Absorption and permeation of water and aqueous solutions of high-temperature vulcanized silicone rubber

This study focuses on absorption and permeation of deionized water and typical aqueous solutions of high-temperature vulcanized (HTV) silicone rubber (SR). The influences of some parameters, such as, filler (fumed silica and aluminum hydroxide) characteristics, solution concentration, temperature, and tensile stress on absorption of water/solution were investigated. Results indicate that tensile stress accelerates water and solution uptake of HTV SR. The dependence of water and solution permeation coefficients of HTV SR on two important parameters, i.e., filler characteristics and the HTV SR sample thickness, were investigated. Permeation coefficient was found to be inversely proportional to SR thickness. The possible influencing mechanism of tensile stress on water and solution absorption and that of filler characteristics on water absorption and permeation were discussed. Moreover, the free volume, which is filled by the absorbed water, plays an important role in water absorption and permeation.