A four-state scheme for treating polymer crystallization and melting suggested by calorimetric and small angle X-ray scattering experiments on syndiotactic polypropylele

摘要

As shown by time-and temperatur dependent SAXS experiments, crystals of s-PP do not change their thickness during isothermal crystallization and a subsequent heating up to melting. This allows an accurate determination of the relations between crystallizaton temperature, crystallite thickness, rate of crystallization and meting points. The main results obtained in a comprehensive SAXS-and DSC-investigation are: Crystals have greatly varying stabilities, in sp[ite of their uniform thickness; the first crystals melt close to the crystallization temperature.