Graphene epoxy resin composite material and preparation method thereof

Abstract

The present application belongs to the technical field of epoxy resin materials. More particularly, it relates to a graphene epoxy resin composite material and a preparation method thereof. The preparation steps of the present application include: raw material preparation: taking 100-120 parts of epoxy resin E-51, 70-80 parts of curing agent, 6-8 parts of accelerator, 8-10 parts of silica-coated graphene filler and 25-30 parts of acetone by weight; pre-dispersion: first mix and disperse the silica-coated graphene filler and acetone, then add the epoxy resin E-51, continue to disperse uniformly to obtain a pre-dispersion liquid; curing system mixing: add the curing agent and the accelerator to the pre-dispersion liquid, mix uniformly at high speed, discharge, heat and cure to obtain the graphene epoxy resin composite material; wherein the silica-coated graphene filler includes a graphene matrix and silica coated on the surface of the graphene matrix, and the silica and the graphene matrix are combined by Si-C chemical bonds.

Description

Technical Field

[0001] This invention belongs to the field of epoxy resin materials technology. More specifically, it relates to a graphene epoxy resin composite material and its preparation method. Background Technology

[0002] The main purpose of adding graphene to epoxy resin is to significantly improve the overall performance of the composite material through the unique properties of graphene.

[0003] Graphene has extremely high tensile strength (about 130 GPa) and modulus (about 1 TPa). Its two-dimensional structure can form an efficient stress transfer network in the resin, which significantly improves the tensile strength, flexural modulus and impact resistance of epoxy resin, while avoiding the increase in brittleness that may be caused by traditional fillers (such as glass fiber).

[0004] In addition, graphene has a thermal conductivity of up to about 5000 W / (m·K), which can effectively construct thermal conduction pathways and solve the problem of poor intrinsic thermal conductivity of epoxy resin. It is suitable for applications such as electronic packaging and heat dissipation coatings that require rapid heat conduction.

[0005] However, the inventors discovered that if graphene is directly added to epoxy resin, microcracks easily appear in localized areas after the epoxy resin cures. In particular, as stress accumulates during product use, these cracks propagate further, leading to a significant decline in product performance. Therefore, how to mitigate the formation of localized microcracks and ensure the continued performance of the product during use is one of the technical challenges that those skilled in the art need to address. Summary of the Invention

[0006] The technical problem this invention aims to solve is that, when graphene is directly added to epoxy resin systems, localized microcracks may appear, leading to a decline in product performance. Based on this challenge, this invention provides a graphene-epoxy resin composite material and its preparation method.

[0007] The purpose of this invention is to provide a method for preparing graphene epoxy resin composite materials.

[0008] Another object of the present invention is to provide a graphene epoxy resin composite material.

[0009] The above-mentioned objective of this invention is achieved through the following technical solution:

[0010] A method for preparing a graphene-epoxy resin composite material, the specific preparation steps of which include:

[0011] Raw material preparation:

[0012] By weight, take 100-120 parts of epoxy resin E-51, 70-80 parts of curing agent, 6-8 parts of accelerator, 8-10 parts of silica-coated graphene filler, and 25-30 parts of acetone.

[0013] Pre-dispersion:

[0014] First, the silica-coated graphene filler is mixed and dispersed with acetone, then epoxy resin E-51 is added and the mixture is further dispersed evenly to obtain a pre-dispersion.

[0015] Curing system mixing:

[0016] Add curing agent and accelerator to the pre-dispersion liquid, mix evenly by high-speed shearing, discharge the material, heat and cure to obtain graphene epoxy resin composite material.

[0017] The silica-coated graphene filler includes a graphene matrix and silica coated on the surface of the graphene matrix, wherein the silica and the graphene matrix are bonded by Si-C chemical bonds.

[0018] The beneficial effects of the above technical solution are as follows:

[0019] During the actual research process, the inventors discovered that the main reason for the occurrence of local microcracks is that the bonding force between the original graphene surface and the epoxy resin is weak. This makes it easy for slippage to occur at the interface during the product curing or use. As the interface slippage gradually worsens during use, the cracks gradually extend and propagate along the weak interface, causing the product's performance to continuously decline and affecting normal use.

[0020] Based on the above findings, the proposed technical solution addresses this problem by introducing silicon dioxide onto the surface of graphene and bonding the silicon dioxide and the graphene matrix through strong Si-C chemical bonds. Specifically, since the bond energy of Si-C chemical bonds is approximately 318 kJ / mol, significantly higher than conventional van der Waals forces (approximately 10 kJ / mol), the adsorbed silicon dioxide on the graphene surface can be used as an anchoring point to effectively anchor the interface between graphene and epoxy resin, reducing interfacial slippage. Furthermore, the silanol groups on the silicon dioxide surface can react with the epoxy groups of the epoxy resin, further strengthening the interfacial bonding. In addition, silicon dioxide is used as an anchoring point because its modulus is between that of graphene and epoxy resin, which can alleviate localized stress concentration at the interface caused by abrupt changes in modulus, thus preventing localized cracking.

[0021] Furthermore, the silica-coated graphene filler is prepared in the following manner:

[0022] By weight, take 10-15 parts graphene matrix, 800-900 parts dilute sulfuric acid with a mass fraction of 10-15%, 6-8 parts hydrogen peroxide with a mass fraction of 20%, 500-600 parts ethanol solution with a mass fraction of 80-85%, and 3-5 parts tetraethyl orthosilicate.

[0023] After mixing graphene matrix and dilute sulfuric acid, the mixture is ultrasonically dispersed evenly. Then hydrogen peroxide is added, and the mixture is heated and stirred at 60-65℃ for 45-60 minutes with a stirring speed of 200-500 r / min. After centrifugation and washing until neutral, edge-activated graphene is obtained.

[0024] Edge-activated graphene was added to an ethanol solution and stirred until homogeneous. The solution was then cooled to 0°C and tetraethyl orthosilicate was slowly added dropwise while stirring. After the addition was complete, the pH was adjusted to 9.0-9.2 with ammonia. The mixture was then stirred for 30-40 minutes, centrifuged, washed, and dried to obtain the precursor coating.

[0025] The precursor coating is placed in an inert atmosphere and reacted at a temperature of 780-820℃ for 60-80 minutes, then cooled and discharged.

[0026] The beneficial effects of the above technical solution are as follows:

[0027] During further research, the inventors discovered that the silica coating on the graphene surface can act as a physical barrier, directly hindering the propagation of crack tips. However, they also accidentally discovered that by further designing the coating, the crack resistance could be further improved. Specifically, by designing a relatively high-density silica coating on the edges of the graphene to form a "hard shell," while achieving a low-coverage area of ​​silica on the base surface, the toughness of the graphene in this area can be preserved. Thus, the hard shell effect at the edges can be used to force the crack to deflect at this point during its propagation, while the preservation of the toughness of the base surface can induce crack branching and dissipate energy through a certain degree of plastic deformation.

[0028] Furthermore, the D50 of the graphene matrix is ​​1-5 μm, and the specific surface area of ​​the graphene matrix is ​​1200-1500 m². 2 / g;

[0029] The specific surface area was obtained by BET nitrogen adsorption.

[0030] Furthermore, the slow addition of tetraethyl orthosilicate is defined as adding tetraethyl orthosilicate at a rate of 4-6 mL / min.

[0031] Furthermore, the curing agent is selected from any one of methyltetrahydrophthalic anhydride, tetrahydrophthalic anhydride, and hexahydrophthalic anhydride.

[0032] Furthermore, the accelerator is selected from any one of 2-ethyl-4-methylimidazole, 1-benzyl-2-methylimidazole, and 1-cyanoethyl-2-ethyl-4-methylimidazole.

[0033] Furthermore, the high-speed shear mixing includes: high-speed shearing for 10-12 minutes at a shear rate of 3000-3200 r / min.

[0034] Furthermore, the heat curing includes:

[0035] Pre-cur at 80-85℃ for 100-120 minutes;

[0036] Subsequently, the primary curing was carried out at 120-125℃ for 100-120 minutes;

[0037] Then cure at 150-155℃ for 50-60 minutes.

[0038] The beneficial effects of the above technical solution are as follows:

[0039] The inventors discovered that further control of the process during heating and curing can also improve the formation and propagation of microcracks. Specifically, if rapid cross-linking curing is carried out, it will lead to internal stress concentration and uneven shrinkage, which will cause microcracks.

[0040] During the curing process described above, in the pre-curing stage, the resin initially cross-links to form a flexible network, allowing the graphene / SiO2 interface to slowly adjust its position, reducing the accumulation of local stress. Furthermore, the Si-OH and epoxy groups on the SiO2 surface gradually react, avoiding interface debonding caused by intense exothermic reactions.

[0041] During the main curing stage, the resin modulus increases, and the gradient interface begins to assume the function of stress transfer.

[0042] During the post-curing stage, complete curing forms a dense network, and the high stability of the Si-C bonds at the interface suppresses post-curing shrinkage stress.

[0043] Ultimately, the shrinkage stress during the curing process is released gradually along the gradient direction, avoiding the occurrence of interface peeling problems.

[0044] A graphene-epoxy resin composite material is prepared by the above-described preparation method. Detailed Implementation

[0045] The present invention will be further illustrated below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field.

[0046] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.

[0047] Example 1

[0048] Preparation of silica-coated graphene filler:

[0049] By weight, take 10 parts graphene matrix, 800 parts dilute sulfuric acid with a mass fraction of 10%, 6 parts hydrogen peroxide with a mass fraction of 20%, 500 parts ethanol solution with a mass fraction of 80%, and 3 parts tetraethyl orthosilicate.

[0050] The graphene matrix has a D50 of 1 μm and a specific surface area of ​​1200 m². 2 / g;

[0051] The specific surface area was obtained by BET nitrogen adsorption.

[0052] After mixing graphene matrix and dilute sulfuric acid, the mixture was ultrasonically dispersed at an ultrasonic frequency of 80 kHz for 30 min. Then hydrogen peroxide was added, and the mixture was heated and stirred at 60 °C and a stirring speed of 200 r / min for 45 min. After centrifugation, the filter cake was collected and washed with deionized water until neutral to obtain edge-activated graphene.

[0053] Edge-activated graphene was added to an ethanol solution and stirred at 300 rpm for 50 min. The mixture was then cooled to 0°C, and tetraethyl orthosilicate was slowly added dropwise while stirring. After the addition was complete, the pH was adjusted to 9.0 with ammonia. The mixture was then kept at 0°C and stirred at 200 rpm for 30 min. After the reaction was complete, the mixture was centrifuged, the filter cake was collected, washed, and dried to obtain the precursor coating.

[0054] The slow addition refers to adding tetraethyl orthosilicate at a rate of 4 mL / min.

[0055] The precursor coating was heated to 780°C at a rate of 3°C / min in an inert atmosphere and reacted at high temperature for 60 min. After cooling, the material was discharged to obtain silica-coated graphene filler.

[0056] The silica-coated graphene filler includes a graphene matrix and silica coated on the surface of the graphene matrix, wherein the silica and the graphene matrix are bonded by Si-C chemical bonds.

[0057] Raw material preparation:

[0058] By weight, take 100 parts epoxy resin E-51, 70 parts curing agent, 6 parts accelerator, 8 parts silica-coated graphene filler, and 25 parts acetone.

[0059] The curing agent is selected from methyltetrahydrophthalic anhydride;

[0060] The accelerator is selected from 2-ethyl-4-methylimidazole;

[0061] Pre-dispersion:

[0062] First, the silica-coated graphene filler was mixed with acetone and dispersed for 20 minutes under ultrasonic frequency of 80 kHz. Then, epoxy resin E-51 was added and the mixture was stirred and dispersed for another 20 minutes at a speed of 500 r / min to obtain a pre-dispersion.

[0063] Curing system mixing:

[0064] Add curing agent and accelerator to the pre-dispersion liquid, and shear at a shear rate of 3000 r / min for 10 min. Discharge the material, pre-cur it at 80℃ for 100 min, then perform primary curing at 120℃ for 100 min, and finally post-cur it at 150℃ for 50 min. After cooling, the graphene epoxy resin composite material is obtained.

[0065] Example 2

[0066] Preparation of silica-coated graphene filler:

[0067] By weight, take 12 parts graphene matrix, 850 parts dilute sulfuric acid with a mass fraction of 12%, 7 parts hydrogen peroxide with a mass fraction of 20%, 560 parts ethanol solution with a mass fraction of 82%, and 4 parts tetraethyl orthosilicate.

[0068] The graphene matrix has a D50 of 3 μm and a specific surface area of ​​1400 m². 2 / g;

[0069] The specific surface area was obtained by BET nitrogen adsorption.

[0070] After mixing graphene matrix and dilute sulfuric acid, the mixture was ultrasonically dispersed at an ultrasonic frequency of 90 kHz for 35 min. Then hydrogen peroxide was added, and the mixture was heated and stirred at 62 °C and a stirring speed of 300 r / min for 50 min. After centrifugation, the filter cake was collected and washed with deionized water until neutral to obtain edge-activated graphene.

[0071] Edge-activated graphene was added to an ethanol solution and stirred at 300 rpm for 50 min. The mixture was then cooled to 0°C, and tetraethyl orthosilicate was slowly added dropwise while stirring. After the addition was complete, the pH was adjusted to 9.1 with ammonia. The mixture was then kept at 0°C and stirred at 200 rpm for 35 min. After the reaction was complete, the mixture was centrifuged, the filter cake was collected, washed, and dried to obtain the precursor coating.

[0072] The slow addition refers to adding tetraethyl orthosilicate at a rate of 5 mL / min.

[0073] The precursor coating was heated to 800°C at a rate of 4°C / min in an inert atmosphere and reacted at high temperature for 70 min. After cooling, the material was discharged to obtain silica-coated graphene filler.

[0074] The silica-coated graphene filler includes a graphene matrix and silica coated on the surface of the graphene matrix, wherein the silica and the graphene matrix are bonded by Si-C chemical bonds.

[0075] Raw material preparation:

[0076] By weight, take 110 parts epoxy resin E-51, 75 parts curing agent, 7 parts accelerator, 9 parts silica-coated graphene filler, and 28 parts acetone.

[0077] The curing agent is selected from tetrahydrophthalic anhydride;

[0078] The accelerator is selected from 1-benzyl-2-methylimidazol;

[0079] Pre-dispersion:

[0080] First, the silica-coated graphene filler was mixed with acetone and dispersed for 20 minutes under ultrasonic frequency of 80 kHz. Then, epoxy resin E-51 was added and the mixture was stirred and dispersed for another 20 minutes at a speed of 500 r / min to obtain a pre-dispersion.

[0081] Curing system mixing:

[0082] Add curing agent and accelerator to the pre-dispersion liquid, and shear at a shear rate of 3100 r / min for 11 min. Discharge the material, pre-cur it at 82℃ for 110 min, then perform primary curing at 122℃ for 110 min, and finally post-cur it at 153℃ for 55 min. After cooling, the graphene epoxy resin composite material is obtained.

[0083] Example 3

[0084] Preparation of silica-coated graphene filler:

[0085] By weight, take 15 parts graphene matrix, 900 parts dilute sulfuric acid with a mass fraction of 15%, 8 parts hydrogen peroxide with a mass fraction of 20%, 600 parts ethanol solution with a mass fraction of 85%, and 5 parts tetraethyl orthosilicate.

[0086] The graphene matrix has a D50 of 5 μm and a specific surface area of ​​1500 m². 2 / g;

[0087] The specific surface area was obtained by BET nitrogen adsorption.

[0088] After mixing graphene matrix and dilute sulfuric acid, the mixture was ultrasonically dispersed at an ultrasonic frequency of 100 kHz for 40 min. Then hydrogen peroxide was added, and the mixture was heated and stirred at 65 ℃ and a stirring speed of 500 r / min for 60 min. After centrifugation, the filter cake was collected and washed with deionized water until neutral to obtain edge-activated graphene.

[0089] Edge-activated graphene was added to an ethanol solution and stirred at 300 rpm for 50 min. The mixture was then cooled to 0°C, and tetraethyl orthosilicate was slowly added dropwise while stirring. After the addition was complete, the pH was adjusted to 9.2 with ammonia. The mixture was then kept at 0°C and stirred at 200 rpm for 40 min. After the reaction was complete, the mixture was centrifuged, the filter cake was collected, washed, and dried to obtain the precursor coating.

[0090] The slow addition refers to adding tetraethyl orthosilicate at a rate of 6 mL / min.

[0091] The precursor coating was heated to 820°C at a rate of 5°C / min in an inert atmosphere and reacted at high temperature for 80 min. After cooling, the material was discharged to obtain silica-coated graphene filler.

[0092] The silica-coated graphene filler includes a graphene matrix and silica coated on the surface of the graphene matrix, wherein the silica and the graphene matrix are bonded by Si-C chemical bonds.

[0093] Raw material preparation:

[0094] By weight, take 120 parts epoxy resin E-51, 80 parts curing agent, 8 parts accelerator, 10 parts silica-coated graphene filler, and 30 parts acetone.

[0095] The curing agent is selected from hexahydrophthalic anhydride;

[0096] The accelerator is selected from 2-ethyl-4-methylimidazole;

[0097] Pre-dispersion:

[0098] First, the silica-coated graphene filler was mixed with acetone and dispersed for 20 minutes under ultrasonic frequency of 80 kHz. Then, epoxy resin E-51 was added and the mixture was stirred and dispersed for another 20 minutes at a speed of 500 r / min to obtain a pre-dispersion.

[0099] Curing system mixing:

[0100] Add curing agent and accelerator to the pre-dispersion liquid, and shear at a shear rate of 3200 r / min for 12 min. Discharge the material, pre-cur it at 85℃ for 120 min, then perform primary curing at 125℃ for 120 min, and finally post-cur it at 155℃ for 60 min. After cooling, the graphene epoxy resin composite material is obtained.

[0101] Example 4

[0102] The difference between this embodiment and Embodiment 1 is as follows:

[0103] The heat curing process differs, specifically:

[0104] Add curing agent and accelerator to the pre-dispersion liquid, and shear at high speed for 10 min at a shear rate of 3000 r / min. Discharge the material, cure at 150℃ for 120 min, and cool to obtain graphene epoxy resin composite material.

[0105] All other conditions remain unchanged.

[0106] Example 5

[0107] The difference between this embodiment and Embodiment 1 is as follows:

[0108] The preparation methods for silica-coated graphene fillers differ, specifically:

[0109] Preparation of silica-coated graphene filler:

[0110] By weight, take 10 parts graphene matrix, 800 parts concentrated sulfuric acid with a mass fraction of 90%, 20 parts hydrogen peroxide with a mass fraction of 20%, 500 parts ethanol solution with a mass fraction of 80%, and 3 parts tetraethyl orthosilicate.

[0111] The graphene matrix has a D50 of 1 μm and a specific surface area of ​​1200 m². 2 / g;

[0112] The specific surface area was obtained by BET nitrogen adsorption.

[0113] After mixing graphene matrix and concentrated sulfuric acid, the mixture was ultrasonically dispersed at an ultrasonic frequency of 80 kHz for 30 min. Then hydrogen peroxide was added, and the mixture was heated and stirred at 160 °C and a stirring speed of 200 r / min for 45 min. After centrifugation, the filter cake was collected and washed with deionized water until neutral to obtain activated graphene.

[0114] Activated graphene was added to an ethanol solution and stirred at 300 rpm for 50 min. Then, tetraethyl orthosilicate was slowly added dropwise while stirring. After the addition was completed, the pH was adjusted to 9.0 with ammonia. The reaction was then carried out at 60 °C and stirred at 200 rpm for 30 min. After the reaction was completed, the mixture was centrifuged, the filter cake was collected, washed, and dried to obtain the precursor coating.

[0115] The slow addition refers to adding tetraethyl orthosilicate at a rate of 4 mL / min.

[0116] The precursor coating was heated to 780°C at a rate of 3°C / min in an inert atmosphere and reacted at high temperature for 60 min. After cooling, the material was discharged to obtain silica-coated graphene filler.

[0117] All other conditions remain unchanged.

[0118] Because concentrated sulfuric acid was introduced during the oxidation process and the amount of hydrogen peroxide was increased, in addition to the edges being activated, too many oxygen-containing functional groups were introduced into the basal surface of graphene during the activation process, resulting in the basal surface being covered with too much silica.

[0119] Comparative Example 1

[0120] The difference between this comparative example and Example 1 is that the surface of the graphene is not coated with silicon dioxide, while the other conditions remain unchanged.

[0121] Comparative Example 2

[0122] The difference between this comparative example and Example 1 is as follows:

[0123] The precursor coating was directly used as a silica-coated graphene filler without undergoing a high-temperature reaction. Therefore, silica and graphene did not form Si-C chemical bonds directly.

[0124] The performance tests were conducted on the products obtained from the above embodiments and comparative examples. The specific test methods and results are as follows:

[0125] A cylindrical specimen was prepared according to the standard ASTM D695, with a diameter of 12.7 mm and a length of 25.4 mm.

[0126] First, test the compressive strength before the vibration test according to the above standards;

[0127] The parallel samples were then subjected to vibration tests using sinusoidal sweep vibration with a frequency range of 50-100Hz, an acceleration of 3g, and a test duration of 56 hours.

[0128] The compressive strength of the specimen after vibration was tested again according to the above standards.

[0129] Thus, the compressive strength retention rate before and after vibration can be calculated;

[0130] The above experiment was conducted with 5 parallel samples, and the average value was taken. The relevant results are shown in Table 1.

[0131] Table 1: Performance Test Results

[0132] Compressive strength retention rate / % Example 1 92.5 Example 2 93.2 Example 3 94.1 Example 4 90.2 Example 5 90.0 Comparative Example 1 79.9 Comparative Example 2 82.6

[0133] As can be seen from the test results in Table 1, the mechanical properties of the product obtained in the embodiment of the present invention are effectively preserved during the vibration test, thanks to the hindered propagation of microcracks. For example, the compressive strength of the product is also effectively preserved.

[0134] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a graphene-epoxy resin composite material, characterized in that, The specific preparation steps include: Raw material preparation: By weight, take 100-120 parts of epoxy resin E-51, 70-80 parts of curing agent, 6-8 parts of accelerator, 8-10 parts of silica-coated graphene filler, and 25-30 parts of acetone. Pre-dispersion: First, the silica-coated graphene filler is mixed and dispersed with acetone, then epoxy resin E-51 is added and the mixture is further dispersed evenly to obtain a pre-dispersion. Curing system mixing: Add curing agent and accelerator to the pre-dispersion liquid, mix evenly by high-speed shearing, discharge the material, heat and cure to obtain graphene epoxy resin composite material. The silica-coated graphene filler includes a graphene matrix and silica coated on the surface of the graphene matrix, wherein the silica and the graphene matrix are bonded by Si-C chemical bonds. The silica-coated graphene filler is prepared in the following manner: By weight, take 10-15 parts graphene matrix, 800-900 parts dilute sulfuric acid with a mass fraction of 10-15%, 6-8 parts hydrogen peroxide with a mass fraction of 20%, 500-600 parts ethanol solution with a mass fraction of 80-85%, and 3-5 parts tetraethyl orthosilicate. After mixing graphene matrix and dilute sulfuric acid, the mixture is ultrasonically dispersed evenly. Then hydrogen peroxide is added, and the mixture is heated and stirred at 60-65℃ for 45-60 minutes with a stirring speed of 200-500 r / min. After centrifugation and washing until neutral, edge-activated graphene is obtained. Edge-activated graphene was added to an ethanol solution and stirred until homogeneous. The solution was then cooled to 0°C and tetraethyl orthosilicate was slowly added dropwise while stirring. After the addition was complete, the pH was adjusted to 9.0-9.2 with ammonia. The mixture was then stirred for 30-40 minutes, centrifuged, washed, and dried to obtain the precursor coating. The precursor coating is placed in an inert atmosphere and reacted at a temperature of 780-820℃ for 60-80 minutes, then cooled and discharged.

2. The method for preparing a graphene-epoxy resin composite material according to claim 1, characterized in that, The graphene matrix has a D50 of 1-5 μm and a specific surface area of ​​1200-1500 m² / g. The specific surface area was obtained by BET nitrogen adsorption.

3. The method for preparing a graphene-epoxy resin composite material according to claim 1, characterized in that, The slow addition of tetraethyl orthosilicate is described as follows: tetraethyl orthosilicate is added dropwise at a rate of 4-6 mL / min.

4. The method for preparing a graphene-epoxy resin composite material according to claim 1, characterized in that, The curing agent is selected from any one of methyltetrahydrophthalic anhydride, tetrahydrophthalic anhydride, and hexahydrophthalic anhydride.

5. The method for preparing a graphene-epoxy resin composite material according to claim 1, characterized in that, The accelerator is selected from any one of 2-ethyl-4-methylimidazole, 1-benzyl-2-methylimidazole, and 1-cyanoethyl-2-ethyl-4-methylimidazole.

6. The method for preparing a graphene-epoxy resin composite material according to claim 1, characterized in that, The high-speed shear mixing includes: high-speed shearing for 10-12 minutes at a shear rate of 3000-3200 r / min.

7. The method for preparing a graphene-epoxy resin composite material according to claim 1, characterized in that, The heat curing includes: Pre-cur at 80-85℃ for 100-120 minutes; Subsequently, the primary curing was carried out at 120-125℃ for 100-120 minutes; Then cure at 150-155℃ for 50-60 minutes.

8. A graphene-epoxy resin composite material, characterized in that, It is prepared by the preparation method according to any one of claims 1-7.