A comparison of the lamellar morphology of melt-crystallized isotactic and syndiotactic polypropylene

The lamellar morphology of melt-crystallized thin film spherulites of isotactic and syndiotactic polypropylene (iPP and sPP) has been investigated by transmission electron microscopy (TEM) in phase contrast conditions. It is found that the arrangement and orientation of the lamellae depend on the crystallization temperature. The spherulitic crystallization of IPP has changed from dominant radial to cross-hatched lamellae growth with decreasing crystallization temperature. sPP has shown preferred branched growth at high crystallization temperatures, a radial lamellae growth at an intermediate temperature range and non-spherulitic disordered crystal growth at low temperatures. Copyright (C) 1996 Elsevier Science Ltd.