MORPHOLOGICAL-STUDIES ON SYNDIOTACTIC POLYPROPYLENE PREPARED BY ANSA-METALLOCENES

Propylene was homopolymerized with the ansa-metallocene luorenyl)(cycl opentadienyl)ZrCl2/methylaluminoxane catalyst to a highly syndiotactic polymer using a constant set of parameters. The properties of the pur e syndiotactic polypropylene (sPP) such as molecular weight, chain mic rostructure and melting point were investigated, and the morphologies of uniaxially oriented films were studied by transmission electron mic roscopy. The oriented sPP films have a lamellar structure and a single -crystal-like texture from typical preparation conditions. In comparis on with the X-ray diffraction pattern reported by De Rosa and Corradin i, the electron diffraction pattern shows more detail but leads to the same structure (cell III structure).