Determination of Non-Isothermal Crystallization Rate Constant for Pseudo-Experimental Calorimetric Data

processing. This proposition is still applied and accepted by publications of the highest level. The nonlinear regression method is being used as an alternative way of obtaining the parameters for kinetic crystallization models, such as Nakamura’s, Kamal and Chu’s, and Dietz and Malkin’s, directly from the non-isothermal crystallization data obtained by DSC. In most cases, the results obtained through this method are considered good. The literature contains reports of unsatisfactory results related to nonlinear regression; however, these unsatisfactory results are more likely to be justified by the limitations of the model of crystallization kinetics in describing the non-isothermal crystallization of the polymer than by the nonlinear regression method itself. One advantage of nonlinear regression is that it requires less work than the master curve approach. However, in order to perform nonlinear regression, which is usually based on the Leven-Marquardt method, sophisticated software is indispensable. The master curve approach has the advantage that it can be applied through any electronic spreadsheet. These two methods are usually employed after previous correction of the temperature lag between the DSC oven and the polymeric sample; in this aspect, they are both equally work-intensive. The master curve approach requires the kinetic crystallization model to be in the form of Equation 1. Other equations, such as Malkin’s, also fit this model; however, the method is applied