Heat-conducting polymer and heat-conducting product prepared from same

Abstract

The invention provides a heat-conducting polymer and a heat-conducting product prepared from the same. The heat-conducting polymer comprises 5-10 wt% of graphene dispersion liquid, 10-20 wt% of aluminum oxide and 70-85 wt% of substrate resin. The preparation method comprises the following steps: mixing graphene with a dispersant at normal temperature, and performing ultrasonic treatment to obtain a graphene dispersion liquid; aluminum oxide powder is added into the dispersing agent and fully stirred, so that the surface of the aluminum oxide powder is fully infiltrated, and surface-treated aluminum oxide powder is obtained; and mixing the substrate resin with the graphene dispersion liquid and the aluminum oxide powder subjected to surface treatment, uniformly stirring, drying, and carrying out compression molding. The heat conductivity coefficient of the obtained resin composite material can reach 6.2-7.5 W / mK at most.

Description

Technical Field

[0001] This invention belongs to the field of thermally conductive polymer composite materials, specifically relating to a thermally conductive polymer and thermally conductive products prepared therefrom. Background Technology

[0002] Thermally conductive polymers are materials based on high molecular weight polymers that exhibit excellent heat transfer properties at specific temperatures. Due to their high thermal conductivity, high temperature resistance, simple preparation, and strong mechanical properties, they play a crucial role in many fields.

[0003] Graphene, as a two-dimensional carbon material, possesses extremely high thermal conductivity and excellent electrical properties, while alumina is widely used in various composite materials due to its high thermal and chemical stability. However, how to effectively combine the advantages of both to prepare polymer composite materials that possess both high thermal conductivity and good processability is currently a research hotspot. Summary of the Invention

[0004] This invention aims to solve the problem of uneven dispersion of graphene and alumina in polymers, and provides a high thermal conductivity resin composite material. The high thermal conductivity resin composite material is obtained by dispersing graphene in a dispersion liquid and mixing it evenly with surface-treated alumina powder and polymer (base resin), followed by thermoforming. This invention also obtains a high thermal conductivity resin composite material with optimal performance by adjusting the ratio between different components.

[0005] The high thermal conductivity resin composite material provided by the present invention comprises the following components: 5-10 wt% graphene dispersion, 10-20 wt% alumina powder, and 70-85 wt% base resin. The graphene dispersion is obtained by adding graphene to a graphene dispersant. The graphene can be prepared by oxidation-reduction method, microwave method, or physical exfoliation method; The graphene dispersant is a polymeric dispersant, specifically one or two of polyvinyl alcohol and polyacrylamide; In the graphene dispersion, the mass concentration of graphene is 0.5-1.5%, specifically 1%. The particle size of the alumina powder can be 0.1-100μm, specifically 20μm or 50μm; The alumina powder undergoes surface treatment, which involves dissolving the alumina powder in a dispersant and stirring thoroughly to ensure that the surface of the alumina powder is fully wetted. The dispersant is an ethanol solution with a mass concentration of 40-80% or a methanol solution with a mass concentration of 40-80%. The ratio of alumina powder to dispersant can be 100g: 5-10mL, specifically 100g: 5mL or 200g: 20mL; The dispersant also includes a binder and a lubricant; The adhesive is one or both of polyvinyl alcohol and polyvinyl butyral. The lubricant is one or both of polyvinylpyrrolidone and sodium polyacrylate; In the dispersant, the mass concentration of the binder can be 0.01-0.05 g / mL, specifically 0.04 g / mL; The mass concentration of the lubricant can be 0.01-0.05 g / mL, specifically 0.04 g / mL; The base resin may be polyethylene resin.

[0006] The above-mentioned high thermal conductivity resin composite material is prepared by a method including the following steps: (1) Under normal temperature conditions, graphene is added to the graphene dispersant, stirred evenly, and ultrasonically treated to obtain a graphene dispersion. (2) Add the alumina powder to the dispersant and stir thoroughly to ensure that the surface of the alumina powder is fully wetted, thereby obtaining surface-treated alumina powder; (3) Mix the base resin with the graphene dispersion prepared in step (1) and the surface-treated alumina powder prepared in step (2), stir evenly, so that the graphene and alumina powder are evenly distributed on the resin surface. (4) Dry the mixture obtained in step (3); (5) The dried mixture is thermoformed to obtain the final product.

[0007] Thermally conductive products made from the above-mentioned high thermal conductivity resin composite material are also within the scope of protection of this invention.

[0008] The thermally conductive product may specifically be a thermally conductive film.

[0009] This invention obtains a high thermal conductivity resin composite material by dispersing graphene in a dispersion liquid and mixing it uniformly with surface-treated alumina powder and a base resin, followed by thermoforming. Furthermore, this invention achieves optimal performance by adjusting the ratio of different components to obtain a high thermal conductivity resin composite material. The preparation method of this invention is simple, requires no large amounts of organic solvents, and is environmentally friendly. Detailed Implementation

[0010] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.

[0011] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0012] Example 1 (1) First, under normal temperature conditions, 0.5g of graphene was added to 49.5g of polyvinyl alcohol and stirred evenly before being placed in an ultrasonic device for treatment to obtain a graphene dispersion. (2) Dissolve 100g of alumina powder with a particle size of 20μm in a dispersant. The dispersant is 5mL of an 80% ethanol solution containing 0.2g of binder and 0.2g of lubricant. The binder is polyvinyl alcohol, and the lubricant is polyvinylpyrrolidone. Stir thoroughly in a mixer to ensure that the surface of the alumina powder is fully wetted. (3) Mix 850g of polyethylene resin with a particle size of 200μm with the graphene dispersion and alumina powder obtained in steps (1) and (2), stir evenly, so that the graphene and alumina powder are evenly distributed on the surface of the polyethylene resin. (4) Place the mixture obtained in step (3) into a constant temperature drying oven at 75°C to dry; (5) The dried mixture was subjected to high-temperature pressing to form a sample that conforms to the mold cavity. The thermal conductivity was tested at 5 points in the center and around the sample. The final thermal conductivity of the sample was 6.5, 6.6, 6.5, 6.5 and 6.6 W / mK.

[0013] Example 2 (1) First, under normal temperature conditions, 1g of graphene was added to 99g of polyvinyl alcohol and stirred evenly, and then placed in an ultrasonic device for treatment to obtain a graphene dispersion. (2) Dissolve 200g of alumina powder with a particle size of 20μm in a dispersant. The dispersant is 20mL of an 80% ethanol solution containing 0.8g of binder and 0.8g of lubricant. The binder is polyvinyl alcohol, and the lubricant is polyvinylpyrrolidone. Stir thoroughly in a mixer to ensure that the surface of the alumina powder is fully wetted. (3) Mix 700g of polyethylene resin with a particle size of 200μm with the graphene dispersion and alumina powder obtained in steps (1) and (2), stir evenly, so that the graphene and alumina powder are evenly distributed on the surface of the polyethylene resin. (4) Place the mixture obtained in step (3) into a constant temperature drying oven at 75°C to dry; (5) The dried mixture was subjected to high-temperature pressing to form a sample that conforms to the mold cavity. The thermal conductivity was tested at 5 points in the center and around the sample. The final thermal conductivity of the sample was 7.5, 7.4, 7.5, 7.5 and 7.4 W / mK.

[0014] Comparative Example 1 (1) First, under normal temperature conditions, 0.3g of graphene was added to 30.0g of polyvinyl alcohol and stirred evenly before being placed in an ultrasonic device for treatment to obtain a graphene dispersion. (2) Dissolve 30g of alumina powder with a particle size of 20μm in a dispersant. The dispersant is 5mL of an 80% ethanol solution containing 0.2g of binder and 0.2g of lubricant. The binder is polyvinyl alcohol, and the lubricant is polyvinylpyrrolidone. Stir thoroughly in a mixer to ensure that the surface of the alumina powder is fully wetted. (3) Mix 700g of polyethylene resin with a particle size of 200μm with the graphene dispersion and alumina powder obtained in steps (1) and (2), stir evenly, so that the graphene and alumina powder are evenly distributed on the surface of the polyethylene resin. (4) Place the mixture obtained in step (3) into a constant temperature drying oven at 75°C to dry; (5) The dried mixture was subjected to high-temperature pressing to form a sample that conformed to the mold cavity. The thermal conductivity was tested at 5 points in the center and around the sample. The final thermal conductivity of the sample was 3.4, 3.4, 3.5, 3.4 and 3.5 W / mK, respectively.

[0015] Comparative Example 2 (1) First, under normal temperature conditions, 1.5g of graphene was added to 140g of polyvinyl alcohol and stirred evenly, and then placed in an ultrasonic device for treatment to obtain a graphene dispersion. (2) Dissolve 250g of alumina powder with a particle size of 20μm in a dispersant. The dispersant is 5mL of an 80% ethanol solution containing 1.0g of binder and 1.0g of lubricant. The binder is polyvinyl alcohol, and the lubricant is polyvinylpyrrolidone. Stir thoroughly in a mixer to ensure that the surface of the alumina powder is fully wetted. (3) Mix 700g of polyethylene resin with a particle size of 200μm with the graphene dispersion and alumina powder obtained in steps (1) and (2), stir evenly, so that the graphene and alumina powder are evenly distributed on the surface of the polyethylene resin. (4) Place the mixture obtained in step (3) into a constant temperature drying oven at 75°C to dry; (5) The dried mixture was subjected to high-temperature pressing to form a sample that conformed to the mold cavity. The thermal conductivity was tested at 5 points on the center and around the sample. The final thermal conductivity of the sample was 7.6, 4.8, 5.2, 5.4 and 5.9 W / mK, respectively. The thermal conductivity of the final sample was unevenly distributed, with the highest being 7.6 W / mK and the lowest being 4.8 W / mK.

[0016] Therefore, adding appropriate amounts of graphene dispersion and alumina to the resin substrate can yield a thermally conductive polymer with stable thermal conductivity, ranging from 6.2 to 7.5 W / mK. However, when the graphene dispersion and alumina are not added within the appropriate range, the thermal conductivity may be low or the thermal conductivity distribution may be uneven.

[0017] Comparative Example 3 (1) First, under normal temperature conditions, 1g of graphene was added to 99g of polyvinyl alcohol and stirred evenly, and then placed in an ultrasonic device for treatment to obtain a graphene dispersion. (2) Mix 700g of polyethylene resin with a particle size of 200μm with the graphene dispersion obtained in step (1) and 200g of alumina powder with a particle size of 20μm, stir evenly, so that the graphene and alumina powder are evenly distributed on the surface of the polyethylene resin. (3) Place the mixture obtained in step (2) into a constant temperature drying oven at 75°C to dry; (4) The dried mixture was subjected to high-temperature pressing to form a sample that conformed to the mold cavity. The thermal conductivity was tested at 5 points in the center and around the sample. The final thermal conductivity of the sample was 5.4, 6.7, 4.4, 7.0 and 6.5 W / mK, respectively.

[0018] Compared with Example 2, the alumina powder was not surface treated, resulting in uneven distribution of thermal conductivity in the prepared resin composite material.

[0019] The present invention has been described in detail above. Those skilled in the art will recognize that the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope, and without requiring unnecessary experiments. While specific embodiments have been provided, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application is intended to include any changes, uses, or improvements to the invention, including changes made using conventional techniques known in the art that depart from the scope disclosed herein.

Claims

1. A high thermal conductivity resin composite material, comprising the following components, by mass percentage: 5-10 wt% graphene dispersion, 10-20 wt% alumina powder, and 70-85 wt% base resin.

2. The high thermal conductivity resin composite material according to claim 1, characterized in that, The graphene dispersion is obtained by adding graphene to a graphene dispersant. The graphene dispersant is a polymeric dispersant, specifically one or two of polyvinyl alcohol and polyacrylamide; The graphene dispersion contains graphene at a mass concentration of 0.5-1.5%.

3. The high thermal conductivity resin composite material according to claim 1 or 2, characterized in that, The alumina powder has a particle size of 0.1-100 μm.

4. The high thermal conductivity resin composite material according to claim 1 or 2, characterized in that, The alumina powder undergoes surface treatment, which involves dissolving the alumina powder in a dispersant and stirring thoroughly to ensure that the surface of the alumina powder is fully wetted. The dispersant is an ethanol solution with a mass concentration of 40-80% or a methanol solution with a mass concentration of 40-80%. The ratio of alumina powder to dispersant is 100g: 5-10mL.

5. The high thermal conductivity resin composite material according to claim 4, characterized in that, The dispersant also includes a binder and a lubricant; The adhesive is one or both of polyvinyl alcohol and polyvinyl butyral. The lubricant is one or both of polyvinylpyrrolidone and sodium polyacrylate; In the dispersant, the mass concentration of the binder is 0.01-0.05 g / mL; The mass concentration of the lubricant is 0.01-0.05 g / mL.

6. The high thermal conductivity resin composite material according to claim 1, characterized in that, The base resin is polyethylene resin.

7. The high thermal conductivity resin composite material according to claim 1, characterized in that, The thermal conductivity of the high thermal conductivity resin composite material is in the range of 6.2-7.5 W / mK.

8. A method for preparing the high thermal conductivity resin composite material according to any one of claims 1-7, comprising the following steps: (1) Under normal temperature conditions, graphene is added to the graphene dispersant, stirred evenly, and ultrasonically treated to obtain a graphene dispersion. (2) Add the alumina powder to the dispersant and stir thoroughly to ensure that the surface of the alumina powder is fully wetted, thereby obtaining surface-treated alumina powder; (3) Mix the base resin with the graphene dispersion prepared in step (1) and the surface-treated alumina powder prepared in step (2), stir evenly, so that the graphene and alumina powder are evenly distributed on the resin surface. (4) Dry the mixture obtained in step (3); (5) The dried mixture is thermoformed to obtain the final product.

9. A thermally conductive product made from the high thermal conductivity resin composite material according to any one of claims 1-7.