Determination of lamellar twisting manner in a banded spherulite with scanning microbeam X-ray scattering

We investigated lamellar twisting manner in a banded spherulite, the blend of poly-(ɛ-caprolactone) and poly-(vinyl butyral), with scanning microbeam X-ray diffraction. We obtained the diffraction contour intensity map with a scanning pitch of 1 μm by employing a rotation of a spherulite around its radial direction along which the microbeam scans. The results confirm that the twisting manner depends on the crystallization temperature and that it changes from continuous twisting to step-wise twisting with the increase of crystallization temperature. Moreover, we observed that the phase of long-period lamellar twisting advanced by about 15° compared to that of short-period lamella. In addition, it was confirmed that c-axis of packing structure was normal to lamella, which was represented by dominant short-period lamella.