Dielectric breakdown strength of alumina filled poly (ethylene-co-butyl acrylate) nanocomposites

Abstract

Abstract-Dielectric breakdown strength of poly (ethylene-cobutyl acrylate) (EBA) nanocomposites filled with spherical alumina particles was studied as a function of particle coating and relative air humidity. The nanocomposites were prepared from a mixture of EBA formulations (13 wt% butyl acrylate groups content) and alumina powder. The particles were either unmodified or surface-treated with aminopropyltriethoxy silane or octyltriethoxy silane. The filler content studied was 6 wt%. Every material formulation was thoroughly examined under SEM in order to verify homogeneous particle dispersion. Two different relative humidities of air were used for conditioning the samples prior to testing: 0 and 86 % RH.The dielectric breakdown strength measurements were performed with a DC ramp of 1.2 kV/s. Ten samples were tested for each material formulation. Results were compared to the pristine EBA samples. Applying Weibull analysis to the measured data indicated a slight increase in breakdown strength for the dry nanocomposites filled with amino-treated particles as compared to the reference material in dry conditions. As expected, conditioning materials in humid environment had a negative impact on breakdown strength. This effect was more pronounced for nanocomposite materials, while the reference unfilled material was affected the least.

Influence of Applied Voltage and Temperature on the Current through the Alumina-filled poly(ethylene-co-butyl acrylate) Nanocomposites Under Constant Stress

“…4(e-h). This could indicate that the latter material is more stable than the former, possessing higher breakdown strength as was seen in [10]. Also the behavior of current decay is different between the two nanofilled materials: for the materials filled with the untreated nanoparticles there is an obvious decay in current magnitude with time after reaching a peak, which is somewhat similar to the trend exhibited by the unfilled reference material, see Fig.…”

“…4(g, h). This could be explained by the reactivity of the amino silane surface treatment of the nanoparticles which could capture charges and result lower currents in comparison to other nanocomposites as was shown in [10].…”

“…Several temperature levels were tried: room temperature, 40 and 50 ºC. The same measurement cell as in [10] was used and the measurement circuit can be seen in Fig. 1.…”