Hexagonal boron nitride/polymethyl-vinyl siloxane rubber dielectric thermally conductive composites with ideal thermal stabilities

Hexagonal boron nitride/polymethyl-vinyl siloxane rubber (hBN/VMQ) dielectric thermally conductive composites were fabricated via kneading followed by hot compression method. The thermally conductive coefficient (λ), thermal diffusion coefficient (α), dielectric constant (ε) and dielectric loss tangent (tan δ) values were all increased with the increasing addition of hBN fillers. When the volume fraction of hBN fillers was 40 vol%, the corresponding λ and α was 1.110 W/m K and 1.174 mm²/s, 6 and 9 times than that of pure VMQ matrix, respectively. The corresponding ε and tan δ was 3.51 and 0.0054, respectively. Furthermore, the tensile strength and T_{Heat-resistance index} (T_HRI) values were both maximum with 20 vol% hBN fillers, tensile strength of 3.31 MPa, 12 times than that of pure VMQ matrix (0.28 MPa), and T_HRI of 253.8 °C. The obtained hBN/VMQ composites present great potential for packaging in continuous integration and miniaturization of microelectronic devices.