Polymer composites containing plasma‐treated mica. II. Dielectric properties

The complex relative premittivity K * (ω) of polymer–mica composites has been studied in the frequency range extending from about 10 −2 to 10 7 Hz. Microwave plasma treatment in ethylene of the mica flakes leads to significant alterations of K * (ω) for the matrix polymers used—polyethylene, polystyrene, and a mixture of these two polymers. The origins of the dispersion characteristics were investigated using a series of polyethylene samples containing up to 50 wt‐% of untreated mica. Comparing experimental results with theoretical analyses of the Maxwell‐Wagner‐Debye‐like interfacial polarization effect, it is possible to identify two major contributions to K * (ω): a Debye‐like dispersion centered near 10 2 Hz and a charge‐diffusion mechanism which contributes primarily at low frequencies (≲10 Hz).