Characteristic properties of High Consistency Rubber and Liquid Silicone Rubber

High temperature vulcanized silicone rubber (HTV) insulators are widely used in power transmission systems due to their excellent mechanical, electrical, and hydrophobic properties. The characteristic properties of materials are of great importance to the safety of power systems. In general, HTV materials are divided into two groups, high consistency rubber (HCR) and liquid silicone rubber (LSR). Mechanical properties (hardness, tensile strength, elongation at break, and tear strength), electrical properties (volume resistivity, relative dielectric constant, dielectric loss tangent, and breakdown strength), hydrophobicity, and low molecular weight silicones (LMWs) of HCR and LSR were measured. Thermo gravimetric analysis (TGA) and dynamic thermal mechanical analysis (DMTA) were also performed to analyze the thermal stability and cold resistance of these two materials. In addition, the groups of HCR and LSR were compared by Fourier Transform Infrared Spectrum (FTIR) to explain the differences between the two materials. It was found that LSR was softer and with better tensile properties, electrical properties, temperature resistance, and more LMWs than HCR. However, due to large amount of accumulated charges on the surface, the hydrophobicity of new vulcanized LSR was poor, which could however be improved by grounding and immersing in water. Besides, LSR is more suitable for cold and hot regions.