Theoretical interpretation of the swelling of elastomers

The swelling dilation moduli reported in the preceding paper are here analyzed with use of a recently proposed theory of rubber elasticity. The theory predicts that the elastic equation of state is dependent on solution thermodynamic parameters, in agreement with the observations. It is successful in accounting for the solvent effects, which is a step forward; it also succeeds in predicting that the Mooney-Rivlin C sub(2) term decreases with increasing extent of swelling. Unfortunately, agreement with experiment cannot be achieved with a single consistent set of parameters. Further progress on the theory of rubber elasticity is needed to understand the swelling process completely, and a suggestion is made as to where this advance might be found.