Equivalent Circuit Model-A Tool for Analysis of the Dielectric Properties of Epoxy Composites

Equivalent circuit analysis of polymer composites with micron and nano fillers has been attempted with the objective of understanding the effect of epoxy, reinforcement, and hybrid fillers on the dielectric properties. The equivalent circuit models help to understand the capacitive nature of the composites and its deviations due to different parameters. The equivalent circuit models of the hybrid composites are visualized through parallel capacitance (C
_P
), series and parallel resistance (R
_S
and R
_P
), and constant phase element (CPE). The changes in the dielectric properties of the polymers are predicted based on transitions from C
_P
R
_P
to constant phase element and vice versa. The series resistance shows dependence on the reinforcement and the fillers, and the parallel resistance is determined by the bulk property. The temperature dependence of interactions between epoxy, reinforcement and the fillers are responsible for the transitions in the equivalent circuits. The modifications in the equivalent circuits with temperature are cyclic, signifying that CPE elements are transitional stages.