Heat conductive h-BN/CTPB/epoxy with enhanced dielectric properties for potential high-voltage applications

To enhance the toughness and electrical insulation properties of cured epoxy, carboxyl-terminated polybutadiene (CTPB) liquid rubber was used to modify epoxy in this study, and the thermal conductivity, mechanical and dielectric properties of modified epoxy were investigated. The results indicate that the CTPB-epoxy exhibits higher impact strength and lower dielectric constant and loss compared with pure epoxy. Further, hexagonal boron nitride (hBN) was used to reinforce epoxy modified with 20 phr CTPB. It is found that compared with the hBN/epoxy under the same filler loading, the heat conductive hBN/CTPB/epoxy possesses a lower dielectric permittivity and dissipation factor in all frequency ranging from 102–107 Hz, a higher electrical resistivity and dielectric breakdown strength, and improved mechanical toughness. Therefore, the prepared hBN/CTPB/epoxy composites are potentially useful in practical electrical insulation applications.