Crystalline phase orientation in biaxially stretched isotactic polypropylene films

摘要

The different kinds of crystalline orientations which can occur in industrially relevant isotactic polypropylene (i-PP) films are compared with those generally observed for other semicrystalline polymers. The peculiar bimodality typical of the uniplanar-axial orientation which is present in two-step biaxially stretched i-PP films is rationalized in terms of the two alternative stackings on the (OkO) face of bilayers of macromolecules of the monoclinic unit cell. [References: 21]