Study of the thermooxidative degradation kinetics of poly(tetrafluoroethene) using iso-conversional calculation procedure
Study of the thermooxidative degradation kinetics of poly(tetrafluoroethene) using iso-conversional calculation procedure
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DOI：
10.1007/s10973-009-0191-4
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发表时间：
2010-02-01
影响因子：
4.4
通讯作者：
Atanassov, A. N.
中科院分区：
文献类型：
--
作者：
Genieva, S. D.;Vlaev, L. T.;Atanassov, A. N.
采用非等温差热分析（DTA）研究了不同升温速率（6、10、12和15 K min(-1)）下聚四氟乙烯（PTFE）在空气中的热氧化降解动力学。采用了基于单条热重曲线和等转换法的6种计算程序和27种机构函数。与这些计算方法所得结果的比较表明，它们在很大程度上取决于选择合适的过程机构函数。因此，确定最可能的机理函数是非常重要的。在这方面，等转换计算程序被证明是更合适的。本文计算了试剂生成活化配合物的表观活化能E、指数前因子A、熵δ s不等于、焓δ h不等于和自由吉布斯能δ G（不等于）的变化。所有的计算都是用自己编写的程序完成的。
The thermooxidative degradation kinetics of poly(tetrafluoroethene) (PTFE) in air flow has been studied at different heating rates (6, 10, 12 and 15 K min(-1)) by non-isothermal differential thermal analysis (DTA). Six calculation procedures based on single TG curves and iso-conversional method, as well as 27 mechanism functions were used. The comparison of the results obtained with these calculation procedures showed that they strongly depend on the selection of proper mechanism function for the process. Therefore, it is very important to determine the most probable mechanism function. In this respect the iso-conversional calculation procedure turned out to be more appropriate. In the present work, the values of apparent activation energy E, pre-exponential factor A in Arrhenius equation, as well as the changes of entropy Delta S-not equal, enthalpy Delta H-not equal and free Gibbs energy Delta G(not equal) for the formation of the activated complex from the reagent are calculated. All calculations were performed using programs compiled by ourselves.