Recrystallization of shish-kebab structures induced by self-seeding nucleation

This article reports melting and recrystallization of shish-kebab (cylindrite) structures in isotactic polypropylene containing high-content (15%wt) of ultra-high molecular weight polyethylene (UHMWPE). UHMWPE molecules can decrease the free volume of iPP molecules, which result in a great improvement of thermodynamic stability of shish. Therefore, some oriented structures can reappear due to inducement of two different kinds of shish (self-seeding nucleation of iPP), which are found with different morphology: One is threadlike, the other is nuclei-row. The way they absorb epitaxial growth of kebab is also different. It can be concluded that two different mechanisms of shish-kebab recrystallization exist. This work provides a new understanding of the formation of shish-kebab structure. (c) 2012 Elsevier B.V. All rights reserved.