Preparation method of boron nitride-silicon rubber composite material

Abstract

The invention provides a preparation method of a boron nitride-silicon rubber composite material. The preparation method is characterized by adding a certain amount of a filling material into silicon rubber in batches, fully stirring in vacuum, pouring the mixture into a stainless steel mold of which upper and lower surfaces are insulatedly isolated by a rubber sheet having a certain thickness, connecting the upper surface and the lower surface of the stainless steel mold respectively to a positive pole and a negative pole of a high-voltage direct-current power supply, and carrying out curing at a temperature of 70 to 90 DEG C for 10 to 60 minutes. In the above technical scheme, the high-voltage direct-current power supply can be replaced by an alternating current power supply so that better effects are obtained. Through use of an applied electric field, effective heat conductivity of the whole system can be improved. An alternating electric field is superior to a direct-current electric field in orientation of filling material particles. Under the action of an electric field, a high-heat conductivity crystal plane of boron nitride is oriented along a direction of the electric field so that heat conductivity in a parallel electric field direction is greatly improved by more than 1.5 times. Electric field-assistant curing preparation of a composite heat-conducting material can effectively improve heat conductivity, reduce a use amount of the filling material, save a cost and reduce self-weight of the composite heat-conducting material.

Description

technical field [0001] The invention relates to a preparation method of a boron nitride-silicone rubber composite material, which belongs to the technical field of new materials. Background technique [0002] Thermally conductive silicone rubber can effectively dissipate the heat generated by electronic equipment, and improve the service life and work efficiency of electronic equipment. Filled thermally conductive rubber consists of a polymer matrix and a high thermally conductive filler, of which the thermally conductive filler is the main thermally conductive carrier. When the amount of fillers is relatively small, they can be uniformly dispersed in the matrix, and there is no contact and interaction between the fillers; when the amount of fillers reaches a certain level, the distance between the fillers decreases and interactions occur, forming a similar formation in the matrix. The chain-like and mesh-like structures are called heat-conducting mesh chains. When the fil...

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Problems solved by technology

[0004] However, after searching, we did not find any reports about the successful preparation of boron nitride and silicon rubber composites by applying an electric field.