Mass transport and mechanical properties of solid polymers

A general mathematical formulation is proposed for the description of the diffusion of low molecular weight species into a polymer matrix, in the presence of significant stress and deformation fields. The model is based on the usual momentum and mass balance equations; a crucial point is that it makes use of constitutive equations for the stress and for the diffusive mass flux which are not chosen independently of each other since they must obey precise thermodynamic restrictions; the latter are found in rather general terms.