将h-BN加入到MVQ和EVA混合物中制备导热绝缘h-BN/MVQ/EVA复合材料,SEM结果表明h-BN选择性分布在EVA,与杨氏方程理论一致。h-BN/MVQ/EVA复合材料中的双逾渗效应,有助于力学性能和导热性能的提升。h-BN/MVQ/EVA复合材料的热导率与h-BN含量和MVQ/EVA比值有关。当EVA质量分数为30%时,h-BN/MVQ/EVA复合材料热导率的相对值最大。h-BN/MVQ/EVA复合材料的拉伸强度和断裂伸长率与EVA含量有关,随着EVA和h-BN含量的增加,复合材料的介电常数降低。
Hexagonal boron nitride (h-BN) was added into polymer blends of methyl-vinyl-silicone rubber (MVQ) and ethy- lene-vinyl-acetate copolymer (EVA) to prepare thermally conductive and electrically insulating composites by melt processing me- thod. According to Young's equation, the wettability coefficient points out that the dispersion of h-BN in EVA is thermodynamically more favorable than in MVQ. The result of SEM showed that h-BN was selectively located in EVA. There existed double percolation effect in h-BN/MVQ/EVA ternary composites, which resulted in promoting for both mechanical properties and thermal conductivity. The thermal conductivity of h-BN/MVQ/EVA composites were related with h-BN content and EVA/MVQ ratio. When EVA con- tent was 30 wt% in the matrix blend, the relatively increased rate of thermal conductivity of h-BN/MVQ/EVA composites was the highest. The tensile strength and the elongation at break were mainly related with the EVA content in polymer matrix. The increa- sing amount of EVA and h-BN in the composites resulted in a decrease in dielectric constant.