RHEOLOGICAL MECHANISM AND OVERVIEW OF NUCLEATED CRYSTALLIZATION KINETICS

Although the function of a nucleating agent in shortening the initiation time and thus enhancing the crystallization rate is well understood, an increased rate at higher melt --> crystalline conversions (e.g., greater-than-or-equal-to 10%), where the active nuclei are in abundance, is less straightforward to explain. Such a behavior is typical of nucleated crystallization of polymer melts. However, its existence and, especially, the underlying mechanism have not been discussed in the literature. In this paper, we have presented (1) a rheological technique for studying the crystallization kinetics and shown it to be more sensitive than conventional techniques like differential scanning calorimetry (DSC) and (2) two possible mechanisms to account for enhanced rate at higher conversions for nucleated crystallization of polymer melts.