Rheo‐Raman Study of Isotactic Polypropylene Under Tensile Deformation
Rheo‐Raman Study of Isotactic Polypropylene Under Tensile Deformation
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DOI：
10.1002/masy.201700019
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发表时间：
2018-02
影响因子：
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通讯作者：
Takumitsu Kida;Yusuke Hiejima;K. Nitta
中科院分区：
文献类型：
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作者：
Takumitsu Kida;Yusuke Hiejima;K. Nitta
利用流变拉曼光谱研究了等规聚丙烯在拉伸条件下的微观变形行为，如载荷分配和结晶链的分子取向。归属于骨架C → C伸缩模式的拉曼谱带在屈服后出现蓝移，表明伸缩应力施加到主链上。CH 3的摇摆带在屈服区出现红移，表明压缩应力是沿晶链的链间方向施加的。虽然结晶链的分子取向在第一屈服点之后开始，但由于刚性和庞大的层状团簇单元的存在，结晶取向受到阻碍。在屈服区之外，朝向拉伸方向的取向迅速进行，并且在高应变区中，晶体链简单地在拉伸方向上取向。
The microscopic deformation behaviors such as the load sharing and the molecular orientation of the crystalline chains of isotactic polypropylene under tensile stretching are examined by using rheo‐Raman spectroscopy. The Raman bands assigned to the skeletal CC stretching modes show blue shifts after the yielding, indicating that the stretching stress is applied to the main chain. The CH3rocking band shows red shift in the yielding region, suggesting that the compression stress is applied in the interchain direction of the crystalline chains. While the molecular orientation of the crystalline chains begins after the first yield point, the crystalline orientation is hindered due to the existence of the rigid and bulky lamellar cluster units. Beyond the yielding region, the orientation toward the stretching direction proceeds rapidly, and the crystalline chains simply orient in the stretching direction in the highly strained region.