Polymer crystallization kinetics, master quotients, master curves and Nakamura‐Ozawa‐equations of iPP and PTFE

Abstract

Evaluation concepts related to Avrami master curves are described for the analysis of isothermal and non-isothermal kinetic processes exhibiting topological nucleation and growth characteristics. These evaluation concepts are shown to be helpful for studies focusing on kinetic data of polymer crystallization experiments with iPP (isotactic polypropylene) and PTFE (polytetrafluoroethylene). An apparent m-order reaction model is discussed with respect to the isokinetic nucleation and growth model of Nakamura as well as to the non-isothermal crystallization kinetics theory of Ozawa. Thus, the cooling functions (T ) of iPP and PTFE, obtained by analyzing DSC (differential scanning calorimetry) experiments with constant cooling rates, are calculated in two alternative ways by using clearly different mathematical approaches. Finally, master quotients, theoretical crystallization limits, and further types of master curves are defined.

Cooling rate dependence of the crystallinity at nonisothermal crystallization of polymers: A phenomenological model

“…29 The kinetics of the growth process is usually described by the Kolmogorov-Johnson-Mehl-Avrami (KJMA) equation. [30][31][32][33][34] For the nonisothermal crystallization, different modifications of the KJMA equation, [35][36][37][38][39][40] or the Ozawa equation [40][41][42] are proposed.…”

Nonisothermal Crystallization of Polytetrafluoroethylene in a Wide Range of Cooling Rates

“…The former type of crystals is produced from thermal nucleation (i.e., homogeneous nucleation), while the latter is formed from athermal nucleation (i.e., heterogeneous nucleation). Lambrigger defined theoretical crystallization limits and Avrami master curves for the PTFE and for isotactic polypropylene (iPP) crystallization, respectively. The author concluded that PTFE crystallization is less symmetrically balanced compared to that of iPP.…”