Nanostructure and thermal behaviour of isotactic polypropylene

The nonisothermal melting and crystallisation process of isotactic polypropylene was investigated by time-resolved simultaneous small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction methods with synchrotron radiation. It was found that the nanostructure of the iPP investigated depends on thermal conditions. The nanostructure can be described based on parameters determined from one-dimensional correlation function analysis. It was shown that real-time synchrotron investigation is an appropriate method for describing changes of supermolecular structure parameters during crystallisation and melting process. Changes of long period values, degree of crystallinity, invariant, thickness of crystalline lamellae and thickness of amorphous layers during heating and cooling on wide range of temperature were discussed.