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Kanaya, Toshiji; Matsuba, Go*; Ogino, Yoshiko*; Takahashi, Nobuaki; Nishida, Koji*
Polymer Journal, 39(11), p.1085 - 1097, 2007/11
Times Cited Count：0 Percentile：0.01(Polymer Science)One of the longstanding issues in polymer science is crystallization of polymers under flow, especially formation of the so-called shish-kebab. Recent progress in quantum beam technology shed light on the substantial nature in the shish-kebab formation. In this paper we review our recent experiments on polymer crystallization under flow using time-resolved depolarized light scattering, small-angle and wide-angle X-ray scattering and small-angle neutron scattering in a wide spatial scale from 0.1 nm to several tens m. These studies revealed that the shish-kebab formation is governed by a competition between the crystallization rate and the chain relaxation rate.
Ogino, Yoshiko*; Fukushima, Hajime*; Takahashi, Nobuaki; Matsuba, Go*; Nishida, Koji*; Kanaya, Toshiji*
Macromolecules, 39(22), p.7617 - 7625, 2006/10
Times Cited Count：77 Percentile：88.82(Polymer Science)We studied crystallization process of isotactic polypropylene (iPP) under shear flow as a function of shear rate using time-resolved wide-angle X-ray scattering (WAXS), small-angle X-ray scattering (SAXS), depolarized light scattering (DPLS) and polarized optical microscope (POM) to elucidate the formation mechanism of the so-called shish-kebab structure in a wide spatial scale from 0.1 nm to several tens micro-m. In the time-resolved DPLS, SAXS and WAXS measurements we observed the formation processes of the shish-like structure, the kebab structure and the crystalline lattice (mostly in the kebab), respectively, and found that there were critical shear rates for the anisotropic structure formation in the DPLS, SAXS and WAXS measurements. The values are very close each other, suggesting the anisotropic structure formations in both of the shish and the kebab are dominated by a common origin. Furthermore, comparing the onset times of intensities in DPLS, SAXS and WAXS, we found that the onset of DPLS intensity is the most accelerated by the shear among the three. On the basis of the observations, we propose a possible mechanism for the shish-kebab structure.
