Graphite film-p-aminophenol-copper composite material and preparation method thereof

Abstract

The invention discloses a graphite film-p-aminophenol-copper composite material and a preparation method thereof, and belongs to the field of metal-based composite material thermal management, and the composite material is structurally characterized in that phenol molecules are introduced to the upper and lower surfaces of a flake graphite film,-OH in phenol and copper ions are coordinated, and the graphite film-p-aminophenol-copper composite material is prepared. The preparation method of the copper-graphite film-copper composite material comprises the following steps: treating the surface of the flaky graphite film, putting the flaky graphite film into absolute ethyl alcohol containing p-aminophenol, magnetically stirring under the protection of nitrogen, adding isoamyl nitrite, magnetically stirring, and reacting at a constant temperature, so as to obtain the copper-graphite film-copper composite material. Taking out the flake graphite film, washing and drying in vacuum; and the dried flake graphite film is electroplated with copper, and the obtained graphite film-p-aminophenol-copper composite material is good in in-plane thermal conductivity and good in bending performance.

Description

Technical Field:

[0001] The present invention belongs to the field of thermal management of metal matrix composites, and particularly relates to a graphite film - p - aminophenol - copper composite material and a preparation method thereof. Technical Background:

[0002] Graphite film has unique advantages as an electronic heat dissipation material. Its thermal conductivity is as high as 600 - 1200 (W / m﹒k). At the same time, the heat dissipation graphite film has a low specific gravity, so it has broad application prospects in the field of electronic device heat dissipation. The composite material with copper coated on the surface of the graphite film can effectively avoid chipping of the graphite film during the assembly process, and the copper layer can also play a role in electronic shielding, having broad application prospects in the field of electronic packaging.

[0003] In the graphite film / copper composite material, the main contribution to the thermal conductivity comes from the phonon propagation of the graphite film and the electron heat transfer of copper. Due to the different heat conduction modes of the graphite film and metallic copper, there will be a large heat loss at the interface, that is, the interface thermal resistance. In the graphite film / copper composite material, the too high interface thermal resistance becomes an obstacle to improving the thermal conductivity performance of the graphite film - copper composite material. How to design the structure at the graphite film - copper interface to reduce the interface thermal resistance is very important. At present, most of the research mainly focuses on the feasibility of phonon tuning in optimizing the interface thermal performance, while ignoring the problem of the contribution of electrons to the interface thermal conductivity of the composite material. On the other hand, considering the poor wettability between the graphite film itself and copper and the weak interface bonding, this weak interface bonding will have a fatal impact on the composite material. Because the temperature rise and fall during the heat dissipation process and the bending during the assembly process are likely to directly generate tiny gaps between the graphite film and copper, thereby increasing the interface thermal resistance between the graphite film and copper. Summary of the Invention:

[0004] The present invention provides a preparation method of a graphite film - p - aminophenol - copper composite material, aiming to simultaneously solve the problems of high interface thermal resistance, low interface bonding strength between the graphite film and copper, and difficulty in bending the composite material in the existing technical solutions.

[0005] To achieve the above object, the present invention adopts the following technical solutions: A graphite film - p - aminophenol - copper composite material, the structure of the composite material is that phenol molecules are introduced on the upper and lower surfaces of the flaky graphite film, the -OH in phenol coordinates with copper ions, and the reduced copper is deposited on the flaky graphite film with phenol molecules, forming a graphite film - p - aminophenol - copper composite material. The structural schematic diagram is shown in Figure 1 .

[0006] The preparation method of the graphite film - p - aminophenol - copper composite material includes the following steps:

[0007] S1, surface - treat the flaky graphite film;

[0008] S2. Dissolve p-aminophenol in absolute ethanol, put in a flaky graphite film, evacuate the air, and introduce nitrogen

[0009] for protection, and magnetically stir for 10 min to obtain a mixed solution;

[0010] S3. Under nitrogen protection, add isoamyl nitrite to the above mixed solution, magnetically stir, heat to 50 - 80 °C, and react at a constant temperature for 10 - 20 h;

[0011] S4. Take out the flaky graphite film obtained in S3, wash it with ethanol, and vacuum dry it at 50 - 100 °C for 2 - 6 h;

[0012] S5. Electroplate copper on the dried flaky graphite film in the form of an electroplating solution for 2 - 15 min to obtain a graphite film - p-aminophenol - copper composite material.

[0013] Furthermore, the thickness of the flaky graphite film is 20 - 100 μm, and the density is 1.7 - 2.3 g / cm 3 .

[0014] Furthermore, the surface treatment of the flaky graphite film in step S1 is specifically: soak and stir the flaky graphite film in absolute ethanol for 10 min, wash and dry it with deionized water, and perform plasma treatment after drying. Use an air atmosphere, the gas flow rate is 100 - 800 sccm, the power is 10 - 300 W, and the treatment time is 10 s - 200 min.

[0015] Furthermore, the mass ratio of p-aminophenol to the graphite film in step S2 is 0.2 - 5:1.

[0016] Furthermore, the molar ratio of isoamyl nitrite to p-aminophenol in step S3 is 3 - 4:1.

[0017]

[0018] In the above molar ratio formula: n 1 is the amount of substance of isoamyl nitrite, n 2 is the amount of substance of p-aminophenol, v is the liquid volume of isoamyl nitrite, ω is the mass fraction of isoamyl nitrite, ρ is the solution density of isoamyl nitrite, m is the mass of p-aminophenol, M 1 and M 2 are the molar masses of isoamyl nitrite and p-aminophenol respectively. The mass fraction of isoamyl nitrite ω = 97%, the density ρ = 0.872 g / cm 3 , the molar mass M 1＝ is 117.15 g / mol; the molar mass of p-aminophenol M 2＝ is 109.13 g / mol.

[0019] Further, in step S5, the electroplating solution is a mixture of copper sulfate pentahydrate, potassium sodium tartrate, trisodium citrate, and potassium nitrate in a concentration ratio of 8:24:4:3. The electroplating is carried out in a constant current mode with a current density of 1-8 A / dm 2 .

[0020] The principle of the present invention is as follows: After p-aminophenol undergoes a diazotization reaction, the benzene ring part in its molecular structure still retains the π electron cloud. As a material composed of stacked carbon atom layers, the graphite film also has a large number of π electron clouds on its surface. When the diazotized p-aminophenol molecules come into contact with the graphite film, the π electron clouds between the two will overlap with each other, thus forming a π-π conjugation effect. This conjugation effect enables the p-aminophenol molecules to be stably adsorbed on the surface of the graphite film. In addition, the π-π conjugation effect is a relatively strong intermolecular interaction force, which can enable molecules to form a stable combination. Therefore, after the diazotized p-aminophenol molecules are adsorbed onto the graphite film surface through the π-π conjugation effect, a stable chemical bond can be formed.

[0021] During the electroplating of copper on the conjugated phenol on the graphite film, it mainly undergoes an oxidation-reduction reaction with copper ions rather than directly reacting with copper atoms. During the electroplating of copper, copper ions are reduced to copper atoms under the action of an electric field and deposited on the surface of the graphite film. The conjugated phenol interacts with copper ions or deposited copper atoms through the conjugated system on its benzene ring, but this interaction is mainly physical adsorption or weak chemical interaction rather than a strong chemical reaction.

[0022] During the electroplating of copper, an electroplating solution containing copper ions is usually used, and an electric current is applied to reduce copper ions to copper atoms on the cathode (i.e., the surface of the graphite film). In this process, copper ions accept electrons and are reduced from +2 valence to 0 valence, forming metallic copper deposited on the graphite film.

[0023] Beneficial effects:

[0024] In the present invention, the surface of the graphite film is roughened by plasma activation, and at the same time, chemically adsorbed phenol-containing chemical molecules are physically and chemically adsorbed on the graphite film through a diazotization reaction. Subsequently, copper is deposited on the modified graphite film by electroplating to form a copper-graphite film-copper composite material. Its beneficial effects are as follows: First, the conjugated small molecules chemically adsorbed on the surface of the graphite film form conjugated π bonds through chemical linkages. Phenol containing electron-donating substituents can increase the electron density of the graphite film at the graphite film / copper interface, increase the contribution of electron heat transfer, and promote the electron-phonon coupling at the interface, thereby effectively reducing the interface thermal resistance. This increases the thermal conductivity of the composite material; Second, the plasma roughens the surface of the graphite film, and the roughened grooves and copper layer form a mechanical bite, improving the interface bonding. Coupled with the conjugated π bond structure established at the interface, it helps to enhance the interface bonding between the graphite film and the copper matrix. Description of the drawings:

[0025] Figure 1 This is a schematic diagram of the graphite film - p - aminophenol - copper composite material of the present application;

[0026] Figure 2 This is a cutting diagram of the samples of Example 1 and Comparative Example 1;

[0027] Figure 3 This is a SEM image of the surface of the composite material at the bent part of Example 1. Specific implementation manner:

[0028] Example 1:

[0029] Select 1.8 g of flaky graphite film with a thickness of 70 μm and a density of 2.1 g / cm 3 . Immerse the graphite film in ethanol and stir for 10 min, then wash it with deionized water and dry. After drying, perform plasma treatment. Use an air atmosphere, with a gas flow rate of 300 sccm, a power of 120 W, and a treatment time of 20 s. Dissolve 1.8 g of p - aminophenol in 400 ml of absolute ethanol, put in the treated graphite film, pour it into a three - necked flask, evacuate the air, introduce nitrogen for protection, stir magnetically for 10 min, then slowly add 7 ml of isoamyl nitrite, stir magnetically, and heat up to 60 °C and react for 20 h. After the reaction is completed, wash the graphite film with ethanol and vacuum - dry at 60 °C for 5 h. Subsequently, electroplate the graphite film at a current density of 2 A / dm 2 for 10 min to obtain a graphite film copper - based composite material with an in - plane thermal conductivity of 1776 W / (m·K). Conduct a bending test on the composite material. Fix the composite material on a metal fixture with a bending radius of 10 mm, and perform a bending experiment with a bending degree of 90° on the composite material at a rate of 20 times per minute. After 30 bends, it does not crack. Figure 3 The SEM image of the surface of the composite material at the bent part. As can be seen from the figure, there are no obvious voids on the microscopic surface after bending, indicating good bending performance of the material.

[0030] Example 2:

[0031] Select 1.8 g of flaky graphite film with a thickness of 70 μm and a density of 2.1 g / cm 31.8 g of flaky graphite film, the graphite film was soaked and stirred in ethanol for 10 min, washed with deionized water and dried; after drying, plasma treatment was carried out. The air atmosphere was used, the gas flow rate was 300 sccm, the power was 120 W, and the treatment time was 20 s. 1.8 g of p-aminophenol was dissolved in 400 ml of absolute ethanol, the treated graphite film was put in, poured into a three-necked flask, the air was evacuated, nitrogen was introduced for protection, after magnetic stirring for 10 min, 9 ml of isoamyl nitrite was slowly added, magnetic stirring was carried out, and the temperature was raised to 60 °C, and the reaction was carried out for 20 h. After the reaction was completed, the graphite film was washed with ethanol and vacuum dried at 60 °C for 5 h. Subsequently, the graphite film was electroplated at a current density of 2 A / dm 2 for 10 min to obtain a graphite film copper matrix composite with an in-plane thermal conductivity of 1730 W / (m·K). The composite material was subjected to a bending test. The composite material was fixed on a metal fixture with a bending radius of 10 mm, and a bending test with a bending degree of 90° was carried out on the composite material at a rate of 20 times / minute. After 20 bends, it did not crack.

[0032] Example 3:

[0033] Select 1.8 g of flaky graphite film with a thickness of 70 μm and a density of 2.1 g / cm 3 The graphite film was soaked and stirred in ethanol for 10 min, washed with deionized water and dried; after drying, plasma treatment was carried out. The air atmosphere was used, the gas flow rate was 500 sccm, the power was 50 W, and the treatment time was 1 min. 1.8 g of p-aminophenol was dissolved in 400 ml of absolute ethanol, the treated graphite film was put in, poured into a three-necked flask, the air was evacuated, nitrogen was introduced for protection, after magnetic stirring for 10 min, 7 ml of isoamyl nitrite was slowly added, magnetic stirring was carried out, and the temperature was raised to 60 °C, and the reaction was carried out for 20 h. After the reaction was completed, the graphite film was washed with ethanol and vacuum dried at 60 °C for 5 h. Subsequently, the graphite film was electroplated at a current density of 2 A / dm 2 for 10 min to obtain a graphite film copper matrix composite with an in-plane thermal conductivity of 1691 W / (m·K). The composite material was subjected to a bending test. The composite material was fixed on a metal fixture with a bending radius of 10 mm, and a bending test with a bending degree of 90° was carried out on the composite material at a rate of 20 times / minute. After 40 bends, it did not crack.

[0034] Example 4:

[0035] Select 1.8 g of flaky graphite film with a thickness of 70 μm and a density of 2.1 g / cm 31.8 g of flaky graphite film, the graphite film was soaked and stirred in ethanol for 10 min, washed with deionized water and dried; after drying, plasma treatment was carried out, using an air atmosphere, the gas flow rate was 300 sccm, the power was 120 W, and the treatment time was 20 s. 1.8 g of p-aminophenol was dissolved in 400 ml of absolute ethanol, the treated graphite film was put in, poured into a three-necked flask, the air was evacuated, nitrogen was introduced for protection, after magnetic stirring for 10 min, 7 ml of isoamyl nitrite was slowly added, magnetic stirring was carried out, and the temperature was raised to 60 °C, and the reaction was carried out for 20 h. After the reaction was completed, the graphite film was washed with ethanol and vacuum dried at 60 °C for 5 h. Subsequently, the graphite film was electroplated at a current density of 2 A / dm 2 for 15 min to obtain a graphite film copper matrix composite with an in-plane thermal conductivity of 1255 W / (m·K). The composite material was subjected to a bending test. The composite material was fixed on a metal fixture with a bending radius of 10 mm, and a bending test with a bending degree of 90° was carried out on the composite material at a rate of 20 times / minute. After 10 bends, it did not crack.

[0036] Comparative Example 1:

[0037] Select 1.8 g of graphite film with a thickness of 70 μm and a density of 2.1 g / cm 3 The graphite film was soaked and stirred in ethanol for 10 min, washed with deionized water and dried; after drying, plasma treatment was carried out, using an air atmosphere, the gas flow rate was 300 sccm, the power was 120 W, and the treatment time was 20 s. Subsequently, the graphite film was electroplated at a current density of 2 A / dm 2 for 10 min to obtain a graphite film copper matrix composite with an in-plane thermal conductivity of 1231 W / (m·K). The composite material was subjected to a bending test. The composite material was fixed on a metal fixture with a bending radius of 10 mm, and a bending test with a bending degree of 90° was carried out on the composite material at a rate of 20 times / minute. After 1 bend, it cracked.

[0038] In Examples 1-4, the mass fraction ω of isoamyl nitrite was 97%, the density ρ was 0.872 g / cm 3 , and the molar mass M 1＝ was 117.15 g / mol; the molar mass M of p-aminophenol 2＝ was 109.13 g / mol.

[0039] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions or substitutions can still be made, which should all be regarded as belonging to the protection scope of the present invention.

Claims

1. A graphite film-p-aminophenol-copper composite material, characterized in that: The composite material structure is that phenol molecules are introduced into the upper and lower surfaces of the flaky graphite film, -OH in the phenol is coordinated with copper ions, and the reduced copper is deposited on the flaky graphite film with phenol molecules to form a graphite film-p-aminophenol-copper composite material.

2. A method for preparing a graphite film-p-aminophenol-copper composite material, characterized in that: The steps include: S1, treating the surface of the flake graphite film; S2, dissolving p-aminophenol in anhydrous ethanol, placing a flake graphite film, removing air, introducing nitrogen for protection, and magnetically stirring for 10 min to obtain a mixed solution; S3, adding isoamyl nitrite to the above mixed solution under nitrogen protection, stirring magnetically, heating to 50-80°C, and reacting at a constant temperature for 10-20 hours; S4, taking out the flake graphite film obtained in S3, washing it with ethanol, and vacuum drying it at 50-100° C. for 2-6 h; S5, electroplating copper on the dried flaky graphite film by using an electroplating solution for 2-15 minutes to obtain a graphite film-p-aminophenol-copper composite material.

3. The method for preparing the graphite film-p-aminophenol-copper composite material according to claim 2, characterized in that: The flake graphite film has a thickness of 20-100 μm and a density of 1.7-2.3 g / cm 3 .

4. The method for preparing the graphite film-p-aminophenol-copper composite material according to claim 2, characterized in that: The surface treatment of the flaky graphite film in step S1 is specifically as follows: the flaky graphite film is immersed in anhydrous ethanol and stirred for 10 minutes, washed with deionized water and dried, and then subjected to plasma treatment after drying, using an air atmosphere, a gas flow rate of 100-800sccm, a power of 10-300W, and a treatment time of 10s-200min.

5. The method for preparing the graphite film-p-aminophenol-copper composite material according to claim 2, characterized in that: The mass ratio of p-aminophenol to graphite film in step S2 is 0.2-5:

1.

6. The method for preparing the graphite film-p-aminophenol-copper composite material according to claim 2, characterized in that: In step S3, the molar ratio of isoamyl nitrite to p-aminophenol is 3-4:

1.

7. The method for preparing the graphite film-p-aminophenol-copper composite material according to claim 2, characterized in that: The electroplating solution in step S5 is a mixture of copper sulfate pentahydrate, potassium sodium tartrate, trisodium citrate and potassium nitrate in a concentration ratio of 8:24:4:

3. The electroplating adopts a constant current mode with a current density of 1-8A / dm 2 .

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