Graphene heat-conducting filler capable of being used for organic silicon system and preparation method of graphene heat-conducting filler

Abstract

The invention provides a graphene heat-conducting filler applicable to an organic silicon system and a preparation method of the graphene heat-conducting filler, and relates to the field of heat-conducting materials. The preparation method comprises the following steps: S1, dispersing graphene oxide in a solvent, and carrying out ultrasonic treatment to obtain a uniformly dispersed suspension; and S2, dissolving the modifier and the silane coupling agent in the solvent. According to the graphene heat-conducting filler capable of being used for the organic silicon system and the preparation method of the graphene heat-conducting filler, polysiloxane macromolecular chains are grafted to the surface of graphene on the basis of hydrolysis reaction of siloxane, so that the properties of the surface of the graphene are improved, the physical compatibility of a graphene material and an organic silicon material is improved, and compared with a micromolecular silane coupling agent, the graphene heat-conducting filler has the advantages that the heat-conducting property is improved; the physicochemical property of macromolecular polysiloxane grafted to the surface of the graphene is closer to that of an organic silicon material, and the stability of the graphene can be improved through interaction of entanglement and the like, so that the compatibility of the graphene and the organic silicon material is better.

Description

Technical Field

[0001] This invention relates to the field of thermal conductive materials technology, specifically to a graphene thermal conductive filler that can be used in organosilicon systems and its preparation method. Background Technology

[0002] Graphene is a two-dimensional honeycomb lattice material composed of a single layer of carbon atoms with sp² hybrid orbitals. It is one of the thinnest, strongest, and most electrically and thermally conductive nanomaterials known to date. Graphene has extremely high electron mobility, with a theoretical in-plane thermal conductivity of up to 5300 W / (m·K). Based on this, graphene composites, by combining graphene's excellent electrical and thermal conductivity with the processability of traditional materials, show great potential in the field of high thermal and electrical conductivity reinforced materials. However, graphene is a single-atom-layer two-dimensional material with a specific surface area as high as 2630 m² / g and an extremely high surface atomic ratio, resulting in extremely high surface energy. To reduce energy, the layers spontaneously stack and aggregate. Therefore, graphene is very prone to aggregation, affecting the uniformity of composite materials and consequently impacting other properties of the composites. CN120137195A discloses a method for grafting and modifying graphene oxide, utilizing the reaction between the hydroxyl and carboxyl groups on graphene oxide and the ester groups contained in polyester to graft polyester onto graphene oxide, significantly improving the compatibility between graphene oxide and polyester polymers. CN120290127A discloses a method for modifying graphene oxide with γ-glycidyl etheroxypropyltrimethoxysilane, thereby preparing graphene-epoxy resin composite materials. In particular, organosilicon materials, due to their excellent elasticity and flexibility, are the most commonly used matrix materials for manufacturing thermally conductive gels, thermally conductive pads, etc. However, organosilicon materials have very low surface energy, resulting in a very weak interaction with graphene. The above modification methods enable graphene to be used as a composite material in polyester and epoxy resin systems, but they cannot be applied to organosilicon resins with low surface energy and low polarity to form an effective thermally conductive filler. Summary of the Invention

[0003] The purpose of this invention is to provide a graphene thermally conductive filler that can be used in organosilicon systems and its preparation method, thereby solving the problems mentioned in the background art.

[0004] Technical solution

[0005] To achieve the above objectives, the present invention provides the following technical solution: a graphene thermally conductive filler applicable to organosilicon systems and its preparation method, comprising the following steps:

[0006] S1: Graphene oxide is dispersed in a solvent and ultrasonically treated to obtain a uniformly dispersed suspension.

[0007] S2: Dissolve the modifier and silane coupling agent in a solvent, add acid to obtain the modified solution;

[0008] S3: Add the modification from step S2 to the suspension of S1 and carry out a hydrolysis reaction;

[0009] S4: After the reaction is complete, centrifuge, wash, and dry to obtain the modified graphene filler.

[0010] Furthermore, in step S1, the solvent is tetrahydrofuran, acetonitrile, dioxane, etc., and the graphene dispersion concentration is 0.1-1 mg / mL.

[0011] Furthermore, in step S1, the graphene is graphene oxide or graphene oxide-reduction.

[0012] Furthermore, the S2 modifier is a polysiloxane polymer with the following structure, a molecular weight of 1000-10000, and its amount is 10-50% of the graphene mass.

[0013] or

[0014] Where R is a methoxy, ethoxy, or similar alkoxy group.

[0015] Furthermore, the S2 silane coupling agent is one or a mixture of decyltrimethoxysilane and ethyltrimethoxysilane, and its dosage is 0-10% of the mass of the modifier.

[0016] Furthermore, in step S2, the solvent is tetrahydrofuran, acetonitrile, dioxane, etc., and the acid is acetic acid, oxalic acid, hydrochloric acid, and other commonly used organic and inorganic acids, with an acid concentration of 0.1% = 5%.

[0017] Furthermore, the reaction in step S3 is carried out under nitrogen protection.

[0018] Furthermore, the hydrolysis reaction in step S3 is carried out under stirring at 60-80°C for 6-24 hours.

[0019] Furthermore, in step S4, the centrifugal washing uses ethanol or deionized water, and the drying method is freeze drying or vacuum drying at 60°C.

[0020] Furthermore, its surface is grafted with long polysiloxane molecular chains, which are covalently bonded to the oxygen-containing functional groups of graphene through Si-OC bonds.

[0021] This invention provides a graphene thermally conductive filler that can be used in organosilicon systems and its preparation method. It has the following beneficial effects:

[0022] This invention relates to a graphene thermally conductive filler applicable to organosilicon systems and its preparation method. Based on the hydrolysis reaction of siloxanes, polysiloxane macromolecules are grafted onto the graphene surface, thereby improving the properties of the graphene surface and increasing the physical compatibility between graphene and organosilicon materials. Compared with small molecule silane coupling agents, the large molecule polysiloxanes grafted onto the graphene surface have physicochemical properties closer to those of organosilicon materials, and can increase the stability of graphene through interactions such as entanglement, thus improving the compatibility between graphene and organosilicon materials. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0024] Examples of the embodiments are provided, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The following embodiments are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0025] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0026] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0027] This invention provides a graphene thermally conductive filler that can be used in organosilicon systems and its preparation method.

[0028] Example 1

[0029] S1: Add 5g of graphene oxide to 100ml of tetrahydrofuran and sonicate for more than 60 minutes to ensure that the graphene is evenly dispersed in the tetrahydrofuran.

[0030] S2: 2g of modifier (molecular weight 5000g / mol) and 0.2g of decyltrimethoxysilane were dissolved in 10ml of tetrahydrofuran, and then 0.1g of acetic acid was added. The mixture was stirred at room temperature for 30min.

[0031] S3: Add the modified droplets from step S2 to the suspension from S1 and react at 50°C for 8 hours under ultrasonic conditions.

[0032] S4: After the reaction is complete, centrifuge, wash, and dry to obtain the modified graphene filler.

[0033] Example 2

[0034] S2 was modified by adding 5g of a modifier with a molecular weight of 10000g / mol;

[0035] The rest is the same as in Example 1, so it will not be repeated here.

[0036] Example 3

[0037] S2 was modified by adding 1g of a modifier with a molecular weight of 1000g / mol;

[0038] Comparative Example 1

[0039] S1: Add 5g of graphene oxide to 100ml of tetrahydrofuran and sonicate for more than 60 minutes to ensure that the graphene is evenly dispersed in the tetrahydrofuran.

[0040] S2: Dissolve 1g of decyltrimethoxysilane in 10ml of tetrahydrofuran, then add 0.1g of acetic acid. Stir at room temperature for 30min;

[0041] S3: Add the modified droplets from step S2 to the suspension from S1 and react at 50°C for 8 hours under ultrasonic conditions.

[0042] S4: After the reaction is complete, centrifuge, wash, and dry to obtain the modified graphene filler.

[0043] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A graphene thermally conductive filler that can be used in organosilicon systems and its preparation method, comprising the following steps: S1: Graphene oxide is dispersed in a solvent and ultrasonically treated to obtain a uniformly dispersed suspension. S2: Dissolve the modifier and silane coupling agent in a solvent, add acid to obtain the modified solution; S3: Add the modification from step S2 to the suspension of S1 and carry out a hydrolysis reaction; S4: After the reaction is complete, centrifuge, wash, and dry to obtain the modified graphene filler.

2. The method for preparing graphene thermally conductive filler for use in organosilicon systems according to claim 1, characterized in that: The solvent mentioned in step S1 is tetrahydrofuran, acetonitrile, dioxane, etc., and the graphene dispersion concentration is 0.1-1 mg / mL.

3. The method for preparing graphene thermally conductive filler for use in organosilicon systems according to claim 1, characterized in that: The graphene mentioned in step S1 is graphene oxide or graphene oxide-reduction.

4. The method for preparing a graphene thermally conductive filler that can be used in organosilicon systems according to claim 1, characterized in that: The modifier described in S2 is a polysiloxane polymer with the following structure, a molecular weight of 1000-10000, and an amount of 10-50% of the graphene mass. or Where R is a methoxy, ethoxy, or similar alkoxy group.

5. The method for preparing graphene thermally conductive filler for use in organosilicon systems according to claim 1, characterized in that: The silane coupling agent mentioned in S2 is one or a mixture of decyltrimethoxysilane and ethyltrimethoxysilane, and its dosage is 0-10% of the mass of the modifier.

6. The method for preparing graphene thermally conductive filler for use in organosilicon systems according to claim 1, characterized in that: The solvent in step S2 is tetrahydrofuran, acetonitrile, dioxane, etc., and the acid is acetic acid, oxalic acid, hydrochloric acid, and other commonly used organic and inorganic acids. The concentration of the acid is 0.1% = 5%.

7. The method for preparing graphene thermally conductive filler for use in organosilicon systems according to claim 1, characterized in that: The reaction in step S3 is carried out under nitrogen protection.

8. The method for preparing graphene thermally conductive filler for use in organosilicon systems according to claim 1, characterized in that: The conditions for the hydrolysis reaction in step S3 are: stirring at 60-80℃ for 6-24 hours.

9. The method for preparing a graphene thermally conductive filler for use in organosilicon systems according to claim 1, characterized in that: In step S4, centrifugal washing is performed using ethanol or deionized water, and drying is performed by freeze drying or vacuum drying at 60°C.

10. A graphene thermally conductive filler for use in organosilicon systems according to claim 1, characterized in that: The surface of the structure is grafted with long polysiloxane molecular chains, which are covalently bonded to the oxygen-containing functional groups of graphene through Si-OC bonds.

Images