Silikon Elastomerlerin Ömür Süresine Etki Eden Parametrelerin Belirlenmesi

Abstract

Silicone rubbers are belongs to the synthetic rubber group. It has many advantages such as high weather resistance, good electrical properties, wide temperature range operation and easy workability [1]. Because of these properties, it is frequently used in outdoor insulation applications such as electrical transmission and distribution systems [1]. Despite their excellent properties and durability, silicone rubbers are subject to degradation over time when exposed to various environmental and chemical agents and high temperatures [2]. This deterioration is called ’aging. Aging occurs as a result of the degradation of the desired properties of a materials [2]. In order to understand the effects of aging on material properties, life expectancy is estimated. Life expectancy gains importance in terms of material improvement [2]. Silicone rubber insulators have been used in many countries for more than 30 years. Silicone insulators are constantly growing by replacing porcelain insulators due to good electrical insulation, hydrophobicity and non-flammability [2]. However, these characteristics of insulators tend to deteriorate due to environmental and electrical factors such as UV rays, corona discharges, temperature, humidity, salt and acid exposure (observed in coastal areas) [2]. In order to evaluate the product performance, it has become important to examine the changes in the materials over time [2]. In this study, thermal and UV aging studies have been carried out within the scope of laboratory scale simulation of environmental factors of commercial silicones used in industry as silicone insulators. The deterioration in material properties proportional to aging was confirmed by mechanical testing and examination of the change in cross-link density. Experimental studies were used to calculate the lifetime. Life time was calculated by two methods determined within the scope of the thesis study and the results were compared by comparing with each other. As a result of the studies and with the literature it has been observed that t life time of the vinyl methyl silicones (VMQ) used in the preparation of the silicone insulator varies depending on the source. In case of 25% loss of silicon insulator properties, the insulator will be used between 0.4 and 1.9 years, with a loss of 50 % between 5.3 and 30 years, and in case of 75% loss, it will be used between 11-2000 years. It has also been observed that these periods vary depending on the method used in determining the lifetime.