Nonisothermal Crystallization Kinetics: Studying the Validity of Different Johnson-Mehl-Avrami-Erofeev-Kolmogorov (JMAEK) Based Equations

The Johnson-Mehl-Avrami-Erofeev-Kolmogorov (JMAEK) equation modifications proposed by Jeziorny, by Atiqullah and by Ruitenberg and Woldt were applied on the nonisothermal crystallization data of Poly(ethylene 2,5-furandicarboxylate)/2.5 wt. % Carbon Nanotubes (PEF/2.5 CNTs) nanocomposite. The classic JMAEK equation and the JMAEK model using the multivariate nonlinear regression method were also used to evaluate the cold crystallization's kinetic parameters of PEF/2.5 CNTs. Differential Scanning Calorimetry (DSC) measurements were carried out at heating rates of 1, 2.5, 5, 10 and 15 K/min. The effective activation energy (E-alpha) of the process was calculated using the isoconversional method of Vyazovkin. The E-alpha values indicate a nonlinear Arrhenian behavior and a complex process. The multivariate nonlinear regression method suggested a consecutive two-mechanism reaction model described by the JMAEK equation for both mechanisms. This method provided better fitting results of the experimental data for all the heating rates simultaneously and kinetic parameters' values within the limits of physical meaning. In any case, Jeziorny's modification of the JMAEK model was the most inadequate since the extracted Avrami exponents exceed in value those with a physical meaning.

Automated summary

The study applied various modifications of the JMAEK equation to analyze the nonisothermal crystallization data of PEF/2.5 CNTs nanocomposite, showing that the multivariate nonlinear regression method can better explain the kinetic parameters of cold crystallization.