Quantitative evaluation of early-stage growth kinetics of heterogeneously nucleated spherulites: Has the nucleation induction time a nonzero value?

Abstract

Early stages of polymer crystallization are pronouncedly influenced by the presence of a foreign phase, the surface of which may increase the formation of crystal nuclei. However, measurement of the initial stages of the crystallization with the aid of conventional methods is extremely difficult. The possibility of using the Avrami equation in its classic form for that purpose is discussed and found inappropriate. Characterization of the initial crystallization stages is corroborated using the crystallization induction time, which represents the most probable value of the nucleation times of individual spherulites. The induction time of polypropylene without a nucleation agent was found to be positive.