Morphological studies on syndiotactic polypropylene prepared by ansa-metallocenes

Propylene was homopolymerized with the ansa-metallocene Ph(2)C(fluorenyl)(cyclopentadienyl)ZrCl2/methylaluminoxane catalyst to a highly syndiotactic polymer using a constant set of parameters. The properties of the pure syndiotactic polypropylene (sPP) such as molecular weight, chain microstructure and melting point were investigated, and the morphologies of uniaxially oriented films were studied by transmission electron microscopy. The oriented sPP films have a lamellar structure and a single-crystal-like texture from typical preparation conditions. In comparison with the X-ray diffraction pattern reported by De Rosa and Corradini, the electron diffraction pattern shows more detail but leads to the same structure (cell III structure).