Preparation method of elastic graphene foam

Abstract

The invention relates to the technical field of high-thermal-conductivity and high-resilience graphene foam, in particular to a preparation method of elastic graphene foam, according to the scheme, by adding a hollow material, the porosity of an original material graphene oxide film is improved. Meanwhile, the graphene foam with multiple micropores and high porosity is obtained through clamp constraint and a high-temperature heat treatment process, so that organic macromolecules can permeate into the graphene foam to form a framework, and the graphene foam with high thermal conductivity and high resilience is obtained; and the overflow speed of thermal decomposition gas can be controlled by adopting a heat treatment process with a certain temperature rising speed at 60-300 DEG C, so that the membrane is controlled not to be broken in the expansion process. And performing high-temperature graphitization to obtain the graphene foam with smooth surface, high expansion rate and high heat-conducting property, so that the high-expansion graphene oxide film permeates into organic polymers through a vacuum permeation method to form a framework, thereby obtaining the high-heat-conducting and high-resilience graphene foam.

Description

Technical Field

[0001] The invention relates to the technical field of high-thermal-conductivity and high-resilience graphene foam, and in particular to a method for preparing elastic graphene foam. Background Art

[0002] With the development of electronic devices and the advancement of chip manufacturing technology, the number of transistors contained in a unit has increased, resulting in an increase in heat generation per unit area. In addition, some devices integrate more chips in a limited space, and the chips will inevitably generate a lot of heat during operation. Therefore, modern electronic equipment has higher requirements for heat dissipation.

[0003] There is a type of thermal interface material in electronic devices, which is used between the heat source and the heat sink structure. Due to the rough surface, the heat cannot be effectively dissipated. The traditional practice is to use thermal grease or thermal conductive silicone as an interface material to play a heat-conducting role. However, thermal grease or thermal conductive silicone has the disadvantages of low thermal conductivity, poor temperature resistance, and easy failure over a long period of time, which can easily cause thermal failure. Therefore, a high thermal conductivity and high rebound graphene foam currently developed has limited its scope of use due to its high thermal conductivity and low rebound.

[0004] In summary, the present invention solves the existing problems by designing a preparation method of elastic graphene foam. Summary of the invention

[0005] The object of the present invention is to provide a method for preparing elastic graphene foam to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for preparing elastic graphene foam, characterized in that it comprises the following steps:

[0008] S1, adding 1-10 parts by mass of graphene oxide and 0-10 parts by mass of graphene into 70-98 parts by mass of deionized water, stirring and dispersing, dispersing by ultrasonic and homogenizing exfoliation process to obtain a high monolayer graphene oxide / graphene slurry, and then adding 1-10 parts by mass of hollow material and stirring until the mixture is uniform, to prepare a graphene oxide composite slurry;

[0009] S2, coating and drying the graphene oxide composite slurry prepared in the previous step to form a pre-foamed graphene oxide film with a thickness of 10-1000 μm;

[0010] S3, pre-treating the graphene oxide film prepared in the previous step at 60°C-300°C, accurately controlling the heating rate and the holding time, and controlling the amount and rate of release of the decomposed gas to obtain a preliminarily foamed graphene oxide film;

[0011] S4, the preliminarily foamed graphene oxide film prepared in the previous step is treated with a special restraining fixture and then placed in a high-temperature graphite furnace, and the temperature is increased to 1700°C-3000°C by gradient, and vacuum or inert gas protection is maintained throughout the process to obtain a graphene foam with a high expansion ratio;

[0012] S5, immersing the high-expansion graphene foam prepared in the previous step into a vacuum infiltration machine filled with an organic solution, evacuating the vacuum, and then taking it out and washing it with pure water, and the organic solution on the surface is cleaned to obtain the infiltration pre-treated graphene foam;

[0013] S6, putting the impregnated pretreated graphene foam prepared in the previous step into an oven, and in the oven at 60-200° C., the organic polymer is solidified in the micropores of the graphene foam to form a skeleton, thereby obtaining a high thermal conductivity and high resilience graphene foam.

[0014] As a preferred solution of the present invention, the thickness of the high thermal conductivity and high resilience graphene foam is 10-1000 microns.

[0015] As a preferred solution of the present invention, the graphene oxide in S1 is a mixture of any one or more of chemical graphene oxide and electrochemical graphene oxide.

[0016] As a preferred solution of the present invention, the graphene in S1 is a mixture of any one or more of mechanically exfoliated graphene, electrochemically exfoliated graphene, and reduced oxidized graphene.

[0017] As a preferred solution of the present invention, the hollow material in S1 is a mixture of any one or more of hollow glass microspheres, porous carbon microspheres, and yangba powder.

[0018] As a preferred embodiment of the present invention, the yangba powder is a mixture of any one or more of expandable plastic microspheres and expanded plastic microspheres.

[0019] As a preferred solution of the present invention, the coating method is a mixture of any one or more of blade coating, flat coating, roller coating and transfer coating.

[0020] As a preferred embodiment of the present invention, the organic solution is a mixture of one or more types of polyurethane, epoxy, silicone, etc.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention improves the porosity of the original material graphene oxide film by adding hollow materials. At the same time, through the clamping and high-temperature heat treatment process, a graphene foam with many micropores and high porosity is obtained, which is conducive to the infiltration of organic polymers into the graphene foam to form a skeleton, thereby obtaining a graphene foam with high thermal conductivity and high resilience.

[0023] The present invention can control the overflow rate of the thermal decomposition gas by adopting a heat treatment process with a certain heating rate between 60-300°C, thereby controlling the film from being broken during expansion. After high-temperature graphitization, a graphene foam with a flat surface, high expansion rate and high thermal conductivity is obtained, and the highly expanded graphene oxide film is infiltrated into the organic polymer through a vacuum infiltration method to form a skeleton, thereby obtaining a high thermal conductivity and high resilience graphene foam, which effectively improves the high thermal conductivity and high resilience of the high thermal conductivity and high resilience graphene foam, while retaining the high thermal conductivity of the graphene foam, which fully satisfies the requirements of replacing thermal conductive silicone grease or thermal conductive silica gel for the bonding of thermal interface materials. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. 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 making creative work are within the scope of protection of the present invention.

[0025] The present invention provides a technical solution:

[0026] A method for preparing high thermal conductivity and high resilience graphene foam comprises the following steps:

[0027] Step 1, 1-10 parts by mass of graphene oxide and 0-10 parts by mass of graphene are mixed and stirred and dispersed in 70-98 parts by mass of deionized water, and a high monolayer graphene oxide / graphene slurry is obtained after dispersion by various processes such as ultrasound and homogenization stripping, and then 1-10 parts by mass of hollow material are added and stirred until the mixture is uniformly mixed to prepare a graphene oxide composite slurry;

[0028] Step 2: The graphene oxide composite slurry prepared in the previous step is coated and dried to form a film to form a pre-foamed graphene oxide film with a thickness of 10-1000 μm;

[0029] Step 3, pretreating the graphene oxide film prepared in the previous step at 60° C.-300° C., accurately controlling the heating rate and the holding time, and controlling the release amount and the release rate of the decomposed gas to obtain a preliminarily foamed graphene oxide film;

[0030] Step 4: The preliminarily foamed graphene oxide film prepared in the previous step is treated with a special restraining fixture and then placed in a high-temperature graphite furnace, and the temperature is increased to 1700° C.-3000° C. by gradient heating, and vacuum or inert gas protection is maintained throughout the process to obtain a graphene foam with a high expansion ratio;

[0031] Step 5, immersing the high-rate expanded graphene foam prepared in the previous step into a vacuum infiltration machine filled with an organic solution, evacuating the vacuum, and then taking it out and washing it with pure water, and the surface organic solution is cleaned to obtain the infiltration pre-treated graphene foam;

[0032] Step 6: Put the impregnated pretreated graphene foam prepared in the previous step into an oven. In the oven at 60-200° C., the organic polymer is solidified in the micropores of the graphene foam to form a skeleton, thereby obtaining a graphene foam with high thermal conductivity and high resilience.

[0033] As an embodiment, the thickness of the high thermal conductivity and high resilience graphene foam is 10-500 microns.

[0034] As an embodiment, the graphene oxide in step 1 is a mixture of any one or more of chemically oxidized graphene and electrochemically oxidized graphene.

[0035] As an embodiment, the graphene in step 1 is a mixture of any one or more of mechanically exfoliated graphene, electrochemically exfoliated graphene, and reduced oxidized graphene.

[0036] As an embodiment, the hollow material is a mixture of any one or more of hollow glass microspheres, porous carbon microspheres, yangba powder, etc.

[0037] As an embodiment, the yangba powder is a mixture of any one or more of expandable plastic microspheres and expanded plastic microspheres.

[0038] As an embodiment, the coating method is a mixture of any one or more of blade coating, flat coating, roller coating and transfer coating.

[0039] As an embodiment, the organic solution is a mixture of one or more types of polyurethane, epoxy, silicone, etc.

[0040] Example 1: 4% chemically oxidized graphene, 1% mechanically exfoliated graphene, and 94% deionized water were weighed and initially mixed and stirred. After dispersion and homogenization, the viscosity was reduced to below 50000 mPa·S. Then, 1% porous carbon microspheres were added, stirred and dispersed evenly, and then defoamed. A graphene oxide film with a thickness of 100 microns is prepared by a doctor blade method, and then the graphene oxide film is expanded by more than 1 time by gradient heating at 60-180°C, and the treated graphene oxide film is placed in a high-temperature graphite furnace, and under argon protection conditions, the temperature is raised to 2850°C for graphitization, and high-expansion graphene foam is obtained after sufficient graphitization. Epoxy resin is taken, ethyl acetate is added to dilute it to a viscosity of less than 100 mPa·S, and poured into a vacuum infiltration machine, and the obtained high-expansion graphene foam is immersed in the epoxy resin. After vacuum treatment, it is taken out, the surface is cleaned with pure water, and then it is dried in a 105°C oven for 30 minutes to obtain a high-thermal conductivity and high-resilience graphene foam with a thickness of 500 microns, and the thermal conductivity coefficient can reach 124w / m·k.

[0041] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing elastic graphene foam, characterized in that: The following steps are involved: S1, adding 1-10 parts by mass of graphene oxide and 0-10 parts by mass of graphene into 70-98 parts by mass of deionized water, stirring and dispersing, dispersing by ultrasonic and homogenizing exfoliation process to obtain a high monolayer graphene oxide / graphene slurry, and then adding 1-10 parts by mass of hollow material and stirring until the mixture is uniform, to prepare a graphene oxide composite slurry; S2, coating and drying the graphene oxide composite slurry prepared in the previous step to form a pre-foamed graphene oxide film with a thickness of 10-1000 μm; S3, pre-treating the graphene oxide film prepared in the previous step at 60°C-300°C, accurately controlling the heating rate and the holding time, and controlling the amount and rate of release of the decomposed gas to obtain a preliminarily foamed graphene oxide film; S4, the preliminarily foamed graphene oxide film prepared in the previous step is treated with a special restraining fixture and then placed in a high-temperature graphite furnace, and the temperature is increased to 1700°C-3000°C by gradient, and vacuum or inert gas protection is maintained throughout the process to obtain a graphene foam with a high expansion ratio; S5, immersing the high-expansion graphene foam prepared in the previous step into a vacuum infiltration machine filled with an organic solution, evacuating the vacuum, and then taking it out and washing it with pure water, and the organic solution on the surface is cleaned to obtain the infiltration pre-treated graphene foam; S6, putting the impregnated pretreated graphene foam prepared in the previous step into an oven, and in the oven at 60-200° C., the organic polymer is solidified in the micropores of the graphene foam to form a skeleton, thereby obtaining a high thermal conductivity and high resilience graphene foam.

2. The method for preparing a high thermal conductivity and high resilience graphene foam according to claim 1, characterized in that: The thickness of the high thermal conductivity and high resilience graphene foam is 10-1000 microns.

3. The method for preparing a high thermal conductivity and high resilience graphene foam according to claim 1, characterized in that: The graphene oxide in S1 is a mixture of any one or more of chemical graphene oxide and electrochemical graphene oxide.

4. The method for preparing a high thermal conductivity and high resilience graphene foam according to claim 1, characterized in that: The graphene in S1 is a mixture of any one or more of mechanically exfoliated graphene, electrochemically exfoliated graphene, and reduced oxidized graphene.

5. The method for preparing a high thermal conductivity and high resilience graphene foam according to claim 1, characterized in that: The hollow material in S1 is a mixture of any one or more of hollow glass microspheres, porous carbon microspheres, and yangba powder.

6. The method for preparing a high thermal conductivity and high resilience graphene foam according to claim 5, characterized in that: The yangba powder is a mixture of any one or more of expandable plastic microspheres and expanded plastic microspheres.

7. The method for preparing a high thermal conductivity and high resilience graphene foam according to claim 1, characterized in that: The coating method is a mixture of any one or more of blade coating, flat coating, roller coating and transfer coating.

8. The method for preparing a high thermal conductivity and high resilience graphene foam according to claim 1, characterized in that: The organic solution is a mixture of one or more types of polyurethane, epoxy, silicone, etc.