Inverse Proportionality of Thermal Conductivity and Complex Permittivity to Filler-Diameter in Epoxy Resin Composites with Silica

Abstract

We prepared six kinds of epoxy resin nanocomposites with silica and an epoxy resin with no silica. The nanocomposites contain silica with different diameters (10, 50, and 100 nm) while their silica contents are 1, 5, 10, and 20 vol%. At 25 and 100 °C, the thermal conductivity has a nearly proportional dependence on the silica content and exhibits an almost reciprocal proportionality to the diameter of the silica. The latter result indicates that the interaction at filler-resin interfaces plays a significant role in heat transfer. However, this view contradicts an easy-to-understand thought that the filler-resin interfaces should work as a barrier for heat transfer. This in turn indicates that the interaction at filler-resin interfaces controls the bulk properties of the resin when the filler is in a nm size. Although the dielectric constant increases with the addition of the silica filler, its increment from the resin with no silica is the smallest in the resin with the 10-nm silica. Therefore, the addition of the 10-nm silica is adequate for electrical insulation purposes.

Thermal ageing of soft and hard epoxy resins

“…First, ε r ′ is 10.0 and ε r ″ is 1.9 in SE at its pristine non‐treated state. These values of ε r ′ and ε r ″ are much higher than the corresponding values of ordinary epoxy resins reported in the literature [21–24]. The reason for the high values seems to be due to various additives, especially rubbery ones included in SE [14, 15].…”

High Quasi-Isotropic Thermal Conductivity of Polydimethylsiloxane Nanocomposites with Hexagonal-Boron Nitride Microspheres and Flakes

“…Additionally, the thickness of 30micro-BN particles is much larger (2.12 μm) than the lateral size of nano-BN, as shown in Table S1. 55,56 The sph-nano-BN/PDMS composite in Figure 7d illustrates the formation of an isotropic thermal pathway by the nature of the spherical-shaped particles of sph-nano-BN, 57 which exerts the highest thermal conductivity among the single-modal filler-utilized composites. Figure 7e,f shows the PDMS composites with a hybrid filler combination.…”

A Reactive Molecular Dynamics Study on Crosslinked Epoxy Resin Decomposition under High Electric Field and Thermal Aging Conditions

“…Accordingly, the casting epoxy polymers are generally utilized for power electronic devices and insulators to withstand insulation failure under high electric and thermal stresses [ 7 ]. On the other hand, epoxy resin nanocomposites, in which inorganic or metallic nanofillers are dispersed uniformly into epoxy resin matrix, have recently attracted great attention due to their prospective potentials in dielectrics and electrical insulation [ 8 , 9 , 10 ].…”