Abstract

In recent years, silicone rubber (SiR) based composites have been widely investigated for outdoor applications due to its promising insulating properties. However, mechanical, thermal and tracking properties of pure silicone rubber are very low, which restrains its application for long-term performance. In this research work, the influence of micro-sized alumina-tri-hydrate (ATH) and micro/nano-sized silica (SiO₂) fillers on mechanical, thermal and electrical properties of room temperature vulcanized (RTV) SiR has been studied. SiR-blends with varying amounts of ATH and SiO₂ particles were prepared, by following blending in a two roll mixing mill, compression moulding and post curing processes sequentially. In order to evaluate relative tracking and erosion resistance of SiR-blends, inclined plane test (IPT) was conducted in accordance with ASTM-D-2303 standard procedure. Surface temperature distribution was recorded using Fluke-Ti25 infrared (IR) camera during IPT experiments. Thermogravimetric analysis (TGA) was carried out to analyze thermal stability of ATH/SiO₂ filled SiR Composites. Surface morphology, tensile strength, percent elongation at break (%EAB), hardness, erosion, tracking resistance and thermal properties were also investigated and discussed. Results showed that the mechanical, thermal and tracking/erosion performance of SiR-blends improves by the incorporation of ATH/silica particles, which is governed by filler type, size and wt% in polymer matrix.

Keywords: ATH; IPT; Characterization; SiR; SiO₂