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Synthesis and microstructural study of stereoblock elastomeric polypropylenes from metallocene catalyst (2-PhInd)2ZrCl2 activated with cocatalyst mixtures

Authors

  • Gholam-Reza Nejabat,

    1. Iran Polymer and Petrochemical Institute (IPPI), Polymerization Engineering Department, P.O. Box 14965/115, Tehran, Iran
    2. The George and Josephine Butler Polymer Research Laboratory, Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200
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  • Mehdi Nekoomanesh,

    Corresponding author
    1. Iran Polymer and Petrochemical Institute (IPPI), Polymerization Engineering Department, P.O. Box 14965/115, Tehran, Iran
    • Iran Polymer and Petrochemical Institute (IPPI), Polymerization Engineering Department, P.O. Box 14965/115, Tehran, Iran
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  • Hassan Arabi,

    1. Iran Polymer and Petrochemical Institute (IPPI), Polymerization Engineering Department, P.O. Box 14965/115, Tehran, Iran
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  • Hamid Salehi-Mobarakeh,

    1. Iran Polymer and Petrochemical Institute (IPPI), Polymerization Engineering Department, P.O. Box 14965/115, Tehran, Iran
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  • Gholam-Hossein Zohuri,

    1. Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, P.O. Box 1436, Mashhad, Iran
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  • Mojtaba Omidvar,

    1. Iran Polymer and Petrochemical Institute (IPPI), Polymerization Engineering Department, P.O. Box 14965/115, Tehran, Iran
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  • Stephen A. Miller

    Corresponding author
    1. The George and Josephine Butler Polymer Research Laboratory, Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200
    • The George and Josephine Butler Polymer Research Laboratory, Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200
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Abstract

Various elastomeric polypropylenes (PPs) are synthesized through homogeneous propylene polymerization with metallocene catalyst (2-PhInd)2ZrCl2 in the presence of different cocatalyst mixtures: triethylaluminum (TEA)/methylaluminoxane (MAO) or triisobutylaluminum (TIBA)/MAO in the range of AlAlR3/AlMAO = 0.0–0.9. The cocatalyst formulation impacts the resultant polymer microstructure and the thermal and dynamic mechanical properties of the produced PPs. 13C NMR analysis of the polymers reveals essentially atactic PP, with mmmm = 7.9%, when AlAlR3/AlMAO = 0.0. The mmmm pentad content is maximized when AlAlR3/AlMAO = 0.8; for TIBA, mmmm = 23.5%; and for TEA, mmmm = 17.6%. Differential scanning calorimetry analysis and dynamic mechanical thermal analysis corroborate these findings. Specifically, Tm, ΔHm, and Tg are essentially maximized under these conditions, and the minimum damping is observed for AlAlR3/AlMAO = 0.6–0.8. 1H NMR analysis of the mixtures of catalyst and cocatalysts (without monomer) shows very minor differences for [Zr]:AlAlR3 in the range of 1:1–1:5. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013

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