Interfacial relaxation phenomena in particulate composites of epoxy resin with copper or iron particles

摘要

Interfacial dielectric relaxations have been studied in composites made with epoxy resin and copper or iron particles. Over the temperature range reported (20-160℃) relaxation peaks are formed in the 10-10~3 Hz frequency range. They are attributed to the Maxwell-Wagner-Sillars (MWS), or interfacial, polarization effect, created in heterogeneous dielectrics. The observed MWS loss peaks shift to lower frequencies if the content of the composites in the metal particles is increased. From the temperature dependence of relaxation frequency, the activation energy for the process is estimated to be 45 kJ mol~(-1) (0.4 eV). Dielectric losses of the composites in the 10-10~3 Hz frequency range can be regarded as the sum of losses from a Debye-type relaxation and of the conductivity term σ/ω. Interfacial dielectric losses are insignificant at high frequencies.