Water absorption and water vapor permeation characteristics of HTV silicone rubber material

The water absorption characteristics of a HTV silicone rubber material were investigated at different relative air humidity (RH). The two-sided water absorption process into disc-like HTV samples at different RH can be described by a Langmuir type diffusion model. The permeation process of water vapor through HTV discs was quantified by adjusting different constant RH at both sides of the discs. The permeation coefficient of the HTV discs amounts to an almost constant value of 10^-7g cm^-1s^-1cmHg^-1 at RH higher than 60%. Finally, a simplified model is introduced by what the water vapor permeation process into an air filled interface defect inside a composite insulator can be simulated.