Kinetics of isothermal and non-isothermal crystallization of poly(vinylidene fluoride) by fast scanning calorimetry
Crystallization from melt of poly(vinylidene fluoride) was studied by thin film chip calorimetry at cooling rates from 500 to 100,000 Ks−1 and isothermally down to 76 °C. At ca. 70 °C, for cooling rates higher than 2000 Ks−1, there appears a change in crystallization from high temperature α phase to...
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Veröffentlicht in: | Polymer (Guilford) 2016-01, Vol.82, p.40-48 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Crystallization from melt of poly(vinylidene fluoride) was studied by thin film chip calorimetry at cooling rates from 500 to 100,000 Ks−1 and isothermally down to 76 °C. At ca. 70 °C, for cooling rates higher than 2000 Ks−1, there appears a change in crystallization from high temperature α phase to low temperature β phase. The amorphous state is preserved at cooling rate 100,000 Ks−1. Analysis of the crystallization kinetics with Ziabicki model reveals maximum of the steady-state crystallization rate of β phase as 2200 s−1 at 22 °C, and the highest crystallization rate of α phase as 200 s−1 at 70 °C. Approximation of the temperature dependent steady-state crystallization rate with the Turnbull and Fisher nucleation model results in the equilibrium melting temperatures 227 and 173 °C for the α and β phase, respectively, and in the energy barrier for short-distance transport, ED, as 70–80 kJ mol−1 at high supercooling.
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•Melt crystallization at ultra-high cooling rates using thin-film chip calorimetry.•Steady-state crystallization rate of the α and β phase obtained with Ziabicki model.•Approximation of the rate with the Turnbull and Fisher nucleation theory.•Equilibrium melting temperatures and the energy barrier for short-distance transport. |
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ISSN: | 0032-3861 1873-2291 |
DOI: | 10.1016/j.polymer.2015.11.020 |