Morphology and melting behavior of lamellar overgrowths after heat treatments of isotactic polystyrene

The morphology and melting behavior of overgrown lamellae (i.e. kebabs) in shish-kebab composite crystals for isothermally cold-crystallized isotactic polystyrene (iPS) have been studied using transmission electron microscopy (TEM). The bright- and dark-field morphological investigations indicate th at the entire shish-kebab entity consists of at least three components: the central backbone (i.e,. extended-chain type shish crystals), the (partiall y extended-chain type) micellar kebabs and the folded-chain type lamellar k ebabs. The morphological transformation between the micro- and macro-kebabs is reversible and can be realized via (partial) melting and recrystallizat ion processes, due to the differences in their thermal stability.