| Abstract: | We obtain the exact solution of a fairly large class of somewhat simplified problems involving the simultaneous nonlinear Fickian diffusion of a poor solvent and a dilute organic penetrant, such as a plasticizer, in a semi-infinite polymer slab immersed in the solvent bath. Such problems can also provide useful estimates during certain time regimes of release of drugs from implants, and pesticides and pheromones from certain slow or controlled-release polymeric devices, insofar as these are affected by an environmental solvent bath. We assess the effect of various simplifications made (e.g., neglect of the penetrant concentration dependence in the diffusion coefficient, cross diffusion of solvent and penetrant, and a variety of boundary conditions) by solving exactly some additional specialized cases. |
