Gradient Degradation Behaviors of Silicone Rubber Under UV-B Radiation

Silicone rubber insulators always work at high altitude regions with strong UV -B radiation, which degrades the silicone rubber materials and threatens the safe operation of insulators. Therefore, this study conducted a 5OOh UV-B accelerated aging test to investigate the impact of UV - B irradiation on the silicone rubber materials. The results indicate that with the prolongation of aging time, on the surface of silicone rubber material, the C-H bond content decreases first and then increases due to competitive relationship between C-H breakage reactions and hydrogen abstraction reactions, while the Si-O-Si bond content increases due to silanol dehydration condensation reaction. The surface becomes rough and the particles are more obvious. On the other hand, as the irradiation depth increased, the C-H bond content of the silicone rubber material decreased owing to hydrogen abstraction reactions. The closer it was to the irradiation surface, the rougher the cross-section is. These results demonstrate that degradation behaviors of silicone rubber under UV-B radiation is gradient, which is important for operation state detection and assessment for outdoor insulators.