Study on the crystallization behavior of especially nucleated Polypropylene

Polypropylene can be crystallized in three forms: α-monoclinic, β-hexagonal and γ-form; the main type of industrial PP is the α-form. The major problem in processing of PP is its narrow processing window and poor melt strength. With broadening the melting region, β-crystal form has a significant effect on this problem. In this study, a β-nucleator agent was used to investigate the relation between crystalline structure and melting behavior of PP. Both structures of α and β crystals were seen in samples including β-nucleator. The percent of β-form area in X-ray patterns increased after nucleation. At the presence of β-nucleator, two melting points were observed, and the crystallization temperature was shifted to the higher temperatures. The rate and degree of crystallinity increased with β-nucleator content.