Solution and Diffusion in Silicone Rubber. II. Influence of Fillers

Abstract

Abstract An investigation has been made of the effect of a high area silica filler upon the solubility and diffusion of some C4 and C5 paraffins in silicone rubbers. The membranes studied contained by weight 0, 10, 20, 30 and 40 parts of filler per 100 parts of polymer. The solubilities have been discussed in terms of two reference models: the first in which silica and rubber phases act independently as sorbents; and the second in which the filler is regarded as completely wetted by polymer and is thus a non-sorbent. Diffusion and permeation have also been considered in terms of the models, assuming with the first model an immobile sorbed layer on the porous silica. It has been found that, although some aspects of the behavior can be explained, the results are not fully in agreement with either model, and that the behavior of the heterogenous membrane is complex.