Melting and crystallization behavior of binary blends of syndiotactic polypropylenes of different stereoregularity. (November 2016)

• Record Type: Journal Article
• Authors: Ruiz de Ballesteros, Odda; De Rosa, Claudio; Auriemma, Finizia; Di Girolamo, Rocco; Scoti, Miriam
• Is Part Of: European polymer journal. Volume 84(2016:Nov.)
• Page Start: 589
• Page End: 601
• Publication Date: 2016-11
• Subjects: Syndiotactic polypropylene -- Polymer blends -- Crystallization -- Thermal behavior; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; Polymerization; Polymers; Periodicals; Electronic journals; 547.705
• DOI: 10.1016/j.eurpolymj.2016.09.034
• Languages: English
• ISSNs: 0014-3057

Abstract

Graphical abstract: Highlights: The melting and crystallization behavior of blends of sPPs of different stereoregularity is studied. Blends show separate melting of the components. Good miscibility of the components in the melt and amorphous state. Abstract: Binary blends of samples of syndiotactic polypropylene of different stereoregularity have been prepared by mixing a more stereoregular and crystalline sample sPP1 having [ rrrr ] = 78%, with low stereoregular and poorly crystalline samples sam PP1 and sam PP2 having [ rrrr ] = 54.6 and 45.8%, respectively, and a nearly atactic fully amorphous sample am PP1 with [ rrrr ] = 26.5%. The blends show separate melting of the two components with the more stereoregular component sPP1 melting at high temperature and the poorly syndiotactic component melting at lower temperature. Crystals of sPP1 are formed by cooling from the melt whereas more defective crystals of sam PP1 and sam PP2 are formed by cold crystallization during aging at room temperature. The presence of the strereoirregular component disturbs the melt crystallization of the stereoregular component sPP1 and depression of the crystallization and melting temperatures of sPP1 in the blends is observed. On the other hand, the cold crystallization at room temperature of the irregular component is accelerated and favored by the presence of the more stereoregular component sPP1, whose crystals act as crystallization nuclei. All data indicate interactions between the components in the melt and amorphous state, compatible with a good degree of mixing.