Structural relaxation in poly(ethylene terephthalate) studied by positron annihilation lifetime spectroscopy

Sathyanarayana, P. M. and Shariff, Gani and Thimmegowda, M. C. and Ashalatha, M. B. and Ramani, R. and Ranganathaiah, C. (2002) Structural relaxation in poly(ethylene terephthalate) studied by positron annihilation lifetime spectroscopy. Polymer International, 51 (9). pp. 765-771. ISSN 1097-0126

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Official URL: https://doi.org/10.1002/pi.924

Abstract

Abstract Positron lifetime technique was used to study the physical ageing process in poly(ethylene terephthalate) (PET). Positron lifetime results show that the structural relaxation processes in PET encompass two different time regimes, one short and the other long. The relaxation function constructed from the measured o-Ps intensity I3 exhibits non-exponential character, which can be best fitted with two additive exponentials. The Narayanaswamy model (Kohlraush-William Watt (KWW) function) is invoked to extract the stretching parameter β indicating the extent of deviation from exponential relaxation. Based on the relaxation times, the activation energies calculated seem to label the different kinetic units of PET structure participating in the relaxation process. © 2002 Society of Chemical Industry

Item Type: Article
Uncontrolled Keywords: poly(ethylene terephthalate), physical ageing, annealing, relaxation time, activation energy
Subjects: D Physical Science > Physics
Divisions: Department of > Physics
Depositing User: manjula User
Date Deposited: 23 Sep 2019 06:02
Last Modified: 23 Sep 2019 06:02
URI: http://eprints.uni-mysore.ac.in/id/eprint/8349

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