INFLUENCE OF ADDITIVES ON THE WATER-UPTAKE OF HYDROSILANIZED SILICONERUBBERS

Water uptake characteristics of a silicone polymer containing additive s of varying solubility have been investigated. A hydrophobic silica, a hydrophilic silica, a sparingly soluble agent and a soluble catalyst were added to a stoichiometrically balanced hydrosilanized silicone p olymer (the inherent absorption of which was 0.09 wt%). The diffusion coefficients for desorption of all materials were of the order 10(-6) cm(2) s(-1), whereas the diffusion coefficients for absorption showed a decrease with increasing hydrophilicity and solubility of the additi ve. The greater the solubility of the additive, the more prolonged the uptake and the greater the deviation from classic diffusion theory. ( C) 1997 Elsevier Science Limited.