Delbreilh, Laurent and Dargent, Eric and Grenet, Jean and Saiter, Jean-marc and Bernès, Alain and Lacabanne, Colette Study of poly(bisphenol A carbonate) relaxation kinetics at the glass transition temperature. (2007) European Polymer Journal, vol. 43 (n° 1). pp. 249-254. ISSN 0014-3057
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Official URL: http://dx.doi.org/10.1016/j.eurpolymj.2006.09.019
In this work, the variations of the relaxation times are investigated above and below the glass transition temperature of a model amorphous polymer, the polycarbonate. Three different techniques (calorimetric, dielectric and thermostimulated currents) are used to achieve this goal. The relaxation time at the glass transition temperature was determined at the temperature dependence convergence of the relaxation times calculated with dynamic dielectric spectroscopy (DDS) for the liquid state and thermostimulated depolarisation currents (TSDC) for the vitreous state. We find a value of s(Tg) = 110 s for PC samples. The knowledge of the temperature dependence, s(T), and the value s(Tg) enables to determine the glass-forming liquid fragility index, m. We find m = 178 ± 5.
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