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

Sathyanarayana, P. M. and Shariff, G. 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.

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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 I-3 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 beta 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. (C) 2002 Society of Chemical Industry.

Item Type:	Article
Uncontrolled Keywords:	poly(ethylene terephthalate); physical ageing; annealing; relaxation time; activation energy
Subjects:	Physical Sciences > Physics
Divisions:	PG Campuses > Manasagangotri, Mysore > Physics
Depositing User:	Users 11 not found.
Date Deposited:	15 Apr 2013 07:03
Last Modified:	14 May 2013 12:34
URI:	http://eprints.uni-mysore.ac.in/id/eprint/4288

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