Impact of Electric Field Application During Curing on Epoxy-Carbon Nanotube Nanocomposite Electrical Conductivity
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In the present work, the conductivity of multi-walled carbon nanotube (MWCNT) and epoxy resin matrix nanocomposites produced under the action of a 100-V/cm external sinusoidal electric field is studied, for five MWCNT concentration values. The results showed that the AC electrical conductivities of the nanocomposite samples exhibited a large increase compared to those of pure epoxy resin samples. The conductivity at 40 Hz increased from ~ 10−9 S/m for the pure resin samples to 10−2–10−3 S/m for materials with 0.30 wt% MWCNT concentration, while a further increase of up to ~ 10−1 S/m was achieved on the samples produced under the effects of a sinusoidal field. This phenomenon was attributed to a spatial alignment of the MWCNT inside the epoxy matrix and/or the bending of close MWCNT due to the electrostatic force, which created efficient electric current conduction paths along the MWCNT. A proposed new method estimated the value of the current percolation threshold, yielding a result of 0.016 wt% for the sample that was not subjected to the electric field, which then decreased by approximately one order of magnitude for the samples subjected to the electric field.
KeywordsCarbon nanotube Epoxy matrix Electrical properties Nanocomposite
The authors would like to thank Profs. I. A. Hümmelgen and C. K. Saul for the use of their laboratory facilities, CAPES (Brazilian Funding Agency), and the CME-UFPR (Centro de Microscopia Eletrônica).
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