Dielectric properties and surface hydrophobicity of silicone rubber under the influence of the artificial tropical climate

This paper reports the experimental results concerning the influence of the artificial tropical climate on dielectric properties (relative permittivity /spl epsi//sub r/ and dissipation factor tan /spl delta/) and surface hydrophobicity (contact angle) of silicone rubber. The samples being used are six different contents of new materials of high temperature vulcanized (HTV) and room temperature vulcanized (RTV) silicone rubbers with different filler levels. The aging was carried out in the test chamber with a given ambient conditions (relative humidity from 70/spl plusmn/5 to 90/spl plusmn/5%, temperature from 50 to 70/spl deg/C, electric stress of 2.5 kV/cm and UV radiation) simultaneously during 96 hours. The experiment results showed that the absorption of moisture in the six different samples varied from 0.084% to 0.22%. Samples with higher filler content showed higher moisture absorption. The dielectric properties and surface hydrophobicity of silicone rubber are less affected by the short time artificial tropical climate stress. This conclusion was confirmed by Fourier Transform Infrared Spectroscopy (FTIR) of materials.