Study of low weight percentage filler on dielectric properties of MWCNT-epoxy nanocomposites

Abstract

An attempt is made to study the effect of low weight percentage multiwall carbon nanotube (MWCNT) powder on dielectric properties of MWCNT reinforced epoxy composites. For that MWCNT (of different low weight percentage) reinforced epoxy composite was prepared by dispersing the MWCNT in resin. Samples were prepared by solution casting process and characterized for their dielectric properties such as dielectric constant (ε'), dielectric dissipation factor (tan δ) and AC conductivity (σac). The main objective is the investigation of the dielectric properties of the prepared samples at the low weight percentage of the filler at different temperatures and frequencies. From the two mechanisms of electrical conduction, first the leakage current obtained by the formation of a percolation network in the matrix and the other by tunneling of electrons formed among conductors nearby (tunneling current); here we are getting conduction by the second mechanism. Generally, leakage current makes more contribution to conductivity than tunneling current. Dielectric dissipation factor at 250 Hz frequency is greater than all other frequencies and starts increasing from 60°C. The peak height of the transition temperature decreases with increasing frequency. This study shows that the addition of a low weight percentage of MWCNT can modify considerably the electrical behavior of epoxy nanocomposites without chemical functionalization of filler.