Thermal and dielectric properties evaluation of low density polyethylene - Boron Nitride - Carbon Black nanocomposites

Preparation of nanocomposites with several nanofillers is a promising way to tailor the physical properties of materials. In this work, Boron Nitride and Carbon Black were chosen as additives. Both are thermally conductive but Boron Nitride is an electric insulator where Carbon Black is conductive. The allying of their properties should produce materials with high thermal conductivity and tailored electrical conductivity. Crystallinity rate, normalized to the LDPE content, and melting temperature remained unchanged at 33 wt% and 105°C respectively. The BDS measurements exhibited a tremendous increase of both real and imaginary parts of the permittivity above 4 wt% of CB (more than 8 orders of magnitude), translating into a sharp increase of conductivity as the percolation threshold of CB is reached. Thermo Gravimetric, Dielectric Breakdown Strength and Thermal Conductivity measurements were also conducted to complete this study. As a conclusion, allying hBN and CB nanoparticles lead to a promising way to tailor both the permittivity and the conductivities of LDPE-based composites.