为了制备高导热、低热阻的大面积导热界面材料,使用静电植绒法在高电压静电场下垂直取向石墨微鳞片,取向后的石墨微鳞片阵列在平面方向上呈现无规且紧凑的结构。通过微粉灌注法向石墨微鳞片中填充高密度聚乙烯(HDPE)或聚氨酯微粉,或者通过液态刮涂法填充低黏度硅橡胶前驱体,加热固化后,形成大面积高导热界面材料。导热性能测试结果表明:石墨微鳞片阵列(粒径1 000 μm)与柔性聚氨酯微粉复合形成的导热膜在68.95 kPa和689.5 kPa的压力下测得的垂直方向导热率分别为4.3 W/(m·K)和8.7 W/(m·K);与柔性硅橡胶复合形成的导热膜在68.95 kPa和344.75 kPa的压力下测得的垂直方向导热率分别为2.0 W/(m·K)和4.1 W/(m·K);与硬质HDPE微粉复合形成的导热膜由于表面过于粗糙和坚硬,无法测得可靠的导热率。实际散热效果显示,柔性硅橡胶导热膜与石墨纸贴合的散热结构能够将热聚集点的热量快速传递到石墨纸表面,并通过石墨纸层均匀散开。
Abstract
In order to prepare large-area thermal conductive interface materials with high thermal conductivity and low thermal resistance, the electrostatic flocking method was used to vertically orient graphite microflakes under a high voltage electrostatic field. The aligned graphite microflake array presents an irregular and compact structure in the plane direction. High density polyethylene (HDPE) or polyurethane powder was filled into graphite microflakes by a micropowder perfusion method, and a low viscosity silicone rubber precursor was filled by a liquid scraping method. After heating and curing, a large area of high thermal conductivity interface material was formed. The thermal conductivity test results showed that the vertical thermal conductivities of the thermal conductive film formed by the graphite microflake array (particle size of 1 000 μm) and flexible polyurethane powder are 4.3 W/(m·K) and 8.7 W/(m·K), under pressures of 68.95 kPa and 689.5 kPa, respectively. The vertical thermal conductivities of the thermal conductive film formed by the composite with the flexible silicone rubber are 2.0 W/(m·K) and 4.1 W/(m·K), under pressures of 68.95 kPa and 344.75 kPa, respectively. Due to its rough and hard surface, the thermal conductivity of the thermal conductive film formed by the composite with hard HDPE powder cannot be accurately measured. The actual heat dissipation effect shows that the heat dissipation structure of the flexible silicone rubber thermal conductive film and graphite paper can quickly transfer heat from the heat accumulation point to the surface of the graphite paper, and disperse the heat uniformly throughout the graphite paper layer.
关键词
导热材料 /
热界面材料 /
静电植绒 /
石墨
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Key words
thermally conductive material /
thermal interface material /
electrostatic flocking /
graphite
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参考文献
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脚注
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基金
海南省高等学校科学研究重点基金(Hnky2020ZD-22);三亚市院地科技合作基金(2019YD13);三亚学院人才引进项目(USYRC19-010)
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