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Permittivity and Tan Delta Characteristics of Epoxy Nanocomposites in the Frequency Range of 1 MHz–1 GHz

Singha, Santanu and Thomas, Joy M (2008) Permittivity and Tan Delta Characteristics of Epoxy Nanocomposites in the Frequency Range of 1 MHz–1 GHz. In: IEEE Transactions on Dielectrics and Electrical Insulation, 15 (1). pp. 2-11.


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To achieve a compact and reliable design of electrical equipment for the present day requirements, there is an urgent need for better and smart insulating materials and in this respect, the reported enhancements in dielectric properties obtained for polymer nanocomposites seems to be very encouraging. To further understand the dielectric behavior of polymer nanocomposites, this experimental work reports the trends of dielectric permittivities and tan delta (loss tangent) of epoxy nanocomposites with single nano-fillers of $Al_2O_3$ and $TiO_2$ at low filler concentrations (0.1%, 0.5%, 1% & 5%) over a frequency range of 1 MHz–1 GHz. Results show that the nanocomposites demonstrate some very different dielectric characteristics when compared to those for polymer microcomposites. Unlike the usual expectations of increasing permittivity with increasing filler concentration in polymer microcomposites, it has been seen that up to a certain nano-filler concentration and depending on the permittivity of the nano-filler, the permittivities of the epoxy nanocomposites are less than that of the unfilled epoxy at all the measured frequencies. This suggests that there is a very strong dependence of the filler concentration and nano-filler permittivity on the final permittivity of the nanocomposites at all these frequencies. But, in the case of tan delta behavior in nanocomposites, significant effects of filler concentrations were not observed with both $Al_2O_3$ and $TiO_2$ fillers. Tan delta values in nanocomposites with $Al_2O_3$ fillers are found to be marginally lower at all filler concentrations when compared with the value for unfilled epoxy. But, in $TiO_2$-epoxy nanocomposites, although the variations in tan delta are not significant with respect to unfilled epoxy, some interesting trends are observed with respect to the frequencies of measurement.

Item Type: Journal Article
Additional Information: ©2008 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
Keywords: Nanocomposites;nanodielectrics;permittivity;tan delta;epoxy
Department/Centre: Division of Electrical Sciences > Electrical Engineering
Date Deposited: 29 Feb 2008
Last Modified: 19 Sep 2010 04:43
URI: http://eprints.iisc.ernet.in/id/eprint/13192

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