Dielectric spectroscopy of onion-like carbon/epoxy resin composites

Dielectric Spectroscopy of Onion-Like Carbon/Epoxy Resin Composites Nanocarbon composite materials have become a subject of great interest due to variety of combinations and functionalities that are employed in industrial applications such as batteries, supercapacitors, sensors, and etc. Broadband dielectric spectroscopy methods are frequently used in order to study the macroscopic properties of new composite materials and their potential uses. The aim of this work is to study dielectric/electrical properties of onion-like carbon (OLC)/epoxy resin composites having typical aggregate sizes 40 nm, 100 nm and 250 nm in broad frequency range and their temperature dependence above and below percolation threshold by using dielectric spectroscopy methods. The findings from the research show that percolation threshold in these composites depends on OLC aggregate size and it is lower for composites having bigger OLC aggregates (0.7 vol%). It has been shown that activation energy is higher for the composites with lower OLC volume fraction. Composites with 250 nm aggregate size demonstrate high dielectric permitivitty values in microvawe range above the percolation threshold. Given results imply that OLC/epoxy resin composites are suitable for electromagnetic shielding