Unique orientation textures induced by confined crystal growth of poly(vinylidene fluoride) in oriented blends with polyamide 6

作者：Kaito Akira^*; Iwakura Yuko; Li Yongjin; Nakayama Kazuo; Shimizu Hiroshi

来源：Macromolecular Chemistry and Physics, 2007, 208(5): 504-513.

DOI：10.1002/macp.200600508

• confined crystal growth
• mechanical properties
• oriented crystallization
• phase morphology
• polymer blends

Unique orientation textures have been induced by the confined crystal growth of PVDF in drawn films PDVF/PA6 blends. Oriented films of PVDF/PA6 blends were prepared by uniaxially drawing melt-mixed blends. The drawn films with fixed lengths were heat-treated at 180 degrees C for 3 minutes to melt the PVDF component, followed by non-isothermal crystalization of PVDF at a cooling rate of 0.5 degrees C (.) min(-1). The crystal orientation was studied by WAXD. When PVDF was melted and recrystallized in the drawn films of the PVD/PA6 = 50/50 blend at a slow cooling rate, the crystal b-axis of the alpha-crystalline form of PVDF was oriented in the drawing direction, forming orthogonal orientation textures. SEM showed that stretched domains of PVDF with diameters of 0.2-0.5 mu m were dispersed in the PA6 phase in the drawn films of the PVDF/PA6 = 50/50 blend. Spatial confinement of the crystal growth resulted in the alignment of the crystal b-axis along the long axis of the domains, because PVDF is crystallized in thin cylindrical domains. The orientation behavior is different from the oriented crystallization of PVDF/PA11 (Y. Li, A. Kaito, Macromol. Rapid Commun. 2003, 24, 255), in which transcrystallization from the interface causes the a-axis orientation to be in the drawing direction. It is thought that the domain size influenced the mechanism of oriented crystallization and the resultant crystal orientation.

• 出版日期2007-3-5