On the reproducibility of Tg measurements on polystyrene using d.s.c.
1976; Elsevier BV; Volume: 17; Issue: 10 Linguagem: Inglês
10.1016/0032-3861(76)90253-6
ISSN1873-2291
AutoresMarion D. Griffiths, L. J. Maisey,
Tópico(s)Analytical chemistry methods development
ResumoIn determining the reproducibility of Tg data of a standard polystyrene measured by differential scanning calorimetry (d.s.c.), the effects of d.s.c. trace interpretation method, extrapolation to zero scan rate, polymer sample form, a thermal treatment and a thermal cycling procedure on the results were examined. The results showed that data from scanning at 8°C/min are preferred to those from extrapolation to zero scan rate while the overall reproducibility was unaffected by the d.s.c. trace interpretation method used. However, the onset of the transition step was selected to define Tg in this work. Similarly, no differences in the reproducibility of data were noted between the overall results for granular or sheet samples, although certain treatments of specific samples did produce changes in some instances. The mean value for Tg at 8°C/min was found to be 102.3°C. Imposing the thermal treatment on the samples did not significantly alter the reproducibility of the results whereas in contrast, cycling markedly improved the reproducibility of sheet sample data but left that of granules unaffected.
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