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Journal of Nanomaterials
Volume 2013 (2013), Article ID 801850, 11 pages
http://dx.doi.org/10.1155/2013/801850
Research Article

Carbon Nanotube-Epoxy Nanocomposites: Correlation and Integration of Dynamic Impedance, Dielectric, and Mechanical Analyses

1Division of Mechanical, Medical and Aerospace Engineering, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK
2Department of Electronic Engineering, University of Surrey, Advanced Technology Institute (ATI), Faculty of Engineering and Physical Sciences and Guildford, Surrey GU2 7XH, UK

Received 26 September 2012; Accepted 23 December 2012

Academic Editor: Jinquan Wei

Copyright © 2013 O. Moudam et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This study focuses on the characterization of MWNT-epoxy composites for different MWNT concentrations of 0–7 wt% by correlating different dynamic analysis techniques, including DMA, impedance, and DEA. An optimum composition was established at 0.1 wt% MWNTs corresponding to the best MWNT dispersion which resulted in the formation of an optimum MWNT network. The addition of this low fraction of MWNTs in epoxy resulted in stiffening the molecular structure and suppressing certain molecular transitions, raising the dielectric constant especially in the low-to-medium frequency range, raising the electrical conductivity especially at the high frequencies, and increasing the electromagnetic shielding effectiveness. The 0.1% MWNT-epoxy nanocomposite switched the electromagnetic shielding behaviour from being a very effective absorber at low frequencies to being an effective reflector at high frequencies. Finally, the Nyquist plot derived from the dynamic impedance spectroscopy proved most useful at providing evidence of multiple size distribution of MWNT agglomerates.