A note on the kinetics of non-isothermal crystallization of polymers

Abstract

On the kinetics of non-isothermal crystallization of polymers, the reinterpreted Ozawa method proposed in a previous report is studied further to generate valuable information. The Ozawa method is used to investigate the crystallization kinetics with constant temperature scanning rates β and is concerned with the basic formula for apparent crystallinity, from which the true crystallinity is derived using the concept of an extended volume of the Kolmogorov–Johnson–Mehl–Avrami model. The formula is expressed by the temperature scanning rate β and a function of temperature T, βOz(T). This study investigates the temperature derivative of βOz(T), which represents the crystal growth rate in the presence of athermal nucleation from foreign heterogeneities including nucleating agents; this case is applicable to most polymer crystallization processes. The validity of this relationship was verified by comparing it directly to the crystal growth rate in numerical simulations and by comparing it to the crystallization peak and half times of isothermal crystallization for experimental results of poly(butylene terephthalate). This evaluation provides basic information on the crystal growth rate, which is necessary for understanding polymer crystallization. As is well known, the temperature derivative of βOz(T) also corresponds to the function required to derive Nakamura et al. model's suggested equation for polymer processing.