Laser Light and X-Ray Diffraction Studies of Oriented Isotactic Polypropylene (iPP) Prepared by Temperature Slope Crystallization |
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Authors: | Tsutomu Asano Takuro Furusho Mohammad Mahay Alam Yukihiro Tamba Chie Sawatari Md Forhad Mina |
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Institution: | 1. Center for Instrumental Analysis , Shizuoka University , Ohya 836, Suruga-ku, Shizuoka, 422–8529, Japan;2. Materials Science, Graduate School of Science and Engineering , Shizuoka University , Ohya 836, Suruga-ku, Shizuoka, 422–8529, Japan;3. Integrated Bioscience Section, Graduate School of Science and Technology , Shizuoka University , Ohya 836, Suruga-ku, Shizuoka, 422–8529, Japan;4. Faculty of Education , Shizuoka University , Ohya 836, Suruga-ku, Shizuoka, 422–8529, Japan;5. Department of Physics , Bangladesh University of Engineering and Technology , Dhaka, 1000, Bangladesh |
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Abstract: | Isotactic polypropylene (iPP) film was melt-crystallized in a temperature gradient. The iPP film showed well oriented α- and β-crystalline textures along the gradient. The crystalline structure, phase transition boundary and lamellar twisting were examined by X-ray diffraction and laser light diffraction (LLD). On the α-β boundary, LLD shows a sharp streak perpendicular to the boundary, where the a-axis of the β-crystal is oriented perpendicular to the temperature gradient. Apart from the boundary, the a-axis of the β-crystal becomes parallel to the gradient. The β-crystal shows lamellar twisting with a pitch of 200 μm at room temperature. When heated the β-crystal, the lamellar distance of 295Å at room temperature decreases to 285Å at 80–100°C and then increases to more than 300Å above 120°C. During the heating, the value of the twist period increases from 200 to 210 μm at 90–100°C, and then to above 224 μm at 140°C. The increase of the twist period is related to the increasing crystalline thickness of the β-lamellae. |
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Keywords: | α-β phase transition lamellar twisting polypropylene temperature slope crystallization X-ray and laser light diffraction |
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