Author : A. Saki, Tahseen
journal of kerbala university,
2012, Volume 8, Issue 1, Pages 348-356
Dielectric behavior and ac conductivity measurements on epoxy resin filled with (5, 10, 15, 20, 25 wt.%.) micro sized particles of TiO2 and ZnO have been studied.. The measurements were carried out in the frequency range (120Hz - 2MHz) and over a wide temperature 30 ◦C and 110◦C. Different dielectric behavior was observed depending on filler type, filler contact, frequency and temperature.
Results show that dielectric permittivity (ε') and dielectric loss(ε") increases with the addition of epoxy resin, which has been attributed to interfacial polarization. The value of (ε') increased with increasing temperature, due to the greater freedom for movement of the dipole molecular chains within the epoxy at high temperature. The value of (ε') decreases with increasing frequency, which indicates that the major contribution to the polarization comes from orientation polarization. Interfacial relaxation is found to be strongly dependent on the presence of micro-filler particles. The Alternating Current (AC) conductivity increases as the temperature and frequency, because of the segmental mobility and electrical conduction.