Dielectric Properties of Polyesterimide/SiO2 Nanocomposites

Dielectric spectroscopy and DC conduction current of Polyesterimide (PEI) -based nanocomposite filled with low concentration, 1.5wt.%, of SiO 2 nanoparticles of about 10nm mean size have been performed and analysis in comparison with the unfilled PEI. The permittivity and dielectric loss of the nanocomposite were found lower than those of neat PEI respectively, particularly at high temperature and low frequencies. A distinct additional relaxation process was observed in the case of the nanocomposite due to the interfacial relaxation occurring at the phases’ boundaries. Both the low field and the high field conductivity was found to be lower in the case of the nanocomposites. Therefore, in view of these result, the incorporation of small amount of SiO 2 nanoparticles in PEI resins, extend the critical limits of use and make them suitable for higher voltage and temperature for dielectric applications.