Based on irreversible thermodynamics, a new approach to study sorption in polymer has been proposed [1]. This treatment gives a standpoint different from the existing sorption models [2 - 9] not only in interpretation and nature, but also in analytical expression. Moreover, the model also accounts for diffusion and the other internal processes stimulated by sorption such as swelling, plasticization, crystallization etc. Some experimental results of fluid sorption in polymer have been interpreted by this model.
