Heat dissipation coating based on modified graphene as well as preparation method and application of heat dissipation coating

Abstract

The invention discloses a heat dissipation coating based on modified graphene as well as a preparation method and application thereof, and belongs to the technical field of heat dissipation coatings. Comprising the following raw materials in parts by weight: 97-113 parts of epoxy resin, 155-165 parts of an acetone solution, 10-20 parts of modified graphene, 7-12 parts of modified spherical aluminum oxide, 1-3 parts of a defoaming agent, 3-5 parts of a coupling agent and 2-4 parts of a resin curing agent. According to the heat dissipation coating prepared by the invention, the graphene is modified, so that the compatibility of the graphene and a coating matrix is improved, the modified graphene can be uniformly dispersed in the coating, and the heat-conducting property of the modified graphene can be fully exerted; 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 aluminum oxide has good compatibility with a resin matrix, and the heat dissipation performance of the coating is further improved, so that the heat dissipation coating prepared by the invention has important application value in the field of electronic components.

Description

Technical Field

[0001] The present invention belongs to the technical field of heat dissipation coatings, and in particular, relates to a heat dissipation coating based on modified graphene, a preparation method thereof, and applications thereof. Background Art

[0002] With the rapid development of modern electronic technology, the integration and power density of electronic devices are constantly increasing, leading to increasingly prominent heat dissipation issues. Electronic components generate significant amounts of heat during operation. If this heat cannot be dissipated promptly and effectively, the device temperature will rise, impacting performance stability and service life. For example, high-performance computers, 5G communication base stations, high-power LED lighting, and battery management systems for electric vehicles all place higher demands on heat dissipation materials. Statistics show that for every 2°C increase in operating temperature, the reliability of electronic components decreases by 10%, and the service life at 50°C is only one-sixth of that at 25°C. Therefore, heat dissipation issues for electronic components have become a bottleneck in the development of the electronics industry. Traditional heat dissipation solutions primarily rely on metal heat sinks (such as aluminum or copper) or thermal grease. However, these materials are heavy, have limited thermal conductivity, or have high interfacial thermal resistance, making them inadequate for meeting the lightweight and efficient heat dissipation requirements of modern electronic devices. Therefore, improving the thermal radiation efficiency of metal surfaces through coating technologies is an important approach to improving 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, 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 thermal conductivity (theoretical thermal conductivity is as high as 5300W / (m·K)), high specific surface area and good mechanical strength. Studies have shown that the thermal conductivity 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, problems such as the interface compatibility between graphene and the coating matrix and large-scale preparation have limited its further promotion. For example, graphene sheets are prone to stacking and agglomeration, resulting in a significant decrease in its thermal conductivity; in addition, the interfacial thermal resistance between graphene and the coating matrix is ​​high, which affects the heat dissipation effect of the overall composite material. Not only that, when the heat dissipating paint is used, the temperature of some metal components is too high. Long-term use will cause the paint to age due to heat and then fall off, which greatly affects the use of the heat dissipating paint. Therefore, it is urgent to solve the above problems to meet the higher application requirements of heat dissipating paint in the field of electronic components. Summary of the Invention

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

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A method for preparing a heat dissipation coating based on modified graphene comprises the following steps:

[0007] The epoxy resin is dissolved in an acetone solution, and then the modified graphene and modified spherical alumina are added. Subsequently, the mixture is stirred and mixed at a high speed of 1200-1500 r / min for 30-60 minutes with a stirrer. Then, a defoaming agent and a resin curing agent are added, and the mixture is stirred and mixed at a low speed of 100-300 r / min for 10-20 minutes to obtain a modified graphene heat dissipation coating.

[0008] Furthermore, the raw materials are calculated in parts by weight as follows: 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] Furthermore, the defoaming agent is a silicone defoaming agent.

[0010] Furthermore, the resin curing agent is one of 2-methylimidazole, 2-ethyl-4-methylimidazole and 2-phenylimidazole.

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

[0012] A1. Mix aluminum nitrate (Al(NO3)3·9H2O) and deionized water and stir thoroughly with a magnetic stirrer to completely dissolve the aluminum salt. Slowly add ammonia water dropwise during stirring to adjust the pH of the solution to 8-9 to form aluminum hydroxide precipitate. Continue stirring for 30 minutes to allow the precipitate to fully age and form a stable suspension.

[0013] A2. Transfer the suspension obtained in step A1 to the feed tank of a spray dryer, start the spray dryer, atomize the suspension into tiny droplets, and form spherical precursor particles after drying;

[0014] A3. Place the precursor particles obtained in step A2 in a muffle furnace and heat them to 1200°C at a heating rate of 5°C / min. Keep the temperature for 2 hours. After calcination, cool the mixture naturally to room temperature to obtain spherical alumina particles.

[0015] A4. Add the spherical alumina particles obtained in step A3 to an ethanol aqueous solution (the volume ratio of ethanol to water is 9:1), ultrasonically disperse them evenly, add γ-glycidyloxypropyltrimethoxysilane, and react in a water bath at 55°C for 6 hours. After the reaction is complete, centrifuge and vacuum dry to obtain modified spherical alumina.

[0016] Furthermore, in step A1, the ratio of aluminum nitrate to deionized water is 10 g:100 mL.

[0017] Furthermore, in step A4, the ratio of the ethanol aqueous solution to γ-glycidyloxypropyltrimethoxysilane is 100 mL:6.7 g.

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

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

[0020] B1. Under ice bath conditions, concentrated sulfuric acid solution was added to the flask, and then graphite powder and sodium nitrate were mixed, and then added to the flask, stirred and mixed for 30 minutes for pre-oxidation. Potassium permanganate was added to the flask three times under ice bath conditions, and the same amount was added each time. After stirring for 3 hours, the ice bath was removed, and the apparatus was heated at 40°C for 2 hours. Deionized water was then slowly added dropwise, and the temperature was raised to 90°C. The reaction was carried out at this temperature for 20 minutes, and deionized water was added to dilute it. Then, hydrogen peroxide was added to reduce the excess potassium permanganate, centrifuged, and washed with hydrochloric acid solution and deionized water to pH = 7, and freeze-dried to obtain graphene oxide;

[0021] The reaction principle of step B1 is: using a modified Hummers method to oxidize graphene to prepare graphene oxide;

[0022] Step B2, a condenser and a constant pressure dropping funnel were installed on a dry three-necked flask, and vacuum-filled with nitrogen was cycled three times to establish an inert reaction environment. 3,5-dichlorophenol and tetrahydrofuran were added to the flask and stirred until completely dissolved. Then, 4-amino-1,2,4-triazole, triethylamine and tetrahydrofuran were mixed and stirred to dissolve. After stirring, the mixture was added dropwise to the flask using a constant pressure dropping funnel. After the addition was complete, the mixture was stirred continuously in a water bath at 50°C for 6 hours. After the reaction was completed, the mixture was filtered, and the solvent and excess triethylamine were removed by rotary evaporation. Finally, the mixture was washed several times with distilled water to obtain a reaction product 1;

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

[0024]

[0025] Step B3, a condenser and a constant pressure dropping funnel were installed on a dry three-necked flask, nitrogen was introduced as a protective gas, bisaminopropyl polydimethylsiloxane and toluene were added to the flask, and the apparatus was placed in an ice bath environment at 2 ° C. Using a constant pressure dropping funnel, formaldehyde solution was added dropwise, and stirring was continued during the addition process. After the addition was completed, reaction product 1 was added to the flask, and the apparatus was heated until the reaction temperature was maintained at 70 ° C. Reflux reaction for 6 hours. After the reaction was completed, it was filtered, the solvent was removed by rotary evaporation, and purified by silica gel column chromatography to obtain reaction product 2;

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

[0027]

[0028] Step B4, mixing graphene oxide with toluene, ultrasonicating for 30 minutes to uniformly disperse the graphene oxide, then adding 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide to activate the graphene oxide, and then adding reaction product 2, raising the temperature to 50 ° C., stirring and reacting for 1 hour, and then stirring the reaction system at room temperature for 12 hours. After the reaction is completed, high-speed centrifugation is performed, and the precipitate is washed with ethanol and water multiple times, and freeze-dried to obtain modified graphene;

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

[0030] Graphene is modified by grafting organic molecular chains on the surface of graphene. The organic molecular chains contain a large number of hydrophobic groups, which improve the surface hydrophobicity of graphene and enhance the compatibility of graphene with the coating matrix. Graphene has excellent thermal conductivity and good mechanical strength. Better compatibility means that the modified graphene can be dispersed more evenly in the coating, reducing the stacking and agglomeration of graphene, so that the modified graphene can better perform its performance and greatly enhance the heat dissipation and mechanical properties of the coating. In addition, the organic molecular chain contains a polysiloxane structure with Si-O bonds as the main chain. It not only has high bond energy but also strong flexibility, which can improve the heat resistance and mechanical properties of the coating. Finally, two heat-resistant groups, oxazine ring and triazole ring, are introduced into the organic molecular chain. Among them, the oxazine ring is a type of six-membered heterocyclic compound containing oxygen atoms and nitrogen atoms. The CO bond and CN bond in the ring have high bond energy and are not easy to break at high temperatures, which can further improve the heat resistance of the coating; the triazole ring is a five-membered heterocyclic structure containing three nitrogen atoms. These nitrogen atoms form a stable aromatic structure through a conjugated system, and the CN bond and NN bond in the triazole ring have high bond energy and are not easy to break, which further improves the heat resistance of the coating. Therefore, the polysiloxane, oxazine ring and triazole ring in the organic molecular chain can play a synergistic role and significantly improve the heat resistance of the coating.

[0031] Furthermore, 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.

[0032] Furthermore, in step B2, the ratio 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.

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

[0034] Furthermore, 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.

[0035] Beneficial effects of the present invention:

[0036] 1. The heat dissipation coating prepared by the present invention improves the compatibility of graphene with the coating matrix by modifying graphene, so that the modified graphene can be more evenly dispersed in the coating, giving full play to its excellent thermal conductivity;

[0037] 2. The modified graphene contains three heat-resistant groups: polysiloxane structure, oxazine ring and triazole ring. These groups work synergistically to significantly improve the heat resistance of the coating and extend the service life of the coating in high temperature environments;

[0038] 3. Modified spherical alumina is modified by silane, which enhances its surface hydrophobicity, improves its compatibility with epoxy resin, and further improves the thermal conductivity of the material;

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

[0040] The present invention will be further described below with reference to the accompanying drawings.

[0041] Figure 1 This is a scanning electron microscope image of the modified spherical alumina prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0042] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0043] Example 1

[0044] Preparation of modified graphene:

[0045] B1. Under ice bath conditions, 50 mL of concentrated sulfuric acid solution was added to the flask, and then 2 g of graphite powder was mixed with 1.2 g of sodium nitrate, and then added to the flask, stirred and mixed for 30 min for pre-oxidation. Continuing under ice bath conditions, 7.3 g of potassium permanganate was added to the flask three times, each adding the same amount. After stirring for 3 h, the ice bath was removed, and the apparatus was heated at 40 ° C for 2 h. Deionized water was then slowly added dropwise, and the temperature was raised to 90 ° C. The reaction was carried out at this temperature for 20 min, deionized water was added to dilute, and then hydrogen peroxide was added to reduce the excess potassium permanganate. The mixture was centrifuged and washed with hydrochloric acid solution and deionized water to pH = 7, and freeze-dried to obtain graphene oxide;

[0046] Step B2, a condenser and a constant pressure dropping funnel were installed on a dry three-necked flask, and the vacuum-nitrogen filling cycle was repeated three times to establish an inert reaction environment. 16.1 g of 3,5-dichlorophenol and 100 mL of tetrahydrofuran were added to the flask and stirred until completely dissolved. Then, 17.3 g of 4-amino-1,2,4-triazole and 23.1 g of triethylamine were mixed with tetrahydrofuran, stirred and dissolved, and then added dropwise to the flask using a constant pressure dropping funnel. After the addition was complete, the mixture was stirred continuously in a water bath at 50 ° C. The reaction was reacted for 6 h. After the reaction was completed, the mixture was filtered, and the solvent and excess triethylamine were removed by rotary evaporation. Finally, the mixture was washed several times with distilled water to obtain a reaction product 1;

[0047] Step B3, a condenser and a constant pressure dropping funnel were installed on a dry three-necked flask, nitrogen was introduced as a protective gas, 100.0 g of bisaminopropyl polydimethylsiloxane (molecular weight 1000) and 200 mL of toluene were added to the flask, and the apparatus was placed in an ice bath at 2 ° C. Using a constant pressure dropping funnel, 10 mL of formaldehyde solution was added dropwise. The addition process was continuously stirred. After the addition was completed, 25.7 g of reaction product 1 was added to the flask, and the apparatus was heated until the reaction temperature was maintained at 70 ° C. The reaction was refluxed for 6 hours. After the reaction was completed, it was filtered, the solvent was removed by rotary evaporation, and purified by silica gel column chromatography to obtain reaction product 2;

[0048] Step B4, 1 g of graphene oxide was mixed with 100 mL of toluene, and the graphene oxide was evenly dispersed by ultrasonication for 30 min. Subsequently, 3.7 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 2.2 g of N-hydroxysuccinimide were added to activate the graphene oxide. Then, 15.8 g of reaction product 2 was added, the temperature was raised to 50 ° C, and the reaction was stirred for 1 h. The reaction system was stirred at room temperature for 12 h. After the reaction was completed, the precipitate was centrifuged at high speed, and washed with ethanol and water several times in sequence, and freeze-dried to obtain modified graphene.

[0049] Example 2

[0050] Preparation of modified graphene:

[0051] B1. Under ice bath conditions, 100 mL of concentrated sulfuric acid solution was added to the flask, and then 4 g of graphite powder was mixed with 2.4 g of sodium nitrate, and then added to the flask, stirred and mixed for 30 min for pre-oxidation. Continuing under ice bath conditions, 14.6 g of potassium permanganate was added to the flask three times, each adding the same amount. After stirring for 3 h, the ice bath was removed, and the apparatus was heated at 40 ° C for 2 h. Deionized water was then slowly added dropwise, and the temperature was raised to 90 ° C. The reaction was carried out at this temperature for 20 min, deionized water was added to dilute, and then hydrogen peroxide was added to reduce the excess potassium permanganate. The mixture was centrifuged and washed with hydrochloric acid solution and deionized water to pH = 7, and freeze-dried to obtain graphene oxide;

[0052] Step B2, a condenser and a constant pressure dropping funnel were installed on a dry three-necked flask, and the vacuum-nitrogen filling cycle was repeated three times to establish an inert reaction environment. 32.2 g of 3,5-dichlorophenol and 200 mL of tetrahydrofuran were added to the flask and stirred until completely dissolved. Then, 34.6 g of 4-amino-1,2,4-triazole and 23.1 g of triethylamine were mixed with tetrahydrofuran, stirred and dissolved, and then added dropwise to the flask using a constant pressure dropping funnel. After the addition was complete, the mixture was stirred continuously in a water bath at 50 ° C. for 6 h. The reaction was completed, filtered, and the solvent and excess triethylamine were removed by rotary evaporation. Finally, the mixture was washed several times with distilled water to obtain a reaction product 1;

[0053] Step B3, a condenser and a constant pressure dropping funnel were installed on a dry three-necked flask, nitrogen was introduced as a protective gas, 200.0 g of bisaminopropyl polydimethylsiloxane (molecular weight 1000) and 400 mL of toluene were added to the flask, and the apparatus was placed in an ice bath at 2 ° C. Using a constant pressure dropping funnel, 20 mL of formaldehyde solution was added dropwise. The addition process was continuously stirred. After the addition was completed, 51.4 g of reaction product 1 was added to the flask, and the apparatus was heated until the reaction temperature was maintained at 70 ° C. The reaction was refluxed for 6 hours. After the reaction was completed, it was filtered, the solvent was removed by rotary evaporation, and purified by silica gel column chromatography to obtain reaction product 2;

[0054] Step B4, 2 g of graphene oxide was mixed with 200 mL of toluene, and the graphene oxide was evenly dispersed by ultrasound for 30 min. Subsequently, 7.4 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 4.4 g of N-hydroxysuccinimide were added to activate the graphene oxide. 31.6 g of reaction product 2 was added, the temperature was raised to 50 ° C, and the reaction was stirred for 1 h. The reaction system was stirred at room temperature for 12 h. After the reaction was completed, the precipitate was centrifuged at high speed, and washed with ethanol and water several times in sequence, and freeze-dried to obtain modified graphene.

[0055] Example 3

[0056] Preparation of modified spherical alumina:

[0057] A1. Mix 10 g of aluminum nitrate and 100 mL of deionized water and stir thoroughly with a magnetic stirrer to completely dissolve the aluminum salt. Slowly add aqueous ammonia dropwise during stirring to adjust the pH of the solution to 8-9 to form aluminum hydroxide precipitate. Continue stirring for 30 min to allow the precipitate to fully age and form a stable suspension.

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

[0059] A3. Place the precursor particles obtained in step A2 in a muffle furnace and heat them to 1200°C at a heating rate of 5°C / min. Keep the temperature for 2 hours. After calcination, cool the mixture naturally to room temperature to obtain spherical alumina particles.

[0060] A4. The spherical alumina particles obtained in step A3 were added to 100 mL of ethanol-water solution (the volume ratio of ethanol to water was 9:1), and after uniform ultrasonic dispersion, 6.7 g of γ-glycidyloxypropyltrimethoxysilane was added. The mixture was reacted in a water bath at 55° C. for 6 h. After the reaction was completed, the mixture was centrifuged and dried in vacuo to obtain modified spherical alumina. The electron micrograph of the modified spherical alumina was obtained using a scanning electron microscope. Figure 1 shown.

[0061] Example 4

[0062] 97 g of epoxy resin was dissolved in 155 g of acetone solution, and then 10 g of the modified graphene prepared in Example 1 and 7 g of the modified spherical alumina prepared in Example 4 were added. After that, the mixture was stirred at a high speed of 1200 r / min with a stirrer for 30 min. Then, 1 g of silicone defoamer (BYK-028) and 2 g of 2-methylimidazole were added, and then stirred at a low speed of 100 r / min for 10 min to obtain a modified graphene heat dissipation coating.

[0063] Example 5

[0064] 105 g of epoxy resin was dissolved in 160 g of acetone solution, and then 15 g of the modified graphene prepared in Example 2 and 10 g of the modified spherical alumina prepared in Example 4 were added. After that, the mixture was stirred at a high speed of 1300 r / min with a stirrer for 45 minutes. Then, 2 g of silicone defoamer (BYK-028) and 3 g of 2-ethyl-4-methylimidazole were added, and then stirred at a low speed of 200 r / min for 15 minutes to obtain a modified graphene heat dissipation coating.

[0065] Example 6

[0066] 113 g of epoxy resin was dissolved in 165 g of acetone solution, and then 20 g of the modified graphene prepared in Example 2 and 12 g of the modified spherical alumina prepared in Example 4 were added. After that, the mixture was stirred at a high speed of 1500 r / min with a stirrer for 60 min. Then, 3 g of silicone defoamer (BYK-028) and 4 g of 2-phenylimidazole were added, and then stirred at a low speed of 300 r / min for 20 min to obtain a modified graphene heat dissipation coating.

[0067] Comparative Example 1

[0068] In the preparation process of Example 6, only the modified graphene was replaced with an equal amount of ordinary graphene, and other conditions remained unchanged to prepare the heat dissipation coating.

[0069] Comparative Example 2

[0070] Use commercially available graphene heat dissipation paint.

[0071] The following performance tests were conducted on Examples 4, 5, and 6 and Comparative Examples 1 and 2 according to different test standards:

[0072] The impact resistance is measured using the national standard GB / T 1732 "Determination of impact resistance of paint films";

[0073] The impact resistance of the sample after standing at 250°C for 12 hours was measured using the national standard GB / T 1735 "Determination of Heat Resistance of Paints and Varnishes" (GB / T 1732). The impact resistance retention rate was calculated as follows: impact resistance retention rate = impact resistance after test / impact resistance before test × 100%.

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

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

[0076]

[0077] It can be seen from the above table that the thermal conductivity of the coating prepared in the embodiment of the present invention is higher than that of the comparative example after the modified graphene is added, which also makes the heat dissipation performance of the coating higher than that of the comparative example. In addition, the mechanical properties and heat resistance of the embodiment are also better than those of the comparative example. Therefore, the coating after the modified graphene is added has excellent performance and has important application value in the field of electronic components.

[0078] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0079] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a heat dissipation coating based on modified graphene, characterized in that: The following steps are involved: The epoxy resin is dissolved in an acetone solution, and then the modified graphene and modified spherical alumina are added, and after high-speed stirring and mixing, a defoaming agent and a resin curing agent are added, and then low-speed stirring and mixing are performed to obtain a modified graphene heat dissipation coating.

2. The method for preparing a heat dissipation coating based on modified graphene according to claim 1, characterized in that: The modified graphene is prepared by the following steps: B1. In an ice bath, concentrated sulfuric acid solution was added to a flask, and then graphite powder and sodium nitrate were mixed, added to the flask, and stirred to mix. Potassium permanganate was added to the flask, and stirring was continued for 3 hours. The mixture was heated and reacted at 40°C for 2 hours. Deionized water was then slowly added dropwise, and the mixture was reacted at 90°C for 20 minutes. The mixture was diluted, centrifuged, washed, and dried to obtain graphene oxide. Step B2: 3,5-dichlorophenol and tetrahydrofuran were added to a flask and stirred. 4-amino-1,2,4-triazole, triethylamine and tetrahydrofuran were then mixed and stirred to dissolve. The mixture was then added to the flask and reacted at 50° C. for 6 h. The reaction was completed to obtain reaction product 1. Step B3: Add bisaminopropyl polydimethylsiloxane and toluene to a flask, add formaldehyde solution in an ice bath at 2°C, then add reaction product 1 to the flask, and reflux at 70°C for 6 hours. The reaction is completed to obtain reaction product 2; Step B4: Mix graphene oxide with toluene, ultrasonicate for 30 minutes to evenly disperse the graphene oxide, then add 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide, and then add reaction product 2. React at 50°C for 1 hour and at room temperature for 12 hours. The reaction is completed to obtain modified graphene.

3. The method for preparing a heat dissipation coating based on modified graphene according to claim 2, 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.

4. The method for preparing a heat dissipation coating based on modified graphene according to claim 2, characterized in that: In step B2, the ratio 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.

5. The method for preparing a heat dissipation coating based on modified graphene according to claim 2, characterized in that: In step B3, the ratio of bisaminopropyl polydimethylsiloxane, toluene, formaldehyde solution, and reaction product 1 is 100.0 g:200 mL:10 mL:25.7 g.

6. The method for preparing a heat dissipation coating based on modified graphene according to claim 2, 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.

7. The method for preparing a heat dissipation coating based on modified graphene according to claim 1, characterized in that: The modified spherical alumina is prepared by 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 spherical precursor particles are formed after drying; A3. The precursor particles obtained in step A2 are placed in a muffle furnace and calcined. After calcination, the particles are naturally cooled 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 uniformly by ultrasonication, add γ-glycidyloxypropyltrimethoxysilane, and react in a water bath at 55° C. for 6 h. After the reaction is complete, centrifuge and vacuum dry to obtain modified spherical alumina.

8. The method for preparing a heat dissipation coating based on modified graphene according to claim 1, characterized in that: The raw materials are calculated in parts by weight as follows: 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.

9. A heat dissipation coating based on modified graphene, characterized in that: Prepared according to the method according to any one of claims 1 to 8.

10. Application of the modified graphene-based heat dissipation coating according to claim 9 in the field of electronic components.

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