Preparation And Property Of Thermally Conductive And Electrically Insulating Silicone Rubber Composites

With the integration of electronic and electrical appliances, the working temperature of electronic components rose sharply. When the working temperature increase 2 ?, the reliability of electronic components will reduce10%. So the heat dissipation has become an important factor to ensure the performance and reliability of electronic equipment. MVQ has been widely applied in many field due to the outstanding properties, such as high and low temperature durability, wide temperature range?-50 250??, old resistance,electric insulator and so on, but the thermal conductivity is very low. According to this article, the preparation and property of thermally conductive and electrically insulating silicone rubber composites filled with hexagonal boron nitride were studied. However, the use of MVQ is limited because of the poor mechanical. Referring to the conductive double-percolation theory, the mechanical properties and thermal double-percolation theory are studied by blending Ethylene-vinyl acetate?EVA?.The thermally conductive and electrically insulating silicone rubber composites were prepared by using hexagonal boron nitride as fillers. The effects of fillers content and molding methods on thermal and insulation properties of composites were studied. The results shown: the thermal conductivity coefficient of the silicone rubber composites was good when the hexagonal boron nitride was used as fillers because of the high specific surface area. When the fillers treated with coupling agent showed good compatibility. The thermal conductivity paths could be formed only when the filler content was high.Also, the high content of fillers made the high thermal conductivity. But the mechanical properties of the composites decreased. The Rubber process Analyzer?RPA-2000?demonstrated that all the samples had different dynamic data when change the fillers contents.Referring to the conductive double-percolation theory, in this paper, the ethylene-vinyl acetate copolymer?EVA? as modified matrix, blending with silicone rubber composite. The effects of EVA contents on composites' performance were studied. The results showed that the h-BN filler selectivedistribution in the EVA phase, increasing the concentration of the fillers;Different modification of the matrix?EVA? was added will cause silicone rubber thermal insulation composite inner structure is different, lead the thermal conductivity is different; Comparing with the pure MVQ composites, the MVQ/EVA blends, lead the thermal conductivity and mechanical properties were obviously increase; Changing the ratio of MVQ and EVA, study on the effect of blending matrix on thermal conductivity of thermal insulation composite material properties, the results showed that the h-BN filler selective distribution in the EVA phase, increasing the concentration of the fillers; When the ratio of MVQ/EVA was 7/3, it is most beneficial to enhance the thermal conductivity of silicone rubber thermal insulation composite material. When the fillers contents was 50wt%, the thermal conductivity of silicone rubber thermal insulation composite material was 1.928 W·m^-1·K^-1.