Water absorption, hydrophobicity characteristics and surface change of polymer

This paper describes the weight change of alumina trihydrate filled silicone rubbers during a water absorption process and the surface changes involved. The weight changes for some samples were particularly examined after being dipped in warm water (20~80°C). Worthwhile results are obtained as follows. For the individual samples, it was found that the rates of weight change increased with increasing temperature. It is understood that silicone oil in the samples soaked in hot water of 80°C for 500 hours begins to be dissolved from basic silicone polymers. Thus the rate of the change in weight decreases in comparison with the virgin sample with time. Because the binding energy of Si-C (4.5 eV) is lower than that of Si-O (8.3 eV), Si-C is broken more easily due to heating, and a remarkable decrease of Si-CH₃ was observed after being dipped in warm water