Permittivity and tan delta characteristics of epoxy nanocomposites in the frequency range of 1 MHz-1 GHz

Abstract

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 2 O 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 2 O 3 and TiO 2 fillers. Tan delta values in nanocomposites with Al 2 O 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.

Improving the Dielectric Properties of High Density Polyethylene by Incorporating Clay-Nanofiller

“…Also an important observation is that Tan δ decreases with increasing the concentrations of clay-nanofiller incorporated in polymeric material up to 6% filler concentration, then it further increases at 10% and 15% filler concentrations. This may be due to the increasing of conductivity according to increasing of nano-filler concentration [17], [18]. It is seen that the values of Tan δ for HDPE 10% sample are less than that of pure material.…”

“…The value of ε r at HDPE 10% is still lower than that of pure HDPE and its value at HDPE 15%, is higher than the pure material. The increasing of ε r at 10% and 15% filler concentrations may be due to the effect of ε r of composites (inclusions + matrix) on the resultant permittivity [17], [18]. This means that an enhancement occurred in dielectric constant at 2%, 6%, and 10% filler concentrations.…”

Studying the Particle Size Effect on Thermal Conductivity for Hybrid Particulate Composite

“…Materials exhibit obtain of preferred properties, polymers were used as a matrix material mixed with different kinds of fillers (fibers or particles).The thermal conductivity of composite materials which are represented as a multiphase substance depends upon the thermal conductivity of each face, the proportion of each phase, and the distribution of the phase [3]. Epoxy resin was chosen as a matrix due to its good adhesion with the fillers, having improved thermal steadiness resistance to chemical set about and resistance to the degradation [4]. In Particulate-polymer composites the mechanical properties had depended impressively on the particle size, particle-matrix interface adhesion and element loading.…”

The influence of interfaces and water uptake on the dielectric response of epoxy-cubic boron nitride composites

“…There are a significant number of publications in which composites exhibit lower permittivity values compared to that of the base material despite the fact that fillers have a higher permittivity than the base polymer [1][2][3][4][5][6][7][8]. The decrease in permittivity of composites can be attributed to the influence of the particles on the polymer structure [9][10][11].…”