Lignocellulose composite liquid metal heat dissipation material and preparation method thereof

Abstract

The invention relates to a lignocellulose composite liquid metal heat dissipation material and a preparation method thereof.The heat dissipation composite material is prepared by packaging liquid metal through lignin, preparing lignin liquid metal particles, then mixing the lignin liquid metal particles with cellulose, and conducting heat dissipation. And the biomass-based liquid metal heat dissipation composite material with the electronic equipment heat dissipation capability is prepared. The biomass-based liquid metal heat dissipation composite material provided by the invention can be used for heat dissipation of electronic equipment, and is simple to prepare and use, good in environmental protection property, easy to remove from the equipment and high in recovery rate.

Description

Technical Field

[0001] The present invention belongs to the technical field of recyclable new materials and energy conservation and environmental protection, and particularly relates to a wood cellulose composite liquid metal heat dissipation material and a preparation method thereof. Background Art

[0002] Liquid metal alloy is a kind of metal material with excellent thermal conductivity. The melting point of this alloy is relatively low, so it is in a liquid state at room temperature. Due to its excellent thermal conductivity itself, liquid metal can be used as a heat dissipation material for heat dissipation of electronic devices. However, there are certain defects in directly using liquid metal as a heat dissipation material in the existing technology. For example, the fluidity and conductivity of liquid metal may cause short circuits in the circuit and malfunctions of electronic devices; the direct contact between liquid metal and electronic devices may corrode electronic components and other metal devices, which greatly limits the application scope of liquid metal. At present, liquid metal / polymer composites prepared by methods such as polymer composite still have limitations in terms of liquid metal loading, heat dissipation performance, material recycling and reuse. Therefore, it is very necessary to develop a liquid metal heat dissipation material with excellent heat dissipation performance, convenient use and high recycling efficiency.

[0003] Wood cellulose is a kind of natural biomass resource, which widely exists in plants, has rich reserves and is renewable. Its components include cellulose fibers, lignin, etc. There are a large number of hydroxyl groups on the surface and in the component molecules of wood cellulose fibers, which can have physical interactions with liquid metal particles to achieve liquid metal encapsulation, thereby restricting the movement of liquid metal, greatly improving the encapsulation rate of liquid metal, and improving the controllability and stability of liquid metal during use. On the other hand, wood cellulose has good dispersibility in common liquid media such as water and ethanol, and is easy to recycle and regenerate. Based on the encapsulation of liquid metal by wood cellulose components, good recycling, regeneration and reuse effects can be achieved. Summary of the Invention

[0004] The purpose of the present invention is to provide a wood cellulose composite liquid metal heat dissipation material and a preparation method thereof. The technical problem to be solved is how to achieve efficient encapsulation of liquid metal and prepare a heat dissipation composite material with good heat dissipation performance, convenient use and complete recyclability.

[0005] The purpose of the present invention and the solution to its technical problems are achieved by the following technical solutions. A preparation method of a wood cellulose composite liquid metal heat dissipation material according to the present invention includes the following steps:

[0006] (1) Lignin purification: Dispersing lignin or its derivatives in absolute ethanol and fully dissolving them to remove insoluble substances;

[0007] (2) Lignin dissolution: Quantitatively dissolving the lignin obtained in step (1) in ethanol to obtain a lignin ethanol solution;

[0008] (3) Lignin-encapsulated liquid metal: Add liquid metal to the lignin ethanol solution obtained in step (2), and perform ultrasonic treatment to obtain a lignin-encapsulated liquid metal colloidal dispersion;

[0009] (4) Preparation of lignocellulose composite liquid metal heat dissipation material: Directly mix the dispersion obtained in step (3) with lignocellulose fibers, and heat to recover ethanol to obtain a lignocellulose composite liquid metal heat dissipation material.

[0010] The object of the present invention and the technical problems to be solved can be further achieved by the following technical measures.

[0011] Preferably, in the aforementioned preparation method, the concentration of the lignin ethanol solution is 10-20 g / L; by mass percentage, the lignin-encapsulated liquid metal colloidal dispersion is composed of 10%-30% lignin, 20%-35% liquid metal, and 30%-70% ethanol; by mass percentage, the lignocellulose composite liquid metal heat dissipation material is composed of 50%-65% lignocellulose fibers, 20%-30% lignin, and 15%-25% liquid metal.

[0012] Preferably, in the aforementioned preparation method, the lignin or its derivatives include at least one of alkali lignin, kraft lignin, lignosulfonate, enzyme-hydrolyzed lignin, organosolv lignin, and phenol-modified lignin obtained by different raw materials through different treatments and chemical modification methods.

[0013] Preferably, in the aforementioned preparation method, the liquid metal is one or more of gallium, indium, tin, rubidium, and cesium.

[0014] Preferably, in the aforementioned preparation method, the ultrasonic treatment power is 200-500 w, and the duration is 5-30 min;

[0015] Preferably, in the aforementioned preparation method, the lignocellulose fibers are selected from at least one of softwood pulp fibers, hardwood pulp fibers, grass pulp fibers, recycled pulp fibers, and cellulose nanofibers.

[0016] Preferably, the aforementioned composite film material is prepared according to the aforementioned preparation method.

[0017] By means of the above technical solutions, a lignocellulose composite liquid metal heat dissipation material and its preparation method and application provided by the present invention have at least the following advantages:

[0018] The wood cellulose composite liquid metal heat dissipation material and its preparation method provided by the present invention contain only liquid metal, lignin, and wood cellulose fiber. Without adding any additives, it has excellent stability and heat dissipation performance, fully meeting the requirements of heat dissipation materials for electronic devices. Moreover, the composite material prepared based on wood cellulose raw materials in the present invention reduces the preparation cost of liquid metal composite materials, facilitating the popularization and application of the materials. Further, the wood cellulose composite liquid metal heat dissipation material provided by the present invention does not contain any chemical additives and difficult-to-recycle components, having excellent recycling performance and environmental friendliness.

[0019] The above description is only an overview of the technical solution of the present invention. In order to understand the technical means of the present invention more clearly and implement it in accordance with the content of the specification, the following provides a detailed description of the preferred embodiments of the present invention. Detailed implementation manners

[0020] Through in-depth research, the inventor of the present invention first prepared a liquid metal heat dissipation material using wood cellulose raw materials.

[0021] In order to understand the technical content of the present invention more clearly, the following specific embodiments are used for detailed description. The purpose is to better understand the content of the present invention rather than limit the protection scope of the present invention.

[0022] Example 1: Preparation of biomass-based liquid metal heat dissipation composite material

[0023] Take 2 g of purified lignin or its derivatives and dissolve them in 100 ml of absolute ethanol at room temperature and stir for 2 h. Through suction filtration, ethanol lignin is obtained. Take 1.7 g of liquid metal and add it to 10 ml of the ethanol lignin solution, and use ultrasonic treatment to prepare particles of lignin liquid metal. Mix the obtained particles with 3 g of nanocellulose and continue stirring for 5 h to obtain the required heat dissipation composite material.

[0024] Example 2: Preparation of biomass-based liquid metal heat dissipation composite material

[0025] Take 5 g of purified lignin or its derivatives and dissolve them in 100 ml of absolute ethanol at room temperature and stir for 2 h. Through suction filtration, ethanol lignin is obtained. Take 1.7 g of liquid metal and add it to 10 ml of the ethanol lignin solution, and use ultrasonic treatment to prepare particles of lignin liquid metal. Mix the obtained particles with 1.5 g of nanocellulose and continue stirring for 5 h to obtain the required heat dissipation composite material.

[0026] Example 3: Preparation of biomass-based liquid metal heat dissipation composite material

[0027] Take 5 g of purified lignin or its derivatives and dissolve them in 100 ml of absolute ethanol at room temperature with stirring for 2 h. Ethanol lignin is obtained by suction filtration. Take 1.7 g of liquid metal and add it to 10 ml of the ethanol lignin solution, and use ultrasonic treatment to prepare particles of lignin liquid metal. Mix the obtained particles with 5 g of nanocellulose and continue stirring for 5 h to obtain the required heat dissipation composite material.

[0028] The comparative example is the silicone grease produced by a Japanese company.

[0029] Perform actual computer chip heat dissipation tests on the biomass-based liquid metal heat dissipation composite material prepared by the present invention. The test results are shown in Table 1:

[0030] Table 1 Changes in time and temperature of the examples and commercial silicone grease as heat dissipation materials under computer working conditions

[0031]

[0032] As can be seen from the data in Table 1, the temperature difference within 30 minutes is an important indicator of the present invention. It can be seen from Table 1 that the temperature difference of Example 1 is 37 °C within 30 minutes, while the temperature difference of the commercial silicone grease is 45 °C within 30 minutes, indicating that the biomass-based liquid metal heat dissipation composite material exhibits better heat dissipation ability. In addition, by comparing the temperature conditions every 5 minutes, Example 1 shows a lower temperature, further confirming that the biomass-based liquid metal heat dissipation composite material is better than the commercial silicone grease in overall performance.

[0033] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a wood cellulose composite liquid metal heat dissipation material, characterized in that: It includes the following steps: (1) Lignin purification: Disperse lignin or its derivatives in anhydrous ethanol and fully dissolve them to remove insoluble matter; (2) dissolving lignin: quantitatively dissolving the lignin obtained in step (1) in ethanol to obtain a lignin ethanol solution; (3) Lignin encapsulated liquid metal: adding liquid metal to the lignin ethanol solution obtained in step (2), and ultrasonically treating the solution to obtain a lignin encapsulated liquid metal colloidal dispersion; (4) Preparation of lignocellulose composite liquid metal heat dissipation material: directly mixing the dispersion obtained in step (3) with lignocellulose fibers, heating and recovering ethanol to obtain a lignocellulose composite liquid metal heat dissipation material; The concentration of the lignin ethanol solution is 10 to 20 g / L; The lignin-encapsulated liquid metal colloidal dispersion is composed of 10% to 30% lignin, 20% to 35% liquid metal, and 30% to 70% ethanol in terms of mass percentage. Calculated by mass percentage, the wood cellulose composite liquid metal heat dissipation material consists of 50% to 65% of wood cellulose fibers, 20% to 30% of lignin, and 15% to 25% of liquid metal.

2. The preparation method according to claim 1, characterized in that: The lignin or its derivatives include at least one of alkali lignin, sulfate lignin, lignin sulfonate, enzyme hydrolyzed lignin, organic solvent lignin and phenol modified lignin obtained by different raw materials through different treatment and chemical modification methods.

3. The preparation method according to claim 1, characterized in that: The liquid metal is one or more of gallium, indium, tin, indium, rubidium, and cesium.

4. The preparation method according to claim 1, characterized in that: The ultrasonic treatment power is 200-500w, and the duration is 5-30min.

5. The preparation method according to claim 1, characterized in that: The wood cellulose fiber is selected from at least one of softwood pulp fibers, hardwood pulp fibers, grass pulp fibers, recycled pulp fibers, and cellulose nanofibers.

6. A wood cellulose composite liquid metal heat dissipation material, characterized in that: The lignocellulose composite liquid metal heat dissipation material is composed of 50% to 65% lignocellulose fibers, 20% to 30% lignin, and 15% to 25% liquid metal in terms of mass percentage; the lignin or its derivatives include at least one of alkali lignin, sulfate lignin, lignin sulfonate, enzyme hydrolyzed lignin, organic solvent lignin, and phenol-modified lignin obtained by different raw materials through different treatments and chemical modification methods; the lignocellulose fibers are selected from at least one of coniferous wood pulp fibers, broadleaf wood pulp fibers, grass pulp fibers, recycled pulp fibers, and cellulose nanofibers.

7. The wood cellulose composite liquid metal heat dissipation material according to claim 6, characterized in that: The heat dissipation material is prepared according to the method for preparing the wood cellulose composite liquid metal heat dissipation material according to any one of claims 1 to 5.

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