Crystallization and phase behavior of crystalline syndiotactic 1,2-polybutadiene/isotactic polypropylene blends in solution-cast thin films

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• 作者：Yong Chen ; Ye Chen and Decai Yang
• 关键词：Syndiotactic 1 ; 2-polybutadiene ; Isotactic polypropylene ; Blends
• 刊名：Polymer
• 出版年：2006
• 出版时间：22 February 2006
• 年：2006
• 卷：47
• 期：5
• 页码：1667-1673
• 全文大小：784 K

文摘

Crystallization and phase behavior in solution-cast thin films of crystalline syndiotactic 1,2-polybutadiene (s-1,2-PB) and isotactic polypropylene (i-PP) blends have been investigated by transmission electron microscopy (TEM), atomic force microscopy (AFM) and field-emission scanning electron microscopy (FESEM) techniques. Thin films of pure s-1,2-PB consist of parallel lamellae with the c-axis perpendicular to the film plane and the lateral scale in micrometer size, while those of i-PP are composed of cross-hatched and single-crystal-like lamellae. For the blends, TEM and AFM observations show that with addition of i-PP, the s-1,2-PB long lamellae become bended and i-PP itself tends to form dispersed convex regions on a continuous s-1,2-PB phase even when i-PP is the predominant component, which indicates a strong phase separation between the two polymers during film formation. FESEM micrographs of both lower and upper surfaces of the films reveal that the s-1,2-PB lamellae pass through i-PP convex regions from the bottom, i.e. the dispersed i-PP regions lie on the continuous s-1,2-PB phase. The structural development is attributed to an interplay of crystallization and phase separation of the blends in the film forming process. With solvent evaporation, s-1,2-PB would crystallize first forming the continuous phase, while the segregated i-PP phase accumulated on s-1,2-PB and crystallized subsequently, forming dispersed i-PP regions.