Permeability, diffusion and sorption of SO2 in polyvinyltrimethyl silane membranes☆

The authors have studied the permeability of SO2 through continuous and asymmetrical polyvinyltrimethyl silane membranes at 10–50°C and pressures 0–250 kPa. The special aspects of the transfer of SO2 in polyvinyltrimethyl silane are the high values of the permeability coefficients P and the dependence of the permeability through the asymmetrical membranes on pressure (above 100 kPa), which is due to the concentration dependence of the diffusion coefficients of SO2, the plasticizing effects of SO2 and the non-linear character of its sorption isotherms. The form of the sorption isotherm agrees with the double sorption model. The parameters of this model are determined and for a number of polymers a correlation established between the adsorption capacity and glass transition point. The high P values for SO2 in polyvinyltrimethyl silane are determined by the large diffusion coefficients.