A modified graphene-based heat dissipation coating, a preparation method and application thereof

Abstract

The application discloses a modified graphene-based heat dissipation coating and a preparation method and application thereof, and belongs to the technical field of heat dissipation coatings. The heat dissipation coating comprises the following raw materials in parts by weight: 97-113 parts of epoxy resin, 155-165 parts of acetone solution, 10-20 parts of modified graphene, 7-12 parts of modified spherical alumina, 1-3 parts of defoaming agent, 3-5 parts of coupling agent and 2-4 parts of resin curing agent. The prepared heat dissipation coating is modified by graphene, the compatibility of the graphene and a coating matrix is improved, the modified graphene can be uniformly dispersed in the coating, and the heat conduction performance of the graphene can be fully played; the modified graphene can also improve the heat resistance of the coating and prolong the service life of the coating in a high-temperature environment; the modified spherical alumina has good compatibility with the resin matrix, and the heat dissipation performance of the coating is further improved; therefore, the prepared heat dissipation coating has important application value in the field of electronic components and devices.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of heat dissipation coatings, and particularly relates to a modified graphene-based heat dissipation coating and a preparation method and application thereof. BACKGROUND

[0002] With the rapid development of modern electronic technology, the integration and power density of electronic devices are continuously improved, and the heat dissipation problem brought thereby is increasingly prominent. Electronic components generate a large amount of heat during operation, and if the heat cannot be effectively dissipated in time, the temperature of the device will rise, thereby affecting the performance stability and service life of the device. For example, high-performance computers, 5G communication base stations, high-power LED lighting devices, and battery management systems of electric vehicles all have higher requirements for heat dissipation materials. Relevant statistical data shows that when the operating temperature of an electronic component increases by 2℃, the reliability of the electronic component will decrease by 10%, and the service life at 50℃ is only 1 / 6 of that at 25℃. Therefore, the heat dissipation problem of electronic components has become a bottleneck for the development of the electronic industry. Traditional heat dissipation solutions mainly rely on metal heat sinks (such as aluminum or copper) or heat-conducting silicone grease, but these materials have problems such as heavy weight, limited heat conduction performance, or high interfacial thermal resistance, and are difficult to meet the needs of modern electronic devices for lightweight and efficient heat dissipation. Therefore, improving the thermal radiation efficiency of the metal surface through coating technology is an important way to improve the heat dissipation performance of metal materials.

[0003] Currently, the materials commonly used in mainstream heat dissipation coatings are mainly aluminum nitride, silicon carbide, hexagonal boron nitride, aluminum oxide, graphite, and graphene. Among them, graphene, as a two-dimensional material composed of a single layer of carbon atoms, has attracted much attention since its discovery in 2004 due to its excellent heat conduction performance (the theoretical heat conduction coefficient is as high as 5300 W / (m·K)), high specific surface area, and good mechanical strength. Studies have shown that the heat conduction performance of graphene far exceeds that of traditional metal materials such as copper and aluminum, making it an ideal candidate for thermal management materials. However, in practical applications, the interfacial compatibility of graphene with the coating matrix and large-scale preparation have limited its further promotion. For example, graphene layers are prone to stacking and agglomeration, which greatly reduces its heat conduction performance; in addition, the interfacial thermal resistance between graphene and the coating matrix is high, which affects the overall heat dissipation effect of the composite material. Furthermore, when the heat dissipation coating is in use, the temperature of some metal components is too high, which can cause the coating to age and fall off over a long period of use, greatly affecting the use of the heat dissipation coating. Therefore, it is urgent to solve the above problems to meet the higher application requirements of heat dissipation coatings in the field of electronic components. SUMMARY

[0004] The purpose of the present application is to overcome the defects of the prior art and provide a modified graphene-based heat dissipation coating and a preparation method and application thereof.

[0005] The purpose of the present application can be achieved by the following technical solutions:

[0006] A preparation method of a modified graphene-based heat dissipation coating, comprising the following steps:

[0007] The epoxy resin is dissolved in an acetone solution, then the modified graphene and the modified spherical alumina are added, and then a stirrer is used to stir and mix at a high speed of 1200-1500 r / min for 30-60 min, then a defoaming agent and a resin curing agent are added, and then low-speed stirring and mixing are performed at a speed of 100-300 r / min for 10-20 min, to obtain the modified graphene-based heat dissipation coating.

[0008] Further, the raw materials are as follows according to weight parts: 97-113 parts of epoxy resin, 155-165 parts of acetone solution, 10-20 parts of modified graphene, 7-12 parts of modified spherical alumina, 1-3 parts of defoaming agent, 3-5 parts of coupling agent, and 2-4 parts of resin curing agent.

[0009] Further, the defoaming agent is an organic silicon defoaming agent.

[0010] Further, the resin curing agent is one of 2-methyl imidazole, 2-ethyl-4-methyl imidazole and 2-phenyl imidazole.

[0011] Further, the modified spherical alumina is prepared by the following steps:

[0012] A1, aluminum nitrate (Al(NO3)3·9H2O) and deionized water are mixed, a magnetic stirrer is used for sufficient stirring, the aluminum salt is completely dissolved, ammonia water is slowly added during stirring, the pH value of the solution is adjusted to 8-9, an aluminum hydroxide precipitate is generated, and stirring is continued for 30 min to fully age the precipitate and form a stable suspension;

[0013] A2, the suspension obtained in step A1 is transferred to the feed tank of a spray dryer, the spray dryer is started, the suspension is atomized into small droplets, and spherical precursor particles are formed after drying;

[0014] A3, the precursor particles obtained in step A2 are placed in a muffle furnace, the temperature is raised at a rate of 5℃ / min to 1200℃, and the temperature is maintained for 2h, after calcination, the temperature is naturally cooled to room temperature, and spherical alumina particles are obtained;

[0015] A4, the spherical alumina particles obtained in step A3 are added to an ethanol aqueous solution (the volume ratio of ethanol to water is 9:1), ultrasonic dispersion is performed, then γ-glycidyl ether propyltrimethoxysilane is added, the reaction is carried out at 55℃ in a water bath for 6h, after the reaction is completed, centrifugal separation is performed, and vacuum drying is performed, to obtain modified spherical alumina.

[0016] Further, the ratio of the amount of aluminum nitrate and deionized water used in step A1 is 10g:100mL.

[0017] Further, the ratio of the amount of ethanol aqueous solution and γ-glycidoxypropyltrimethoxysilane used in step A4 is 100mL:6.7g.

[0018] The prepared modified spherical alumina is modified by silane, which enhances its surface hydrophobicity, improves its compatibility with epoxy resin, and also improves the heat resistance of the coating due to the low Na+ content and good thermal conductivity of the spherical alumina.

[0019] Further, the modified graphene is prepared by the following steps:

[0020] B1, under ice bath conditions, add concentrated sulfuric acid solution to the flask, then mix graphite powder with sodium nitrate, and then add it to the flask, stir and mix for 30min, pre-oxidize, continue to add potassium permanganate to the flask under ice bath conditions, the amount of each addition is the same, continue to stir for 3h, then remove the ice bath, heat the device again, react at 40℃ for 2h, then slowly add deionized water and heat to 90℃, react at this temperature for 20min, dilute with deionized water, then add hydrogen peroxide to reduce excess potassium permanganate, centrifuge, wash with hydrochloric acid solution and deionized water in sequence until pH=7, freeze-dry to obtain graphene oxide;

[0021] The reaction principle of step B1 is to use the improved Hummers method to oxidize graphene to prepare graphene oxide.

[0022] Step B2, install a condenser and a constant pressure dropping funnel on a dry three-necked flask, vacuum-nitrogen circulation three times to establish an inert reaction environment, add 3,5-dichlorophenol and tetrahydrofuran to the flask, stir until completely dissolved, then mix 4-amino-1,2,4-triazole, triethylamine and tetrahydrofuran, stir and dissolve, then use the constant pressure dropping funnel to add to the flask, after the addition is completed, constantly stir under water bath conditions at 50℃, react for 6h, filter after the reaction is completed, remove the solvent and excess triethylamine by rotary evaporation, and finally wash with distilled water several times to obtain the reaction product 1.

[0023] The reaction principle of step B2 is that 3,5-dichlorophenol and 4-amino-1,2,4-triazole undergo nucleophilic substitution reaction, triethylamine acts as an acid-binding agent to catalyze the reaction, and the molar ratio of the two is accurately controlled to be 1:2 to ensure complete reaction; the reaction formula is as follows:

[0024]

[0025] Step B3, install a condenser and a constant pressure dropping funnel on a dry three-neck flask, introduce nitrogen as a protective gas, add bisaminopropyl polydimethylsiloxane and toluene into the flask, place the device in an ice bath environment at 2℃, use the constant pressure dropping funnel to add the formaldehyde solution drop by drop, continuously stir during the dropping process, after the dropping process is completed, add the reaction product 1 into the flask, heat the device until the reaction temperature is maintained at 70℃, reflux the reaction for 6h, after the reaction is completed, filter, remove the solvent by rotary evaporation, purify by using a silica gel column chromatography to obtain the reaction product 2;

[0026] The reaction principle of Step B3 is that the amino group of bisaminopropyl polydimethylsiloxane, the hydroxyl group of the reaction product 1 and the formaldehyde undergo a Mannich condensation reaction to obtain the reaction product 2; the reaction formula is as follows:

[0027]

[0028] Step B4, mix graphene oxide with toluene, ultrasonically disperse the graphene oxide for 30min, then add 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide to activate the graphene oxide, then add the reaction product 2, increase the temperature to 50℃, stir the reaction for 1h, then stir the reaction at room temperature for 12h, after the reaction is completed, high-speed centrifugation, wash the precipitate with ethanol and water for multiple times, freeze-drying to obtain the modified graphene;

[0029] The reaction principle of Step B4 is that the carboxyl group of the activated graphene oxide can undergo an amidation reaction with the amino group of the reaction product 2 to obtain the modified graphene.

[0030] The graphene is modified by grafting organic molecular chains on the surface of the graphene, the organic molecular chains contain a large number of hydrophobic groups, the surface hydrophobicity of the graphene is improved, the compatibility of the graphene with the coating matrix is enhanced, and because the graphene has excellent heat conduction performance and good mechanical strength, the better compatibility means that the modified graphene can be more uniformly dispersed in the coating, the stacking and agglomeration of the graphene are reduced, the modified graphene can better play the performance, and the heat dissipation and mechanical properties of the coating are greatly enhanced, in addition, the organic molecular chains contain a polysiloxane structure, the structure mainly has Si-O bonds, the bond energy is high, and the flexibility is strong, so that the heat resistance and mechanical properties of the coating can be improved, finally, the organic molecular chains further introduce two heat-resistant groups of oxazine ring and triazole ring, the oxazine ring is a kind of six-membered heterocyclic compound containing oxygen atoms and nitrogen atoms, the C-O bond and C-N bond in the ring have high bond energy and are not easy to break at high temperature, so that the heat resistance of the coating is further improved; the triazole ring is a five-membered heterocyclic structure containing three nitrogen atoms, the nitrogen atoms form a stable aromatic structure through a conjugated system, and the C-N bond and N-N bond in the triazole ring have high bond energy and are not easy to break, so that the heat resistance of the coating is further improved, therefore, the polysiloxane, oxazine ring and triazole ring in the organic molecular chains can play a synergistic effect, and the heat resistance of the coating is significantly improved.

[0031] Further, the ratio of the amount of concentrated sulfuric acid solution, graphite powder, sodium nitrate and potassium permanganate in step B1 is 50mL:2g:1.2g:7.3g.

[0032] Further, the ratio of the amount of 3,5-dichlorophenol, tetrahydrofuran, 4-amino-1,2,4-triazole and triethylamine in step B2 is 16.1g:100mL:17.3g:23.1g.

[0033] Further, the ratio of the amount of bisaminopropyl polydimethylsiloxane, toluene, formaldehyde solution and reaction product 1 in step B3 is 100.0g:200mL:10mL:25.7g.

[0034] Further, the ratio of the amount of graphene oxide, toluene, 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride, N-hydroxysuccinimide and reaction product 2 in step B4 is 1g:100mL:3.7g:2.2g:15.8g.

[0035] The beneficial effects of the present application are as follows:

[0036] 1. The heat dissipation coating prepared in the present application is modified by modifying the graphene, the compatibility of the graphene with the coating matrix is improved, so that the modified graphene can be more uniformly dispersed in the coating, and the excellent heat conduction performance of the graphene can be fully played.

[0037] 2、The modified graphene contains three heat-resistant groups of polysiloxane structure, oxazine ring and triazole ring, the groups synergistically act to significantly improve the heat resistance of the coating, and prolong the service life of the coating in a high-temperature environment;

[0038] 3、The modified spherical alumina is modified by silane, the surface hydrophobicity is enhanced, the compatibility with the epoxy resin is improved, and the thermal conductivity of the material is further improved;

[0039] Therefore, the heat dissipation coating prepared by the application has excellent heat resistance, heat dissipation and mechanical properties, solves the shortcomings of traditional heat dissipation materials, prolongs the service life of electronic components, and has important application value in the field of electronic components. BRIEF DESCRIPTION OF DRAWINGS

[0040] The application will be further described below with reference to the drawings.

[0041] Figure 1 The scanning electron microscope image of the modified spherical alumina prepared in Example Three of the application. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0043] Example One

[0044] Preparation of modified graphene:

[0045] B1, under ice bath condition, 50mL concentrated sulfuric acid solution is added into a flask, then 2g graphite powder and 1.2g sodium nitrate are mixed and then added into the flask, stirring and mixing for 30min, pre-oxidation, 7.3g potassium permanganate is added into the flask in three times under ice bath condition, each time with the same amount, stirring for 3h, then the ice bath is removed, the device is heated, and the reaction is carried out at 40℃ for 2h, then deionized water is slowly added dropwise, and the temperature is increased to 90℃, the reaction is carried out at this temperature for 20min, deionized water is added for dilution, then hydrogen peroxide is added to reduce the excess potassium permanganate, centrifugation, washing with hydrochloric acid solution and deionized water in sequence until pH=7, and freeze-drying to obtain graphene oxide;

[0046] Step B2, install a condenser and a constant pressure dropping funnel on a dry three-port flask, vacuum-nitrogen circulation three times, establish an inert reaction environment, add 16.1 g of 3,5-dichlorophenol and 100 mL of tetrahydrofuran into the flask, stir until completely dissolved, then add 17.3 g of 4-amino-1,2,4-triazole, 23.1 g of triethylamine and tetrahydrofuran, stir to dissolve, then use the constant pressure dropping funnel to drop into the flask, after dropping is completed, continuously stir under the condition of a water bath at 50°C, react for 6 h, the reaction is completed, filter, remove the solvent and excess triethylamine by rotary evaporation, and finally wash with distilled water for multiple times to obtain reaction product 1;

[0047] Step B3, install a condenser and a constant pressure dropping funnel on a dry three-port flask, introduce nitrogen as a protective gas, add 100.0 g of bisaminopropyl polydimethylsiloxane (molecular weight 1000) and 200 mL of toluene into the flask, then place the device in an ice bath environment at 2°C, use a constant pressure dropping funnel to add 10 mL of formaldehyde solution drop by drop, continuously stir during the dropping process, after dropping is completed, add 25.7 g of reaction product 1 into the flask, heat the device until the reaction temperature is maintained at 70°C, reflux for 6 h, the reaction is completed, filter, remove the solvent by rotary evaporation, purify using a silica gel column, and obtain reaction product 2;

[0048] Step B4, mix 1 g of graphene oxide with 100 mL of toluene, ultrasonically disperse for 30 min, then add 3.7 g of 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and 2.2 g of N-hydroxysuccinimide to activate the graphene oxide, and then add 15.8 g of reaction product 2, increase the temperature to 50°C, stir for 1 h, then stir at room temperature for 12 h, the reaction is completed, high-speed centrifugation, the precipitate is washed with ethanol and water for multiple times, and freeze-drying to obtain modified graphene.

[0049] Example Two

[0050] Preparation of modified graphene:

[0051] B1, under the condition of an ice bath, add 100 mL of concentrated sulfuric acid solution into a flask, then mix 4 g of graphite powder with 2.4 g of sodium nitrate, and then add into the flask, stir and mix for 30 min for pre-oxidation, continue to add 14.6 g of potassium permanganate into the flask in three portions, continue to stir for 3 h, remove the ice bath, then heat the device, react for 2 h at 40°C, slowly drop deionized water, and increase the temperature to 90°C, react for 20 min at this temperature, dilute with deionized water, then add hydrogen peroxide to reduce the excess potassium permanganate, centrifuge, wash with hydrochloric acid solution and deionized water for multiple times until pH=7, and freeze-drying to obtain graphene oxide;

[0052] Step B2, install a condenser and a constant pressure dropping funnel on a dry three-necked flask, vacuum-nitrogen circulation for three times, establish an inert reaction environment, add 32.2 g of 3,5-dichlorophenol and 200 mL of tetrahydrofuran into the flask, stir until completely dissolved, then add 34.6 g of 4-amino-1,2,4-triazole, 23.1 g of triethylamine and tetrahydrofuran, after stirring and dissolving, drop into the flask using the constant pressure dropping funnel, after the dropping is completed, continuously stir under the condition of a water bath at 50°C, react for 6 h, after the reaction is completed, filter, remove the solvent and excess triethylamine by rotary evaporation, and finally wash with distilled water for multiple times to obtain a reaction product 1;

[0053] Step B3, install a condenser and a constant pressure dropping funnel on a dry three-necked flask, introduce nitrogen as a protective gas, add 200.0 g of bisaminopropyl polydimethylsiloxane (molecular weight 1000) and 400 mL of toluene into the flask, then place the device in an ice bath environment at 2°C, drop 20 mL of formaldehyde solution using a constant pressure dropping funnel, continuously stir during the dropping process, after the dropping is completed, add 51.4 g of the reaction product 1 into the flask, heat the device until the reaction temperature is maintained at 70°C, reflux for 6 h, after the reaction is completed, filter, remove the solvent by rotary evaporation, purify using a silica gel column chromatography to obtain a reaction product 2;

[0054] Step B4, mix 2 g of graphene oxide with 200 mL of toluene, ultrasonically disperse for 30 min, then add 7.4 g of 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and 4.4 g of N-hydroxysuccinimide to activate the graphene oxide, further add 31.6 g of the reaction product 2, increase the temperature to 50°C, stir for 1 h, then stir at room temperature for 12 h after the reaction is completed, high-speed centrifugation, sequentially wash the precipitate with ethanol and water for multiple times, and freeze-dry to obtain modified graphene.

[0055] Example Three

[0056] Preparation of modified spherical alumina:

[0057] A1, mix 10 g of aluminum nitrate and 100 mL of deionized water, fully stir using a magnetic stirrer to completely dissolve the aluminum salt, slowly drop ammonia water during stirring to adjust the pH value of the solution to 8-9 to generate aluminum hydroxide precipitate, continue to stir for 30 min to fully age the precipitate and form a stable suspension;

[0058] A2, transfer the suspension obtained in step A1 into the feed tank of a spray dryer, start the spray dryer to atomize the suspension into tiny droplets, and form spherical precursor particles after drying;

[0059] A3, the precursor particles obtained in step A2 were placed in a muffle furnace and heated to 1200°C at a heating rate of 5°C / min and maintained for 2h, and then naturally cooled to room temperature to obtain spherical alumina particles;

[0060] A4, the spherical alumina particles obtained in step A3 were added to 100mL of an ethanol aqueous solution (volume ratio of ethanol to water was 9:1), and then ultrasonically dispersed, and then 6.7g of γ-glycidoxypropyltrimethoxysilane was added, and then the mixture was reacted in a water bath at 55°C for 6h, and then centrifuged and vacuum dried to obtain modified spherical alumina; a scanning electron microscope image of the modified spherical alumina is shown in FIG. 2. Figure 1

[0061] Example Four

[0062] 97g of epoxy resin was dissolved in 155g of an acetone solution, and then 10g of the modified graphene obtained in Example One and 7g of the modified spherical alumina obtained in Example Four were added, and then the mixture was stirred at a high speed of 1200r / min for 30min, and then 1g of a silicone defoaming agent (BYK-028) and 2g of 2-methyl imidazole were added, and then the mixture was stirred at a low speed of 100r / min for 10min to obtain a modified graphene heat dissipation coating.

[0063] Example Five

[0064] 105g of epoxy resin was dissolved in 160g of an acetone solution, and then 15g of the modified graphene obtained in Example Two and 10g of the modified spherical alumina obtained in Example Four were added, and then the mixture was stirred at a high speed of 1300r / min for 45min, and then 2g of a silicone defoaming agent (BYK-028) and 3g of 2-ethyl-4-methyl imidazole were added, and then the mixture was stirred at a low speed of 200r / min for 15min to obtain a modified graphene heat dissipation coating.

[0065] Example Six

[0066] 113g of epoxy resin was dissolved in 165g of an acetone solution, and then 20g of the modified graphene obtained in Example Two and 12g of the modified spherical alumina obtained in Example Four were added, and then the mixture was stirred at a high speed of 1500r / min for 60min, and then 3g of a silicone defoaming agent (BYK-028) and 4g of 2-phenyl imidazole were added, and then the mixture was stirred at a low speed of 300r / min for 20min to obtain a modified graphene heat dissipation coating.

[0067] Comparative Example One

[0068] In the preparation process of Example Six, only the modified graphene was replaced with an equal amount of ordinary graphene, and the other conditions were unchanged to obtain a heat dissipation coating.​

[0069] Comparative Example Two

[0070] The commercially available graphene heat dissipation coating was used.

[0071] Examples Four, Five, Six, Comparative Examples One and Two were tested for performance according to different test standards as follows:

[0072] The impact resistance was determined using the national standard GB / T 1732 “Paint film impact resistance test method”;

[0073] The impact resistance after the sample was placed in an environment of 250℃ for 12h (GB / T 1732) was determined using the national standard GB / T 1735 “Determination of heat resistance of color paint and varnish”, and the impact resistance retention rate was calculated; impact resistance retention rate = impact resistance after test / impact resistance before test x 100%;

[0074] The thermal conductivity of the sample was determined using the thermal resistance method;

[0075] The results are shown in the following table:

[0076]

[0077] As shown in the above table, the thermal conductivity of the coating prepared in the examples is higher than that of the comparative examples after adding the modified graphene, which also makes the heat dissipation performance of the coating higher than that of the comparative examples. In addition, the mechanical properties and heat resistance of the examples are better than those of the comparative examples. Therefore, the coating after adding the modified graphene has excellent performance and has important application value in the field of electronic components.

[0078] In the description of the specification, the description of the reference terms “one embodiment”, “example”, “specific example” and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0079] The above is only an example and description of the present application, and those skilled in the art can make various modifications or supplements to the described specific embodiments or use similar ways to replace them, as long as they do not deviate from the invention or exceed the scope defined by the present claims, which shall belong to the protection scope of the present application.

Claims

1. A method for preparing a heat-dissipating coating based on modified graphene, characterized in that, Includes the following steps: Epoxy resin is dissolved in acetone solution, then modified graphene and modified spherical alumina are added, and the mixture is stirred at high speed of 1200-1500 r / min. Then, defoamer and resin curing agent are added, and the mixture is stirred at low speed of 100-300 r / min to obtain a heat dissipation coating of modified graphene. The modified graphene is prepared through the following steps: B1. Under ice bath conditions, add concentrated sulfuric acid solution to the flask, then mix graphite powder and sodium nitrate, add to the flask, stir and mix, add potassium permanganate to the flask, continue stirring for 3 hours, heat, react at 40°C for 2 hours, then slowly add deionized water, react at 90°C for 20 minutes, dilute, centrifuge, wash, dry, and obtain graphene oxide. Step B2: Add 3,5-dichlorophenol and tetrahydrofuran to the flask, stir, then mix 4-amino-1,2,4-triazole, triethylamine and tetrahydrofuran, stir to dissolve, add to the flask, and react at 50°C for 6 hours. The reaction is complete, and reaction product 1 is obtained. Step B3: Add diaminopropyl polydimethylsiloxane and toluene to a flask, add formaldehyde solution in an ice bath at 2°C, then add reaction product 1 to the flask, reflux at 70°C for 6 hours, and the reaction is complete to obtain reaction product 2. Step B4: Mix graphene oxide with toluene and sonicate for 30 min to disperse the graphene oxide evenly. Then add 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide, followed by reaction product 2. React at 50°C for 1 h and at room temperature for 12 h until the reaction is complete, and obtain modified graphene.

2. The method for preparing a heat dissipation coating based on modified graphene according to claim 1, characterized in that, In step B1, the ratio of concentrated sulfuric acid solution, graphite powder, sodium nitrate, and potassium permanganate is 50 mL: 2 g: 1.2 g: 7.3 g.

3. The method for preparing a heat dissipation coating based on modified graphene according to claim 1, characterized in that, In step B2, the ratio of the amounts of 3,5-dichlorophenol, tetrahydrofuran, 4-amino-1,2,4-triazole, and triethylamine is 16.1 g: 100 mL: 17.3 g: 23.1 g.

4. The method for preparing a heat dissipation coating based on modified graphene according to claim 1, characterized in that, In step B3, the ratio of the amounts of diaminopropyl polydimethylsiloxane, toluene, formaldehyde solution, and reaction product 1 is 100.0g:200mL:10mL:25.7g.

5. The method for preparing a heat dissipation coating based on modified graphene according to claim 1, characterized in that, In step B4, the ratio of graphene oxide, toluene, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide, and reaction product 2 is 1 g: 100 mL: 3.7 g: 2.2 g: 15.8 g.

6. The method for preparing a heat dissipation coating based on modified graphene according to claim 1, characterized in that, The modified spherical alumina is obtained through the following steps: A1. Mix aluminum nitrate and deionized water, stir thoroughly, adjust the pH to 8-9, and continue stirring to obtain a suspension; A2. The suspension obtained in step A1 is atomized into tiny droplets in a spray dryer and dried to form spherical precursor particles. A3. Place the precursor particles obtained in step A2 into a muffle furnace for calcination. After calcination, allow it to cool naturally to room temperature to obtain spherical alumina particles. A4. Add the spherical alumina particles obtained in step A3 to an ethanol aqueous solution, disperse them evenly by ultrasonication, add γ-glycidoxypropyltrimethoxysilane, and react for 6 hours under a water bath at 55°C. After the reaction is complete, centrifuge and vacuum dry to obtain modified spherical alumina.

7. The method for preparing a heat dissipation coating based on modified graphene according to claim 1, characterized in that, The raw materials are as follows by weight: 97-113 parts epoxy resin, 155-165 parts acetone solution, 10-20 parts modified graphene, 7-12 parts modified spherical alumina, 1-3 parts defoamer, and 2-4 parts resin curing agent.

8. A heat-dissipating coating based on modified graphene, characterized in that, Prepared according to the method according to any one of claims 1-7.

9. The application of the modified graphene-based heat dissipation coating according to claim 8 in the field of electronic components.

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