Hexagonal boron nitride (h-BN) was added into polymer blends of methyl-vinyl-silicone rubber (MVQ) and ethylene-vinyl-acetate copolymer (EVA) to prepare thermally conductive and electrically insulating composites by m...Hexagonal boron nitride (h-BN) was added into polymer blends of methyl-vinyl-silicone rubber (MVQ) and ethylene-vinyl-acetate copolymer (EVA) to prepare thermally conductive and electrically insulating composites by melt processing method. 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 content 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 increasing amount of EVA and h-BN in the composites resulted in a decrease in dielectric constant.展开更多
文摘Hexagonal boron nitride (h-BN) was added into polymer blends of methyl-vinyl-silicone rubber (MVQ) and ethylene-vinyl-acetate copolymer (EVA) to prepare thermally conductive and electrically insulating composites by melt processing method. 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 content 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 increasing amount of EVA and h-BN in the composites resulted in a decrease in dielectric constant.
