Preparation method of reaction type graphene reinforced spherical core-shell structure Al2O3 (at) Al heat conduction interface material

Abstract

The invention relates to a preparation method and application of a reaction type graphene reinforced spherical core-shell structure aluminum oxide-aluminum heat conduction interface material. The preparation method comprises the following steps: performing oxidation treatment on aluminum powder through an oxidizing agent to prepare a hydroxylated Al2O3 (at) Al core-shell structure spherical material, then performing covalent functional modification on the Al2O3 (at) Al core-shell structure spherical material and hydroxylated graphene by using a silane coupling agent, and grafting reactive acrylate functional groups. The thermal interface material is prepared by taking vinyl silicone oil and the like as a polymer matrix and compounding the polymer matrix with Al2O3 (at) Al and hydroxylated graphene filler. According to the thermal interface material, the dispersity of the filler in a silicone oil system is improved, agglomeration of the filler in a polymer matrix is reduced, the interface compatibility between the filler and silicon resin can be effectively improved, the flowing property of the thermal interface material is improved, meanwhile, the thermal interface material has a good heat conduction effect, and the contact thermal resistance is effectively reduced. The preparation method is simple, low in cost, high in repeatability, universal and suitable for large-scale industrial production, the thermal conductivity of the thermal interface material can be regulated and controlled to be 3.169-7.811 W.m <-1 >. K <-1 >, the interface thermal resistance can be regulated and controlled to be 0.0315-0.8792 K.cm < 2 >. W <-1 >, and the contact thermal resistance can be regulated and controlled to be 0.0129-0.3235 K.cm < 2 >. W <-1 >.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal conductive interface materials, and relates to a preparation method and application of a reactive graphene-enhanced spherical core-shell structured alumina@aluminum thermal conductive interface material. Background Art

[0002] In recent years, the rapid development of microelectronics packaging and integration technologies has driven electronic and power equipment toward increasing multifunctionality and high power. Heat dissipation has become a pressing issue, necessitating the development of novel thermal interface materials to enhance interfacial heat conduction and reduce contact thermal resistance, an effective way to ensure device performance and lifespan.

[0003] Interface functionalization can increase the low-frequency phonon state density and phonon overlap energy by regulating the intermolecular forces and increasing the contact area, thereby realizing a strategy to enhance interfacial thermal conductivity. Functionalization can effectively reduce the agglomeration of thermally conductive fillers, making a certain breakthrough in the thermal conductivity of thermal interface materials. For example, Chinese patent CN202410302925.5 discloses a "method for preparing a modified spherical alumina / corrugated structure hydroxylated graphene / polysiloxane composite thermal conductive interface material". This method prepares hydroxylated graphene powder loaded with nano-alumina, then prepares modified spherical alumina powder, and then prepares hydroxylated graphene / spherical alumina / silicone prepolymer, which is then thermally cured and finally hot-pressed to obtain a modified spherical alumina / corrugated structure hydroxylated graphene / polysiloxane composite thermal conductive interface material. The current method for improving the problems of thermal interface materials mainly uses silane coupling agents to non-covalently functionalize the filler. This method uses physical interactions such as electrostatic interactions, van der Waals forces and hydrogen bonds between the filler and the modifier to achieve surface functionalization of the filler. Although non-covalent functionalization improves the dispersion of fillers in the polymer matrix and reduces the thermal resistance between fillers, the weak chemical bonding of non-covalent bonds leads to poor compatibility between the thermally conductive filler and the matrix, resulting in interfacial problems. Therefore, finding an appropriate method to regulate the interfacial properties between aluminum powder, hydroxylated graphene, and organosilicon is an urgent problem to be solved. Summary of the Invention

[0004] The present invention aims to address the shortcomings of existing thermal interface materials, such as poor compatibility and interface issues, by providing a method for preparing a reactive graphene-reinforced spherical core-shell alumina@aluminum thermal interface material. This thermal interface material utilizes organosilicon as the matrix, with the vinyl bonds in vinyl silicone oil reacting with the silicon-hydrogen bonds in hydrogen-containing silicone oil to form a cross-linked organosilicon compound. Al2O3@Al core-shell spherical materials were prepared by oxidizing aluminum powder with an oxidant. Subsequently, the Al2O3@Al spherical materials and hydroxylated graphene were modified with a silane coupling agent, covalently grafting acrylate functional groups. The modified Al2O3@Al spherical materials and hydroxylated graphene reacted with a silicone matrix through a hydrosilylation reaction. Strong chemical bonds formed between the silicone matrix and the fillers (Al2O3@Al spherical materials and hydroxylated graphene). These strong interactions resulted in a tighter and more stable bond between the filler and the polymer matrix, improving not only the filler's dispersion in the polymer matrix but also its compatibility, enhancing interfacial interactions, and facilitating the formation of thermal conductive pathways, thereby increasing thermal conductivity. A polymer matrix composed of vinyl silicone oil, hydrogenated silicone oil, a platinum catalyst, and an inhibitor was uniformly mixed with the Al2O3@Al spherical materials and hydroxylated graphene in appropriate proportions. Finally, vacuum defoaming and curing were performed to obtain the thermal interface material. The oxidizing agent alumina powder can hydroxylate the surface of aluminum powder. The surface of the filler is modified with a silane coupling agent and grafted with reactive acrylate functional groups, which can effectively reduce the agglomeration of aluminum powder and hydroxylated graphene, allowing the polymer matrix and filler to be better combined, reducing the contact thermal resistance between them, and reducing the viscosity of the silicone oil system, allowing more fillers to be added. Hydroxylated graphene can effectively play its "thermal bridge" role, thereby effectively improving the fluidity and thermal conductivity of the thermal interface material.

[0005] In order to solve the above technical problems, the present invention is achieved through the following technical solutions.

[0006] The present invention provides a method for preparing a reactive graphene-enhanced spherical core-shell structured alumina@aluminum thermal conductive interface material, comprising the following steps:

[0007] (1) placing aluminum powder and an oxidant in a container, mixing and stirring to react, and then washing the reaction mixture and placing it in anhydrous ethanol;

[0008] (2) adding a silane coupling agent and deionized water to carry out a heating and stirring reaction, and centrifuging, washing, and drying the obtained product to obtain surface functionalized Al2O3@Al core-shell particles;

[0009] (3) placing hydroxylated graphene, a silane coupling agent, and deionized water in a container for heating and stirring to react, and centrifuging, washing, and drying the resulting product to obtain surface-functionalized hydroxylated graphene;

[0010] (4) Vinyl silicone oil, hydrogenated silicone oil, platinum catalyst, and inhibitor are placed in a container and mixed evenly, and then the surface-functionalized Al2O3@Al core-shell particles prepared in step (2) and the surface-functionalized hydroxylated graphene prepared in step (3) are added, and the mixture is sequentially mixed, defoamed, and cured at high temperature to obtain the product.

[0011] Preferably, the oxidant in step (1) is selected from one or more of hydrogen peroxide solution, sodium peroxide solution, and potassium peroxide solution.

[0012] Preferably, the concentration of the oxidant is 3-30%; more preferably, the concentration of the oxidant is 3-10%.

[0013] Preferably, the mass ratio of the aluminum powder to the oxidant in step (1) is 1:1-4.

[0014] Preferably, the temperature of the mixing and stirring reaction in step (1) is 25-300° C., and the time is 1-1.5 h.

[0015] Preferably, the aluminum powder in step (1) comprises aluminum powder of different particle sizes within the range of 10-40 μm; more preferably, the aluminum powder comprises the following particle sizes: 10-13 μm aluminum powder, 25-30 μm aluminum powder, and 30-40 μm aluminum powder; most preferably, the mass ratio of the 10-13 μm aluminum powder, 25-30 μm aluminum powder, and 30-40 μm aluminum powder is 1:1-2:2-3.

[0016] Preferably, the aluminum powder in step (1) is spherical aluminum powder.

[0017] Preferably, the washing in step (1) is performed using deionized water.

[0018] Preferably, the silane coupling agent in step (2) is selected from one or more of VTPS (vinyl tri-tert-butyl peroxide silane), A151 (vinyl triethoxy silane), A171 (vinyl trimethoxy silane), A172 (vinyl tris(β-methoxyethoxy) silane), and KH570 (γ-methacryloxypropyltrimethoxy silane).

[0019] Preferably, the amount of the silane coupling agent in step (2) is 1-15% of the mass of the aluminum powder in step (1); more preferably, the amount of the silane coupling agent in step (2) is 2-10% of the mass of the aluminum powder in step (1).

[0020] Preferably, the temperature of the heating and stirring reaction in step (2) is 60-100° C., and the time is 1-8 h; more preferably, the temperature of the heating and stirring reaction is 70-90° C., and the time is 2-6 h.

[0021] Preferably, the centrifugal speed in step (2) is 1000-1000 rpm, and the time is 2-20 min; more preferably, the centrifugal speed is 2000-8000 rpm, and the time is 5-15 min.

[0022] Preferably, the washing in step (2) is performed using anhydrous ethanol for 2-6 times.

[0023] Preferably, the drying temperature in step (2) is 80-150° C., and the drying time is 0.5-5 h; more preferably, the drying temperature is 90-130° C., and the drying time is 1-4 h.

[0024] Preferably, the mass ratio of the surface-functionalized hydroxylated graphene to the surface-functionalized Al2O3@Al core-shell particles in step (3) is 1:45-165.

[0025] Preferably, the silane coupling agent in step (3) is selected from one or more of VTPS (vinyl tri-tert-butyl peroxide silane), A151 (vinyl triethoxy silane), A171 (vinyl trimethoxy silane), A172 (vinyl tris(β-methoxyethoxy) silane), and KH570 (γ-methacryloxypropyltrimethoxy silane).

[0026] Preferably, the amount of the silane coupling agent in step (3) is 1-15% of the mass of the aluminum powder in step (1); more preferably, the amount of the silane coupling agent in step (3) is 2-10% of the mass of the aluminum powder in step (1).

[0027] Preferably, the temperature of the heating and stirring reaction in step (3) is 60-100°C, and the time is 1-8 hours; more preferably, the temperature of the heating and stirring reaction is 70-90°C, and the time is 2-6 hours.

[0028] Preferably, the centrifugal speed in step (3) is 1000-1000 rpm, and the time is 2-20 min; more preferably, the centrifugal speed is 2000-8000 rpm, and the time is 5-15 min.

[0029] Preferably, the washing in step (3) is performed using anhydrous ethanol for 2-6 times.

[0030] Preferably, the drying temperature in step (3) is 80-150° C. and the drying time is 0.5-5 h; more preferably, the drying temperature is 90-130° C. and the drying time is 1-4 h.

[0031] Preferably, the platinum catalyst in step (4) is selected from one or more of a Custer catalyst, a chloroplatinic acid catalyst, a platinum-carbon catalyst, a platinum dioxide catalyst, an Ashby's catalyst, a Speier catalyst, and a Lamoreaux catalyst; more preferably, the platinum catalyst is selected from a Custer catalyst.

[0032] Preferably, the inhibitor in step (4) is selected from one or more of 1-ethynyl-1-cyclohexanol, TMDO (3,7,11-trimethyldodecene-3-ol), maleate, fumarate, 2-methyl-3-butyn-2-ol, benzotriazole, and β-alkynol; more preferably, the inhibitor is selected from 1-ethynyl-1-cyclohexanol.

[0033] Preferably, the viscosity of the vinyl silicone oil in step (4) is 50-300 mPa·s.

[0034] Preferably, in step (4), the mass ratio of the vinyl silicone oil to the hydrogenated silicone oil is 2-6:1; the amount of the platinum catalyst is 0.01-0.2 wt% of the mass of the vinyl silicone oil; and the amount of the inhibitor is 0.02-0.05 wt% of the mass of the vinyl silicone oil.

[0035] Preferably, the high temperature curing in step (4) is performed at a temperature of 120° C. and for a time of 3-12 hours.

[0036] Preferably, in step (4), the mass ratio of the total mass of the surface-functionalized Al2O3@Al core-shell particles and the surface-functionalized hydroxylated graphene to the total mass of the vinyl silicone oil and the hydrogenated silicone oil is 1:0.05-0.3; more preferably, in step (4), the mass ratio of the total mass of the surface-functionalized Al2O3@Al core-shell particles and the surface-functionalized hydroxylated graphene to the total mass of the vinyl silicone oil and the hydrogenated silicone oil is 1:0.052-0.25.

[0037] A second aspect of the present invention provides a reactive graphene-enhanced spherical core-shell structured alumina@aluminum thermal conductive interface material prepared according to the above preparation method.

[0038] A third aspect of the present invention provides the use of the above-mentioned reactive graphene-enhanced spherical core-shell structure alumina@aluminum thermal conductive interface material in the field of integrated circuits and / or microelectronic packaging.

[0039] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0040] (1) The present invention selects aluminum powders of different particle sizes and strictly controls the dosage ratio of aluminum powders of different particle sizes, and uses an oxidant to oxidize the aluminum powder to obtain core-shell hybrid particles Al2O3@Al with a surface rich in hydroxyl groups. The Al2O3@Al particles can be uniformly dispersed in a matrix material, thereby forming a uniform thermal conductive network and further improving the thermal conductivity of the material. Subsequently, the Al2O3@Al core-shell particles are modified with a silane coupling agent and grafted with reactive acrylate functional groups. The Al2O3@Al core-shell particles can form covalent bonds with the matrix material, promote the transfer of phonons between the Al2O3@Al core-shell particles and the matrix, improve the compatibility between the Al2O3@Al and the matrix, and improve the flow properties and thermal conductivity of the system.

[0041] (2) Hydroxylated graphene modified with silane coupling agent can form covalent bonds with the matrix material, promoting the transfer of phonons between the hydroxylated graphene and the matrix, thereby improving the thermal conductivity of the material. Hydroxylated graphene can play the role of a "thermal bridge", strengthening the interaction between the polymer matrix and the Al2O3@Al powder. A good synergistic effect is formed between the hydroxylated graphene and the Al2O3@Al powder, and a mutually overlapping thermal conductive network is established. The two fillers can be better dispersed in the silicone oil matrix, and more fillers can be added. The fluidity of the thermal interface material is good. The hydroxylated graphene builds a "bridge" for the transmission of phonons across the interface, thereby reducing the interfacial thermal resistance and effectively improving the interfacial thermal conductivity, thereby effectively improving the thermal conductivity of the thermal interface material.

[0042] (3) The thermal interface material prepared by the present invention has simple preparation process, good fluidity, low cost, stable performance, good thermal conductivity, and thermal conductivity can be adjusted to 3.169-7.811 W·m -1 ·K -1 The interface thermal resistance can be adjusted to 0.0315-0.8792K·cm 2 W -1 , the contact thermal resistance can be adjusted to 0.0129-0.3235K·cm 2 W -1 , thermal interface materials with high thermal conductivity can conduct heat more effectively, thereby reducing the risk of overheating and extending the service life of electronic devices; the density can be adjusted to 1.729-2.298g·cm -3 , easy to carry, low-density thermal interface materials can reduce the weight of equipment and can be widely used in the preparation of thermal interface materials. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail with reference to the following examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0044] Unless otherwise defined, all technical terms used hereinafter have the same meanings as those generally understood by those skilled in the art. The technical terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the scope of the present invention. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0045] Example 1

[0046] A reactive hydroxylated graphene-reinforced spherical core-shell structured alumina@aluminum thermal conductive interface material, the preparation method of which comprises the following steps:

[0047] (1) 25 g of spherical aluminum powder (5 g of 10-13 μm spherical aluminum powder, 8.75 g of 25-30 μm spherical aluminum powder, and 11.25 g of 30-40 μm spherical aluminum powder) and 50 g of 5% hydrogen peroxide solution were placed in a 100 mL beaker, mixed and stirred at 140° C. for 1 h, and then the reaction mixture was washed with deionized water and placed in 50 mL of anhydrous ethanol.

[0048] (2) 1.25 g of VTPS and 4 mL of deionized water were added, and the mixture was stirred at 80 °C for 5 h under condensation reflux. The obtained product was centrifuged at 4000 rpm for 10 min, and then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 120 °C for 2 h to obtain surface functionalized Al2O3@Al core-shell particles.

[0049] (3) 0.5 g of hydroxylated graphene, 1.25 g of VTPS, and 4 mL of deionized water were placed in a beaker and stirred at 80 °C for 5 h under condensation reflux. The obtained product was centrifuged at 4000 rpm for 10 min, and then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 120 °C for 2 h to obtain surface functionalized hydroxylated graphene.

[0050] (4) 4.41 mg of Custer catalyst, 1.323 mg of 1-ethynyl-1-cyclohexanol, and an organosilicon matrix (4.41 g of vinyl silicone oil with a viscosity of 100 mPa·s and 0.9 g of hydrogenated silicone oil) were placed in a 100 mL beaker and stirred for 5 min. Then, fillers (21.11 g of surface-functionalized Al2O3@Al core-shell particles prepared in step (2) and 0.13 g of surface-functionalized hydroxylated graphene prepared in step (3)) were added and mechanically mixed for 10 min using a high-speed homogenizer. The sample was poured into a mold, defoamed in a vacuum oven for 15 min, and finally cured at 120°C for 3 h.

[0051] Example 2

[0052] A reactive hydroxylated graphene-reinforced spherical core-shell structured alumina@aluminum thermal conductive interface material, the preparation method of which comprises the following steps:

[0053] (1) 30 g of spherical aluminum powder (6 g of 10-13 μm spherical aluminum powder, 10.5 g of 25-30 μm spherical aluminum powder, and 13.5 g of 30-40 μm spherical aluminum powder) and 120 g of 8% hydrogen peroxide solution were placed in a 200 mL beaker, mixed and stirred at 25° C. for 1.5 h, and then the reaction mixture was washed with deionized water and placed in 60 mL of anhydrous ethanol.

[0054] (2) 1.5 g of A151 and 8 mL of deionized water were added, and the mixture was stirred at 75 °C for 5 h under condensation reflux. The obtained product was centrifuged at 3000 rpm for 15 min, and then washed with anhydrous ethanol four times to ensure that the unreacted silane coupling agent was completely removed. Finally, the product was placed in a vacuum oven at 100 °C for 1 h to obtain surface-functionalized Al2O3@Al core-shell particles.

[0055] (3) 0.5 g of hydroxylated graphene, 1.25 g of A151, and 4 mL of deionized water were placed in a beaker and stirred at 75 °C for 3 h under condensation reflux. The obtained product was centrifuged at 3000 rpm for 15 min, and then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 100 °C for 1 h to obtain surface functionalized hydroxylated graphene.

[0056] (4) 4.41 mg of chloroplatinic acid catalyst, 1.323 mg of TMDO, and an organosilicon matrix (4.41 g of vinyl silicone oil with a viscosity of 50 mPa·s and 0.9 g of hydrogenated silicone oil) were placed in a 50 mL beaker and stirred thoroughly for 4 min. Then, fillers (24.04 g of surface-functionalized Al2O3@Al core-shell particles prepared in step (2) and 0.15 g of surface-functionalized hydroxylated graphene prepared in step (3)) were added and mechanically mixed for 15 min using a high-speed homogenizer. The sample was poured into a mold, defoamed in a vacuum oven for 10 min, and finally cured at 120°C for 3 h.

[0057] Example 3

[0058] A reactive hydroxylated graphene-reinforced spherical core-shell structured alumina@aluminum thermal conductive interface material, the preparation method of which comprises the following steps:

[0059] (1) 33 g of spherical aluminum powder (6.6 g of 10-13 μm spherical aluminum powder, 11.55 g of 25-30 μm spherical aluminum powder, and 14.85 g of 30-40 μm spherical aluminum powder) and 99 g of 3% hydrogen peroxide solution were placed in a 500 mL beaker, stirred and reacted at 200° C. for 70 min, and the reaction mixture was then washed with deionized water and placed in 60 mL of anhydrous ethanol.

[0060] (2) 1.65 g of A171 and 4 mL of deionized water were added, and the mixture was stirred at 85 °C for 4 h under condensation reflux. The obtained product was centrifuged at 6000 rpm for 6 min, and then washed with anhydrous ethanol three times to ensure that the unreacted silane coupling agent was completely removed. Finally, the product was placed in a vacuum oven at 110 °C for 1.5 h to obtain surface-functionalized Al2O3@Al core-shell particles.

[0061] (3) 1 g of hydroxylated graphene, 1.5 g of A171, and 4 mL of deionized water were placed in a beaker and stirred at 85 °C for 4 h under condensation reflux. The resulting product was centrifuged at 6000 rpm for 6 min, then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 110 °C for 1.5 h to obtain surface-functionalized hydroxylated graphene.

[0062] (4) 4.41 mg of platinum-carbon catalyst, 1.323 mg of maleate, and an organosilicon matrix (4.41 g of vinyl silicone oil with a viscosity of 150 mPa·s and 0.9 g of hydrogenated silicone oil) were placed in a 100 mL beaker and stirred thoroughly for 3 min. Fillers (27.70 g of surface-functionalized Al2O3@Al core-shell particles prepared in step (2) and 0.17 g of surface-functionalized hydroxylated graphene prepared in step (3)) were then added and mechanically mixed for 20 min using a high-speed homogenizer. The sample was poured into a mold, defoamed in a vacuum oven for 20 min, and finally cured at 120°C for 8 h.

[0063] Example 4

[0064] A reactive hydroxylated graphene-reinforced spherical core-shell structured alumina@aluminum thermal conductive interface material, the preparation method of which comprises the following steps:

[0065] (1) 30 g of spherical aluminum powder (6 g of 10-13 μm spherical aluminum powder, 9 g of 25-30 μm spherical aluminum powder, and 15 g of 30-40 μm spherical aluminum powder) and 120 g of 8% hydrogen peroxide solution were placed in a 250 mL beaker, mixed and stirred at 300 ° C for 80 min, and then the reaction mixture was washed with deionized water and placed in 40 mL of anhydrous ethanol.

[0066] (2) 1.5 g of A151 and 8 mL of deionized water were added, and the mixture was stirred at 80 °C for 5 h under condensation reflux. The obtained product was centrifuged at 3000 rpm for 15 min, and then washed with anhydrous ethanol four times to ensure that the unreacted silane coupling agent was completely removed. Finally, the product was placed in a vacuum oven at 100 °C for 1 h to obtain surface-functionalized Al2O3@Al core-shell particles.

[0067] (3) 1.8 g of hydroxylated graphene, 4.96 g of A172, and 6 mL of deionized water were placed in a beaker and stirred at 80 °C for 5 h under condensation reflux. The resulting product was centrifuged at 3000 rpm for 15 min, then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 100 °C for 1 h to obtain surface functionalized hydroxylated graphene.

[0068] (4) 4.41 mg of chloroplatinic acid catalyst, 1.323 mg of fumarate, and an organosilicon matrix (4.41 g of vinyl silicone oil with a viscosity of 100 mPa·s and 0.9 g of hydrogenated silicone oil) were placed in a 100 mL beaker and stirred thoroughly for 4 min. Fillers (23.92 g of surface-functionalized Al2O3@Al core-shell particles prepared in step (2) and 0.27 g of surface-functionalized hydroxylated graphene prepared in step (3)) were then added and mechanically mixed for 15 min using a high-speed homogenizer. The sample was poured into a mold, defoamed in a vacuum oven for 10 min, and finally cured at 120°C for 8 h.

[0069] Example 5

[0070] A reactive hydroxylated graphene-reinforced spherical core-shell structured alumina@aluminum thermal conductive interface material, the preparation method of which comprises the following steps:

[0071] (1) 36 g of spherical aluminum powder (7.2 g of 10-13 μm spherical aluminum powder, 10.8 g of 25-30 μm spherical aluminum powder, and 18 g of 30-40 μm spherical aluminum powder) and 144 g of 8% hydrogen peroxide solution were placed in a 500 mL beaker, stirred and reacted at 300° C. for 80 min, and the reaction mixture was then washed with deionized water and placed in 60 mL of anhydrous ethanol.

[0072] (2) 2.52 g of KH570 and 5 mL of deionized water were added, and the mixture was stirred at 80 °C for 5 h under condensation reflux. The obtained product was centrifuged at 3000 rpm for 15 min, and then washed with anhydrous ethanol four times to ensure that the unreacted silane coupling agent was completely removed. Finally, the product was placed in a vacuum oven at 100 °C for 1 h to obtain surface functionalized Al2O3@Al core-shell particles.

[0073] (3) 1.8 g of hydroxylated graphene, 1.323 mg of A172, and 6 mL of deionized water were placed in a beaker and stirred at 80 °C for 5 h under condensation reflux. The resulting product was centrifuged at 3000 rpm for 15 min and then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 100 °C for 1 h to obtain surface-functionalized hydroxylated graphene.

[0074] (4) 4.41 mg of chloroplatinic acid catalyst, 0.02 g of fumarate, and an organosilicon matrix (4.41 g of vinyl silicone oil with a viscosity of 100 mPa·s and 0.9 g of hydrogenated silicone oil) were placed in a 100 mL beaker and stirred thoroughly for 4 min. Fillers (32.25 g of surface-functionalized Al2O3@Al core-shell particles prepared in step (2) and 0.37 g of surface-functionalized hydroxylated graphene prepared in step (3)) were then added and mechanically mixed for 15 min using a high-speed homogenizer. The sample was poured into a mold, defoamed in a vacuum oven for 10 min, and finally cured at 120°C for 8 h.

[0075] Example 6

[0076] A reactive hydroxylated graphene-reinforced spherical core-shell structured alumina@aluminum thermal conductive interface material, the preparation method of which comprises the following steps:

[0077] (1) 43 g of spherical aluminum powder (8.6 g of 10-13 μm spherical aluminum powder, 12.9 g of 25-30 μm spherical aluminum powder, and 21.5 g of 30-40 μm spherical aluminum powder) and 172 g of 8% hydrogen peroxide solution were placed in a 250 mL beaker, stirred and reacted at 150 ° C for 1.5 h, and then the reaction mixture was washed with deionized water and placed in 70 mL of anhydrous ethanol.

[0078] (2) 1.29 g of KH570 and 6 mL of deionized water were added, and the mixture was stirred at 75 °C for 3 h under condensation reflux. The obtained product was centrifuged at 6000 rpm for 6 min, and then washed with anhydrous ethanol three times to ensure that the unreacted silane coupling agent was completely removed. Finally, the product was placed in a vacuum oven at 110 °C for 1.5 h to obtain surface-functionalized Al2O3@Al core-shell particles.

[0079] (3) 1.5 g of hydroxylated graphene, 2.8 g of KH570, and 5 mL of deionized water were placed in a beaker and stirred at 75 °C for 3 h under condensation reflux. The resulting product was centrifuged at 6000 rpm for 6 min, then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 110 °C for 1.5 h to obtain surface-functionalized hydroxylated graphene.

[0080] (4) 4.41 mg of platinum-carbon catalyst, 1.323 mg of 2-methyl-3-butyn-2-ol, and an organosilicon matrix (4.41 g of vinyl silicone oil with a viscosity of 50 mPa·S and 0.9 g of hydrogenated silicone oil) were placed in a 100 mL beaker and stirred thoroughly for 3 min. Fillers (38.50 g of surface-functionalized Al2O3@Al core-shell particles prepared in step (2) and 0.44 g of surface-functionalized hydroxylated graphene prepared in step (3)) were then added and mechanically mixed for 20 min using a high-speed homogenizer. The sample was poured into a mold, defoamed in a vacuum oven for 20 min, and finally cured at 120°C for 8 h.

[0081] Example 7

[0082] A reactive hydroxylated graphene-reinforced spherical core-shell structured alumina@aluminum thermal conductive interface material, the preparation method of which comprises the following steps:

[0083] (1) 105 g of spherical aluminum powder (of which 10-13 μm spherical aluminum powder has a mass of 21 g, 25-30 μm spherical aluminum powder has a mass of 31.5 g, and 30-40 μm spherical aluminum powder has a mass of 52.5 g) and 420 g of 8% hydrogen peroxide solution are placed in a 1000 mL beaker, mixed and stirred at 140° C. for 80 min, and the reaction mixture is then washed with deionized water and placed in 200 mL of anhydrous ethanol.

[0084] (2) 8.4 g of VTPS and 7 mL of deionized water were added, and the mixture was stirred at 80 °C for 5 h under condensation reflux. The obtained product was centrifuged at 4000 rpm for 10 min, and then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 120 °C for 2 h to obtain surface-functionalized Al2O3@Al core-shell particles.

[0085] (3) 3 g of hydroxylated graphene, 7.2 g of VTPS, and 6 mL of deionized water were placed in a beaker and stirred at 80 °C for 5 h under condensation reflux. The resulting product was centrifuged at 4000 rpm for 10 min and then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 120 °C for 2 h to obtain surface-functionalized hydroxylated graphene.

[0086] (4) 4.41 mg of Custer catalyst, 1.323 mg of 1-ethynyl-1-cyclohexanol, and an organosilicon matrix (4.41 g of vinyl silicone oil with a viscosity of 100 mPa·s and 0.9 g of hydrogenated silicone oil) were placed in a 100 mL beaker and stirred thoroughly for 5 min. Fillers (99.82 g of surface-functionalized Al2O3@Al core-shell particles prepared in step (2) and 1.07 g of surface-functionalized hydroxylated graphene prepared in step (3)) were then added and mechanically mixed for 10 min using a high-speed homogenizer. The sample was poured into a mold, defoamed in a vacuum oven for 20 min, and finally cured at 120°C for 12 h.

[0087] Example 8

[0088] A reactive hydroxylated graphene-reinforced spherical core-shell structured alumina@aluminum thermal conductive interface material, the preparation method of which comprises the following steps:

[0089] (1) 105 g of spherical aluminum powder (of which 10-13 μm spherical aluminum powder has a mass of 26.25 g, 25-30 μm spherical aluminum powder has a mass of 26.25 g, and 30-40 μm spherical aluminum powder has a mass of 52.5 g) and 420 g of 8% hydrogen peroxide solution are placed in a 1000 mL beaker, mixed and stirred at 140° C. for 80 min, and the reaction mixture is then washed with deionized water and placed in 200 mL of anhydrous ethanol.

[0090] (2) 8.4 g of VTPS and 7 mL of deionized water were added, and the mixture was stirred at 80 °C for 5 h under condensation reflux. The obtained product was centrifuged at 4000 rpm for 10 min, and then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 120 °C for 2 h to obtain surface-functionalized Al2O3@Al core-shell particles.

[0091] (3) 3.5 g of hydroxylated graphene, 7.6 g of VTPS, and 6 mL of deionized water were placed in a beaker and stirred at 80 °C for 5 h under condensation reflux. The obtained product was centrifuged at 4000 rpm for 10 min, and then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 120 °C for 2 h to obtain surface functionalized hydroxylated graphene.

[0092] (4) 4.41 mg of Custer catalyst, 1.323 mg of 1-ethynyl-1-cyclohexanol, and an organosilicon matrix (4.41 g of vinyl silicone oil with a viscosity of 100 mPa·s and 0.9 g of hydrogenated silicone oil) were placed in a 100 mL beaker and stirred thoroughly for 5 min. Fillers (99.82 g of surface-functionalized Al2O3@Al core-shell particles prepared in step (2) and 1.07 g of surface-functionalized hydroxylated graphene prepared in step (3)) were then added and mechanically mixed for 10 min using a high-speed homogenizer. The sample was poured into a mold, defoamed in a vacuum oven for 20 min, and finally cured at 120°C for 12 h.

[0093] Example 9

[0094] A reactive hydroxylated graphene-reinforced spherical core-shell structured alumina@aluminum thermal conductive interface material, the preparation method of which comprises the following steps:

[0095] (1) 105 g of spherical aluminum powder (of which 21 g was spherical aluminum powder with a particle size of 10-13 μm, 21 g was spherical aluminum powder with a particle size of 25-30 μm, and 63 g was spherical aluminum powder with a particle size of 30-40 μm) and 420 g of 8% hydrogen peroxide solution were placed in a 1000 mL beaker, mixed and stirred at 140° C. for 80 min, and the reaction mixture was then washed with deionized water and placed in 200 mL of anhydrous ethanol.

[0096] (2) 8.4 g of VTPS and 7 mL of deionized water were added, and the mixture was stirred at 80 °C for 5 h under condensation reflux. The obtained product was centrifuged at 4000 rpm for 10 min, and then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 120 °C for 2 h to obtain surface-functionalized Al2O3@Al core-shell particles.

[0097] (3) 3.5 g of hydroxylated graphene, 7.6 g of VTPS, and 6 mL of deionized water were placed in a beaker and stirred at 80 °C for 5 h under condensation reflux. The obtained product was centrifuged at 4000 rpm for 10 min, and then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 120 °C for 2 h to obtain surface functionalized hydroxylated graphene.

[0098] (4) 4.41 mg of Custer catalyst, 1.323 mg of 1-ethynyl-1-cyclohexanol, and an organosilicon matrix (4.41 g of vinyl silicone oil with a viscosity of 100 mPa·s and 0.9 g of hydrogenated silicone oil) were placed in a 100 mL beaker and stirred thoroughly for 5 min. Fillers (99.82 g of surface-functionalized Al2O3@Al core-shell particles prepared in step (2) and 1.07 g of surface-functionalized hydroxylated graphene prepared in step (3)) were then added and mechanically mixed for 10 min using a high-speed homogenizer. The sample was poured into a mold, defoamed in a vacuum oven for 20 min, and finally cured at 120°C for 12 h.

[0099] Example 10

[0100] A reactive hydroxylated graphene-reinforced spherical core-shell structured alumina@aluminum thermal conductive interface material, the preparation method of which comprises the following steps:

[0101] (1) 105 g of spherical aluminum powder (of which 10-13 μm spherical aluminum powder has a mass of 21 g, 25-30 μm spherical aluminum powder has a mass of 31.5 g, and 30-40 μm spherical aluminum powder has a mass of 52.5 g) and 420 g of 8% hydrogen peroxide solution are placed in a 1000 mL beaker, mixed and stirred at 140° C. for 80 min, and the reaction mixture is then washed with deionized water and placed in 200 mL of anhydrous ethanol.

[0102] (2) 8.4 g of VTPS and 7 mL of deionized water were added, and the mixture was stirred at 80 °C for 5 h under condensation reflux. The obtained product was centrifuged at 4000 rpm for 10 min, and then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 120 °C for 2 h to obtain surface-functionalized Al2O3@Al core-shell particles.

[0103] (3) 3.5 g of hydroxylated graphene, 7.6 g of VTPS, and 6 mL of deionized water were placed in a beaker and stirred at 80 °C for 5 h under condensation reflux. The obtained product was centrifuged at 4000 rpm for 10 min, and then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 120 °C for 2 h to obtain surface functionalized hydroxylated graphene.

[0104] (4) 4.41 mg of Custer catalyst, 1.323 mg of 1-ethynyl-1-cyclohexanol, and an organosilicon matrix (4.41 g of vinyl silicone oil with a viscosity of 100 mPa·s and 0.9 g of hydrogenated silicone oil) were placed in a 100 mL beaker and stirred thoroughly for 5 min. Then, fillers (98.77 g of surface-functionalized Al2O3@Al core-shell particles prepared in step (2) and 2.12 g of surface-functionalized hydroxylated graphene prepared in step (3)) were added and mechanically mixed for 10 min using a high-speed homogenizer. The sample was poured into a mold, defoamed in a vacuum oven for 20 min, and finally cured at 120°C for 12 h.

[0105] Comparative Example 1

[0106] A spherical core-shell structured alumina@aluminum / hydroxylated graphene thermal conductive interface material, the preparation method of which comprises the following steps:

[0107] 4.41 mg of Custer catalyst, 1.323 mg of 1-ethynyl-1-cyclohexanol, and an organosilicon matrix (4.41 g of vinyl silicone oil with a viscosity of 100 mPa·s and 0.9 g of hydrogenated silicone oil) were placed in a 100 mL beaker and stirred thoroughly for 5 min. Subsequently, 21.11 g of spherical aluminum powder (4.222 g of 10-13 μm spherical aluminum powder, 7.3885 g of 25-30 μm spherical aluminum powder, and 9.4995 g of 30-40 μm spherical aluminum powder) and 0.13 g of hydroxylated graphene were added and mechanically mixed for 10 min using a high-speed homogenizer. The sample was poured into a mold, defoamed in a vacuum oven for 15 min, and finally cured at 120°C for 3 h.

[0108] Comparative Example 2

[0109] A spherical core-shell structured alumina@aluminum (modified) / hydroxylated graphene thermal conductive interface material, the preparation method of which comprises the following steps:

[0110] (1) 25 g of spherical aluminum powder (5 g of 10-13 μm spherical aluminum powder, 8.75 g of 25-30 μm spherical aluminum powder, and 11.25 g of 30-40 μm spherical aluminum powder) and 50 g of 5% hydrogen peroxide solution were placed in a 100 mL beaker, mixed and stirred at 140° C. for 1 h, and then the reaction mixture was washed with deionized water and placed in 50 mL of anhydrous ethanol.

[0111] (2) 1.25 g of VTPS and 4 mL of deionized water were added, and the mixture was stirred at 80 °C for 5 h under condensation reflux. The obtained product was centrifuged at 4000 rpm for 10 min, and then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 120 °C for 2 h to obtain surface functionalized Al2O3@Al core-shell particles.

[0112] (3) 4.41 mg of Custer catalyst, 1.323 mg of 1-ethynyl-1-cyclohexanol, and an organosilicon matrix (4.41 g of vinyl silicone oil with a viscosity of 100 mPa·s and 0.9 g of hydrogenated silicone oil) were placed in a 100 mL beaker and stirred thoroughly for 5 min. Then, fillers (21.11 g of surface-functionalized Al2O3@Al core-shell particles prepared in step (2) and 0.13 g of hydroxylated graphene) were added and mechanically mixed for 10 min using a high-speed homogenizer. The sample was poured into a mold, defoamed in a vacuum oven for 15 min, and finally cured at 120°C for 3 h.

[0113] Comparative Example 3

[0114] A spherical core-shell structured alumina@aluminum / hydroxylated graphene (modified) thermal conductive interface material, the preparation method of which comprises the following steps:

[0115] (1) 0.5 g of hydroxylated graphene, 1.25 g of VTPS, and 4 mL of deionized water were placed in a beaker and stirred at 80 °C for 5 h under condensation reflux. The obtained product was centrifuged at 4000 rpm for 10 min, then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 120 °C for 2 h to obtain surface functionalized hydroxylated graphene.

[0116] (2) 4.41 mg of Custer catalyst, 1.323 mg of 1-ethynyl-1-cyclohexanol, and an organosilicon matrix (4.41 g of vinyl silicone oil with a viscosity of 100 mPa·S and 0.9 g of hydrogenated silicone oil) were placed in a 100 mL beaker and stirred for 5 min. Subsequently, 21.11 g of spherical aluminum powder (of which 10-13 μm spherical aluminum powder had a mass of 4.222 g, 25-30 μm spherical aluminum powder had a mass of 7.3885 g, and 30-40 μm spherical aluminum powder had a mass of 9.4995 g) and 0.13 g of the surface-functionalized hydroxylated graphene prepared in step (1) were added, and mechanically mixed for 10 min using a high-speed homogenizer. The sample was poured into a mold, defoamed in a vacuum oven for 15 min, and finally cured at 120° C. for 3 h.

[0117] Comparative Example 4

[0118] An aluminum oxide / hydroxylated graphene thermal conductive interface material, the preparation method of which comprises the following steps:

[0119] (1) 0.5 g of hydroxylated graphene, 1.25 g of VTPS, and 4 mL of deionized water were placed in a beaker and stirred at 80 °C for 5 h under condensation reflux. The obtained product was centrifuged at 4000 rpm for 10 min, then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 120 °C for 2 h to obtain surface functionalized hydroxylated graphene.

[0120] (2) 4.41 mg of Custer catalyst, 1.323 mg of 1-ethynyl-1-cyclohexanol, and an organosilicon matrix (4.41 g of vinyl silicone oil with a viscosity of 100 mPa·S and 0.9 g of hydrogenated silicone oil) were placed in a 100 mL beaker and stirred for 5 min. Subsequently, 21.11 g of filler alumina and 0.13 g of surface-functionalized hydroxylated graphene prepared in step (1) were added and mechanically mixed for 10 min using a high-speed homogenizer. The sample was poured into a mold, defoamed in a vacuum oven for 15 min, and finally cured at 120° C. for 3 h.

[0121] Comparative Example 5

[0122] A reactive hydroxylated graphene-reinforced spherical core-shell structured alumina@aluminum thermal conductive interface material, the preparation method of which comprises the following steps:

[0123] (1) 25 g of spherical aluminum powder with a particle size of 10-13 μm and 50 g of a 5% hydrogen peroxide solution were placed in a 100 mL beaker, mixed and stirred at 140° C. for 1 h, and then the reaction mixture was washed with deionized water and placed in 50 mL of anhydrous ethanol.

[0124] (2) 1.25 g of VTPS and 4 mL of deionized water were added, and the mixture was stirred at 80 °C for 5 h under condensation reflux. The obtained product was centrifuged at 4000 rpm for 10 min, and then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 120 °C for 2 h to obtain surface functionalized Al2O3@Al core-shell particles.

[0125] (3) 0.5 g of hydroxylated graphene, 1.25 g of VTPS, and 4 mL of deionized water were placed in a beaker and stirred at 80 °C for 5 h under condensation reflux. The obtained product was centrifuged at 4000 rpm for 10 min, and then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 120 °C for 2 h to obtain surface functionalized hydroxylated graphene.

[0126] (4) 4.41 mg of Custer catalyst, 1.323 mg of 1-ethynyl-1-cyclohexanol, and an organosilicon matrix (4.41 g of vinyl silicone oil with a viscosity of 100 mPa·s and 0.9 g of hydrogenated silicone oil) were placed in a 100 mL beaker and stirred for 5 min. Then, fillers (21.11 g of surface-functionalized Al2O3@Al core-shell particles prepared in step (2) and 0.13 g of surface-functionalized hydroxylated graphene prepared in step (3)) were added and mechanically mixed for 10 min using a high-speed homogenizer. The sample was poured into a mold, defoamed in a vacuum oven for 15 min, and finally cured at 120°C for 3 h.

[0127] Comparative Example 6

[0128] A reactive hydroxylated graphene-reinforced spherical core-shell structured alumina@aluminum thermal conductive interface material, the preparation method of which comprises the following steps:

[0129] (1) 25 g of spherical aluminum powder with a particle size of 25-30 μm and 50 g of a 5% hydrogen peroxide solution were placed in a 100 mL beaker, mixed and stirred at 140° C. for 1 h, and then the reaction mixture was washed with deionized water and placed in 50 mL of anhydrous ethanol.

[0130] (2) 1.25 g of VTPS and 4 mL of deionized water were added, and the mixture was stirred at 80 °C for 5 h under condensation reflux. The obtained product was centrifuged at 4000 rpm for 10 min, and then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 120 °C for 2 h to obtain surface functionalized Al2O3@Al core-shell particles.

[0131] (3) 0.5 g of hydroxylated graphene, 1.25 g of VTPS, and 4 mL of deionized water were placed in a beaker and stirred at 80 °C for 5 h under condensation reflux. The obtained product was centrifuged at 4000 rpm for 10 min, and then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 120 °C for 2 h to obtain surface functionalized hydroxylated graphene.

[0132] (4) 4.41 mg of Custer catalyst, 1.323 mg of 1-ethynyl-1-cyclohexanol, and an organosilicon matrix (4.41 g of vinyl silicone oil with a viscosity of 100 mPa·s and 0.9 g of hydrogenated silicone oil) were placed in a 100 mL beaker and stirred for 5 min. Then, fillers (21.11 g of surface-functionalized Al2O3@Al core-shell particles prepared in step (2) and 0.13 g of surface-functionalized hydroxylated graphene prepared in step (3)) were added and mechanically mixed for 10 min using a high-speed homogenizer. The sample was poured into a mold, defoamed in a vacuum oven for 15 min, and finally cured at 120°C for 3 h.

[0133] Comparative Example 7

[0134] A reactive hydroxylated graphene-reinforced spherical core-shell structured alumina@aluminum thermal conductive interface material, the preparation method of which comprises the following steps:

[0135] (1) 25 g of spherical aluminum powder with a particle size of 30-40 μm and 50 g of a 5% hydrogen peroxide solution were placed in a 100 mL beaker, mixed and stirred at 140° C. for 1 h, and then the reaction mixture was washed with deionized water and placed in 50 mL of anhydrous ethanol.

[0136] (2) 1.25 g of VTPS and 4 mL of deionized water were added, and the mixture was stirred at 80 °C for 5 h under condensation reflux. The obtained product was centrifuged at 4000 rpm for 10 min, and then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 120 °C for 2 h to obtain surface functionalized Al2O3@Al core-shell particles.

[0137] (3) 0.5 g of hydroxylated graphene, 1.25 g of VTPS, and 4 mL of deionized water were placed in a beaker and stirred at 80 °C for 5 h under condensation reflux. The obtained product was centrifuged at 4000 rpm for 10 min, and then washed with anhydrous ethanol five times to ensure that the unreacted silane coupling agent was completely removed. Finally, it was placed in a vacuum oven at 120 °C for 2 h to obtain surface functionalized hydroxylated graphene.

[0138] (4) 4.41 mg of Custer catalyst, 1.323 mg of 1-ethynyl-1-cyclohexanol, and an organosilicon matrix (4.41 g of vinyl silicone oil with a viscosity of 100 mPa·s and 0.9 g of hydrogenated silicone oil) were placed in a 100 mL beaker and stirred for 5 min. Then, fillers (21.11 g of surface-functionalized Al2O3@Al core-shell particles prepared in step (2) and 0.13 g of surface-functionalized hydroxylated graphene prepared in step (3)) were added and mechanically mixed for 10 min using a high-speed homogenizer. The sample was poured into a mold, defoamed in a vacuum oven for 15 min, and finally cured at 120°C for 3 h.

[0139] Verification Example 1

[0140] The thermal interface materials prepared in Examples 1-10 and Comparative Examples 1-7 were tested for thermal conductivity, thermal resistance (tested according to ASTM D5470), and density. Density was tested using the balance-cylinder method. The sample mass was weighed using a balance and measured using a graduated cylinder. Three parallel measurements were taken and the average value was calculated. Density was calculated using ρ = m / v. The thermal interface materials had a thickness of 3 mm and a diameter of 30 mm. Thermal conductivity and thermal resistance were measured using the heat flow method. The test results are shown in Table 1 below.

[0141] Table 1 Performance data of thermal interface materials of Examples 1-10 and Comparative Examples 1-7

[0142]

[0143]

[0144] As can be seen from Table 1, compared with Example 1, the thermal conductivity of Comparative Example 1 decreases, and the interface thermal resistance and contact thermal resistance increase. This is because the filler has not undergone surface functionalization treatment. As the content of thermally conductive filler increases, the fluidity of the thermal interface material decreases, the filler is easily agglomerated, and the aluminum powder and hydroxylated graphene have different polarities from silicone, and have poor compatibility with silicone, resulting in certain interface problems. Compared with Example 1, Comparative Example 2 shows a decrease in thermal conductivity and an increase in interfacial thermal resistance and contact thermal resistance. This is because the hydroxylated graphene was not surface-functionalized with a silane coupling agent. The hydroxylated graphene has a large specific surface area and needs to be combined with more polymer matrix, which weakens the fluidity of the polymer system. In addition, the hydroxylated graphene has poor compatibility with organosilicon, resulting in certain interface problems and failure to form an effective heat conduction path. Compared with Example 1, Comparative Example 3 shows a decrease in thermal conductivity and an increase in interfacial thermal resistance and contact thermal resistance. This is because the aluminum powder has not been oxidized and surface-functionalized with a silane coupling agent. The inorganic filler aluminum powder has different polarities from organosilicon, resulting in a lattice vibration mismatch between the filler and the matrix, which seriously hinders heat transfer. The aluminum powder has poor compatibility with organosilicon and has certain interface problems, which fails to form an effective heat conduction path. Compared with Example 1, Comparative Example 4 uses a different thermally conductive filler. The density of aluminum powder is less than that of aluminum oxide, but the thermal conductivity of aluminum powder is much greater than that of aluminum oxide. According to the test results, the density of the thermal interface material increases, the thermal conductivity decreases, and the interfacial thermal resistance and contact thermal resistance increase. Compared with Example 1, Comparative Examples 5, 6, and 7 use aluminum powder of a single particle size, and the thermal conductivity decreases, while the interface thermal resistance and contact thermal resistance increase. This is because the aluminum powder of a single particle size cannot form a good heat conduction network path.

[0145] In addition to the surface functionalized filler and the specific particle size of aluminum powder composition having a key influence on the performance of the thermal interface material of the present invention, the oxidant concentration, the silane coupling agent content, the ratio of thermal conductive filler to silicone matrix, the ratio of the three particle sizes of aluminum powder and the ratio of the two thermal conductive fillers will also have a certain impact on the performance of the thermal interface material. Specifically, appropriately increasing the oxidant concentration helps to increase the active group hydroxyl groups on the surface of the alumina@aluminum core-shell structure particles, which is beneficial to the complete functionalization reaction of the silane coupling agent on the surface of the alumina@aluminum particles, thereby improving thermal conductivity and reducing interface thermal resistance and contact thermal resistance; increasing the content of the silane coupling agent to a certain extent helps to fully disperse the alumina@aluminum particles and hydroxylated graphene fillers in the silicone, avoid filler agglomeration, thereby improving the compatibility of the filler with the silicone, increasing thermal conductivity, and reducing interface thermal resistance and contact thermal resistance; appropriately increasing the amount of thermally conductive filler helps to form more thermal conductive paths in the thermally conductive interface material; for the amount of aluminum powder with three particle sizes, when the content of 10-13μm aluminum powder is increased, it may be due to Excessive content of small-particle aluminum powder cannot adhere to a large amount of hydroxylated graphene, and cannot form an effective heat conduction path, which affects the thermal conductivity and thermal resistance to a certain extent; when the content of 30-40μm aluminum powder is increased, the excessive content of large-particle aluminum powder may easily destroy the heat conduction path of hydroxylated graphene in the vertical direction, reduce the "thermal bridge" effect of hydroxylated graphene, and thus affect the thermal conductivity and thermal resistance to a certain extent; in addition, increasing the proportion of surface-functionalized hydroxylated graphene in the thermal conductive filler to a certain extent can help improve thermal conductivity and reduce thermal resistance. The reason is that hydroxylated graphene has high thermal conductivity and can exert a "thermal bridge" effect to cooperate with alumina@aluminum core-shell particles to form a good heat conduction path.

[0146] The above detailed description of the analytical methods involved in the present invention provides a detailed introduction. It should be noted that the above description is intended solely to help those skilled in the art better understand the methods and concepts of the present invention, and is not intended to limit the relevant content. Without departing from the principles of the present invention, those skilled in the art may make appropriate adjustments or modifications to the present invention, and such adjustments and modifications shall also fall within the scope of protection of the present invention.

Claims

1. A method for preparing a reactive graphene-enhanced spherical core-shell structured alumina@aluminum thermal conductive interface material, characterized in that: The steps include: (1) placing aluminum powder and an oxidant in a container, mixing and stirring to react, and then washing the reaction mixture and placing it in anhydrous ethanol; (2) adding a silane coupling agent and deionized water to carry out a heating and stirring reaction, and centrifuging, washing, and drying the obtained product to obtain surface functionalized Al2O3@Al core-shell particles; (3) placing hydroxylated graphene, a silane coupling agent, and deionized water in a container for heating and stirring to react, and centrifuging, washing, and drying the resulting product to obtain surface-functionalized hydroxylated graphene; (4) Vinyl silicone oil, hydrogenated silicone oil, platinum catalyst, and inhibitor are placed in a container and mixed evenly, and then the surface-functionalized Al2O3@Al core-shell particles prepared in step (2) and the surface-functionalized hydroxylated graphene prepared in step (3) are added, and the mixture is sequentially mixed, defoamed, and cured at high temperature to obtain the product.

2. The preparation method according to claim 1, characterized in that The oxidant in step (1) is selected from one or more of hydrogen peroxide solution, sodium peroxide solution, and potassium peroxide solution.

3. The preparation method according to claim 1, characterized in that The aluminum powder in step (1) comprises aluminum powders of different particle sizes within the range of 10-40 μm.

4. The preparation method according to claim 1, characterized in that The silane coupling agent in step (2) and step (3) is selected from one or more of VTPS, A151, A171, A172, and KH570.

5. The preparation method according to claim 1, characterized in that The amount of the silane coupling agent used in step (2) and step (3) is 1-15% of the mass of the aluminum powder in step (1).

6. The preparation method according to claim 1, characterized in that The platinum catalyst in step (4) is selected from one or more of Custer's catalyst, chloroplatinic acid catalyst, platinum-carbon catalyst, platinum dioxide catalyst, Ashby's catalyst, Speier catalyst and Lamoreaux catalyst.

7. The preparation method according to claim 1, characterized in that The inhibitor in step (4) is selected from one or more of 1-ethynyl-1-cyclohexanol, TMDO, maleate, fumarate, 2-methyl-3-butyn-2-ol, benzotriazole, and β-alkynol.

8. The preparation method according to claim 1, characterized in that The viscosity of the vinyl silicone oil in step (4) is 50-300 mPa·s.

9. A reactive graphene-enhanced spherical core-shell structured alumina@aluminum thermal conductive interface material prepared by the preparation method according to any one of claims 1 to 8.

10. Application of the reactive graphene-enhanced spherical core-shell structured alumina@aluminum thermal conductive interface material prepared by the preparation method according to any one of claims 1 to 8 in the field of integrated circuits and / or microelectronic packaging.

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