Synchrotron small-angle X-ray scattering studies of the nature of shear-induced shish-kebab structure in polymer melt (Hsiao):

Synchrotron small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) have been utilized to elucidate the nature of shear-induced shish-kebab structures at the early stages of crystallization in polymer melt. The corresponding SAXS patterns showed a meridional streak, which can be modeled by a shish-kebab structure containing cylindrical symmetry along the shish axis and polydispersities in diameter, thickness and long period of kebabs. The shish-kebab model was formulated in a closed analytical form under the assumption of independent statistics. The fitted mean diameter of kebabs using our shish-kebab model was found to be consistent with the value obtained by using the Ruland’s streak method. The radial growth rate, G, calculated from the kebab evolution followed the relationship G  t^-1/2, which confirmed the diffusion-controlled growth with spontaneous nucleation in polymer blend.