Deformation Behavior of Isotactic Polypropylene Spherulite during Hot Drawing Investigated by Simultaneous Microbeam SAXS-WAXS and POM Measurement

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• 作者：Yoshinobu Nozue ; Yuya Shinohara ; Yasuo Ogawa ; Takashi Sakurai ; Hideaki Hori ; Tatsuya Kasahara ; Noboru Yamaguchi ; Naoto Yagi ; Yoshiyuki Amemiya
• 刊名：Macromolecules
• 出版年：2007
• 出版时间：March 20, 2007
• 年：2007
• 卷：40
• 期：6
• 页码：2036 - 2045
• 全文大小：1082K
• 年卷期：v.40,no.6(March 20, 2007)
• ISSN：1520-5835

文摘

The process of rearranging lamella crystal structures in isotactic polypropylene (iPP) and butenerandomly copolymerized iPP (bPP) spherulites during hot drawing was investigated by in-situ microbeam small-angle X-ray scattering (SAXS)-wide-angle X-ray scattering (WAXS)-polarized optical microscopy (POM)simultaneous measurements. We subjected a fixed position in an upper quadrant of a spherulite, which is stretchedin the horizontal direction, to microbeam X-ray irradiation, and observed local structural changes, such as thosein ordered crystal size and orientation, and a lamella stacking structure. We successfully obtained the structuralinformation on parent and daughter lamellae in various orientations. In iPP, the long period of perpendicularparent lamellae increased, and then the disordering of crystal packing structures along the a-axis started. Whennecking started, the long periods of parent and daughter lamellae drastically started to decrease with the alignmentof the c-axis in the stretching direction. The ease of crystal fragmentation and c-axis alignment strongly dependedon the type of lamella, indicating the order of stress concentration during drawing. In bPP, it was found that thealignments of all the lamellae occur almost simultaneously and that parent and daughter lamellae independentlyrotate until necking.