Nonisothermal melt-crystallization kinetics for three linear aromatic polyesters

Abstract

The kinetics of nonisothermal crystallization of three different types of linear aromatic polyester, namely poly(ethylene terephthalate) (PET), poly(trimethylene terephthalate) (PTT), and poly(butylene terephthalate) (PBT), which are different in their number of methylene groups (i.e. 2, 3, and 4 for PET, PTT, and PBT, respectively), was investigated using differential scanning calorimetry (DSC). Analysis of the data was carried out based on the Avrami, Tobin, Ozawa, and Ziabicki models. It was found that the Avrami model provided a more satisfactorily good fit to the experimental data for these polyesters than did the Tobin model. The Ozawa model was found to describe the experimental data fairly well. The Ziabicki's kinetic crystallizability parameter G for these polyesters was found to be of the following order: PBT > PTT > PET. The effective energy barrier for nonisothermal crystallization process of these polyesters, determined by the Friedman method, was found to be an increase function with the relative degree of crystallinity.

(nBuCp)2ZrCl2‐catalyzed ethylene‐4M1P copolymerization: Copolymer backbone structure, melt behavior, and crystallization

“…Our model, as stated above, duly considers isokinetic concept, crystal growth as well as primary and secondary crystallizations; and mathematically shows that the activation energy does not depend on cooling rate. Based on the overall findings of Figures 9 and 10, this study ratifies the invariance of activation energy articulated by Galwey and cothinkers, 100,101 and does not support the concept of variable/instantaneous activation energy 94,98,99,[102][103][104] which is practiced in analyzing nonisothermal crystallization kinetic data. This conclusion originates from the appropriate application of isokinetic concept and the current nonisothermal Avrami-Erofeev crystallization model, and the calculation algorithm that we developed.…”

“…This ratifies the invariance of activation energy articulated by Galwey and cothinkers, 100,101 and does not support the concept of variable/instantaneous activation energy 94,98,99,[102][103][104] which is practiced in analyzing nonisothermal kinetic data. The nucleation process, intermediate between instantaneous and sporadic, generated crystal dimensions that varied between cylindrical and spherical.…”

“…Depending on the polymer type, it either monotonically increases, or it first increases and then it decreases as the relative crystallinity increases. 98 This functional behavior was attributed to the dependence of nucleation energy barrier on temperature. Such a justification ignores isokinetic concept, crystal growth as well as primary and secondary crystallizations.…”

Isothermal melt-crystallization and melting behavior for three linear aromatic polyesters

“…Based on previous non-isothermal melt-crystallization kinetic analyses for these three polyesters [20], comparison of the values of the Ziabicki's kinetic crystallizability parameter (which describes the ability for a semicrystalline polymer to crystallize when it is cooled from the melt to the glassy state at a Table 1 Overall crystallization kinetic data for PET, PTT, and PBT based on the Avrami model …”

Non-isothermal Crystallization of Poly(ethylene-co-glycidyl methacrylate)/Silica Nanocomposites

“…Avrami equation [24][25][26][27][28][29][30][31][32][33][34] can be used to describe the primary stage of nonisothermal crystallization. The Avrami equation is expressed as:…”