Preparation method of high-dispersion and high-thermal-conductivity carbon black-based filler

Abstract

The present invention discloses a preparation method of a highly dispersed and highly thermally conductive filler based on carbon black, which relates to the technical field of carbon black modification. Specifically, the method includes: treating carbon black in a first acid solution to obtain activated carbon black; treating single-walled carbon nanotubes in a second acid solution to obtain activated single-walled carbon nanotubes; treating the activated single-walled carbon nanotubes with a sulfanilamide solution to obtain functionalized single-walled carbon nanotubes; treating graphene nanosheets in a third acid solution to obtain activated graphene nanosheets; mixing an amino-silane hydrolysis solution and an epoxy-silane hydrolysis solution, and adding the activated carbon black, the functionalized single-walled carbon nanotubes, and the activated graphene nanosheets for treatment to obtain a pre-modified filler; pre-polymerizing an amino acid and a cross-linking agent to obtain an amino acid prepolymer solution, and treating the pre-modified filler with the amino acid prepolymer solution to obtain a highly dispersed and highly thermally conductive filler. The method of the present invention is simple to operate and has low energy consumption. The prepared filler has good thermal conductivity and good dispersibility in a polymer matrix, greatly improving the thermal conductivity and mechanical properties of the polymer.

Description

Technical Field

[0001] The invention relates to the technical field of carbon black modification, and in particular to a method for preparing a highly dispersed and highly thermally conductive filler of carbon black. Background Art

[0002] Carbon black is a kind of amorphous carbon, whose main component is carbon, and also contains a small amount of oxygen, hydrogen and sulfur, etc. It has a large specific surface area and has good adsorption capacity, electrical conductivity and thermal conductivity. Carbon black is widely used in industry. It is used as a reinforcing agent in the rubber industry, which can significantly improve the wear resistance, tear resistance and aging resistance of rubber products. It is an important raw material for manufacturing rubber products such as tires; in the ink and coating industry, carbon black, as a black pigment, can provide good tinting power and hiding power; in the plastics industry, carbon black can improve the strength, stiffness and aging resistance of plastics. In addition, with the gradual increase in people's requirements for thermal conductive materials, thermal conductive composite materials based on polymers are developing rapidly. Since polymer materials are poor conductors of heat and the thermal conductivity of carbon black is limited, the application of carbon black in thermal conductive materials is limited. In order to improve the thermal conductivity of carbon black, carbon black needs to be modified.

[0003] The patent with application number 201510212453.5 provides a modified carbon black and its preparation method and application. The surface carboxyl content of carbon black is increased by a strong oxidant, and the acyl chloride group is introduced on the surface of carbon black with a thionyl chloride solution. Finally, hydroxy polybutadiene is grafted with the acylated carbon black to prepare a modified carbon black with a surface grafted with a polymer. Although the above scheme can improve the compatibility of carbon black and the polymer matrix, thereby reducing the interfacial thermal resistance, toxic reagents are used in the modification process, and a large amount of waste liquid and tail gas will be generated during the acyl chloride process, causing environmental pollution. The patent with application number 202111243337.1 provides a method for graphitization modification of carbon black, which is to place a graphite crucible in a closed graphitization furnace; fill the graphite crucible with carbon black, and remove the air in the graphitization furnace; heat the graphite crucible to 2800-3000°C, keep it warm for 3-5 hours, and cool it with the furnace. Although this method can improve the electrical conductivity and thermal conductivity of carbon black, it has harsh conditions, high energy consumption and high equipment requirements. Therefore, it is of great significance to provide an environmentally friendly, low-energy-consuming and high-thermal-conductivity carbon black. Summary of the invention

[0004] The technical problem to be solved by the present invention is: in view of the shortcomings of the prior art, a method for preparing a highly dispersed and highly thermally conductive filler based on carbon black is provided. The method is simple to operate, has low energy consumption, and the prepared filler has good thermal conductivity and can be well dispersed in a polymer matrix, thereby greatly improving the thermal conductivity of the polymer.

[0005] In order to solve the above technical problems, the technical solution of the present invention is:

[0006] A method for preparing a highly dispersed and highly thermally conductive filler based on carbon black comprises the following steps:

[0007] (1) placing carbon black in a first acid solution for acidification treatment to obtain activated carbon black;

[0008] (2) placing the single-walled carbon nanotubes in a second acid solution for a primary activation treatment to obtain activated single-walled carbon nanotubes; adding the activated single-walled carbon nanotubes to a p-aminobenzenesulfonamide solution for a secondary activation treatment to obtain functionalized single-walled carbon nanotubes;

[0009] (3) placing the graphene nanosheets in a third acid solution for acidification to obtain activated graphene nanosheets;

[0010] (4) mixing the aminosilane hydrolyzate and the epoxysilane hydrolyzate, adding activated carbon black, functionalized single-walled carbon nanotubes, and activated graphene nanosheets, performing ultrasonic treatment and heating to react, filtering after the reaction, washing and pre-drying the solid, and then performing heat treatment to obtain a pre-modified filler;

[0011] (5) The amino acid is dissolved in a buffer solution, a cross-linking agent is added, and a prepolymerization reaction is performed to obtain an amino acid prepolymer solution. The pre-modified filler is added to the amino acid prepolymer solution, and the mixture is stirred for reaction after ultrasonic dispersion. After the reaction is completed, the reaction solution is filtered, and the solid is washed and vacuum dried to obtain a highly dispersed and highly thermally conductive filler based on carbon black.

[0012] Preferably, in step (1), the first acid solution is a mixture of concentrated nitric acid and concentrated sulfuric acid, and the volume ratio of concentrated nitric acid to concentrated sulfuric acid is (2-3):1; the conditions of the acidification treatment are: temperature 75-80°C, reflux time 4-6h, and the amount ratio of carbon black to the first acid solution is (5-10) mg:1ml.

[0013] Preferably, in step (2), the second acid solution is concentrated nitric acid; the conditions for the primary activation treatment are: treatment at 80-90°C for 1-2h; the concentration of the p-aminobenzenesulfonamide solution is 0.15-0.22 mol / L, the temperature of the secondary activation treatment is 90-95°C, the time is 1-2h, and the amount ratio of activated single-walled carbon nanotubes to p-aminobenzenesulfonamide solution during the secondary activation treatment is (10-15) mg:1 ml.

[0014] Preferably, in step (3), the third acid solution is a mixture of concentrated sulfuric acid and concentrated nitric acid, and the volume ratio of concentrated sulfuric acid to concentrated nitric acid is 3:1; the conditions for acidification treatment of the graphene nanosheets in the third acid solution are: temperature 60-80°C, time 2-6h, and the amount ratio of graphene nanosheets to the third acid solution during treatment is (3-8) mg: 1 ml.

[0015] Preferably, in step (4), the aminosilane hydrolyzate is prepared by mixing aminosilane and an ethanol solution, adjusting the pH of the system to 4-5, and stirring and hydrolyzing at room temperature for 1-2 hours; the epoxysilane hydrolyzate is prepared by mixing epoxysilane and an ethanol solution, adjusting the pH of the system to 7-8, and stirring and hydrolyzing at room temperature for 2-3 hours.

[0016] Preferably, in step (4), when the aminosilane hydrolyzate is mixed with the epoxysilane hydrolyzate, the molar ratio of aminosilane to epoxysilane is controlled to be 1:(1-1.2); when the aminosilane hydrolyzate is prepared, the mass ratio of aminosilane to ethanol solution is 1-3:50; when the epoxysilane hydrolyzate is prepared, the mass ratio of epoxysilane to ethanol solution is 1-3:50.

[0017] Preferably, in step (4), in the ethanol solution, the volume ratio of ethanol to deionized water is 9:1; the mass ratio of the activated carbon black, the functionalized single-walled carbon nanotubes, and the activated graphene nanosheets is (5-7): (1-2): (1-3); when adding the activated carbon black, the functionalized single-walled carbon nanotubes, and the activated graphene nanosheets, the solid-liquid ratio is controlled to be 1: (10-20).

[0018] Preferably, in step (4), the conditions for ultrasonic treatment are: ultrasonic power 300-400 W, ultrasonic time 20-30 min; the conditions for temperature reaction are: temperature 40-60 ° C, time 2-4 h, stirring speed 500-800 rpm; the conditions for pre-drying are: temperature 60-70 ° C, time 5-6 h, and the conditions for heat treatment are temperature 120-130 ° C, time 1-2 h.

[0019] Preferably, in step (5), the amino acid is a mixture of phenylalanine, tyrosine and histidine, and the molar ratio of phenylalanine, tyrosine and histidine is 1:1:1; the buffer is a phosphate buffer with a pH of 7.5 and a concentration of 0.045M; the mass ratio of amino acid to buffer is (5-10):100; the cross-linking agent is a mixture of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide, and the molar ratio of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide, N-hydroxysuccinimide and total amino acids is 1:(0.5-0.6):(1.2-1.3).

[0020] Preferably, in step (5), the conditions for the prepolymerization reaction are: protected from light, time is 2-4h; the mass ratio of the pre-modified filler to the amino acid prepolymer liquid is 1:(10-12); the conditions for ultrasonic dispersion are: room temperature, ultrasonic power 200-300W, time 20-30min; the stirring speed of the stirring reaction is 800-900rpm, time is 12-24h, the temperature of ultrasonic dispersion and stirring reaction is 40-50°C, and the pH is 7-8.

[0021] Due to the adoption of the above technical solution, the present invention has at least the following beneficial effects:

[0022] The present invention provides a highly dispersed and highly thermally conductive filler based on carbon black, including carbon black, graphene nanosheets and single-walled carbon nanotubes. Carbon black, single-walled carbon nanotubes and graphene are compounded to form a multidimensional thermal conductive network. Graphene forms a main thermal conductive channel through its high thermal conductivity in the plane; carbon nanotubes have a high aspect ratio and good thermal conductivity, and they connect the gaps between graphene sheets to form a "bridge" structure to reduce the interfacial thermal resistance; carbon black is used as a node to fill the gaps between single-walled carbon nanotubes and graphene nanosheets to form a point-line-surface thermal conductive path to optimize the continuity of the thermal conductive network. In addition, graphene nanosheets provide rigid support through high modulus and high specific surface area, which can improve the tensile strength of rubber. Carbon nanotubes have a large aspect ratio and can disperse stress through a mechanical interlocking effect; carbon black, as a traditional reinforcing agent, is low in cost and can disperse local stress. The three can synergistically effectively improve the strength of rubber.

[0023] In order to improve the interfacial properties between graphene nanosheets, carbon black, carbon nanotubes and between them and polymer matrix, the present invention pre-activates graphene nanosheets, carbon black and carbon nanotubes respectively, thereby introducing active groups such as hydroxyl, amino and carboxyl groups on their surfaces, which is convenient for subsequent modification treatment; and the amino groups on the surface of single-walled carbon nanotubes form hydrogen bonds or covalent bonds with the carboxyl groups on the surface of graphene nanosheets and the hydroxyl groups on the surface of carbon black, thereby reducing the interfacial thermal resistance. The present invention also sequentially performs silanization and polyamino acid coating modification treatments on the activated graphene nanosheets, carbon black and carbon nanotubes, the pre-treatment of the silanization agent constructs a thermal conductive network with low interfacial thermal resistance, and the polyamino acid coating layer protects the thermal conductive network through a flexible interface, reduces structural damage during processing or use, and achieves long-term stability of thermal conductivity; in addition, the polar groups of the silanization agent combine with the non-polar segments of the polyamino acid to form a gradient interface structure, further reducing phonon scattering and improving the performance of the material.

[0024] When the present invention uses a silanization agent to modify the filler, aminosilane and epoxysilane are used for joint modification. The amino group in the aminosilane and the epoxy group in the epoxysilane can form a stable chemical bond with the active group on the surface of the filler, thereby improving the dispersibility of the filler and reducing the interfacial thermal resistance between the filler and the matrix. The epoxy group of the epoxysilane has a high reactivity and can induce the filler to be arranged in a directional manner in the polymer matrix to form a denser thermal conductive network. The amino group of the aminosilane assists the good dispersion of the filler through hydrogen bonding. In addition, the flexible amino chain segment of the aminosilane can alleviate the stress concentration between the filler and the polymer matrix, while the rigid epoxy group of the epoxysilane enhances the interfacial bonding strength through a cross-linking reaction, thereby improving the mechanical properties of the material.

[0025] When the present invention adopts polyamino acid to coat filler, in order to avoid the influence of polyamino acid coating on material thermal conductivity, the ratio of amino acid to filler is effectively adjusted to avoid too thick coating, and phenylalanine, histidine and tyrosine are selected for compounding, the benzene ring of phenylalanine, the phenol ring of tyrosine and the imidazole ring of histidine are arranged in order through π-π stacking or van der Waals force, promoting the directional distribution of filler in polymer matrix, thereby forming a continuous heat conduction path, improving the interface performance of filler and polymer matrix, reducing phonon scattering at the interface, thereby reducing interface thermal resistance and improving thermal conductivity. And the coating of polyamino acid enhances the interface bonding between filler and matrix, reduces stress concentration, thereby improving the tensile strength of material. DETAILED DESCRIPTION

[0026] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all of the embodiments.

[0028] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0029] In the following examples and comparative examples, carbon black: Cabot carbon black N550; single-walled carbon nanotubes: tube diameter ≤ 2 nm, tube length: 5-30 μm, XFS32 from Jiangsu Xianfeng Nanomaterial Technology Co., Ltd.; graphene nanosheets: diameter: 5-10 μm, thickness: 3-10 nm, specific surface area: 31.657 m 2 / g, carbon content: >99.5%, from XF021 of Jiangsu Xianfeng Nanomaterial Technology Co., Ltd.

[0030] Unless otherwise specified, other raw materials are commercially available, and the conditions described are conventional conditions in the art unless otherwise specified. Example 1

[0031] A method for preparing a highly dispersed and highly thermally conductive filler based on carbon black comprises the following steps:

[0032] (1) 0.25 g of carbon black N550 was placed in 50 ml of the first acid solution (a mixture of concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 3:1), refluxed at 75°C for 6 h in the dark. After the reflux, the reaction system was cooled to room temperature and filtered. The solid was washed with anhydrous ethanol and deionized water in turn until it was neutral, and dried to obtain activated carbon black;

[0033] (2) Place 0.25g of single-walled carbon nanotubes in 50ml of concentrated nitric acid, protect from light, and treat at 80°C for 2h. Then, cool the reaction system to room temperature and filter it. Dry the solid to obtain activated single-walled carbon nanotubes. Add 1g of activated single-walled carbon nanotubes to 100ml of 0.15mol / L p-aminobenzenesulfonamide solution and treat it at 90°C for 1h. After the treatment, cool the reaction solution to room temperature and filter it. Wash the solid with anhydrous ethanol and deionized water in turn until it is neutral, and finally dry it to obtain functionalized single-walled carbon nanotubes.

[0034] (3) placing 0.2 g of graphene nanosheets in 50 ml of a third acid solution (a mixture of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1), and acidifying the mixture at 70°C for 3 h in a dark environment. After the treatment, the reaction solution was cooled to room temperature and filtered. The solid was washed with anhydrous ethanol and deionized water in sequence until it was neutral to obtain activated graphene nanosheets.

[0035] (4) 1.5 g of γ-aminopropyltriethoxysilane was mixed with 50 ml of ethanol solution (the volume ratio of ethanol to deionized water was 9:1), the pH of the system was adjusted to 4, and the mixture was stirred and hydrolyzed at room temperature and 300 rpm for 2 h to obtain an aminosilane hydrolyzate; 1.5 g of (3-glycidylpropoxy)trimethoxysilane was mixed with 50 ml of ethanol solution (the volume ratio of ethanol to deionized water was 9:1), the pH of the system was adjusted to 7, and the mixture was stirred and hydrolyzed at room temperature and 300 rpm for 2 h to obtain an epoxysilane hydrolyzate; 50 ml of the aminosilane hydrolyzate and the epoxysilane hydrolyzate were mixed (control the γ- The molar ratio of aminopropyltriethoxysilane to (3-glycidylpropoxy)trimethoxysilane is 1:1.2), activated carbon black, functionalized single-walled carbon nanotubes, and activated graphene nanosheets (the mass ratio of activated carbon black, functionalized single-walled carbon nanotubes, and activated graphene nanosheets is 6:1:2) are added, the solid-liquid ratio is controlled to be 1:10, ultrasonic treatment is performed at 300W power for 20min, and then the temperature is raised to 50℃ and stirred at 500rpm for 2h. After the reaction is completed, it is filtered, the solid is washed and pre-dried at 60℃ for 5h, and finally treated at 120℃ for 1h to obtain a pre-modified filler;

[0036] (5) A mixture of phenylalanine, tyrosine and histidine (the molar ratio of phenylalanine, tyrosine and histidine is 1:1:1) is dissolved in 50 ml of buffer (phosphate buffer with a pH of 7.4 and a concentration of 0.1 M), and a crosslinker (a mixture of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide with a molar ratio of 1:0.5) is added. The molar ratio of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide to total amino acids is controlled to be 1:1.2. The mixture is prepolymerized at room temperature in the dark for 2 h to obtain an amino acid prepolymer solution. A premodified filler (the mass ratio of the premodified filler to the amino acid prepolymer solution is 1:10) is added to the amino acid prepolymer solution. The mixture is ultrasonically dispersed at room temperature and 200 W for 20 min. The mixture is then heated to 40°C and stirred at 800 rpm for 24 h. After the reaction is completed, the reaction solution is filtered, the solid is washed and vacuum dried to obtain a highly dispersed and highly thermally conductive filler based on carbon black. Example 2

[0037] A method for preparing a highly dispersed and highly thermally conductive filler based on carbon black comprises the following steps:

[0038] (1) 0.3 g of carbon black N550 was placed in 50 ml of the first acid solution (a mixture of concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 3:1), refluxed at 75°C for 5 h in the dark, and after the reflux, the reaction system was cooled to room temperature and filtered. The solid was washed with anhydrous ethanol and deionized water in turn until it was neutral, and dried to obtain activated carbon black;

[0039] (2) Place 0.3 g of single-walled carbon nanotubes in 50 ml of concentrated nitric acid, protect from light, and treat at 80°C for 2 h. Then, cool the reaction system to room temperature and filter it. Dry the solid to obtain activated single-walled carbon nanotubes. Add 1.5 g of activated single-walled carbon nanotubes to 100 ml of 0.17 mol / L p-aminobenzenesulfonamide solution and treat it at 90°C for 1 h. After the treatment, cool the reaction solution to room temperature and filter it. Wash the solid with anhydrous ethanol and deionized water in turn until it is neutral, and finally dry it to obtain functionalized single-walled carbon nanotubes.

[0040] (3) placing 0.2 g of graphene nanosheets in 50 ml of a third acid solution (a mixture of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1), and acidifying the mixture at 75°C for 3 h in a dark environment. After the treatment, the reaction solution was cooled to room temperature and filtered. The solid was washed with anhydrous ethanol and deionized water in sequence until it was neutral to obtain activated graphene nanosheets.

[0041] (4) 1.5 g of γ-aminopropyltriethoxysilane was mixed with 50 ml of ethanol solution (the volume ratio of ethanol to deionized water was 9:1), the pH of the system was adjusted to 5, and the mixture was stirred and hydrolyzed at room temperature and 400 rpm for 1 h to obtain an aminosilane hydrolyzate; 1.5 g of (3-glycidylpropoxy)trimethoxysilane was mixed with 50 ml of ethanol solution (the volume ratio of ethanol to deionized water was 9:1), the pH of the system was adjusted to 8, and the mixture was stirred and hydrolyzed at room temperature and 400 rpm for 2.5 h to obtain an epoxysilane hydrolyzate; 50 ml of the aminosilane hydrolyzate and the epoxysilane hydrolyzate were mixed (control the γ -aminopropyltriethoxysilane and (3-glycidylpropoxy)trimethoxysilane in a molar ratio of 1:1.2), activated carbon black, functionalized single-walled carbon nanotubes, activated graphene nanosheets (the mass ratio of activated carbon black, functionalized single-walled carbon nanotubes, and activated graphene nanosheets is 5:1:3), the solid-liquid ratio is controlled to be 1:15, ultrasonic treatment is performed at 300W power for 20min, and then the temperature is raised to 50℃, and the reaction is stirred at 600rpm for 3h. After the reaction is completed, it is filtered, the solid is washed and pre-dried at 60℃ for 5h, and finally treated at 120℃ for 1h to obtain a pre-modified filler;

[0042] (5) A mixture of phenylalanine, tyrosine and histidine (the molar ratio of phenylalanine, tyrosine and histidine is 1:1:1) is dissolved in 50 ml of buffer (phosphate buffer with a pH of 7.4 and a concentration of 0.1 M), and a crosslinker (a mixture of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide with a molar ratio of 1:0.6) is added, and the molar ratio of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide to total amino acids is controlled to be 1:1.2. The mixture is prepolymerized at room temperature in the dark for 3 h to obtain an amino acid prepolymer solution. A premodified filler (the mass ratio of the premodified filler to the amino acid prepolymer solution is 1:11) is added to the amino acid prepolymer solution, and ultrasonically dispersed at room temperature and 200 W for 30 min, then the temperature is raised to 40°C, and the mixture is stirred at 900 rpm for 24 h. After the reaction is completed, the reaction solution is filtered, and the solid is washed and vacuum dried to obtain a highly dispersed and highly thermally conductive filler based on carbon black. Example 3

[0043] A method for preparing a highly dispersed and highly thermally conductive filler based on carbon black comprises the following steps:

[0044] (1) 0.4 g of carbon black N550 was placed in 50 ml of the first acid solution (a mixture of concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 3:1), refluxed at 80°C for 6 h in the dark. After the reflux, the reaction system was cooled to room temperature and filtered. The solid was washed with anhydrous ethanol and deionized water in turn until it was neutral, and dried to obtain activated carbon black;

[0045] (2) 0.45 g of single-walled carbon nanotubes were placed in 50 ml of concentrated nitric acid, protected from light and treated at 80 °C for 2 h. The reaction system was then cooled to room temperature and filtered. The solid was dried to obtain activated single-walled carbon nanotubes. 1.3 g of activated single-walled carbon nanotubes were added to 100 ml of 0.20 mol / L p-aminobenzenesulfonamide solution and treated at 90 °C for 1.5 h. After the treatment, the reaction solution was cooled to room temperature and filtered. The solid was washed with anhydrous ethanol and deionized water in turn until neutral, and finally dried to obtain functionalized single-walled carbon nanotubes.

[0046] (3) placing 0.3 g of graphene nanosheets in 50 ml of a third acid solution (a mixture of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1), and acidifying the mixture at 70°C for 4 h in a dark environment. After the treatment, the reaction solution was cooled to room temperature and filtered. The solid was washed with anhydrous ethanol and deionized water in sequence until it was neutral to obtain activated graphene nanosheets.

[0047] (4) Mix 2 g of γ-aminopropyltriethoxysilane with 50 ml of ethanol solution (the volume ratio of ethanol to deionized water is 9:1), adjust the pH of the system to 4, and stir and hydrolyze at room temperature and 400 rpm for 1.5 h to obtain an aminosilane hydrolyzate; mix 2 g of (3-glycidylpropoxy)trimethoxysilane with 50 ml of ethanol solution (the volume ratio of ethanol to deionized water is 9:1), adjust the pH of the system to 8, and stir and hydrolyze at room temperature and 500 rpm for 3 h to obtain an epoxysilane hydrolyzate; mix 50 ml of the aminosilane hydrolyzate and the epoxysilane hydrolyzate (control the γ-aminopropyltriethoxysilane solution); The molar ratio of propyltriethoxysilane to (3-glycidylpropoxy)trimethoxysilane is 1:1.2), activated carbon black, functionalized single-walled carbon nanotubes, activated graphene nanosheets (the mass ratio of activated carbon black, functionalized single-walled carbon nanotubes, activated graphene nanosheets is 6:2:3), the solid-liquid ratio is controlled to be 1:20, ultrasonic treatment is carried out at 400W power for 30min, and then the temperature is raised to 50℃, and the reaction is stirred at 800rpm for 4h. After the reaction is completed, it is filtered, the solid is washed and pre-dried at 70℃ for 6h, and finally treated at 120℃ for 1h to obtain a pre-modified filler;

[0048] (5) A mixture of phenylalanine, tyrosine and histidine (the molar ratio of phenylalanine, tyrosine and histidine is 1:1:1) is dissolved in 50 ml of buffer (phosphate buffer with a pH of 7.4 and a concentration of 0.1 M), and a crosslinker (a mixture of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide with a molar ratio of 1:0.6) is added, and the molar ratio of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide to total amino acids is controlled to be 1:1.2. Prepolymerization is carried out at room temperature in the dark for 4 h to obtain an amino acid prepolymer solution. A pre-modified filler is added to the amino acid prepolymer solution (the mass ratio of the pre-modified filler to the amino acid prepolymer solution is 1:12, and ultrasonic dispersion is carried out at room temperature and 300 W for 30 min, and then the temperature is raised to 50°C, and the reaction is stirred at a speed of 800 rpm for 24 h. After the reaction is completed, the reaction solution is filtered, and the solid is washed and vacuum dried to obtain a highly dispersed and highly thermally conductive filler based on carbon black.

[0049] In order to verify that the filler prepared by the present invention has excellent performance, the following is a detailed description of the comparative examples with reference to Example 3.

[0050] Comparative Example 1

[0051] The difference between this comparative example and Example 3 is that no graphene nanosheets are included, and other operations are the same as Example 3.

[0052] Comparative Example 2

[0053] The difference between this comparative example and Example 3 is that single-walled carbon nanotubes are not included, and other operations are the same as those in Example 3.

[0054] Comparative Example 3

[0055] The difference between this comparative example and Example 3 is that carbon black N550 is not included, and other operations are the same as Example 3.

[0056] Comparative Example 4

[0057] The difference between this comparative example and Example 3 is that steps (1) to (3) are not included, and other operations are the same as those in Example 3.

[0058] Comparative Example 5

[0059] The difference between this comparative example and Example 3 is that step (4) is not included, and the other operations are the same as those in Example 3.

[0060] Comparative Example 6

[0061] The difference between this comparative example and Example 3 is that in step (4), an equal amount of aminosilane hydrolyzate is used to replace epoxysilane hydrolyzate, and the other operations are the same as those in Example 3.

[0062] Comparative Example 7

[0063] The difference between this comparative example and Example 3 is that in step (4), an equal amount of epoxysilane hydrolyzate is used instead of aminosilane hydrolyzate, and the other operations are the same as those in Example 3.

[0064] Comparative Example 8

[0065] The difference between this comparative example and Example 3 is that step (4) does not include step (5), and the other operations are the same as those in Example 3.

[0066] Comparative Example 9

[0067] The difference between this comparative example and Example 3 is that in step (5), phenylalanine is not included, and the dosage ratio of tyrosine and histidine and other operations are the same as those in Example 3.

[0068] Comparative Example 10

[0069] The difference between this comparative example and Example 3 is that in step (5), tyrosine is not included, and the dosage ratio of phenylalanine and histidine and other operations are the same as those in Example 3.

[0070] Comparative Example 11

[0071] The difference between this comparative example and Example 3 is that in step (5), histidine is not included, and the dosage ratio of phenylalanine and tyrosine and other operations are the same as those in Example 3.

[0072] Comparative Example 12

[0073] The difference between this comparative example and Example 3 is that in step (5), only phenylalanine is included, and the other operations are the same as in Example 3.

[0074] Comparative Example 13

[0075] The difference between this comparative example and Example 3 is that in step (5), only tyrosine is included, and the other operations are the same as those in Example 3.

[0076] Comparative Example 14

[0077] The difference between this comparative example and Example 3 is that in step (5), only histidine is included, and the other operations are the same as in Example 3.

[0078] Application Examples

[0079] 100g NR (smoked sheet rubber, Dongtai International Group Co., Ltd.) was thinned 6 times on an open double-roll mill at 55°C. The speed ratio of the front roller to the rear roller was 1:1.2. After the rubber was rolled, 5g zinc oxide, 2g stearic acid, 2g vulcanization accelerator CZ, and 1g antioxidant 4020 were added in sequence. 10g of the fillers prepared in the examples and comparative examples were added respectively. After the fillers were wrapped with rubber, 1g antioxidant RD and 2g sulfur were added. The rubber was thinned to make triangular packages, the roller spacing was adjusted to 2mm, and the sheets were removed.

[0080] The mixed rubber was left to stand for 24 hours after being cut into sheets, and then vulcanized on a flat vulcanizer. The vulcanization conditions were: 15 MPa, 16°C, and vulcanization time of 30 minutes to obtain different composite materials.

[0081] Performance Test:

[0082] 1. Thermal conductivity

[0083] The thermal conductivity was measured according to ASTM E1461 standard using a TC 3000E thermal conductivity meter; specifically, the composite material was cut into blocks with a thickness of 2 mm, a length of 30 mm, and a width of 20 mm. During the test, each test sample was measured three times, and the average value was taken as the final result.

[0084] 2. Tensile properties

[0085] The tensile strength of the composite material was tested according to the national standard GB / T528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber". The test samples used were dumbbell-shaped splines, and the tensile speed was set to 500 mm / min. Five samples were tested in each group of experiments, and the average value of the experimental data was taken as the final experimental result.

[0086] 3. Dispersion performance

[0087] 1 g of the fillers in the examples and comparative examples were respectively mixed with 100 ml of ethanol, and ultrasonicated at 500 W for 40 min to obtain a dispersion. The dispersion was placed at room temperature for 1 month, and the presence of precipitation was observed by visual inspection.

[0088] The above test results are shown in Table 1.

[0089] Table 1

[0090]

[0091] It can be seen from the test results in Table 1 that the present invention uses carbon black, single-walled carbon nanotubes and graphene nanosheets as composite fillers, which are added to natural rubber after modification, have good dispersibility and effectively improve the thermal conductivity of the material while ensuring high mechanical properties of the material.

[0092] Compared with the comparative example, the present invention respectively performs activation pretreatment on carbon black, single-walled carbon nanotubes, and graphene nanosheets, and introduces active groups on their surfaces to facilitate subsequent treatment of the filler; the present invention performs silanization on the pretreated filler and then performs amino acid polymerization coating. The silane layer serves as an intermediate transition layer to enhance the bonding strength between the polyamino acid coating layer and the filler, forming a multi-level interface structure, achieving stress dispersion and efficient heat transfer, and thereby improving the mechanical properties and thermal conductivity of the material.

[0093] Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas, including the best mode, and also enable any technician in the field to practice the present invention, including making and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements similar to the literal expression of the claims, or if they include equivalent structural elements that are not substantially different from the literal expression of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A method for preparing a highly dispersed and highly thermally conductive filler based on carbon black, characterized in that: The following steps are involved: (1) placing carbon black in a first acid solution for acidification treatment to obtain activated carbon black; (2) placing the single-walled carbon nanotubes in a second acid solution for a primary activation treatment to obtain activated single-walled carbon nanotubes; adding the activated single-walled carbon nanotubes to a p-aminobenzenesulfonamide solution for a secondary activation treatment to obtain functionalized single-walled carbon nanotubes; (3) placing the graphene nanosheets in a third acid solution for acidification to obtain activated graphene nanosheets; (4) mixing the aminosilane hydrolyzate and the epoxysilane hydrolyzate, adding activated carbon black, functionalized single-walled carbon nanotubes, and activated graphene nanosheets, performing ultrasonic treatment and then heating the mixture for reaction, filtering the mixture after the reaction, washing the solid, pre-drying the solid, and then performing heat treatment to obtain a pre-modified filler; when the aminosilane hydrolyzate and the epoxysilane hydrolyzate are mixed, the molar ratio of the aminosilane to the epoxysilane is controlled to be 1:(1-1.2), and when the aminosilane hydrolyzate is prepared, the mass ratio of the aminosilane to the ethanol solution is 1-3:50; when the epoxysilane hydrolyzate is prepared, the mass ratio of the epoxysilane to the ethanol solution is 1-3:50; (5) dissolving an amino acid in a buffer solution, adding a cross-linking agent, and performing a prepolymerization reaction to obtain an amino acid prepolymer solution; adding a pre-modified filler to the amino acid prepolymer solution, performing ultrasonic dispersion and stirring for reaction; filtering the reaction solution after the reaction is completed, washing the solid and performing vacuum drying to obtain a highly dispersed and highly thermally conductive filler based on carbon black; the amino acid is a mixture of phenylalanine, tyrosine and histidine, and the molar ratio of phenylalanine, tyrosine and histidine is 1:1:

1.

2. The method for preparing a highly dispersed and highly thermally conductive filler based on carbon black according to claim 1, characterized in that: In step (1), the first acid solution is a mixture of concentrated nitric acid and concentrated sulfuric acid, and the volume ratio of concentrated nitric acid to concentrated sulfuric acid is (2-3):1; the acidification treatment condition is reflux at 75-80°C for 4-6h, and the amount ratio of carbon black to the first acid solution is (5-10) mg:1ml.

3. The method for preparing a highly dispersed and highly thermally conductive filler based on carbon black according to claim 1, characterized in that: In step (2), the second acid solution is concentrated nitric acid; the conditions for the primary activation treatment are: treatment at 80-90°C for 1-2h; the concentration of the p-aminobenzenesulfonamide solution is 0.15-0.22mol / L, the temperature of the secondary activation treatment is 90-95°C, the time is 1-2h, and the amount ratio of activated single-walled carbon nanotubes to p-aminobenzenesulfonamide solution during the secondary activation treatment is (10-15)mg:1ml.

4. The method for preparing a highly dispersed and highly thermally conductive filler based on carbon black according to claim 1, characterized in that: In step (3), the third acid solution is a mixture of concentrated sulfuric acid and concentrated nitric acid, and the volume ratio of concentrated sulfuric acid to concentrated nitric acid is 3:1; the conditions for acidification treatment of the graphene nanosheets in the third acid solution are: temperature 60-80°C, time 2-6h, and the amount ratio of the graphene nanosheets to the third acid solution during the treatment is (3-8) mg: 1 ml.

5. The method for preparing a highly dispersed and highly thermally conductive filler based on carbon black according to claim 1, characterized in that: In step (4), the aminosilane hydrolyzate is prepared by mixing aminosilane and an ethanol solution, adjusting the pH of the system to 4-5, and stirring and hydrolyzing at room temperature for 1-2 hours; the epoxysilane hydrolyzate is prepared by mixing epoxysilane and an ethanol solution, adjusting the pH of the system to 7-8, and stirring and hydrolyzing at room temperature for 2-3 hours.

6. The method for preparing a highly dispersed and highly thermally conductive filler based on carbon black according to claim 5, characterized in that: In step (4), the volume ratio of ethanol to deionized water in the ethanol solution is 9:1; the mass ratio of the activated carbon black, the functionalized single-walled carbon nanotubes, and the activated graphene nanosheets is (5-7): (1-2): (1-3); when the activated carbon black, the functionalized single-walled carbon nanotubes, and the activated graphene nanosheets are added to the mixture of the aminosilane hydrolyzate and the epoxysilane hydrolyzate, the solid-liquid ratio is controlled to be 1: (10-20).

7. The method for preparing a highly dispersed and highly thermally conductive filler based on carbon black according to claim 1, characterized in that: In step (4), the conditions for ultrasonic treatment are: ultrasonic power 300-400W, ultrasonic time 20-30min; the conditions for temperature reaction are: temperature 40-60°C, time 2-4h, stirring speed 500-800rpm; the conditions for pre-drying are: temperature 60-70°C, time 5-6h, and the conditions for heat treatment are temperature 120-130°C, time 1-2h.

8. The method for preparing a highly dispersed and highly thermally conductive filler based on carbon black according to claim 1, characterized in that: In step (5), the buffer is a phosphate buffer with a pH of 7.5 and a concentration of 0.045 M; the mass ratio of amino acid to buffer is (5-10):100; the cross-linking agent is a mixture of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide, and the molar ratio of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, N-hydroxysuccinimide and total amino acids is 1:(0.5-0.6):(1.2-1.3).

9. The method for preparing a highly dispersed and highly thermally conductive filler based on carbon black according to claim 1, characterized in that: In step (5), the conditions for the prepolymerization reaction are: protected from light, time is 2-4 hours; the mass ratio of the pre-modified filler to the amino acid prepolymer liquid is 1: (10-12); the conditions for ultrasonic dispersion are: room temperature, ultrasonic power 200-300W, time 20-30min; the stirring speed of the stirring reaction is 800-900rpm, time is 12-24h, and the temperature of ultrasonic dispersion and stirring reaction is 40-50°C.

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