| Summary: | 碩士 === 國立臺北科技大學 === 製造科技研究所 === 105 === Recently, due to the miniaturization of electronic products, its life is limited by cooling efficiency. The packaging composite materials needs high thermal conductivity. Among these fillers, boron nitride has good thermal conductivity, electrical insulation and chemical stability. Therefore, it can applied to different high thermal conductivity composites of the fillers.
In this study, two kinds of composite powders were prepared by emulsion polymerization and spray drying. The emulsified polymer was surface modified boron nitride and MMA polymerize into PMMA composite microspheres. Spray dry use the original boron nitride and PMMA powder to prepare into a slurry. Also, spherical composite powder was prepared through spray granulator. Moreover, according to different solid content, the composite powders were filled in the PU resin. Then, resin was prepared into thermal conductive elastic composite materials. And the thermal properties of composite powders and elastic composites were analyzed and discussed.
The results showed that the spray dry powder is a bigger spherical structure with boron nitride adhered to the surface of PMMA. However, the emulsified polymer powder is the structure of the flaked boron nitride intercalated inside the PMMA microspheres. The thermal properties of the elastomeric composites showed that the spray dry have a multi-directional thermal conductivity and maximum thermal conductivity of 1.31 W/m•K. Since boron nitride is colloid inside the emulsified polymer powder, so the thermal imaging results showed that it has a good thermal diffusion phenomenon.
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