Dubaj Tibor, Cibulková Zuzana, Šimon Peter
Department of Physical Chemistry, Institute of Physical Chemistry and Chemical Physics, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, 812 37, Bratislava, Slovakia.
J Comput Chem. 2015 Mar 5;36(6):392-8. doi: 10.1002/jcc.23813. Epub 2014 Dec 18.
The parameters obtained from a kinetic analysis of thermoanalytical data often exhibit a conversion-dependent behavior. A novel incremental isoconversional method able to deal with this phenomenon is proposed. The kinetic model is directly fitted to the experimental data using nonlinear orthogonal least squares procedure. The data are processed without transformations, so their error distribution is preserved. As the objective function is based on a maximum likelihood approach, reliable uncertainties of the parameters can be estimated. In contrast to other methods, the activation energy and the pre-exponential factor are treated as equally important kinetic parameters and are estimated simultaneously. Validity of the method is verified on simulated data, including a dataset with local nonlinearity in the temperature variation. A practical application on the nonisothermal cold crystallization of polyethylene terephthalate is presented.
从热分析数据的动力学分析中获得的参数通常表现出与转化率相关的行为。本文提出了一种能够处理这种现象的新型增量等转化率方法。使用非线性正交最小二乘法将动力学模型直接拟合到实验数据。数据在不进行变换的情况下进行处理，因此保留了其误差分布。由于目标函数基于最大似然法，因此可以估计参数的可靠不确定度。与其他方法不同，活化能和指前因子被视为同等重要的动力学参数并同时进行估计。该方法的有效性在模拟数据上得到验证，包括一个温度变化具有局部非线性的数据集。本文还给出了该方法在聚对苯二甲酸乙二酯非等温冷结晶中的实际应用。
