium permanganate respectively, and mixing them thoroughly in an ice bath to obtain a mixture, wherein the added mass ratio of graphite, sodium nitrate and potassium permanganate is 2:1:6; 2) Place the mixture in concentrated sulfuric acid at a solid-liquid ratio of 0.02 g / ml-0.03 g / ml, react in a beaker for 12 hours, and stir until a slurry-like substance appears; 3) Add deionized water to the beaker while stirring, the amount of deionized water added is 3-4 times the volume of concentrated sulfuric acid, then transfer the beaker to a 90° C. constant temperature water bath and continue stirring for 7 hours, then add hydrogen peroxide and continue stirring for 30 minutes, the amount of hydrogen peroxide added is 1.2-1.4 times the volume of concentrated sulfuric acid, to obtain a solution; 4) filtering the solution through dialysis to remove a large amount of sulfate ions present in the solution, and storing the solution after multiple centrifugation treatments, at a centrifugal speed of 9000 rpm-13500 rpm, measuring the concentration of graphene oxide, and obtaining purified graphene oxide; 5) The purified graphene oxide is ultrasonically treated by a constant temperature ultrasonic device, and a single layer of graphene oxide is screened out. The constant temperature ultrasonic device is constructed by a low-temperature coolant circulating pump with a submersible pump inside and an ultrasonic cleaner. The submersible pump inside the low-temperature coolant circulating pump is connected to the ultrasonic cleaner through a pipeline. The maximum flow rate of the submersible pump is 1800L / h, the stirring speed is 500rpm, and the water temperature inside the low-temperature coolant circulating pump is maintained at 7°C-9°C.

3. The method for preparing the graphene / carbon fiber / epoxy resin composite material according to claim 1, characterized in that: The organic solvent in steps (1) and (2) includes any one of dimethylformamide, N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide.

4. The method for preparing the graphene / carbon fiber / epoxy resin composite material according to claim 1, characterized in that: In step (3), the thermal reaction is carried out under nitrogen protection with mechanical stirring at a temperature of 50° C.-65° C. and a reaction time of 6 h-10 h.

5. The method for preparing the graphene / carbon fiber / epoxy resin composite material according to claim 1, characterized in that: In step (4), the spinning temperature of the dry-jet wet spinning method is set to 35°C-50°C, the diameter of the spinneret hole is 0.03mm-0.5mm, the temperature of the coagulation bath is 25°C-50°C, the stretching speed is 5m / min-20m / min, and the stretching multiple is 2 times-5 times.

6. The method for preparing the graphene / carbon fiber / epoxy resin composite material according to claim 5, characterized in that: in, The coagulation bath is a mixed solution of the organic solvent and deionized water, the ratio of which is 20-50:10, and the temperature is 25°C-40°C.

7. The method for preparing the graphene / carbon fiber / epoxy resin composite material according to claim 1, characterized in that: In step (4), the pre-oxidation treatment is to heat the graphene / carbon fiber precursor to 200° C.-300° C. and perform pre-oxidation in an air atmosphere for 0.5 h-1.5 h.

8. The method for preparing the graphene / carbon fiber / epoxy resin composite material according to claim 7, characterized in that: In step (4), the carbonization treatment is carried out by heating the temperature to 1000°C-1200°C, passing nitrogen for protection, and the treatment time is 1h-4h.

9. The method for preparing the graphene / carbon fiber / epoxy resin composite material according to any one of claims 1 to 8, characterized in that: In step (5), the antioxidant includes any one of antioxidant 168, antioxidant 1076, antioxidant 1010, dilauryl thiodipropionate (DLTP), and 2,6-di-tert-butyl-4-methylphenol.

10. A graphene / carbon fiber / epoxy resin composite material, characterized in that: It is prepared by the preparation method described in any one of claims 1 to 9.

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