Analysis of the dielectric spectra of composite sealing coatings in a wide frequency range

Abstract

Polymer coatings on the basis of the biphenol-Novolac potting epoxy compound with a 65% content of spherical particles of fused quartz as a filler were studied by the method of dielectric spectroscopy in a wide frequency range. Dielectric measurements were performed in frequency and temperature ranges of (10−2 to 5 × 109) Hz and 20 to 200°C, respectively, on film samples of composite coatings formed on different substrates. It was shown that the application of dielectric spectroscopy allows one to study the effect of the degree of the adhesion interaction with the substrate on the processes of structuring in the epoxy polymer matrix and to investigate the degradation processes in the coatings under the effect of high temperature and relative humidity. It was also shown that the values of the glass transition temperature (Tg) of the composite determined by applying the method of low-frequency dielectric spectroscopy agree well with the Tg values obtained by applying the method of dynamic mechanical analysis (DMA).