Influence of regioirregular structural units on the crystallization of isotactic polypropylene

Seven samples of isotactic polypropylene were examined to study the influence on the formation of the γ crystalline phase of possible regiodefects along the chain. Wide-angle X-ray diffraction allowed the determination of the percentage of the γ phase in the samples and 13C-NMR spectroscopy was used to correlate the development of the γ phase with the existence of regioirregular structural units along the chain. Furthermore, it was possible to appraise the contributions given by the different families of lamellae to the small-angle X-ray diffraction patterns.