; Jiang, Shichun
; Men, Yongfeng
; An, Lijia] Chinese Acad Sci, Changchun Inst Appl Chem, State Key Lab Polymer Phys & Chem, Changchun 130022, Peoples R China
; [Jiang, Shichun] Tianjin Univ, Sch Mat Sci & Engn, Tianjin 300072, Peoples R China
; [Wen, Huiying] NE Foresty Univ, Coll Engn & Technol, Harbin 150040, Peoples R China
; [Wu, Zhonghua] Chinese Acad Sci, Inst High Energy Phys, Beijing Synchrotron Radiat Lab, Beijing 100039, Peoples R China
; Kyoto Univ, Int Innovat Ctr, Sakyo Ku, Kyoto 6068501, Japan
The in situ crystallization kinetics of syndiotactic poly(propylene) (sPP) has been investigated by synchrotron small-angle X-ray scattering (SAXS). The structure evolutions during the isothermal crystallization of sPP with different shear rates have been observed. The results show that shear accelerates the process of crystallization kinetics. Even under low shear rate, the lamellae can be distinctly oriented. In contrast, the lamellar parameters such as the long period, lamellar thickness, and the scattering invariant 0 can change obviously only under high shear rate. A mesomorphic structure proposed by Strobl is adopted to elucidate the differences of shear effects with low and high shear rates. Based on all the analysis we are convinced that a relatively stable mesomorphic structure forms before shear is composed and the shear effects on the mesophase will be retained to a certain extent until crystallization is finished.