High thermal conductive polyimide/boron nitride composite material and preparation method thereof

A technology of polyimide and composite materials, which is applied in the field of high thermal conductivity polyimide/boron nitride composite materials and its preparation, can solve the problem of limited improvement of thermal conductivity of composite materials, inability to form a thermal conductivity network, and boron nitride agglomeration Serious problems, to achieve the effect of being suitable for industrial production, simple and practical molding method, and avoiding the influence of thermal stability

Active Publication Date: 2016-12-21

NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI

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AI-Extracted Technical Summary

Problems solved by technology

It can be seen that the surface chemical modification of boron nitride has a limited effect ...

Abstract

The invention discloses a preparation method of a high thermal conductive polyimide/boron nitride composite material. The method comprises the steps of: (1) dispersing polyimide microspheres with boron nitride into a solvent respectively to obtain a uniform polyimide microsphere dispersion and a boron nitride dispersion; (2) adding the boron nitride dispersion into the polyimide microsphere dispersion, performing stirring, then conducting centrifugation and collecting polyimide/boron nitride composite microspheres; and (3) subjecting the polyimide/boron nitride composite microspheres to compression molding, thus obtaining the high thermal conductive polyimide/boron nitride composite material. The invention also discloses the high thermal conductive polyimide/boron nitride composite material prepared by the method, and the composite material comprises, by mass percentage, 50-90% of polyimide microspheres and 10-50% of boron nitride. According to the invention, a three-dimensional ordered boron nitride heat conducting network is constructed inside the polyimide/boron nitride composite material to greatly improve the thermal conductivity of the composite material.

Application Domain

Heat-exchange elements

Technology Topic

SolventThermal conductivity +6

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Examples

Experimental program(8)
Comparison scheme(2)

Example Embodiment

[0059] Example 1

[0060] (1) Add 0.54g of self-made polyimide microspheres to 54g of water, stir and disperse uniformly to obtain a dispersion of polyimide microspheres; add 0.06g of boron nitride to 6g of water, and ultrasonically disperse for 1 hour to obtain nitride Boron dispersion.

[0061] (2) Slowly add the boron nitride dispersion to the polyimide microsphere dispersion, and stir at 25°C for 1 hour to obtain polyimide/boron nitride composite microspheres. Scanning electron micrograph of the obtained composite microspheres Such as figure 2 (B) shown.

[0062] (3) Place the polyimide/boron nitride composite microspheres in a mold, and maintain the pressure at 230°C and 1000MPa pressure for 1 hour to obtain a polyimide/boron nitride composite material with a thickness of about 1 mm. The mass percentage is composed of 90% polyimide microspheres and 10% boron nitride. The scanning electron microscope image of the cross section of the composite material is as follows image 3 (b) Shown.

[0063] Among them, the preparation method of self-made polyimide microspheres is as follows:

[0064] (I) Add polyimide to N,N-dimethylacetamide at 90°C and stir to dissolve, then add polyvinyl alcohol and stir to dissolve to obtain a polyimide/polyvinyl alcohol mixture, wherein The concentrations of imide and polyvinyl alcohol are both 5 mg/mL.

[0065] (Ii) Use water as the solvent to prepare an aqueous solution of polyvinyl alcohol with a concentration of 5 mg/mL; add the aqueous solution of polyvinyl alcohol dropwise to the vigorously stirred polyimide/polyvinyl alcohol mixture at 90°C, namely A suspension of polyimide microspheres is obtained; after centrifugal filtration, washing, and drying at 120° C., polyimide microspheres are obtained, and the average particle size of the obtained polyimide microspheres is about 1 μm.

Example Embodiment

[0066] Example 2

[0067] (1) Add 0.48g of self-made polyimide microspheres to 48g of water, stir and disperse uniformly to obtain a dispersion of polyimide microspheres; add 0.12g of boron nitride to 12g of water, and ultrasonically disperse for 1h to obtain nitride Boron dispersion.

[0068] (2) Slowly add the boron nitride dispersion to the polyimide microsphere dispersion and stir at 25°C for 3 hours to obtain polyimide/boron nitride composite microspheres. Scanning electron micrograph of the obtained composite microspheres Such as figure 2 (C) Shown.

[0069] (3) Place the polyimide/boron nitride composite microspheres in a mold, and maintain the pressure at 230°C and 1000MPa pressure for 1 hour to obtain a polyimide/boron nitride composite material with a thickness of about 1 mm. The mass percentage is composed of 80% polyimide microspheres and 20% boron nitride. The scanning electron microscope image of the cross section of the composite material is as follows image 3 (c) Shown.

[0070] Among them, the preparation method of self-made polyimide microspheres is the same as that of Example 1.

Example Embodiment

[0071] Example 3

[0072] (1) Add 0.42g of self-made polyimide microspheres to 42g of water, stir and disperse uniformly to obtain a dispersion of polyimide microspheres; add 0.18g of boron nitride to 18g of water, and ultrasonically disperse for 1 hour to obtain nitride Boron dispersion.

[0073] (2) Slowly add the boron nitride dispersion to the polyimide microsphere dispersion and stir for 0.5h at 25°C to obtain polyimide/boron nitride composite microspheres. Scanning electron microscope of the obtained composite microspheres Picture like figure 2 (D) shown.

[0074] (3) Place the polyimide/boron nitride composite microspheres in a mold, and maintain the pressure at 230°C and 1000MPa pressure for 1 hour to obtain a polyimide/boron nitride composite material with a thickness of about 1 mm. The mass percentage is 70% polyimide microspheres and 30% boron nitride. The scanning electron microscope image of the cross-section of the composite material is as follows image 3 (d) Shown.

[0075] Among them, the preparation method of self-made polyimide microspheres is the same as that of Example 1.

PUM

Property	Measurement	Unit
The average particle size	1.0	µm
Thickness	1.0	mm
Thermal conductivity	1.269	W/mK

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Simple process

High thermal conductive polyimide/boron nitride composite material and preparation method thereof

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Description & Claims & Application Information

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