Carbon-ion-induced modifications of the diffusion kinetics in poly (ethylene terephthalate): a free volume study

摘要

The free volume modifications in carbon-ion irradiated poly (ethylene terephthalate) (PET) have been investigated using positron lifetime method and sorption kinetics by the gravimetric method. The positron results indicate the formation of linear tracks and free radicals. Iodine sorption suggests Longmuir type of filling of the free volume sites by iodine in the initial stages of sorption, and in the later stages, swelling and conformational changes dominate. Using dual sorption model, diffusion- and relaxation-controlled sorption have been separated. Further, it has been found that the diffusion process deviates from Fick's law and hence from Fujita's free volume theory for both virgin and C-ion irradiated PET. (C) 2003 Elsevier Ltd. All rights reserved. [References: 16]