Structure Model of a Poly(vinyl alcohol) Film Uniaxially Stretched in Water and the Role of Crystallites on the Stress-Strain Relationship

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• 作者：Tsukasa Miyazaki ; Akie Hoshiko ; Midori Akasaka ; Miki Sakai ; Yuuki Takeda ; Shinichi Sakurai
• 刊名：Macromolecules
• 出版年：2007
• 出版时间：November 13, 2007
• 年：2007
• 卷：40
• 期：23
• 页码：8277 - 8284
• 全文大小：645K
• 年卷期：v.40,no.23(November 13, 2007)
• ISSN：1520-5835

文摘

We propose a structure model of a poly(vinyl alcohol) (PVA) film during uniaxial stretching inwater. In addition to the relaxation of microfibrils and the extension of interfibrillar amorphous regions shown inour previous paper, it was described that the strain-induced crystallization takes place in the interfibrillar extendedamorphous regions, which bear the increasing stress with strain, by conducting simultaneously the tensile stress-strain measurement with the wide-angle X-ray diffraction (WAXD) measurements for the film stretched in water.Furthermore, we examined the dissolution behavior of the PVA film in water by using in-situ WAXD and small-angle X-ray scattering. It was concluded that the dissolution of crystallites in the lamellar stacks, which areconsidered to be precursors of the microfibrils formed with film stretching, softens the system, as shown with thestress-strain measurement in water above 333 K, leading to the ineffective amorphous chain extension of PVAmolecules.