The effect of SiO2 microparticle concentration on the electrical and thermal properties of silicone rubber for electrical insulation applications

Introduction. Polymeric insulators, first developed in the 1950s, have since seen substantial advancements in both design and manufacturing, making them increasingly appealing to users and manufacturers in the electrical industry. Extensive testing in both laboratory and outdoor environments has consistently demonstrated that polymeric insulators outperform traditional porcelain and glass counterparts. Among the various polymeric materials, silicone rubber (SiR) has emerged as one of the most promising candidates for high-voltage insulators. Its superiority is attributed to a unique combination of properties, including a non-conductive chemical structure, high dielectric strength, and excellent resistance to scaling. To further enhance these properties, SiR is often combined with fillers to form composite materials. These SiR composites are at the forefront of advanced high-voltage insulation systems, offering improved mechanical, thermal, and electrical performance. As a result, they not only meet the rigorous demands of high-voltage applications but also provide a significantly extended service life. Goal. This study aims to enhance the dielectric and thermal properties of SiR by incorporating micron-sized silicon dioxide (SiO2) filler. Methodology. SiR-based composite samples were prepared by incorporating micron-sized SiO2 at weight fractions of 10 %, 20 %, 30 %, and 40 % of the total composition. Initially, the samples were heated to specific temperatures (25°C, 60°C, 80°C, and 100°C) before undergoing dielectric strength testing to evaluate their performance under varying thermal conditions. Additionally, the samples were subjected to thermal aging for durations of 10, 20, and 30 minutes at the same temperatures before dielectric strength assessment. The results indicated that increasing the filler concentration enhanced the dielectric strength of the SiR/SiO2 composites. The highest breakdown voltage was observed at a filler concentration of 30 %. Practical value. Incorporating micron-sized SiO2 filler into the SiR matrix enhanced the composite's resistance to thermal stress. Compared to SiR-based composites with varying SiO2 concentrations, pure SiR exhibited the lowest dielectric strength. References 48, tables 5, figures 8.