Temperature dependent complex permittivities of graphitized carbon blacks at microwave frequencies between 0.2 and 26 GHz

Many carbonaceous materials are amenable to dielectric heating at microwave frequencies. The primary indicator of microwave susceptibility is the complex permittivity (epsilon*), of which, the real component correlates with polarization, and the imaginary term represents dielectric loss. For a given material, the complex permittivity is dependent upon both frequency and temperature. Here we report the complex permittivities over the frequency range from 0.2 to 26 GHz of four laboratory grade graphitized carbon blacks which are used as adsorbents and chromatographic media in a variety of separation, purification, and analytical applications. Measurements were made using a vector network analyzer based system across the temperature region between 23degreesC and 191degreesC. Dielectric polarization-relaxation phenomena are also characterized. (C) 2004 Kluwer Academic Publishers.