Phase transition II → I in isotactic poly-1-butene: wide- and small-angle X-ray scattering measurements

Phase transition II → I in isotactic poly-1-butene was studied by wide- and small-angle X-ray scattering in order to follow the change of crystallinity and of the characteristic parameters of the lamellar stacks over time. Small-angle X-ray scattering experimental patterns were analyzed by a fitting method with the profiles calculated from some theoretical distribution models of the lamellar thickness. The mathematical evaluation of small-angle X-ray scattering patterns provided crystallinity values which were compared with those obtained by wide-angle X-ray scattering, in order to obtain information on the lamellar stacks organization. The transition nucleation seems to be localized on lamellar distortion points and the transition itself involves the rearrangement of lamellae and of lamellar stacks.