Microbeam Wide-Angle X-ray Scattering Study on Precursor of Shish Kebab. Effects of Shear Rate and Annealing on Inner Structure

We have investigated the inner structure of shear-induced precursor of shish kebab of isotactic polystyrene (iPS) above the nominal melting temperature T-m using microbeam wide-angle X-ray scattering. We first studied the effects of the shear rate on the inner structure and found that the crystallinity in the precursor increased with the shear rate while the crystallite size was independent of that. This was explained in terms of effects of chain entanglements on shear-induced crystallization. We also studied effects of annealing below the nominal melting temperature Tm and found no changes in the crystallites size before and after the annealing, suggesting that the crystallites did not grow into shishs during the annealing below Tm although the kebabs grew.