Permittivity characteristics of epoxy/alumina nanocomposite with high particle dispersibility by combining ultrasonic wave and centrifugal force

Abstract

This paper proposes a novel technique to fabricate epoxy/alumina nanocomposites with nanoparticle composite process by combination of ultrasonic wave and centrifugal force. The particle dispersion effect of the nanoparticle composite process and its influence on dielectric permittivity were discussed quantitatively. Experimental results clarified that the combination of ultrasonic wave and centrifugal force was effective to increase dispersed nanoparticles and as well as to separate residual agglomerates. We verified that the improvement of particle dispersibility in the nanoparticle composite process by combination of ultrasonic wave and centrifugal force could bring about lower permittivity of the nanocomposites, especially than that of unfilled epoxy material.

Influence of filler/matrix interactions on resin/hardener stoichiometry, molecular dynamics, and particle dispersion of silicon nitride/epoxy nanocomposites

“…In [24], the reduction in 0 r was accompanied by a reduction in the b relaxation, which may imply a reduction in crosslinking density. In the other study [25], the 0 r reduction was more pronounced in the samples prepared following a specific route that included mixing the particles with the resin for 12 h. In this preparation route, any (a) (b) Figure 9 Imaginary relative permittivity of sample E/100H/5SiN at: a different temperatures, and b different water content.…”

“…Even in studies that have reported a nanofiller effect on the glass transition, the smaller scale b relaxation was not perturbed [37,43]. On the other hand, other studies [24,25], which investigated the effect of nanofiller on dielectric response of epoxy matrices, claimed that nanofiller inclusion can lead to 0 r values that are lower than the 0 r of both the filler and the host matrix. These studies justified this reduction by postulating a layer of restricted polymer chain mobility around the nanoparticles; however, no experimental exploration has been attempted to validate this proposition.…”

“…For the filled samples, the nanofiller was manually mixed with the resin, and then a probe sonicator was used for 45 min to disperse the particles further. This was followed by heating the particle/resin mixture for 4 h at 100°C so as to stimulate or accelerate any potential interactions between the particles and the resin [25]. After that, the hardener was added and the above epoxy processing procedure was followed.…”

“…Commonly, such models were proposed to interpret the unexpectedly significant impact of adding a small amount of nanofiller on one or more of the properties of the resulting composites, where two-component effective medium theories cannot explain such effect; some workers have termed this a nanoeffect [23]. For example, the dielectric permittivity of epoxy nanocomposites was found to be lower than that of both the filler and polymer materials in [24][25][26]. Therefore, the above proposal suggests the formation of an interphase layer and, consequently, defines nanocomposites as a tertiary system that consists of filler, matrix and interphase layer around the particles.…”

DC dielectric breakdown characteristics of mesoporous-alumina/epoxy composite

“…We measured the specific gravity of the composite specimens [9]. The specific gravity of the filler  f [g/ml] and particle porosity P [vol%] were obtained as following equations.…”