Infrared radiation heat dissipation composite material and its preparation method, coating and application

Abstract

The present invention discloses an infrared radiation heat dissipation composite material and its preparation method, coating and application. The preparation method of the infrared radiation heat dissipation composite material comprises the following steps: first, dispersing a soluble rare earth metal salt and graphene oxide in deionized water, adjusting the pH value, heating, and performing a hydrothermal reaction; then washing and drying the reaction product, and calcining it under a protective atmosphere. The present invention adopts a hydrothermal in-situ loading method, utilizing the rich electronic structure of the synthesized rare earth metal oxide to promote the carrier absorption of the reduced graphene oxide, and the porous structure constructed by the rare earth metal oxide between the reduced graphene oxide makes the rare earth metal oxide uniformly loaded on the surface of the reduced graphene oxide, and causes the incident light to undergo multiple diffuse reflections and absorptions, thereby promoting the improvement of the emissivity. The prepared composite material is added to a high molecular polymer to form an infrared radiation heat dissipation coating, which not only has high emissivity in the entire band, but also has high thermal conductivity.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional materials, and specifically relates to an infrared radiation heat dissipation composite material, a preparation method, a coating and applications thereof, and more particularly to a rare earth metal oxide@reduced graphene oxide infrared radiation heat dissipation composite material, an infrared radiation heat dissipation coating enhanced by the composite material, and a preparation method and applications thereof. Background Art

[0002] As electronic devices develop towards miniaturization and high integration, their heat generation power and heat flux density continue to increase. Excessive temperature of electronic devices will not only seriously affect the performance of electronic devices, but also significantly shorten the service life of electronic devices. Traditional heat dissipation methods based on heat conduction and heat convection mechanisms are difficult to apply to electronic devices with limited space due to the huge volume they occupy. Passive radiation heat dissipation technology achieves heat dissipation by emitting heat into low-temperature space or low-temperature environments in the form of thermal radiation. It does not require any additional energy input and occupies a small volume. Passive radiation heat dissipation provides a new approach to the thermal management of electronic devices.

[0003] With the advancement of nano-optics, researchers have developed a series of materials, including photonic structures and metamaterials, that exhibit efficient radiative heat dissipation. The spectral properties of most of these materials exhibit atmospheric window selective emission, meaning high emission in the 8-13μm band and high reflection in other bands. This spectral design enables daytime sub-ambient cooling. However, when electronic devices generate heat, their temperatures are generally higher than those of the atmosphere and the surrounding environment. Radiative heat dissipation coatings that selectively emit from the atmospheric window only radiate energy in the 8-13μm band, making it difficult to achieve efficient radiative heat dissipation from electronic devices. Summary of the Invention

[0004] The present invention aims to address at least one of the technical problems existing in the aforementioned prior art. To this end, the present invention provides an infrared radiation heat dissipation composite material, its preparation method, coating, and application. The coating contains an infrared radiation heat dissipation composite material with high infrared emissivity in the 2.5-15 μm band, providing a new solution for heat dissipation in electronic devices.

[0005] In order to solve the above technical problems, the first aspect of the present invention provides a method for preparing an infrared radiation heat dissipation composite material, comprising the following steps:

[0006] (1) Dispersing soluble rare earth metal salt and graphene oxide in deionized water, adjusting the pH value, and performing a hydrothermal reaction;

[0007] (2) The reaction product obtained in step (1) is washed and dried, and then calcined under a protective atmosphere to obtain the infrared radiation composite material.

[0008] Specifically, the present invention uses soluble rare earth metal salts and graphene oxide as main raw materials, adopts the method of hydrothermal in situ loading, makes the synthesized rare earth metal oxide particles and reduced graphene oxide dispersed evenly, and the rare earth metal oxide particles are rod-shaped particles, and the rod-shaped particles help to build a porous structure in the reduced graphene oxide, so that the incident light can undergo multiple diffuse reflections and absorptions, promoting the improvement of emissivity. At the same time, the rich electronic structure of the rare earth metal oxide is conducive to promoting the carrier absorption of the reduced graphene oxide, and the porous structure constructed by the rare earth metal oxide between the reduced graphene oxide makes the rare earth metal oxide uniformly loaded on the surface of the reduced graphene oxide, avoiding the agglomeration phenomenon between the particles, thereby further improving the emissivity of the composite material, and then improving the infrared radiation heat dissipation effect.

[0009] Preferably, in step (1), the soluble rare earth metal salt is selected from at least one of europium nitrate, cerium nitrate, yttrium nitrate, samarium nitrate, lanthanum nitrate, neodymium nitrate, praseodymium nitrate, europium chloride, cerium chloride, yttrium chloride, samarium chloride, lanthanum chloride, neodymium chloride, and praseodymium chloride.

[0010] Preferably, in step (1), the mass ratio of the soluble rare earth metal salt to graphene oxide is (2-20):1.

[0011] Preferably, in step (1), the pH value is adjusted by ammonia water, and the adjusted pH value is 9-10.

[0012] Preferably, in step (1), the temperature of the hydrothermal reaction is 120-180°C.

[0013] Preferably, in step (1), the hydrothermal reaction time is 6-24 hours.

[0014] Preferably, in step (2), the washing is performed by alternating deionized water and ethanol for 2-4 times to remove residual soluble rare earth metal salts and graphene oxide.

[0015] Preferably, in step (2), the protective atmosphere is an argon atmosphere.

[0016] Preferably, in step (2), the calcination temperature is 400-800°C.

[0017] Preferably, in step (2), the calcination time is 2-6 hours.

[0018] The second aspect of the present invention provides an infrared radiation heat dissipation composite material, which is prepared by the above-mentioned preparation method. The infrared radiation heat dissipation composite material includes rare earth metal oxide and reduced graphene oxide, and the rare earth metal oxide is uniformly loaded on the surface of the reduced graphene oxide.

[0019] The study found that rare earth metal oxides have a rich electronic structure and reduced graphene oxide has excellent thermal conductivity. Loading rare earth metal oxides onto the surface of reduced graphene oxide and the interaction between the two will effectively improve the emissivity and thermal conductivity of the composite material.

[0020] Preferably, the mass ratio of the rare earth metal oxide to the reduced graphene oxide is (2.5-10):1.

[0021] Further preferably, the mass ratio of the rare earth metal oxide to the reduced graphene oxide is (5-10):1.

[0022] A third aspect of the present invention provides an infrared radiation heat dissipation coating, the raw material components of which include the above-mentioned infrared radiation heat dissipation composite material, a high molecular polymer and an additive, wherein the additive includes a curing agent or a coupling agent.

[0023] Preferably, the mass ratio of the infrared radiation heat dissipation composite material, the high molecular polymer and the additive is 1: (5-20): (0.5-2).

[0024] Preferably, the high molecular polymer is selected from at least one of polyvinylidene fluoride, polydimethylsiloxane (PDMS), polyimide, and polymethyl methacrylate.

[0025] Specifically, these polymers all possess a certain degree of infrared radiation capability. The addition of the rare earth metal oxide@reduced graphene oxide composite material further complicates the polymer structure, which helps improve its spectral emissivity. Furthermore, due to the high thermal conductivity of reduced graphene oxide, the rod-shaped particles of the rare earth metal oxide form a "thermal bridge" within the reduced graphene oxide, further increasing the coating's thermal conductivity and thus overall improving the coating's heat dissipation performance.

[0026] Preferably, the coupling agent is selected from at least one of γ-aminopropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane.

[0027] Preferably, the curing agent is selected from at least one of methyltriethoxysilane and methyltripropoxysilane.

[0028] A fourth aspect of the present invention provides a method for preparing an infrared radiation heat dissipation coating, comprising the following steps:

[0029] The infrared radiation heat dissipation composite material, high molecular polymer and additives are mixed into slurry, and then the slurry is poured into a mold, and film-formed and dried to form the infrared radiation heat dissipation coating.

[0030] Preferably, the infrared radiation heat dissipation coating has a thickness of 400-600 μm.

[0031] Preferably, the film forming method is a blade coating method.

[0032] Preferably, the drying is carried out at 70-90° C. for 1-3 hours.

[0033] A fifth aspect of the present invention provides the use of the above-mentioned infrared radiation heat dissipation coating in electronic devices, LED lighting, photovoltaic modules or chips.

[0034] Compared with the prior art, the above technical solution of the present invention has at least the following technical effects or advantages:

[0035] (1) The present invention uses soluble rare earth metal salts and graphene oxide as main raw materials, adopts a hydrothermal in-situ loading method, utilizes the rich electronic structure of the synthesized rare earth metal oxide to promote the carrier absorption of reduced graphene oxide, and the porous structure constructed by the rare earth metal oxide between the reduced graphene oxide makes the rare earth metal oxide uniformly loaded on the surface of the reduced graphene oxide, avoiding the agglomeration phenomenon between the particles; and utilizes the porous structure constructed by the rod-shaped rare earth metal oxide particles in the reduced graphene oxide to make the incident light undergo multiple diffuse reflections and absorptions, thereby promoting the improvement of the emissivity.

[0036] (2) The infrared radiation heat dissipation composite material prepared by the present invention includes rare earth metal oxides and reduced graphene oxide, and the rare earth metal oxides are uniformly loaded on the surface of the reduced graphene oxide. The rare earth metal oxides are used to improve the spectral properties of the reduced graphene oxide, so that it has a high emissivity in the entire band.

[0037] (3) The rare earth metal oxide@reduced graphene oxide composite material prepared by the present invention is added to a high molecular polymer to form an infrared radiation heat dissipation coating, which not only has high emissivity in the entire band, but also has high thermal conductivity. At an input power of 5W, a cooling temperature difference of more than 12°C can be obtained, which has great application prospects in the field of electronics industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a microscopic morphology of the infrared radiation heat dissipation composite material prepared in Example 1;

[0039] Figure 2 This is a microscopic morphology of the infrared radiation heat dissipation coating prepared in Example 1;

[0040] Figure 3 This is a microscopic morphology of the infrared radiation heat dissipation coating prepared in Example 2;

[0041] Figure 4 This is a microscopic morphology of the infrared radiation heat dissipation coating prepared in Example 3;

[0042] Figure 5spectral emissivity diagrams of the infrared radiation heat dissipation composite materials prepared in Example 1 and Comparative Example 1;

[0043] Figure 6 spectral emissivity diagram of the infrared radiation heat dissipation coating prepared in Examples 1-3;

[0044] Figure 7 This is a temperature change diagram of the infrared radiation heat dissipation coating prepared in Examples 1-3 when attached to an electronic device indoors. DETAILED DESCRIPTION

[0045] The present invention is described in detail below with reference to the examples to facilitate understanding of the present invention by those skilled in the art. It is necessary to point out that the examples are only used to further illustrate the present invention and are not to be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made to the present invention by those skilled in the art based on the above-mentioned invention should still fall within the scope of protection of the present invention. At the same time, the raw materials mentioned below that are not described in detail are all commercially available products; the process steps or preparation methods that are not mentioned in detail are all process steps or preparation methods known to those skilled in the art.

[0046] Example 1

[0047] A method for preparing an infrared radiation heat dissipation composite material comprises the following steps:

[0048] 0.1 g of graphene oxide was weighed and dissolved in 50 mL of deionized water and ultrasonically dispersed. 2.544 g of Y(NO₃)₃·6H₂O was weighed and dissolved in 20 mL of deionized water. The two solutions were mixed and ultrasonically dispersed uniformly. Ammonia was then added dropwise to adjust the pH to 10. After stirring for 1 hour, the mixture was placed in a 100 mL reactor and reacted at 180°C for 12 hours. During the reaction, the graphene oxide was reduced to form reduced graphene oxide (rGO). After the reaction, the product was washed three times with deionized water and ethanol, then dried in a forced air drying oven at 60°C for 12 hours. The dried product was ground and calcined in a tube furnace at 600°C for 3 hours under an argon atmosphere. During the calcination, Y₃(OH)₃ dehydrated to Y₂O₃, resulting in a Y₂O₃@rGO infrared radiative heat dissipation composite material with a mass ratio of Y₂O₃ to rGO of 7.5:1.

[0049] A method for preparing an infrared radiation heat dissipation coating comprises the following steps:

[0050] In a beaker, weigh 2.85g of PDMS and 0.285g of the curing agent, methyltriethoxysilane, and stir thoroughly. Then, weigh 0.15g of the Y2O3@rGO prepared in this example and add it to the PDMS. Using a glass rod, stir repeatedly under ultrasonication until the PDMS, curing agent, and Y2O3@rGO are evenly dispersed to form a slurry. Apply the slurry to a 40×40mm polytetrafluoroethylene mold, scrape off any excess with a scraper, and dry in a forced-air drying oven at 80°C for 2 hours. After demolding, the Y2O3@rGO@PDMS infrared heat dissipation coating is obtained.

[0051] Example 2

[0052] A method for preparing an infrared radiation heat dissipation composite material comprises the following steps:

[0053] 0.1 g of graphene oxide was weighed and dissolved in 50 mL of deionized water and ultrasonically dispersed. 2.534 g of Eu(NO₃)₃·6H₂O was weighed and dissolved in 20 mL of deionized water. The two solutions were mixed and ultrasonically dispersed uniformly. Ammonia was then added dropwise to adjust the pH to 10. After continuous stirring for 1 hour, the mixture was placed in a 100 mL reactor and reacted at 180°C for 12 hours. During the reaction, the graphene oxide was reduced to form reduced graphene oxide (rGO). After the reaction, the product was washed three times with deionized water and ethanol, then dried in a forced-air drying oven at 60°C for 12 hours. The dried product was ground and calcined in a tube furnace at 600°C for 3 hours under an argon atmosphere. During the calcination, Eu₃(OH)₃ dehydrated to Eu₂O₃, resulting in the Eu₂O₃@rGO infrared radiative heat dissipation composite material, where the mass ratio of Eu₂O₃ to rGO was 10:1.

[0054] A method for preparing an infrared radiation heat dissipation coating comprises the following steps:

[0055] In a beaker, weigh 2.85g of PDMS and 0.285g of the curing agent, methyltriethoxysilane, and stir thoroughly. Then, weigh 0.15g of the Eu2O3@rGO prepared in this example and add it to the PDMS. Using a glass rod, stir repeatedly under ultrasonication until the PDMS, curing agent, and Eu2O3@rGO are evenly dispersed to form a slurry. Apply the slurry to a 40×40mm polytetrafluoroethylene mold, scrape off any excess with a scraper, and dry in a forced-air drying oven at 80°C for 2 hours. After demolding, the Eu2O3@rGO@PDMS infrared heat dissipation coating is obtained.

[0056] Example 3

[0057] A method for preparing an infrared radiation heat dissipation composite material comprises the following steps:

[0058] 0.1 g of graphene oxide was weighed and dissolved in 50 mL of deionized water and ultrasonically dispersed. 1.892 g of Ce(NO₃)₃·6H₂O was weighed and dissolved in 20 mL of deionized water. The two solutions were mixed and ultrasonically dispersed uniformly. Ammonia was then added dropwise to adjust the pH to 10. After continuous stirring for 1 hour, the mixture was placed in a 100 mL reactor and reacted at 180°C for 12 hours. During the reaction, the graphene oxide was reduced to form reduced graphene oxide (rGO). After the reaction, the product was washed three times with deionized water and ethanol, then dried in a forced air drying oven at 60°C for 12 hours. The dried product was ground and calcined in a tube furnace at 600°C for 3 hours under an argon atmosphere. During the calcination, Ce(OH)₄ dehydrated to CeO₂, resulting in a CeO₂@rGO infrared radiative heat dissipation composite material with a mass ratio of CeO₂ to rGO of 7.5:1.

[0059] A method for preparing an infrared radiation heat dissipation coating comprises the following steps:

[0060] Weigh 2.85g of PDMS and 0.285g of the curing agent, methyltriethoxysilane, into a beaker and stir thoroughly. Then, weigh 0.15g of the CeO2@rGO prepared in this example and add it to the PDMS. Use a glass rod to repeatedly stir under ultrasonication until the PDMS, curing agent, and CeO2@rGO are evenly dispersed to form a slurry. Apply the slurry to a 40×40mm polytetrafluoroethylene mold, scrape off any excess with a scraper, and dry in a forced-air drying oven at 80°C for 2 hours. After demolding, the CeO2@rGO@PDMS infrared heat dissipation coating is obtained.

[0061] Examples 4-6

[0062] The only difference between Examples 4-6 and Example 1 is the mass ratio of Y2O3 to rGO, which are 2.5:1, 5:1 and 10:1, respectively.

[0063] Examples 7-9

[0064] The only difference between Examples 7-9 and Example 2 is the mass ratio of Eu2O3 to rGO, which are 2.5:1, 5:1 and 7.5:1, respectively.

[0065] Examples 10-12

[0066] The only difference between Examples 10-12 and Example 3 is the mass ratio of CeO2 to rGO, which are 2.5:1, 5:1 and 10:1, respectively.

[0067] Comparative Example 1

[0068] The difference between Comparative Example 1 and Example 1 is that the infrared radiation heat dissipation material in Comparative Example 1 is a single rGO, and its preparation method includes the following steps:

[0069] 0.1 g of graphene oxide was weighed and dissolved in 50 mL of deionized water, then ultrasonically dispersed. Ammonia was then added dropwise to adjust the pH to 10. After stirring for 1 hour, the mixture was placed in a 100 mL reactor and reacted at 180°C for 12 hours. During the reaction, the graphene oxide was reduced to form reduced graphene oxide (rGO). After the reaction, the product was washed three times with alternating deionized water and ethanol, then dried in a forced air drying oven at 60°C for 12 hours to obtain the rGO infrared radiant heat dissipation material.

[0070] Comparative Example 2

[0071] A method for preparing an infrared radiation heat dissipation coating comprises the following steps:

[0072] In a beaker, 2.85g of PDMS and 0.285g of the curing agent, methyltriethoxysilane, were weighed and stirred thoroughly. Subsequently, 0.15g of Y2O3 and graphene (mass ratio of 7.5:1) were weighed and dispersed evenly to form a slurry. The slurry was applied to a 40×40mm polytetrafluoroethylene mold. Excess slurry was scraped off with a scraper and dried in a forced air drying oven at 80°C for 2 hours. After demolding, the infrared heat dissipation coating was obtained.

[0073] Performance Testing

[0074] 1. Microstructure

[0075] Figure 1 The microscopic morphology of the Y2O3@rGO infrared radiation heat dissipation composite material prepared in Example 1 is shown in FIG. Figure 1 It can be seen that the rod-shaped Y2O3 is evenly dispersed on the surface of the rGO sheets, and Y2O3 forms a porous structure between the rGO sheets.

[0076] Figure 2-4 The microscopic morphology of the infrared radiation heat dissipation coatings prepared in Examples 1-3 are shown in FIG. Figure 2-4 It can be seen that the coating surfaces prepared in Examples 1-3 are relatively uniform and smooth, and have no obvious defects such as holes and cracks.

[0077] 2. Spectral emission

[0078] The infrared radiation heat dissipation materials prepared in Example 1 and Comparative Example 1 were measured using FTIR equipped with a gold integrator accessory. Since the powder is black, the apparent transmittance is 0, and the emissivity is calculated by measuring the reflectivity. The results are as follows: Figure 5 As shown (the horizontal axis Wavelenth represents wavelength, and the vertical axis Emissivity represents emissivity). Figure 5 It can be seen that compared with pure rGO, the loading of Y2O3 significantly improves the emissivity in all bands.

[0079] Figure 6 The spectral emissivity diagram of the infrared radiation heat dissipation coating prepared in Examples 1-3 is obtained by measuring the reflectivity and transmittance (emissivity = 1-transmittance-reflectivity). Figure 6 It can be seen that the emissivity of the three infrared radiation heat dissipation composite materials is at a high level. In the 2.5-7.5μm band, Eu2O3@rGO has the highest emissivity, and there is no obvious difference among the three in the 7.5-15μm band.

[0080] The same method was used to measure the emissivity of the infrared radiation heat dissipation composite materials prepared in Examples 1-12 and Comparative Examples 1-2. The results are shown in Table 1.

[0081] Table 1:

[0082]

[0083] As shown in Table 1, the average emissivity of different infrared radiation heat dissipation composite materials prepared in Examples 1-12 in the 2.5-15μm band is all above 0.9, among which Example 1 has the highest, reaching 0.979. The loading of rare earth oxide particles can effectively improve the emissivity of reduced graphene oxide, and the in-situ loading by the hydrothermal method has a greater improvement than the direct mixing method. Compared with Example 1, Comparative Examples 1-2 have an average emissivity in the 2.5-15μm band due to the use of a single rGO or Y2O3 directly mixed with rGO.

[0084] Both are significantly lower than those in Example 1.

[0085] 3. Heat dissipation performance

[0086] After 1.5 hours at an input power of 5 W, the surface temperature of the copper plate not covered with the infrared radiation heat dissipation coating was 99.4°C. The coatings prepared in Examples 1-3 and Comparative Examples 1-2 were then applied to an electronic heating component with a surface area of ​​40×40 mm. The stable temperature of the coating was obtained at the same power and power-on time, and the heat dissipation temperature difference was calculated. The results are shown in Tables 2 and 3. Figure 7 shown.

[0087] Table 2:

[0088]

[0089] As shown in Table 2, the infrared radiation heat dissipation coatings prepared in the present invention all have good heat dissipation effects, and the heat dissipation temperature difference is all above 11°C. Among them, the Y2O3@rGO@PDMS infrared radiation heat dissipation coating prepared in Example 1 has the best heat dissipation effect, and the heat dissipation temperature difference reaches 12.3°C (see Figure 7 , Figure 7 (Time represents time, and Temperature represents temperature.) In Comparative Examples 1-2, compared with Example 1, the heat dissipation effect is significantly reduced due to the use of single rGO or direct mixing of Y2O3 and rGO.

[0090] For those skilled in the art to which the present invention belongs, a number of simple deductions or substitutions can be made without departing from the concept of the present invention, without having to resort to creative work. Therefore, based on the disclosure of the present invention, simple improvements made by those skilled in the art to the present invention should be within the scope of protection of the present invention. The above embodiments are preferred embodiments of the present invention, and all processes similar to the present invention and equivalent changes made should fall within the scope of protection of the present invention.

Claims

1. An infrared radiation heat dissipation coating, characterized in that: The raw material components include infrared radiation heat dissipation composite material, high molecular polymer and additives, and the additives include curing agent or coupling agent; The infrared radiation heat dissipation composite material comprises rare earth metal oxide and reduced graphene oxide, wherein the rare earth metal oxide is uniformly loaded on the surface of the reduced graphene oxide, and the rare earth metal oxide is rod-shaped particles Y2O3; The preparation method of the infrared radiation heat dissipation composite material comprises the following steps: (1) Dispersing soluble rare earth metal salt and graphene oxide in deionized water, adjusting the pH value, and performing a hydrothermal reaction; The soluble rare earth metal salt is selected from at least one of yttrium nitrate and yttrium chloride; The pH value is adjusted by ammonia water, and the adjusted pH value is 9-10; The temperature of the hydrothermal reaction is 180° C., and the time of the hydrothermal reaction is 12 hours; The mass ratio of the rare earth metal oxide to the reduced graphene oxide is 7.5:1; (2) washing and drying the reaction product obtained in step (1), and then calcining it under a protective atmosphere to obtain the infrared radiation heat dissipation composite material; The calcination temperature is 600° C., and the calcination time is 3 hours.

2. The infrared radiation heat dissipation coating according to claim 1, characterized in that: The mass ratio of the infrared radiation heat dissipation composite material, the high molecular polymer and the additive is 1: (5-20): (0.5-2); And / or, the high molecular polymer is at least one selected from polyvinylidene fluoride, polydimethylsiloxane, polyimide, and polymethyl methacrylate; And / or, the coupling agent is selected from at least one of γ-aminopropyltriethoxysilane and γ-glycidyloxypropyltrimethoxysilane; And / or, the curing agent is selected from at least one of methyltriethoxysilane and methyltripropoxysilane.

3. Use of the infrared radiation heat dissipation coating according to claim 1 or 2 in electronic devices.

4. Use of the infrared radiation heat dissipation coating according to claim 1 or 2 in LED lighting, photovoltaic modules or chips.

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