Solvent transport in spherical polymer-penetrant systems

This paper studies the transport phenomenon of solvent-penetrant systems in spherical glassy polymers. This problem involves a moving interface betwee n a glassy region and rubbery region, the solution of which has traditional ly proven very difficult. In this paper, the perturbation method is used fo r the complete time history of the penetrant front for a small range of per turbation control parameter a. Then, a local similarity numerical simulatio n is used to expand the results for a large range of epsilon. Results revea l that interface velocity near time = 0 is constant regardless of sphere di mensions, and that the interface velocity decreases after its initial const ant phase, accelerating again as the interface position approaches the cent er of the sphere. With the proposed technique, the penetration times for di fferent radii can be predicted. (C) 2001 Elsevier Science Ltd. All rights r eserved.