Preparation method of diamond particle reinforced heat-conducting silicone grease fluid

Abstract

The invention discloses a preparation method of diamond particle reinforced heat-conducting silicone grease fluid, belongs to the technical field of heat-conducting silicone grease processing, and aims to solve the technical problem that the heat-conducting property and wear resistance of the heat-conducting silicone grease fluid in the prior art need to be further improved. The prepared modified diamond particles and epoxidized heat-conducting silicone oil form a stable structure through chemical reaction crosslinking, the wear resistance of the material is improved, and the modified diamond particles serve as a chain extender to hybridize space chain segments of the epoxidized heat-conducting silicone oil and serve as a heat-conducting bridge, so that the wear resistance of the material is improved. A stable and efficient heat transfer path is formed in the material, the mechanical property of the material is remarkably enhanced, the interface thermal resistance of the heat-conducting silicone grease fluid is reduced, a large number of fluorine groups in the epoxidized heat-conducting silicone oil enable the material to have high surface energy, and the corrosion resistance of the heat-conducting silicone grease fluid is remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of thermal conductive silicone grease processing, and in particular to a method for preparing diamond particle-reinforced thermal conductive silicone grease fluid. Background Art

[0002] Diamond particle-enhanced thermally conductive silicone grease fluid is widely used due to its excellent thermal conductivity and wear resistance. This composite material integrates the ultra-high thermal conductivity of diamond particles into the silicone grease matrix, significantly improving the heat dissipation efficiency. It is especially suitable for thermal management of high-performance electronic equipment. With the development of technology, the research focus has shifted to how to reduce thermal resistance and enhance wear resistance by optimizing the particle size of diamond particles and improving their dispersion uniformity in silicone grease. The advancement of this technology has significantly improved the performance of the product and broadened its application in multiple industries such as aviation, automobile and electronic manufacturing.

[0003] Prior art CN116410602A discloses a high thermal conductivity thermal conductive silicone grease and a preparation method thereof, comprising silicone oil, a first type of thermal conductive material, a second type of thermal conductive material and a coupling agent. The preparation method comprises: material preparation, material production, material mixing and thermal conductive silicone grease preparation. The thermal conductive material is added during the preparation of the thermal conductive silicone grease, which can effectively improve the thermal conductivity of the thermal conductive silicone grease and further improve the thermal conductivity of the thermal conductive silicone grease. By adding different types of thermal conductive materials, the thermal conductive silicone can be ensured to have good plasticity, good thermal conductivity, good wear resistance and plasticity.

[0004] The above patent content is to introduce a large amount of thermal conductive materials and coupling agents into silicone oil so that the thermal conductivity and wear resistance of the thermal grease finally prepared are significantly improved. However, due to the large difference in polarity between silicone oil and inorganic thermal conductive filler, and the coupling agent is added as an auxiliary material instead of forming a stable structure by grafting on the material, the bonding strength between the interfaces of the materials needs to be further improved. Finally, due to the incompatibility between the materials, the interfacial thermal resistance of the thermal grease is large, so that the wear resistance and thermal conductivity of the thermal grease finally obtained need to be further improved.

[0005] In view of the technical defects in this aspect, a solution is now proposed. Summary of the invention

[0006] The purpose of the present invention is to provide a method for preparing a heat-conducting silicone grease fluid reinforced with diamond particles, so as to solve the technical problem in the prior art that the thermal conductivity and wear resistance of the heat-conducting silicone grease fluid need to be further improved.

[0007] The purpose of the present invention can be achieved by the following technical solution: A method for preparing a diamond particle-reinforced thermally conductive silicone grease fluid comprises the following steps:

[0008] S1, adding thermal conductive silicone oil, 30-40wt% hydrogen peroxide solution, sodium hydroxide powder and dimethyl sulfoxide into a reaction kettle and stirring, raising the temperature of the reaction kettle to 30-50°C, keeping the temperature for reaction for 1-2h, and post-treating to obtain epoxidized thermal conductive silicone oil;

[0009] The reaction equation for preparing epoxidized thermally conductive silicone oil is:

[0010]

[0011] The reaction principle for preparing epoxidized thermally conductive silicone oil is as follows: under alkaline conditions, hydrogen peroxide fully oxidizes the carbon-carbon double bonds at the ends of the thermally conductive silicone oil to form more active epoxy groups, and finally epoxidized thermally conductive silicone oil is prepared.

[0012] S2, adding oxidized diamond particles, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, triethylamine and N,N-dimethylamide into a reaction kettle and stirring, raising the temperature of the reaction kettle to 40-60° C., keeping the temperature for 1-2 hours, and post-treating to obtain modified diamond particles;

[0013] The reaction principle for preparing modified diamond particles is as follows: the surface of the oxidized diamond particles has a large number of active groups, such as hydroxyl, epoxy and carboxyl groups, which react with the active epoxy groups on 3-(2,3-epoxypropyloxy)propyltrimethoxysilane to form a stable grafting structure on the surface of the oxidized diamond particles, and finally the modified diamond particles are prepared.

[0014] S3, adding modified diamond particles, epoxidized thermal conductive silicone oil, aluminum chloride and dimethyl sulfoxide into a reaction kettle, raising the temperature of the reaction kettle to 40-60° C., maintaining the temperature for 1-2 hours, and post-treating to obtain a thermal conductive silicone grease matrix;

[0015] The reaction principle for preparing the thermal grease matrix is ​​as follows: under the catalysis of high temperature and alkaline conditions, the epoxy group at the end of the epoxidized thermal silicone oil reacts with the active functional groups on the surface of the modified diamond particles to form a complex spatial structure, and finally the thermal grease matrix is ​​prepared.

[0016] S4. Add the thermal conductive silicone grease matrix and auxiliary materials into the reaction kettle and stir evenly to obtain the thermal conductive silicone grease fluid.

[0017] Furthermore, in step S1, the method for preparing the thermally conductive silicone oil comprises the following steps:

[0018] A1. Add tetramethyldivinyldisiloxane, hexaphenylcyclotrisiloxane, modified silicone oil and diethyl ether into a reaction kettle, and stir at room temperature for 15-20 minutes to obtain a reaction precursor solution;

[0019] A2. Add the reaction precursor solution and 98 wt% sulfuric acid solution into the reactor, and keep the reaction at room temperature for 8-10 hours. Then, add solid sodium bicarbonate into the reactor containing the reaction solution until the pH value of the reaction solution is 7-8. Then, perform post-treatment to obtain thermal conductive silicone oil.

[0020] The reaction equation for preparing thermal conductive silicone oil is:

[0021]

[0022] Where:

[0023] The reaction principle for preparing thermal conductive silicone oil is as follows: under the catalysis of concentrated sulfuric acid, tetramethyldivinyldisiloxane, hexaphenylcyclotrisiloxane and modified silicone oil are subjected to a telomerization reaction, with tetramethyldivinyldisiloxane serving as a telomerization agent, hexaphenylcyclotrisiloxane and modified silicone oil serving as main chain monomer substances, and at the same time, the carbon-oxygen-silicon structure of the side chain is hydrolyzed, thereby finally preparing thermal conductive silicone oil.

[0024] Furthermore, in step A1, the amount ratio of tetramethyldivinyldisiloxane, hexaphenylcyclotrisiloxane, modified silicone oil and ether is 2-4g:5-8g:8-10g:60-80mL; in step A2, the amount ratio of the reaction precursor solution and the 98wt% sulfuric acid solution is 8-10mL:1mL, and the post-treatment includes: after the reaction is completed, adding the reaction solution to a rotary evaporator with a water bath temperature of 80-100°C, and distilling under reduced pressure until no liquid is produced to obtain thermal conductive silicone oil.

[0025] Furthermore, the preparation method of the modified silicone oil comprises the following steps:

[0026] B1, adding trimethylsilyl chloride, trans-2-[4-(trifluoromethyl)phenyl]vinylboronic acid, triethylamine and dichloromethane into a reaction kettle, raising the temperature of the reaction kettle to 30-50° C., keeping the temperature for reaction for 1-2 hours, and post-treating to obtain a modified monomer;

[0027] The reaction equation for preparing the modified monomer is:

[0028]

[0029] The reaction principle for preparing the modified monomer is: under the catalysis of alkaline conditions, trimethylsilyl chloride and trans-2-[4-(trifluoromethyl)phenyl]vinylboronic acid undergo elimination reaction to form a lipid bond, and finally the modified monomer is prepared. The mass spectrometry analysis data of the modified monomer are m / z: 360.14 (100.0%), 361.14 (27.2%), 359.14 (23.3%), 362.13 (6.3%), 362.14 (3.7%), 363.14 (1.3%).

[0030] B2. Add the modified monomer, high hydrogen silicone oil, bis(dimethyl(vinyl)silyl)platinum dihydride and toluene into the reactor, raise the temperature of the reactor to 30-40°C, keep the reaction temperature for 1-2h, and post-treat to obtain the modified silicone oil.

[0031] The reaction equation for preparing modified silicone oil is:

[0032]

[0033] Where:

[0034] The reaction principle for preparing modified silicone oil is as follows: under the catalysis of a catalyst, high hydrogen-containing silicone oil and modified monomer undergo a silylation reaction, and finally the modified monomer is grafted onto the chain segment of the high hydrogen-containing silicone oil to finally prepare the modified silicone oil.

[0035] Further, in step B1, the amount ratio of trimethylsilyl chloride, trans-2-[4-(trifluoromethyl)phenyl]vinylboronic acid, triethylamine and dichloromethane is 2-3g:8-10g:0.5-0.8g:40-60mL, and the post-treatment includes: after the reaction is completed, the reaction solution is added to a rotary evaporator with a water bath temperature of 80-100°C, and distilled under reduced pressure until no liquid is produced to obtain a modified monomer; in step B2, the amount ratio of the modified monomer, high hydrogen silicone oil, bis(dimethyl(vinyl)silyl)platinum dihydrogen and toluene is 5-8g:4-6g:0.5-0.8g:40-60mL, and the post-treatment includes: after the reaction is completed, the reaction solution is added to a rotary evaporator with a water bath temperature of 80-100°C, and distilled under reduced pressure until no liquid is produced to obtain a modified silicone oil.

[0036] Furthermore, in step S2, the method for preparing the oxidized diamond particles comprises the following steps:

[0037] C1. Mixing the pre-treated diamond particles with nickel powder and adding them into a tube furnace, calcining and etching at high temperature to obtain a calcined product, and post-treating to obtain etched diamond particles;

[0038] The reaction principle for preparing etched diamond particles is as follows: when diamond particles are heated together with nickel powder, the nickel powder first forms nickel-carbon compounds with carbon atoms on the surface of the diamond particles. When the temperature is high enough to allow oxygen to penetrate and participate in the reaction, these nickel-carbon compounds will promote the reaction of carbon atoms with oxygen to produce carbon dioxide. Since carbon dioxide is a gas, it will escape from the reaction system, leaving more and more nickel and unreacted carbon atoms, and finally preparing etched diamond particles.

[0039] C2. Put the etched diamond particles into a plasma generator, and obtain oxidized diamond particles after plasma oxidation.

[0040] The reaction principle for preparing oxidized diamond particles is as follows: when diamond particles are introduced into a plasma environment, the active oxidizing particles in the plasma react with the carbon atoms on the surface of the diamond to form oxidizing functional groups such as hydroxyl and carboxyl groups, and finally oxidized diamond particles are prepared.

[0041] Furthermore, in step C1, the amount ratio of diamond particles to nickel powder is 1-3g:5-8g, and the pretreatment operation includes: placing the diamond particles in a sodium hydroxide solution with a concentration of 1-1.5mol / L and a sulfuric acid solution with a concentration of 1-1.5mol / L for 30-40min, washing with ethanol and deionized water for 3-5 times after the soaking, placing the material in a drying oven at a temperature of 60°C and vacuum drying until the material has a constant weight to obtain pretreated diamond particles; the high-temperature calcination and etching operation is: after nitrogen protection is introduced into the tubular furnace, the tubular furnace is heated to 800-900°C at a heating rate of 5°C / min, and a mixed gas of oxygen and nitrogen in a volume ratio of 1:4 is introduced, the gas flow rate is 600-800sccm, and the heat preservation treatment is performed for 4-6h to obtain a calcined product.

[0042] Furthermore, in step C1, the post-treatment includes: placing the calcined product in a decontamination solution obtained by mixing 30-40wt% sulfuric acid solution and 20-30wt% hydrogen peroxide solution in a volume ratio of 1:1 to obtain a mixed solution, adding the mixed solution to a water bath and heating it for 60 minutes at a heating temperature of 60-80°C, and ultrasonically oscillating at a frequency of 20-40kHz for 30-40 minutes, repeating this operation three times, and then centrifuging it at a centrifugal speed of 3000r / min in a centrifuge, filtering it, and washing it with deionized water to make it neutral, and finally placing it in a drying oven at a temperature of 80°C for 2h for vacuum drying to obtain etched diamond particles; in step C2, the power of the plasma generator is 800-1000W, the pressure is 20-40Pa, the oxygen flow rate is 100mL / min, the argon flow rate is 50mL / min, and the treatment time is 2-4h.

[0043] Furthermore, in step S1, the amount ratio of thermal conductive silicone oil, 30-40wt% hydrogen peroxide solution, sodium hydroxide powder and dimethyl sulfoxide is 5-8g:10-15mL:0.7-1.2g:20-30mL, and the post-treatment includes: after the reaction is completed, the temperature of the reactor is cooled to room temperature, the reaction solution is added to a rotary evaporator with a water bath temperature of 80-100°C, and reduced pressure distillation is performed until no liquid is extracted to obtain epoxidized thermal conductive silicone oil.

[0044] Furthermore, in step S2, the amount ratio of oxidized diamond particles, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, triethylamine and N,N-dimethylamide is 5-8g:3-4g:0.7-1.2g:30-40mL, and the post-treatment includes: after the reaction is completed, the reaction kettle is lowered to room temperature, the reaction liquid is filtered and the filter cake is collected, and the filter cake is washed with ethanol and deionized water for 3-5 times, and then the filter cake is placed in a drying oven at a temperature of 80°C for vacuum drying until the filter cake has a constant weight to obtain modified diamond particles.

[0045] Furthermore, in step S3, the amount ratio of modified diamond particles, epoxidized thermal conductive silicone oil, aluminum chloride and dimethyl sulfoxide is 20-24g:4-6g:0.5-0.8g:40-60mL, and the post-treatment includes: after the reaction is completed, adding the reaction solution into a rotary evaporator with a water bath temperature of 80-100°C, and distilling under reduced pressure until no liquid is extracted to obtain a thermal conductive silicone grease matrix.

[0046] Furthermore, in step S4, the auxiliary materials include: stabilizer, tackifier, dispersant, preservative and surfactant, and the usage ratio of thermal conductive silicone grease matrix, stabilizer, tackifier, dispersant, preservative and surfactant is 80-100g:10-12g:10-15g:6-8g:3-5g:4-6g.

[0047] Furthermore, the stabilizer is one or more of butylhydroxymethyl benzoate, dibutylhydroxytoluene and dimethylphenol; the thickener is one or more of polyisobutylene, hydrogenated polybutadiene and 3-aminopropyltrimethoxysilane; the dispersant is one or more of polyvinyl pyrrolidone, phosphate diester and polymethyl methacrylate; the preservative is one or more of phenoxyethanol, benzalkonium chloride and isothiazolinone; the surfactant is one or more of sodium dodecylbenzene sulfonate, polysorbate and polyethylene glycol.

[0048] The present invention has the following beneficial effects:

[0049] 1. The present invention etches and oxidizes the surface of diamond particles by plasma gas, so that the surface of the diamond particles has a large number of active functional groups, and further modifies the surface of the diamond particles with a silane coupling agent to obtain modified diamond particles, which are cross-linked with epoxidized thermal conductive silicone oil rich in boron groups, fluorine groups and benzene rings obtained by monomer modification and polymerization and modified at the end in the form of epoxy groups through chemical reactions to form a stably combined structure, thereby improving the wear resistance of the material. The large number of active functional groups on the surface of the modified diamond particles make it act as a chain extender, hybridize the spatial chain segments of the epoxidized thermal conductive silicone oil and serve as a thermal conductive bridge, so that a more stable and efficient heat transfer path is formed inside the material and the mechanical properties of the material are significantly enhanced. The combination between the materials greatly reduces the interfacial thermal resistance of the thermal conductive silicone grease fluid, significantly reduces the influence of organic components on the thermal conductive silicone grease fluid, and the large number of fluorine groups inside the material make the material have a strong surface energy, so that the corrosion resistance of the thermal conductive silicone grease fluid is significantly improved.

[0050] 2. In the process of preparing the thermal conductive silicone grease fluid, the present invention selects to perform surface etching treatment on the diamond particles to form grooves on the surface and increase the specific surface area of ​​the diamond particles, thereby enhancing the contact area with the organic components and providing stronger heat conduction capacity, while providing more sufficient reaction space for further oxidation. After further oxidation, a large number of active functional groups are formed, and finally the compatibility with the organic components is significantly improved by cross-linking with a silane coupling agent.

[0051] 3. In the process of preparing the thermal conductive silicone grease fluid of the present invention, firstly, the trans-2-[4-(trifluoromethyl)phenyl]vinylboronic acid is modified to obtain a modified monomer, and then branched into the chain segment structure of the high hydrogen-containing silicone oil through hydrosilylation, and the thermal conductivity of the silicone oil component is significantly improved through the boron, fluorine and benzene ring inside the silicone oil, and the thermal conductive silicone oil is prepared as one of the telomerization base products. The thermal conductive silicone oil contains a large number of benzene ring structures. The high symmetry of the benzene ring structure enables the thermal conductive silicone oil to form a regular stacking structure after curing, which is conducive to the effective transfer of thermal energy, and the molecular structure of the benzene ring shows a resonance phenomenon, wherein the three double bonds formed between the six carbon atoms can move freely between the six carbon atoms. The delocalization of the π electron cloud enhances the freedom of the electrons, which is conducive to more efficient transfer of thermal energy through the conduction of electrons. Finally, by modifying the end of the thermal conductive silicone oil, an epoxidized thermal conductive silicone oil with excellent cross-linking ability with the modified diamond particles is obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0053] Figure 1 This is a SEM image of the diamond particles used in Example 3;

[0054] Figure 2 This is the SEM image of the etched diamond particles prepared in Example 3. DETAILED DESCRIPTION

[0055] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] The methyl high hydrogen silicone oil used in the present invention is purchased from Anhui Mingyi Silicon Industry Co., Ltd., and the product is MY202 high hydrogen silicone oil.

[0057] Example 1

[0058] This embodiment provides a method for preparing a diamond particle-reinforced thermally conductive silicone grease fluid, comprising the following steps:

[0059] S1. Preparation of modified diamond particles

[0060] The diamond particles were placed in a 1.0 mol / L sodium hydroxide solution and a 1.0 mol / L sulfuric acid solution and soaked for 30 min, respectively. After soaking, the particles were washed with ethanol and deionized water for 3 times. The particles were placed in a drying oven at 60°C and vacuum dried until the weight of the particles was constant, thereby obtaining pre-treated diamond particles.

[0061] Weigh: 30.0 g of pre-treated diamond particles and 50.0 g of nickel powder are mixed and added into a tube furnace. After nitrogen protection is introduced into the tube furnace, the temperature of the tube furnace is increased to 800° C. at a heating rate of 5° C. / min, and a mixed gas of oxygen and nitrogen in a volume ratio of 1:4 is introduced, and the gas flow rate is 600-800 sccm. The mixture is kept warm for 4 hours to obtain a calcined product;

[0062] The calcined product is placed in a decontamination solution obtained by mixing a 30wt% sulfuric acid solution and a 20wt% hydrogen peroxide solution in a volume ratio of 1:1 to obtain a mixed solution, the mixed solution is added to a water bath and heated for 60 minutes at a heating temperature of 60°C, and ultrasonically oscillated at a frequency of 20kHz for 30 minutes, and the operation is repeated three times, and then centrifuged at a centrifugal speed of 3000r / min in a centrifuge, filtered, and washed with deionized water to be neutral, and finally placed in a drying oven for vacuum drying at a temperature of 80°C for 2 hours to obtain etched diamond particles;

[0063] The etched diamond particles were placed in a plasma generator with a power of 800 W, a pressure of 20 Pa, an oxygen flow rate of 100 mL / min, an argon flow rate of 50 mL / min, and a treatment time of 2 h to obtain oxidized diamond particles;

[0064] Weigh: 20.0g of oxidized diamond particles, 10.0g of 3-(2,3-epoxypropoxy)propyltrimethoxysilane, 2.1g of triethylamine and 100.0mL of N,N-dimethylamide, add into the reactor and stir, raise the temperature of the reactor to 40°C, keep warm for 1h, after the reaction is completed, lower the temperature of the reactor to room temperature, filter the reaction liquid and collect the filter cake, wash the filter cake with ethanol and deionized water for 3 times, place the filter cake in a drying oven at 80°C for vacuum drying until the filter cake has a constant weight, and obtain modified diamond particles.

[0065] S2. Preparation of epoxy thermal conductive silicone oil

[0066] Weigh: 20.0 g of trimethylsilyl chloride, 80.0 g of trans-2-[4-(trifluoromethyl)phenyl]vinylboronic acid, 5.0 g of triethylamine and 400.0 mL of dichloromethane are added to a reactor, the temperature of the reactor is raised to 30° C., and the reaction is kept warm for 1 hour. After the reaction is completed, the reaction liquid is added to a rotary evaporator with a water bath temperature of 80° C., and distilled under reduced pressure until no liquid is produced to obtain a modified monomer;

[0067] Weigh: 30.0g of modified monomer, 20.0g of high hydrogen silicone oil, 2.4g of bis(dimethyl(vinyl)silyl)platinum dihydride and 160.0mL of toluene are added to a reactor, the temperature of the reactor is raised to 30°C, and the reaction is kept warm for 1h. After the reaction is completed, the reaction liquid is added to a rotary evaporator with a water bath temperature of 80°C, and distilled under reduced pressure until no liquid is produced to obtain modified silicone oil;

[0068] Weigh: 10.0 g of tetramethyldivinyldisiloxane, 18.0 g of hexaphenylcyclotrisiloxane, 24.0 g of modified silicone oil and 180.0 mL of ether, add into a reaction kettle, stir at room temperature for 15 min, and obtain a reaction precursor solution;

[0069] Weigh: 16.0 mL of reaction precursor solution and 2.0 mL of 98 wt% sulfuric acid solution are added to a reactor, and the reaction is kept at room temperature for 8 hours, and then solid sodium bicarbonate is added to the reactor containing the reaction solution until the pH of the reaction solution is 8. After the reaction is completed, the reaction solution is added to a rotary evaporator with a water bath temperature of 80° C., and decompressed and distilled until no liquid is produced to obtain thermal conductive silicone oil;

[0070] Weigh: 20.0g thermal conductive silicone oil, 40.0mL 30-40wt% hydrogen peroxide solution, 2.1g sodium hydroxide powder and 60.0mL dimethyl sulfoxide, add into the reactor and stir, raise the temperature of the reactor to 30°C, keep warm for 1h, after the reaction is completed, wait for the temperature of the reactor to cool to room temperature, add the reaction liquid into a rotary evaporator with a water bath temperature of 80°C, and distill under reduced pressure until no liquid is produced to obtain epoxidized thermal conductive silicone oil.

[0071] S3. Preparation of thermal conductive silicone grease fluid

[0072] Weigh: 200.0g modified diamond particles, 50.0g epoxidized thermal conductive silicone oil, 5.0g aluminum chloride and 400.0mL dimethyl sulfoxide are added to a reactor, the temperature of the reactor is raised to 40°C, and the temperature is kept for 1h. After the reaction is completed, the reaction liquid is added to a rotary evaporator with a water bath temperature of 80°C, and the reaction liquid is distilled under reduced pressure until no liquid is extracted to obtain a thermal conductive silicone grease matrix;

[0073] Weigh: 96.0 g of thermal conductive silicone grease base, 10.0 g of butyl hydroxymethyl benzoate, 12.0 g of 3-aminopropyl trimethoxy silane, 7.2 g of phosphoric acid diester, 4.8 g of phenoxyethanol and 5.6 g of sodium dodecylbenzene sulfonate, add into a reaction kettle and stir evenly to obtain a thermal conductive silicone grease fluid.

[0074] Example 2

[0075] This embodiment provides a method for preparing a diamond particle-reinforced thermally conductive silicone grease fluid, comprising the following steps:

[0076] S1. Preparation of modified diamond particles

[0077] The diamond particles were placed in a 1.5 mol / L sodium hydroxide solution and a 1.5 mol / L sulfuric acid solution for 40 minutes, respectively. After the soaking, they were washed with ethanol and deionized water for 5 times. The materials were placed in a drying oven at a temperature of 60°C and vacuum dried until the materials had a constant weight, thereby obtaining pre-treated diamond particles.

[0078] Weigh: 20.0 g of pre-treated diamond particles and 60.0 g of nickel powder are mixed and added into a tube furnace. After nitrogen protection is introduced into the tube furnace, the temperature of the tube furnace is increased to 900° C. at a heating rate of 5° C. / min, and a mixed gas of oxygen and nitrogen in a volume ratio of 1:4 is introduced at a gas flow rate of 600-800 sccm. The mixture is kept warm for 6 hours to obtain a calcined product.

[0079] The calcined product is placed in a decontamination solution obtained by mixing 40.0wt% sulfuric acid solution and 30.0wt% hydrogen peroxide solution in a volume ratio of 1:1 to obtain a mixed solution, the mixed solution is added to a water bath and heated for 60 minutes at a heating temperature of 80°C, and ultrasonically oscillated at a frequency of 40kHz for 40 minutes, and the operation is repeated three times, and then centrifuged at a centrifugal speed of 3000r / min in a centrifuge, filtered, and washed with deionized water to be neutral, and finally placed in a drying oven for vacuum drying at a temperature of 80°C for 2 hours to obtain etched diamond particles;

[0080] The etched diamond particles were placed in a plasma generator with a power of 1000 W, a pressure of 40 Pa, an oxygen flow rate of 100 mL / min, an argon flow rate of 50 mL / min, and a treatment time of 4 h to obtain oxidized diamond particles;

[0081] Weigh: 24.0g of oxidized diamond particles, 12.0g of 3-(2,3-epoxypropoxy)propyltrimethoxysilane, 3.0g of triethylamine and 100.0mL of N,N-dimethylamide, add into the reactor and stir, raise the temperature of the reactor to 60°C, keep warm for 2h, after the reaction is completed, lower the temperature of the reactor to room temperature, filter the reaction liquid and collect the filter cake, wash the filter cake with ethanol and deionized water for 5 times, place the filter cake in a drying oven at 80°C for vacuum drying until the filter cake has a constant weight, and obtain modified diamond particles.

[0082] S2. Preparation of epoxy thermal conductive silicone oil

[0083] Weigh: 12.0 g of trimethylsilyl chloride, 54.0 g of trans-2-[4-(trifluoromethyl)phenyl]vinylboronic acid, 3.6 g of triethylamine and 300.0 mL of dichloromethane are added to a reactor, the temperature of the reactor is raised to 50° C., and the reaction is kept warm for 2 hours. After the reaction is completed, the reaction liquid is added to a rotary evaporator with a water bath temperature of 100° C., and distilled under reduced pressure until no liquid is produced to obtain a modified monomer;

[0084] Weigh: 20.0g of modified monomer, 15.0g of high hydrogen silicone oil, 2.1g of bis(dimethyl(vinyl)silyl)platinum dihydride and 150.0mL of toluene are added to a reactor, the temperature of the reactor is raised to 40°C, and the reaction is kept warm for 2h. After the reaction is completed, the reaction liquid is added to a rotary evaporator with a water bath temperature of 100°C, and distilled under reduced pressure until no liquid is produced to obtain modified silicone oil;

[0085] Weigh: 20.0 g of tetramethyldivinyldisiloxane, 36.0 g of hexaphenylcyclotrisiloxane, 48.0 g of modified silicone oil and 360.0 mL of ether, add into a reaction kettle, stir at room temperature for 20 min, and obtain a reaction precursor solution;

[0086] Weigh: 24.0 mL of reaction precursor solution and 3.0 mL of 98 wt% sulfuric acid solution are added to a reactor. After the reaction is kept at room temperature for 10 hours, solid sodium bicarbonate is added to the reactor containing the reaction solution until the pH of the reaction solution is 7. After the reaction is completed, the reaction solution is added to a rotary evaporator with a water bath temperature of 100° C. and distilled under reduced pressure until no liquid is produced to obtain thermal conductive silicone oil;

[0087] Weigh: 20.0g thermal conductive silicone oil, 40.0mL30.0wt% hydrogen peroxide solution, 3.0g sodium hydroxide powder and 60.0mL dimethyl sulfoxide, add into the reactor and stir, raise the temperature of the reactor to 30°C, keep warm and react for 2h. After the reaction is completed, wait for the reactor temperature to cool to room temperature, add the reaction liquid into a rotary evaporator with a water bath temperature of 80°C, and distill under reduced pressure until no liquid is produced to obtain epoxidized thermal conductive silicone oil.

[0088] S3. Preparation of thermal conductive silicone grease fluid

[0089] Weigh: 240.0g modified diamond particles, 60.0g epoxidized thermal conductive silicone oil, 6.0g aluminum chloride and 400.0mL dimethyl sulfoxide are added to a reactor, the temperature of the reactor is raised to 60°C, and the temperature is kept for 2h. After the reaction is completed, the reaction liquid is added to a rotary evaporator with a water bath temperature of 100°C, and the reaction liquid is distilled under reduced pressure until no liquid is extracted to obtain a thermal conductive silicone grease matrix;

[0090] Weigh: 96.0 g of thermal conductive silicone grease base, 10.8 g of butyl hydroxymethyl benzoate, 12.4 g of 3-aminopropyl trimethoxy silane, 7.2 g of phosphoric acid diester, 4.8 g of phenoxyethanol and 5.6 g of sodium dodecylbenzene sulfonate, add into a reaction kettle and stir evenly to obtain a thermal conductive silicone grease fluid.

[0091] Example 3

[0092] This embodiment provides a method for preparing a diamond particle-reinforced thermally conductive silicone grease fluid, comprising the following steps:

[0093] S1. Preparation of modified diamond particles

[0094] The diamond particles were placed in a 1.2 mol / L sodium hydroxide solution and a 1.2 mol / L sulfuric acid solution and soaked for 30 min, respectively. After soaking, the particles were washed with ethanol and deionized water for 4 times. The particles were placed in a drying oven at 60°C and vacuum dried until the weight of the particles was constant, thereby obtaining pre-treated diamond particles.

[0095] Weigh: 30.0 g of pre-treated diamond particles and 50.0 g of nickel powder are mixed and added into a tube furnace. After nitrogen protection is introduced into the tube furnace, the temperature of the tube furnace is increased to 850° C. at a heating rate of 5° C. / min, and a mixed gas of oxygen and nitrogen in a volume ratio of 1:4 is introduced, and the gas flow rate is 600-800 sccm. The mixture is kept warm for 5 hours to obtain a calcined product;

[0096] The calcined product is placed in a decontamination solution obtained by mixing 35.0wt% sulfuric acid solution and 25.0wt% hydrogen peroxide solution in a volume ratio of 1:1 to obtain a mixed solution, the mixed solution is added to a water bath and heated for 60 minutes at a heating temperature of 70°C, and ultrasonically oscillated at a frequency of 30kHz for 35 minutes, and the operation is repeated three times, and then centrifuged at a centrifugal speed of 3000r / min in a centrifuge, filtered, and washed with deionized water to be neutral, and finally placed in a drying oven at a temperature of 80°C for 2 hours to obtain etched diamond particles;

[0097] The etched diamond particles were placed in a plasma generator with a power of 900 W, a pressure of 30 Pa, an oxygen flow rate of 100 mL / min, an argon flow rate of 50 mL / min, and a treatment time of 3 h to obtain oxidized diamond particles;

[0098] Weigh: 7.2g of oxidized diamond particles, 3.6g of 3-(2,3-epoxypropyloxy)propyltrimethoxysilane, 0.8g of triethylamine and 36.0mL of N,N-dimethylamide, add them into a reactor and stir, raise the temperature of the reactor to 50°C, and keep the reaction for 1h. After the reaction is completed, lower the temperature of the reactor to room temperature, filter the reaction liquid and collect the filter cake. Wash the filter cake with ethanol and deionized water for 4 times, and place the filter cake in a drying oven at 80°C for vacuum drying until the filter cake has a constant weight to obtain modified diamond particles.

[0099] S2. Preparation of epoxy thermal conductive silicone oil

[0100] Weigh: 24.0 g of trimethylsilyl chloride, 96.0 g of trans-2-[4-(trifluoromethyl)phenyl]vinylboronic acid, 5.0 g of triethylamine and 400.0 mL of dichloromethane are added to a reactor, the temperature of the reactor is raised to 40° C., and the reaction is kept warm for 1 hour. After the reaction is completed, the reaction liquid is added to a rotary evaporator with a water bath temperature of 90° C., and distilled under reduced pressure until no liquid is produced to obtain a modified monomer;

[0101] Weigh: 36.0g of modified monomer, 30.0g of high hydrogen silicone oil, 3.0g of bis(dimethyl(vinyl)silyl)platinum dihydride and 240.0mL of toluene are added to a reactor, the temperature of the reactor is raised to 35°C, and the reaction is kept warm for 1h. After the reaction is completed, the reaction liquid is added to a rotary evaporator with a water bath temperature of 90°C, and distilled under reduced pressure until no liquid is produced to obtain modified silicone oil;

[0102] Weigh: 36.0 g of tetramethyldivinyldisiloxane, 60.0 g of hexaphenylcyclotrisiloxane, 80.0 g of modified silicone oil and 600.0 mL of ether, add into a reaction kettle, stir at room temperature for 18 min, and obtain a reaction precursor solution;

[0103] Weigh: 18.0 mL of reaction precursor solution and 2 mL of 98 wt% sulfuric acid solution are added to the reactor. After the reaction is kept at room temperature for 9 hours, solid sodium bicarbonate is added to the reactor containing the reaction solution until the pH of the reaction solution is 7. After the reaction is completed, the reaction solution is added to a rotary evaporator with a water bath temperature of 90° C. and distilled under reduced pressure until no liquid is produced to obtain thermal conductive silicone oil;

[0104] Weigh: 28.0g thermal conductive silicone oil, 40.0mL 30-40wt% hydrogen peroxide solution, 4.0g sodium hydroxide powder and 100.0mL dimethyl sulfoxide, add into the reactor and stir, raise the temperature of the reactor to 40°C, keep warm for 1h, after the reaction is completed, wait for the temperature of the reactor to cool to room temperature, add the reaction liquid into a rotary evaporator with a water bath temperature of 90°C, and distill under reduced pressure until no liquid is produced to obtain epoxidized thermal conductive silicone oil.

[0105] S3. Preparation of thermal conductive silicone grease fluid

[0106] Weigh: 200.0g modified diamond particles, 50.0g epoxidized thermal conductive silicone oil, 5.0g aluminum chloride and 400.0mL dimethyl sulfoxide are added into a reactor, the temperature of the reactor is raised to 50°C, and the temperature is kept for 2h. After the reaction is completed, the reaction liquid is added into a rotary evaporator with a water bath temperature of 90°C, and the reaction liquid is distilled under reduced pressure until no liquid is extracted to obtain a thermal conductive silicone grease matrix;

[0107] Weigh: 96.0 g of thermal grease base, 10.8 g of butyl hydroxymethyl benzoate, 12.4 g of 3-aminopropyl trimethoxy silane, 7.2 g of phosphoric acid diester, 4.8 g of phenoxyethanol and 5.4 g of sodium dodecylbenzene sulfonate, add into a reaction kettle and stir evenly to obtain a thermal grease fluid.

[0108] Comparative Example 1

[0109] The difference between this comparative example and Example 3 is that step S1 is eliminated, and in step S3, an equal amount of dimethyl silicone oil is used to replace the epoxidized thermal conductive silicone oil.

[0110] Comparative Example 2

[0111] The difference between this comparative example and Example 3 is that step S2 is eliminated, and in step S3, an equal amount of diamond particles are used to replace the modified diamond particles.

[0112] Comparative Example 3

[0113] The difference between this comparative example and Example 3 is that step S1 and step S2 are eliminated, and in step S3, a mixture of diamond particles and dimethyl silicone oil is used in equal amounts to replace the thermal grease matrix.

[0114] Performance Testing:

[0115] The thermal conductivity of the thermally conductive silicone grease fluids prepared in Examples 1-3 and Comparative Examples 1-3 was determined according to the standard GB / T 10297-2015 "Hot wire method for determination of thermal conductivity of non-metallic solid materials";

[0116] The volume wear loss of the thermal conductive silicone grease fluids prepared in Examples 1-3 and Comparative Examples 1-3 after solidification was tested with reference to the standard GB / T 9867-2008 "Determination of wear resistance of vulcanized rubber or thermoplastic rubber (rotating roller abrasion machine method)";

[0117] The tensile strength of the thermal conductive silicone grease fluids prepared in Examples 1-3 and Comparative Examples 1-3 after solidification was tested with reference to the standard GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber";

[0118] The corrosion resistance of the thermal conductive silicone grease fluids prepared in Examples 1-3 and Comparative Examples 1-3 after solidification was tested with reference to the standard JB / T 6073-1992 “Laboratory Full Immersion Corrosion Test for Metal Coverings”. Specific data are shown in Table 1.

[0119] Table 1-Performance test data of each sample

[0120]

[0121]

[0122] Data Analysis:

[0123] By comparing and analyzing the data in Table 1 above, it can be found that the thermal conductivity of the thermally conductive silicone grease fluid prepared by the present invention is 8.624 W·(m·K) -1 , volume wear is 32mm 3 , the tensile strength reaches 92.1MPa and the corrosion rate is 0.65%, which fully demonstrates that:

[0124] The present invention involves etching and plasma gas oxidation on the surface of diamond particles so that the surface of the diamond particles has a large number of active functional groups, and further modifying the surface of the diamond particles with a silane coupling agent to obtain modified diamond particles, which are cross-linked with epoxidized heat-conducting silicone oil rich in boron groups, fluorine groups and benzene rings obtained by monomer modification and polymerization and having terminal modified epoxy groups through chemical reaction to form a stably combined structure, thereby improving the wear resistance of the material. The large number of active functional groups on the surface of the modified diamond particles enable the particles to function as a chain extender, hybridize the spatial chain segments of the epoxidized heat-conducting silicone oil and serve as a heat-conducting bridge, thereby forming a more stable and efficient heat transfer path inside the material and significantly enhancing the mechanical properties of the material. The combination between the materials greatly reduces the interfacial thermal resistance of the heat-conducting silicone grease fluid, significantly reduces the influence of organic components on the heat-conducting silicone grease fluid, and the large number of fluorine groups inside the particles enable the material to have a strong surface energy, thereby significantly improving the corrosion resistance of the heat-conducting silicone grease fluid.

[0125] The above contents are merely examples and explanations of the structure of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a diamond particle-reinforced thermally conductive silicone grease fluid, characterized in that: The following steps are involved: S1, adding thermal conductive silicone oil, 30-40wt% hydrogen peroxide solution, sodium hydroxide powder and dimethyl sulfoxide into a reaction kettle and stirring, raising the temperature of the reaction kettle to 30-50°C, keeping the temperature for reaction for 1-2h, and post-treating to obtain epoxidized thermal conductive silicone oil; S2, adding oxidized diamond particles, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, triethylamine and N,N-dimethylamide into a reaction kettle and stirring, raising the temperature of the reaction kettle to 40-60° C., keeping the temperature for 1-2 hours, and post-treating to obtain modified diamond particles; S3, adding modified diamond particles, epoxidized thermal conductive silicone oil, aluminum chloride and dimethyl sulfoxide into a reaction kettle, raising the temperature of the reaction kettle to 40-60° C., maintaining the temperature for 1-2 hours, and post-treating to obtain a thermal conductive silicone grease matrix; S4. Add the thermal conductive silicone grease matrix and auxiliary materials into the reaction kettle and stir evenly to obtain the thermal conductive silicone grease fluid.

2. The method for preparing a diamond particle-reinforced thermally conductive silicone grease fluid according to claim 1, characterized in that: In step S1, the method for preparing the thermally conductive silicone oil comprises the following steps: A1. Add tetramethyldivinyldisiloxane, hexaphenylcyclotrisiloxane, modified silicone oil and diethyl ether into a reaction kettle, and stir at room temperature for 15-20 minutes to obtain a reaction precursor solution; A2. Add the reaction precursor solution and 98 wt% sulfuric acid solution into the reactor, and keep the reaction at room temperature for 8-10 hours. Then, add solid sodium bicarbonate into the reactor containing the reaction solution until the pH value of the reaction solution is 7-8. Then, perform post-treatment to obtain thermal conductive silicone oil.

3. The method for preparing a diamond particle-reinforced thermally conductive silicone grease fluid according to claim 2, characterized in that: In step A1, the amount ratio of tetramethyldivinyldisiloxane, hexaphenylcyclotrisiloxane, modified silicone oil and ether is 2-4g:5-8g:8-10g:60-80mL; in step A2, the amount ratio of reaction precursor solution and 98wt% sulfuric acid solution is 8-10mL:1mL.

4. The method for preparing a diamond particle-reinforced thermally conductive silicone grease fluid according to claim 2, characterized in that: The preparation method of the modified silicone oil comprises the following steps: B1, adding trimethylsilyl chloride, trans-2-[4-(trifluoromethyl)phenyl]vinylboronic acid, triethylamine and dichloromethane into a reaction kettle, raising the temperature of the reaction kettle to 30-50° C., keeping the temperature for reaction for 1-2 hours, and post-treating to obtain a modified monomer; B2, modified monomer, high hydrogen silicone oil, bis(dimethyl(vinyl)silyl)platinum dihydride and toluene are added to the reactor, the temperature of the reactor is increased to 30-40°C, the reaction is kept warm for 1-2 hours, and the modified silicone oil is obtained by post-treatment.

5. The method for preparing a diamond particle-reinforced thermally conductive silicone grease fluid according to claim 4, characterized in that: In step B1, the amount ratio of trimethylsilyl chloride, trans-2-[4-(trifluoromethyl)phenyl]vinylboronic acid, triethylamine and dichloromethane is 2-3g:8-10g:0.5-0.8g:40-60mL; in step B2, the amount ratio of modified monomer, high hydrogen silicone oil, bis(dimethyl(vinyl)silyl)platinum dihydride and toluene is 5-8g:4-6g:0.5-0.8g:40-60mL.

6. The method for preparing a diamond particle-reinforced thermally conductive silicone grease fluid according to claim 1, characterized in that: In step S2, the method for preparing the oxidized diamond particles comprises the following steps: C1. Mixing the pre-treated diamond particles with nickel powder and adding them into a tube furnace, calcining and etching at high temperature to obtain a calcined product, and post-treating to obtain etched diamond particles; C2. Put the etched diamond particles into a plasma generator, and after plasma oxidation, obtain oxidized diamond particles.

7. The method for preparing a diamond particle-reinforced thermally conductive silicone grease fluid according to claim 6, characterized in that: In step C1, the dosage ratio of diamond particles to nickel powder is 1-3g:5-8g, and the pretreatment operation includes: placing the diamond particles in a sodium hydroxide solution with a concentration of 1-1.5mol / L and a sulfuric acid solution with a concentration of 1-1.5mol / L for 30-40min, washing with ethanol and deionized water for 3-5 times after the soaking, placing the material in a drying oven at a temperature of 60°C and vacuum drying until the material has a constant weight, so as to obtain pretreated diamond particles; in step C2, the power of the plasma generator is 800-1000W, the pressure is 20-40Pa, the oxygen flow rate is 100mL / min, the argon flow rate is 50mL / min, and the treatment time is 2-4h.

8. The method for preparing a diamond particle-reinforced thermally conductive silicone grease fluid according to claim 1, characterized in that: In step S3, the amount ratio of modified diamond particles, epoxidized thermal conductive silicone oil, aluminum chloride and dimethyl sulfoxide is 20-24g:4-6g:0.5-0.8g:40-60mL, and the post-treatment includes: after the reaction is completed, adding the reaction solution into a rotary evaporator with a water bath temperature of 80-100°C, and distilling under reduced pressure until no liquid is extracted to obtain a thermal conductive silicone grease matrix.

9. The method for preparing a diamond particle-reinforced thermally conductive silicone grease fluid according to claim 1, characterized in that: In step S4, the auxiliary materials include: stabilizer, tackifier, dispersant, preservative and surfactant, and the usage ratio of thermal conductive silicone grease matrix, stabilizer, tackifier, dispersant, preservative and surfactant is 80-100g:10-12g:10-15g:6-8g:3-5g:4-6g.

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