Thermal and Mechanical Properties of Epoxy/Micro- and Nano- Mixed Silica Composites for Insulation Materials of Heavy Electric Equipment

Abstract

A 10 nm nano-silica was introduced to a conventional 3 μm micro-silica composite to develop an eco-friendly new electric insulation material for heavy electric equipment. Thermal and mechanical properties, such as glass transition temperature (Tg), dynamic mechanical analysis, tensile and flexural strength, were studied. The mechanical results were estimated by comparing scale and shape parameters in Weibull statistical analysis. The thermal and mechanical properties of conventional epoxy/micro-silica composite were improved by the addition of nano-silica. This was due to the increment of the compaction via the even dispersion of the nano-silica among the micro-silica particles.

Effects of Nano-silica/Nano-alumina on Mechanical and Physical Properties of Polyurethane Composites and Coatings

“…Since the surface area of nano-particles is high, a high polymerfiller interaction would restrict polymer chain mobility, and hence increase the glass transition temperature. The entanglements between chains could increase the Tg of the polymer [12]. As observed in Fig.…”

“…However, PU has the drawbacks of low thermal stability and low mechanical strength. Efforts have been devoted to improving the properties of PU by chemical modification of the molecular structure, and by addition of organic or inorganic fillers [10][11][12]. PU coating is an attractive coating for the automotive industry, because of its excellent properties.…”

“…PU coating is an attractive coating for the automotive industry, because of its excellent properties. These properties, for example, include dimensional stability, adhesion to various substrates, resistance to chemicals, solvent, water, abrasion resistance, thermal stability, flexibility, and toughness [8][9][10][11][12].…”

Mechanical and Electrical Properties of Cycloaliphatic Epoxy/Silica Systems for Electrical Insulators for Outdoor Applications

“…Because the Tg of a polymer is closely related to the polymer chain structure such as backbone, branching, and degree of crosslinking, this should be considered in investigating the electrical and mechanical properties of the polymeric materials [8]. Figure 1 shows DSC curves for epoxy/silica microcomposites with various contents of epoxysilane-treated silica (55, 57, 60, and 63 wt%) at a heating rate of 10℃/min, where all samples were pre-cured at 100℃ for 2 h after curing at 140℃ for 16 h. No curve showed exothermic heat above Tg, indicating that these systems were completely cured without remaining unreacted functional groups that could generate heat under the cure conditions of this measurement.…”

Effect of Silicone-modified Microsilica Content on Electrical and Mechanical Properties of Cycloaliphatic Epoxy/Microsilica System

“…The effect of humidity and pollutants can be addressed by reducing the wettability of the surface or increasing the repellency to moisture and humidity by imparting hydrophobicity. In order to increase hydrophobicity, water repellents such as silicone oils are introduced to epoxy system [7,8].…”