Investigation on relationship between breakdown strength enhancement of composites and dielectric characteristics of nanoparticle

Abstract

In this work, the relationship between dielectric characteristics of nanoparticle and its effects on dielectric breakdown strength of Epoxy was investigated. The dielectric characteristic was tailored through silica surface encapsulation on TiO2. It was found that in contrast to raw TiO2, addition of TiO2@SiO2 core-shell nanoparticle obviously improved the dielectric breakdown strength of epoxy resin. Meanwhile, peculiar increase of resistivity was also observed. Based on the results, a mechanism through "barrier effect" by electric double layer was proposed to explain this enhancement, which was regarded closely associated with the highly polarizable and surface insulating features of TiO2 after silica encapsulation. Experimental validation was also conducted with permittivity and space charge distribution measurement of composites. It was concluded that the high polarizability and surface insulativity firstly favored formation of the double layer, synergistically from which the resulted space charge in homo-pattern then suppressed excessive charge injection through Coulomb repulsive interaction, and improved electrical strength by retarding exorbitant localized field occurrence which had been found to be direct cause of breakdown when it exceed a critical value.Index Terms -Barrier effect, core-shell nanoparticle, dielectric breakdown, dielectric characteristics of nanoparticle, dielectric double layer, enhancing mechanism, epoxy nanocomposites.

The tracking and erosion performance of silicone rubber incorporated with novel TiO2@SiO2 core-shell nano fillers under the IEC 60587 standard

“…As reported by many researchers previously, this study also indicated that every NP has an optimum concentration threshold at which it gives maximum benefit. This percentage is usually below 1 percent by weight in the for many kinds of base material [20][21][22]26].…”

“…5 wt% of nano-ATH showed equivalent results to 20 wt% of micro SiO 2 . Chen and Wu [20] used TiO 2 @SiO 2 core-shell nanoparticles in epoxy and concluded an increase in resistivity and dielectric breakdown strength when the nano-fillers were less than 1% by weight. The reason to this enhancement is the barrier effect, which is basically the formation of electrical double layer between inorganic (TiO 2 @SiO 2 ) and organic (epoxy).…”

Effect of nano filler concentration on leakage current and partial discharge properties of zepoxy nano composites

“…Chen et al [17] investigated the dielectric properties of TiO 2 and TiO 2 @SiO 2 epoxy nano composites. It was observed that TiO 2 @SiO 2 nano composite gives higher breakdown strength and lower LC than TiO 2 nano composites.…”

Controllable synthesis of unique Ni/mesoporous carbon composites with lightweight and high EM wave absorption performance

“…As suggest by the BET specic area measuring results (Table 1), there is tremendous interface between the two discontinuous dielectrics where mobile charges accumulate according to the Maxwell-Wagner theory and polarize under the alternating external eld. 31 Consequently, the resulted interfacial polarization will contribute to the improvement of the EM wave dissipation efficiency as widely acknowledged. 32 Furthermore, regarding to the specially designed structure of Ni/DMC in present work, it is also anticipated to make a difference on the EM wave multi-reection.…”