微米氮化硼-纳米氧化铝复合环氧材料的导热与绝缘特性

环氧树脂(epoxy resin, EP)以其粘附力强、绝缘性能好等优点,在电气领域中得到广泛应用。但环氧树脂的低热导率限制其在器件中的使用,尤其在高频条件下。文中通过多巴胺改性微米氮化硼和纳米氧化铝,将制备的微纳米二元填料填充环氧树脂,研究环氧树脂复合材料的导热性能和电气绝缘性能。结果表明,质量分数22.5%BN和7.5%Al2O3环氧树脂复合材料的导热系数可以达到1.35 W/(m·K),相比于纯EP增加了812.5%,而介电损耗维持在较低水平。高频击穿实验结果展示出复合材料击穿时间明显提高,比纯环氧树脂提高了387%。该种方法制备所得的环氧树脂复合材料,具有热导率高、介电损耗低、高频击穿强度大等优点,为开发适用于高频电力电子器件的导热绝缘材料提供参考。

Thermal Conductivity and Insulating Property of Epoxy Composites with Micro-BN and Nano-Al2O3

Epoxy resin is widely used in the electrical industries because of its strong adhesion and excellent insulating properties. However, the low thermal conductivity of epoxy resin limits its application, especially in a high-frequency condition. In this paper, the thermal conductivity and electrical insulating property of the epoxy resin composite were studied by filling the epoxy resin with the micro-nano binary filler prepared by dopamine modified micro-BN and nano-Al2O3. The results showed that the thermal conductivity of 22.5 wt% BN and 7.5 wt% Al2O3 composite could reach 1.35 W/(m·K), which was 812.5% higher than that of neat EP, while the dielectric loss was kept at a low level. The results of high frequency breakdown experiments showed that the breakdown time of the composite was significantly increased, which was 38.7% higher than that of neat EP. The composite prepared by this method has the advantages of high thermal conductivity, low dielectric loss, high frequency breakdown strength, providing a reference for the development of thermally conductive but electrically insulating materials for high frequency power electronic equipment.