DC and AC Conductivity in Epoxy Resin/Multiwall Carbon Nanotubes Percolative System

This study attempts to investigate how the inclusion of Multiwalled Carbon-NanoTubes (MWCNT) influences the DC and AC conductivity response of standard high performance epoxy systems. Towards this direction, the highly electrical conductive fillers were homogenously dispersed at various weight contents (in the range of 0.1% up to 1.0%) using a well established shear mixing protocol. The DC and AC conductivity of the prepared nanocomposites was measured. AC conductivity was examined in the frequency range from 101 to 106 HZ at ambient temperature. An enhancement of conductivity, in accordance to percolation theory, was evidenced increasing the weight content of the conductive nano-filler. The AC conductivity was found to be frequency dependent beyond a critical frequency that increased with the nano-filler content. It is proposed that the critical frequency follows also a percolation type law with the weight fraction of the nano-tubes. A deeper analysis of all aforementioned observations highlights the multiparametric reliance of the macroscopic electrical response on the properties of the nanotubes, their electrical network topology, and their interactions with the surrounding polymer and CNTs. POLYM. COMPOS., 31:1874-1880, 2010. (C) 2010 Society of Plastics Engineers