Crystallization of s-polypropylene: a qualitative change in the kinetics induced by the Ttemperature of the melt

The crystallization of syndiotactic polypropylene (sPP) can be strongly affected by the temperature of the melt prior to cooling to the crystallization temperature. We observed, for a commercial sample, a variation in the form of the crystallization isotherm that cannot be explained simply on the basis of a changing number of growing hedrites