Morphology Development, Structure and Dielectric Properties of Biaxially Oriented Polypropylene

  • Ilkka Rytöluoto
  • Mikael Ritamäki
  • Antonis Gitsas
  • Satu Pasanen
  • Kari Lahti
Keywords: PP, Morphology,


This paper outlines our recent study on effects of cast film extrusion and biaxial orientation on the morphological development and dielectric performance of biaxially oriented polypropylene (PP) films based on two capacitor-grade isotactic PP (iPP) raw materials. Results on polymorphic composition, melting behavior, microstructure and dielectric properties are reported. Morphological development during film manufacturing is found to have a profound effect on film structure and dielectric characteristics. Formation of structural defects was traced back to beta --> alfa crystal transformation upon biaxial stretching.