Doubly oriented β-form films of poly(vinylidene fluoride) |
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Authors: | Toshiya Mizuno Kenichi Nakamura Naohiro Murayama Kensuke Okuda |
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Affiliation: | Kureha Chemical Industries Co. Ltd., Nishiki Research Laboratories, 16, Ochiai, Nishikimachi, Iwaki-city, Fukushima, 974Japan |
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Abstract: | PVDF sheets, rapidly quenched, were (1) two-step transversely stretched at various temperatures and (2) stretched at various temperatures, rolled at room temperature and then annealed. The orientation patterns of the β-form crystal (which contains the polar b-axis) in these films were analysed on the basis of X-ray diffraction photographs taken with flat and cylindrical cameras. In the case of (1), when both of the two-step transversely stretching temperatures were below 100°C, a doubly oriented film with the plar b-axis oriented parallel to the film surface was obtained. In the case of (2), when the stretching temperature was below 100°C, the sheets then rolled without annealing, another doubly oriented film with the polar b-axis preferentially oriented at 30° to the film surface was obtained. On the other hand, when these films were annealed above 100°C, or the stretching temperatures were above 100°C, orientation patterns in which the polar b-axis was partially rotated through 60° were obtained. The orientation mechanisms of these films are discussed using the measurements of the lattice spacings of the β-form crystal. |
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Keywords: | poly(vinylidene fluoride) double orientation X-ray cylindrical camera pseudo-hexagonal crystal structure stretching rolling annealing) |
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