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首页> 外文期刊>Journal of Physics, D. Applied Physics: A Europhysics Journal >TSDC study of the glass transition: correlation with calorimetric data
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TSDC study of the glass transition: correlation with calorimetric data

机译：TSDC研究玻璃化转变：与量热数据的相关性

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摘要

The glass transition in amorphous poly( ethylene terephthalate) is studied by thermally stimulated depolarization currents ( TSDC) and differential scanning calorimetry ( DSC). The ability of TSDC to decompose a distributed relaxation, as the glass transition, into its elementary components is demonstrated. Two fractional polarization techniques, windows polarization ( WP) and non-isothermal windows polarization ( NIW) are employed to assess the influence of thermal history in the results. The Tool-Narayanaswami-Moynihan model has been used to fit the TSDC spectra. The most important contributions to the relaxation comes from modes with a value of the non-linearity parameter ( x) around 0.7. Activation energies yield by this model are located around 1 eV ( 96 kJ mol(-1)) for polarization temperature ( T-p) below 50 degrees C and they rise up to values higher than 8 eV ( 771 kJ mol(-1)) as Tp increases ( up to 80 degrees C). There are few differences between results obtained with WP and NIW but, nonetheless, these are discussed. The obtained kinetic parameters are tested against DSC results in several conditions. Calculated DSC curves at several cooling and heating rates can reproduce qualitatively experimental DSC results. These results also demonstrate that modelling of the non-equilibrium kinetics involved in TSDC spectroscopy is a useful experimental tool for glass transition studies in polar polymers.
机译：通过热激发去极化电流（TSDC）和差示扫描量热法（DSC）研究了非晶态聚对苯二甲酸乙二酯中的玻璃化转变。证明了TSDC能够将玻璃化转变时的分布弛豫分解为基本成分。两种分数极化技术，窗极化（WP）和非等温窗极化（NIW）被用来评估热历史对结果的影响。 Tool-Narayanaswami-Moynihan模型已用于拟合TSDC光谱。对松弛最重要的贡献来自非线性参数（x）约为0.7的模式。对于低于50摄氏度的极化温度（Tp），此模型产生的活化能位于1 eV（96 kJ mol（-1））左右，并且随着上升到8 eV（771 kJ mol（-1））更高。 Tp升高（最高80摄氏度）。用WP和NIW获得的结果之间几乎没有差异，但是，仍在讨论中。在几种条件下针对DSC结果测试了获得的动力学参数。在几个冷却和加热速率下计算得出的DSC曲线可以定性地再现实验DSC结果。这些结果还表明，对TSDC光谱中涉及的非平衡动力学建模是用于极性聚合物中玻璃化转变研究的有用实验工具。

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