CN107501861A - A kind of composite heat interfacial material based on graphene and preparation method thereof - Google Patents

Abstract

The invention discloses a graphene-based composite thermal interface material and a preparation method thereof, relates to the technical field of thermal interface materials, solves the problems of poor dispersion of graphene in epoxy resin and large interface thermal resistance, thereby improving epoxy resin The thermal conductivity of the resin matrix material. This method improves the dispersion state of graphene in the matrix by modifying the surface of graphene oxide; and uses the vacuum stirring and drying method to make graphene and nano-silver particles uniformly dispersed in the matrix material. , to solve the problem of agglomeration and sedimentation in ordinary mixing; moreover, the silver nanoparticles will appear in a molten state during the thermal curing of the composite material, so as to strengthen the interlayer connection of graphene and form a three-dimensional network heat transfer path. The invention can make the graphene oxide be well dispersed in the matrix material, prevent aggregation, and simultaneously improve the thermal conductivity of the epoxy resin matrix material.

Description

A kind of graphene-based composite thermal interface material and preparation method thereof

technical field

The invention relates to the technical field of thermal interface materials, in particular to a graphene-based composite thermal interface material and a preparation method thereof.

Background technique

In recent years, the electronics industry and energy technology have developed rapidly. These developments have greatly improved the performance of electronic devices such as diodes, transistors, and LED components, and have also made great contributions to energy management. But on the other hand, a serious heat dissipation problem has gradually emerged. For example, in the electronics industry, in recent years, electronic equipment and devices are developing rapidly in the direction of miniaturization, high power, and high-density assembly, which will undoubtedly increase the internal thermal power consumption density of electronic equipment and devices, resulting in The sharp rise in the internal temperature of equipment and device systems will eventually limit the performance and service life of electronic equipment and devices. Clearly, effective thermal management has become a must for the development of the electronics and energy industries. Studies have found that with the gradual miniaturization of electronic devices, the interfacial thermal resistance between solid-solid interfaces has become one of the most important factors restricting the heat dissipation of electronic devices, which greatly hinders the heat transfer performance between solids. In order to solve the problem of heat transfer between solid-solid interfaces, thermal interface materials have been widely used between solid-solid interfaces to fill the holes and grooves between the interfaces and build new heat transfer channels, thus solving the problems to a certain extent. The problem of low heat transfer performance due to incomplete contact between interfaces. At present, the commonly used thermal interface materials on the market mainly include thermal pads, thermal greases, thermal gels, etc. Most of these thermal interface materials are made by adding aluminum nitride, boron nitride, ceramics, etc. to base materials such as epoxy resin and silicone resin. It is made of fillers with relatively high thermal conductivity. Although the thermal conductivity of the base material has been improved to a certain extent after adding filler materials, usually in the range of 0.5-2W/mK, this value still cannot meet the heat dissipation requirements of electronic equipment. In addition, the performance of these polymer thermal interface materials will be severely degraded as the temperature of the heat source increases and the exposure time increases, leading to problems such as aging, failure, and leakage of the interface materials, which will further affect the reliability and life of electronic devices. Therefore, adding fillers with high thermal conductivity to base materials such as epoxy resin to improve the overall thermal conductivity of high thermal interface materials is still a hot research topic at present.

Contents of the invention

In view of the deficiencies in the prior art, the technical problem to be solved in the present invention is how to solve the problem of poor dispersion of graphene in epoxy resin and relatively large interfacial thermal resistance, improve the dispersion of graphene in matrix materials and strengthen the graphene Interlayer heat transfer, thereby improving the thermal conductivity of the epoxy resin matrix material.

In view of the above technical problems, the technical solution provided by the present invention is: a preparation method of a graphene-based composite thermal interface material, comprising the following steps:

Step 1, preparing modified graphene oxide, the specific sub-steps are as follows:

(1) Mix and stir the coupling agent and the organic solvent in a ratio of 1:5~10 to obtain a mixed solution;

(2) adding the vacuum-dried graphene oxide into the mixed solution and stirring evenly to obtain the graphene oxide mixed solution;

(3) heating the graphene oxide mixed liquid under vacuum to react to obtain a functionalized graphene oxide liquid;

(4) Washing, suction filtering, and drying the functionalized graphene oxide liquid to obtain modified graphene oxide;

Step 2, preparing a composite thermal interface material of graphene and epoxy resin, the specific sub-steps are as follows:

(1) Add epoxy resin and curing agent to organic solvent and mix and stir to obtain a mixed solution;

(2) adding the modified graphene oxide to the mixed liquid, adding an organic solvent to dilute, stir and grind to obtain a graphene oxide mixed liquid;

(3) ultrasonically dispersing the graphene oxide mixture;

(4) Heating the graphene oxide mixed solution after ultrasonic dispersion under vacuum and stirring slowly, and vacuum defoaming for 5-15 minutes;

Step 3, preparing a graphene-based composite thermal interface material, the specific steps are as follows:

(1) adding the dried nano-silver particles to the composite thermal interface material of graphene and epoxy resin, and adding an organic solvent to stir and grind to obtain a mixed solution;

(2) ultrasonically dispersing the mixed solution;

(3) Heat the mixed solution after ultrasonic dispersion under vacuum and stir slowly, and vacuum degassing for 5~15min;

(4) Inject the mixed liquid after vacuum defoaming into the mold, heat up and solidify to obtain a graphene-based composite thermal interface material.

The organic solvent is at least one of acetone, methyl ethyl ketone, ether, propylene oxide, cyclohexane, cyclohexanone, toluene, and toluene cyclohexanone;

In sub-step (3) of step 1, the reaction temperature of graphene oxide and the mixed solution is 40-80°C, and the reaction time is 2-12 hours;

The mixing and stirring temperature in the sub-step (1) of the step 1 and the sub-step (1) of the step 2 are both 40°C, and the mixing and stirring time is 30 minutes;

The ultrasonic dispersion temperature in the sub-step (3) of the second step and the sub-step (2) of the third step is 40°C, and the ultrasonic dispersion time is 20 minutes;

The vacuum degassing in the sub-step (4) of the step 2 and the sub-step (3) of the step 3 all use a vacuum mixer, the heating temperature under the vacuum is 60°C, and the vacuum suction rate is 0.1-2L/s;

The curing temperatures in the sub-step (4) of the third step are 90°C, 120°C, 150°C, and 180°C in sequence, and the curing times are 1-2 hours respectively.

The present invention also provides a graphene-based composite thermal interface material, which is made according to the above-mentioned preparation method of the graphene-based composite thermal interface material, and its component composition is calculated in parts by weight:

Graphene oxide 5~10 parts,

Nano silver particles 30~40 parts,

100 parts of epoxy resin,

Curing agent 1~5 parts,

1~5 parts of coupling agent.

The epoxy resin refers to liquid bisphenol A epoxy resin; further, the model of the bisphenol A epoxy resin is at least one of E-42, E-44, and E-51;

The curing agent is at least one of aromatic polyamines, acid anhydrides, and imidazole curing agents;

The coupling agent is a silane coupling agent or a titanate coupling agent;

The mean particle diameter of described silver nano particle is 50～100nm;

The thickness of the graphene oxide is 0.55-1.2nm.

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

1. By modifying graphene oxide, the affinity between graphene oxide and the matrix material is improved, so that it can be well dispersed in the matrix material and is not easy to agglomerate.

2. By doping nano-silver particles into graphene and epoxy resin composite thermal interface materials, using the molten state of nano-silver particles when solidified at high temperature to enhance the connection between graphene layers and form a three-dimensional network of heat transfer pathways, Reduced interfacial thermal resistance inside the composite.

Description of drawings

Fig. 1 is the preparation flowchart of graphene and epoxy resin composite thermal interface material;

Fig. 2 is a flow chart of the preparation of the graphene-based composite thermal interface material.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and embodiments, but the present invention is not limited thereto.

Fig. 1 to Fig. 2 have shown the preparation method of the composite thermal interface material based on graphene, comprises the steps:

Step 1, preparing modified graphene oxide, the specific sub-steps are as follows:

(1) Mix and stir the coupling agent and the organic solvent in a ratio of 1:5~10 to obtain a mixed solution;

(2) adding the vacuum-dried graphene oxide into the mixed solution and stirring evenly to obtain the graphene oxide mixed solution;

(3) heating the graphene oxide mixed liquid under vacuum to react to obtain a functionalized graphene oxide liquid;

(4) Washing, suction filtering, and drying the functionalized graphene oxide liquid to obtain modified graphene oxide;

Step 2, preparing a composite thermal interface material of graphene and epoxy resin, the specific sub-steps are as follows:

(1) Add epoxy resin and curing agent to organic solvent and mix and stir to obtain a mixed solution;

(2) adding the modified graphene oxide to the mixed liquid, adding an organic solvent to dilute, stir and grind to obtain a graphene oxide mixed liquid;

(3) ultrasonically dispersing the graphene oxide mixture;

(4) Heating the graphene oxide mixed solution after ultrasonic dispersion under vacuum and stirring slowly, and vacuum defoaming for 5-15 minutes;

Step 3, preparing a graphene-based composite thermal interface material, the specific steps are as follows:

(1) adding the dried nano-silver particles to the composite thermal interface material of graphene and epoxy resin, and adding an organic solvent to stir and grind to obtain a mixed solution;

(2) ultrasonically dispersing the mixed solution;

(3) Heat the mixed solution after ultrasonic dispersion under vacuum and stir slowly, and vacuum degassing for 5~15min;

(4) Inject the mixed liquid after vacuum defoaming into the mold, heat up and solidify to obtain a graphene-based composite thermal interface material.

The organic solvent is at least one of acetone, methyl ethyl ketone, ether, propylene oxide, cyclohexane, cyclohexanone, toluene, and toluene cyclohexanone;

In sub-step (3) of step 1, the reaction temperature of graphene oxide and the mixed solution is 40-80°C, and the reaction time is 2-12 hours;

The mixing and stirring temperature in the sub-step (1) of the step 1 and the sub-step (1) of the step 2 are both 40°C, and the mixing and stirring time is 30 minutes;

The ultrasonic dispersion temperature in the sub-step (3) of the second step and the sub-step (2) of the third step is 40°C, and the ultrasonic dispersion time is 20 minutes;

The vacuum degassing in the sub-step (4) of the step 2 and the sub-step (3) of the step 3 all use a vacuum mixer, the heating temperature under the vacuum is 60°C, and the vacuum suction rate is 0.1-2L/s;

The curing temperatures in the sub-step (4) of the third step are 90°C, 120°C, 150°C, and 180°C in sequence, and the curing times are 1-2 hours respectively.

Example 1:

In order to make graphene better dispersed in epoxy resin, graphene oxide was modified with coupling agent. Mix 1g of silane coupling agent KH-550 with 30g of acetone and stir for 30min; add 5g of vacuum-dried graphene oxide to the above mixture; heat the above mixture to 80°C under vacuum, and react for 4 hours A functionalized graphene oxide feed liquid is obtained; the above feed liquid is washed, suction filtered, and dried to obtain modified graphene oxide.

Add 100g of epoxy resin E-42 and 1g of m-phenylenediamine resin curing agent to 100g of acetone and mix for 30 minutes; add 2g of modified graphene oxide to the above mixed liquid, and add 150g of acetone to dilute at 40°C Stir for 30 minutes; ultrasonically disperse the above mixture at 40°C for 20 minutes; put the ultrasonically dispersed mixture into a vacuum mixer, adjust the vacuum suction rate to 0.5L/s and heat to 60°C, slowly stir and vacuum defoam After 10 minutes, a composite thermal interface material of graphene and epoxy resin was obtained.

Add 30g of dried nano-silver particles to 80g of the above prepared graphene and epoxy resin composite thermal interface material, and add 50g of acetone to stir and grind for 30min; ultrasonically disperse the above mixed liquid at 40°C for 20min; Put the dispersed mixed solution into a vacuum mixer, adjust the vacuum suction rate to 0.5L/s and heat to 60°C, stir slowly and vacuum defoam for 10min to obtain a graphene-based composite thermal interface material; the above composite liquid material Inject into the mold for heating and curing. The high-temperature curing temperatures are 90°C, 120°C, 150°C, and 180°C in sequence, and the curing time is 1 hour respectively.

Example 2:

In order to make graphene better dispersed in epoxy resin, graphene oxide was modified with coupling agent. Mix and stir 5g of silane coupling agent KH-550 and 30g of acetone for 30 minutes; add 10g of vacuum-dried graphene oxide to the above mixture; heat the above mixture to 80°C under vacuum and react for 4 hours to obtain Functionalized graphene oxide feed liquid; the above feed liquid is washed, suction filtered, and dried to obtain modified graphene oxide.

Add 100g of epoxy resin E-42 and 5g of m-phenylenediamine resin curing agent to 100g of acetone and mix for 30 minutes; add 3g of modified graphene oxide to the above mixed liquid, and add 150g of acetone to dilute at 40°C Stir for 30 minutes; ultrasonically disperse the above mixture at 40°C for 20 minutes; put the ultrasonically dispersed mixture into a vacuum mixer, adjust the vacuum suction rate to 0.5L/s and heat to 60°C, slowly stir and vacuum defoam After 10 minutes, a composite thermal interface material of graphene and epoxy resin was obtained.

Add 40g of dried nano-silver particles to 80g of the graphene and epoxy resin composite thermal interface material prepared above, and add 50g of acetone to stir and grind for 30min; ultrasonically disperse the above mixed liquid at 40°C for 20min; Put the dispersed mixed solution into a vacuum mixer, adjust the vacuum suction rate to 0.5L/s and heat to 60°C, stir slowly and vacuum defoam for 10min to obtain a graphene-based composite thermal interface material; the above composite liquid material Inject into the mold for heating and curing. The high-temperature curing temperatures are 90°C, 120°C, 150°C, and 180°C in sequence, and the curing time is 1 hour respectively.

Adopting the technical solution of the invention can further reduce the interfacial thermal resistance inside the composite material, thereby improving the thermal conductivity of the composite material as a whole.

The embodiments of the present invention have been described in detail above with reference to the drawings and examples, but the present invention is not limited to the described embodiments. For those skilled in the art, without departing from the principle and spirit of the present invention, various changes, modifications, replacements and modifications to these embodiments still fall within the protection scope of the present invention.

Claims (10)

1. A kind of 1. preparation method of the composite heat interfacial material based on graphene, it is characterised in that：Comprise the following steps：

   Step 1, modified graphene oxide is prepared, it is specifically as follows step by step：

   （1）By coupling agent and organic solvent in proportion 1:5 ~ 10 mixings obtain mixed liquor；

   （2）Graphene oxide after vacuum drying is added in the mixed liquor and is uniformly mixing to obtain graphene oxide and is mixed Liquid；

   （3）The graphene oxide liquid mixture is heated under vacuo to react to obtain functional graphene oxide feed liquid；

   （4）The functional graphene oxide feed liquid through and washing, filter, being dried to obtain modified graphene oxide；

   Step 2, the composite heat interfacial material of graphene and epoxy resin is prepared, it is specifically as follows step by step：

   （1）Epoxy resin and curing agent are added in organic solvent and mixed and obtains mixed liquor；

   （2）The graphene oxide of the modification is added in the mixed liquor, and adds organic solvent diluting agitation grinding and obtains To graphene oxide liquid mixture；

   （3）Ultrasonic disperse is carried out to the graphene oxide liquid mixture；

   （4）The graphene oxide liquid mixture after ultrasonic disperse is heated and is slowly stirred under vacuo, vacuum defoamation 5 ~ 15min；

   Step 3, the composite heat interfacial material based on graphene is prepared, it is specifically as follows step by step：

   （1）Dried nano-Ag particles are added to the composite heat interfacial material of the graphene and epoxy resin, and addition has Solvent agitation grinding obtains mixed liquor；

   （2）Ultrasonic disperse is carried out to the mixed liquor；

   （3）The mixed liquor after ultrasonic disperse is heated and is slowly stirred under vacuo, 5 ~ 15min of vacuum defoamation；

   （4）The mixed liquor after vacuum defoamation is injected into mould, heating is solidified to obtain based on the compound of graphene Thermal interfacial material.
2. 2. the preparation method of the composite heat interfacial material according to claim 1 based on graphene, it is characterised in that：It is described Organic solvent is at least one in acetone, espeleton, ether, expoxy propane, hexamethylene, cyclohexanone, toluene, toluene cyclohexanone Kind.
3. 3. the preparation method of the composite heat interfacial material according to claim 1 or 2 based on graphene, it is characterised in that：

   The step 1 is step by step（3）The reaction temperature of middle graphene oxide and the mixed liquor is 40-80 DEG C, the reaction time For 2-12 hours；

   The step 1 is step by step（1）With the step 2 step by step（1）Described in mixing temperature be 40 DEG C, it is 30min to mix the time；

   The step 2 is step by step（3）With the step 3 step by step（2）Described in ultrasonic disperse temperature be for 40 DEG C, The ultrasonic disperse time is 20min；

   The step 2 is step by step（4）With the step 3 step by step（3）Described in vacuum defoamation using be stirred under vacuum Machine, the heating under vacuum temperature are 60 DEG C, and the aspiration rate of vacuum is 0.1-2L/s；

   The step 3 is step by step（4）In solidification temperature be followed successively by 90 DEG C, 120 DEG C, 150 DEG C, 180 DEG C, hardening time point Wei not be 1 ~ 2 hour.
4. 4. it is based on graphite made of a kind of preparation method of composite heat interfacial material based on graphene as described in claim 1 The composite heat interfacial material of alkene, it is characterised in that：Its component forms：

   5 ~ 10 parts of graphene oxide,

   30 ~ 40 parts of nano-Ag particles,

   100 parts of epoxy resin,

   1 ~ 5 part of curing agent,

   1 ~ 5 part of coupling agent.
5. 5. the composite heat interfacial material according to claim 4 based on graphene, it is characterised in that：The epoxy resin is Refer to liquid bisphenol A type epoxy resin.
6. 6. the composite heat interfacial material according to claim 5 based on graphene, it is characterised in that：The bisphenol-A type ring At least one of model E-42, E-44, E-51 of oxygen tree fat.
7. 7. the composite heat interfacial material according to claim 4 based on graphene, it is characterised in that：The curing agent is virtue At least one of fragrant race's polyamines, acid anhydrides, imidazole curing agent.
8. 8. the composite heat interfacial material according to claim 4 based on graphene, it is characterised in that：The coupling agent is silicon Alkane coupling agent or titanate coupling agent.
9. 9. the composite heat interfacial material based on graphene according to any one of claim 4 to 8, it is characterised in that：It is described The average grain diameter of nano-Ag particles is 50 ~ 100nm.
10. 10. the composite heat interfacial material based on graphene according to any one of claim 4 to 8, it is characterised in that：It is described The thickness of graphene oxide is 0.55 ~ 1.2nm.