Crystalline memory effect in isothermal crystallization of syndiotactic polypropylenes: effect of fusion temperature on crystallization and melting behavior

In this manuscript, studies on the crystalline memory effect in syndiotactic polypropylene (s-PP) were focused on the effect of prior melt annealing on the subsequent isothermal crystallization kinetics, crystalline structure, lamellar morphology, and subsequent melting behavior using a combination of differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), and small-angle X-ray scattering (SAXS) techniques. On partial melting, choices of the fusion temperature used to melt the samples played an important role in determining the overall rate of isothermal crystallization, while they had no effect on the resulting values of the apparent crystallinity content, the long period, the lamellar thickness, and the low-melting peak temperature.