Abstract
AbstractThe stereochemistry of polypropenes obtained in the presence of several MgCl2‐supported Ziegler‐Natta catalyst systems comprising different Lewis bases has been investigated by 13C NMR spectroscopy, with special attention paid to the “less tactic” (heptane‐soluble) fractions. These have been found to consist of “tendentially isotactic” and “tendentially syndiotactic” stereosequences, in largely variable amounts (depending on the catalyst system). The microstructure of the former is in accordance with the enantiomorphic site model, whereas that of the latter suggests a stereocontrol arising from the asymmetry of the growing chain end. In both cases, propene insertion is primary (1–2). Polymerization conditions leading to the formation of “syndiotacticrich” polymers showing syndiotactic crystallinity have been identified.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
