Effect of ATH content on electrical and aging properties of EVA and silicone rubber blends for high voltage insulator compound

Abstract

The effect of trihydrated alumina (Al 2 O 3 , 3H 2 O) (ATH) filler in ethylene-vinyl acetate copolymer (EVA) and silicone rubber blends was investigated by performing a series of laboratory experiments to simulate different natural aging conditions. Samples with varying ATH content in a 50-50 blend of EVA and polydimethylsiloxane (PDMS) (silicone rubber, MQ) were tested to investigate the tracking resistance, resistance to UV radiation, corona, heat, and water immersion. Changes in surface resistivity, volume resistivity, and hydrophobic characteristics were evaluated for different compounds having ATH content. These exercises were mainly carried out to optimize the filler level. In immersed condition the water absorption increases with ATH content. The recovery of hydrophobicity, after aging by heat, is appreciable at higher ATH levels, than at lower ATH levels. The tracking and erosion resistance decrease as ATH content increases. When compounds containing different ATH content were subjected to corona treatment, the samples with higher ATH levels exhibited better results. All samples changed their color to a darker shade and there was an increase in the hydrophobicity, when subjected to UV radiation.

Effects of electric partial discharges on the rheological and chemical properties of polymers used in HV composite insulators after railway service

“…In other words, the ATH concentration was the most reduced for aged HTV elastomer. This ATH defect could be interpreted as being at the origin of the low value of the corona inception voltage as already proposed by Pradeep [33]. But, at the same time, one of the liners taken from new production presented an ATH concentration higher than that of the used liner whereas the respective insulator inception corona voltage was slightly lower (10 kV against 12 kV).…”

EVA reactive blending with Si–H terminated polysiloxane by carbonyl hydrosilylation reaction: From compatibilised blends to crosslinking networks

“…Polydimethylsiloxanes (PDMS) are widely used for polymer blends because of their gas barrier and electrical properties, their low glass-transition temperature, their low surface energy and high thermal, UV and oxidative stabilities [1]. However, due to their low surface energy and relatively low viscosity compared to most thermoplastics, the dispersion of PDMS is generally difficult and results in phase segregation of PDMS in most polymer blend systems.…”

Effects of Magnesium Hydroxide on the Flame Retardancy of Ethylene-Vinyl Acetate Copolymers/Nitrile Rubber Blends

“…[6,7] However, their low effectiveness makes it necessary to incorporate them at a very high content to gain a satisfying flame retardancy, which leads to a poor dispersion and damage of the material's mechanical properties. [8] What's more, the particle size and types of flame retardants are also of great importance in flame-retarding behavior. For instance, Li et al [9] has reported that the flame-retardant effect of ATH was better than that of MDH for similar shapes and particle sizes in ethylene-vinyl acetate.…”