46th IUPAC POLYMER CONGRESS , 2016-07-17

Title : ( Ethylene polymerization using a binary catalytic system; activity and microstructure study )

Authors: mostafa khosh sefat , Saeid Ahmadjo , Mohammad Mehdi Mortazavi , Gholamhossein Zohuri , meisam haghpanah ,

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Abstract: There are three main methods which can be used for combination of different types of catalysts including catalyst alloys, hybrid catalysts and multi-catalyst systems. Through these systems, each catalyst can produce polymer with a different microstructure and properties in absence of cooperation. As a result, the obtained polymer is a blend of two or more kind of polymers [Mortazavi et al., 2015]. In this study, a binary catalytic system was used in polymerization of ethylene. A mixture of Ziegler-Natta (ZN) and a binuclear late transition metal (BLTM) catalyst was employed in presence of methylaluminoxane (MAO) and triethylaluminium (TEA) as cocatalyst and impurity scavenger, respectively. To study on binary catalytic system and polyethylene (PE) properties, the experiments were performed under similar polymerization condition for each single catalyst and mixture of them. Initial experiments showed ZN/BLTM with a moderate catalytic performance between activities of each catalysts (Figure A). Chains vinylend and branching, caused by β-hydrogen elimination transfer reactions to the metal center or to the monomer followed by a ubsequent olefin reinsertion which called chain-walking mechanism allowing the growing center to migrate along the polymer chain, is more pronounced in polymers produced by LTM catalysts [Chen et al., 2015]. Based on forementioned reasons, branching degree and vinyl content for ZN/BLTM catalytic system was higher than pure ZN. In comparison to pure BLTM, vinyl content increased and branching degree decreased which can be attribute to presence of the counterpart catalyst (ZN) which leads to weaker M—C bond and dissociation of the chain along with vinyl-end.


, Keywords: ethylene polymerization, binary catalytic system, microstructure, Ziegler-Natta, binuclear late transition
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author = {Khosh Sefat, Mostafa and Saeid Ahmadjo and Mohammad Mehdi Mortazavi and Zohuri, Gholamhossein and Haghpanah, Meisam},
title = {Ethylene polymerization using a binary catalytic system; activity and microstructure study},
booktitle = {46th IUPAC POLYMER CONGRESS},
year = {2016},
location = {Istanbul},
keywords = {Keywords: ethylene polymerization; binary catalytic system; microstructure; Ziegler-Natta; binuclear late transition metal},


%0 Conference Proceedings
%T Ethylene polymerization using a binary catalytic system; activity and microstructure study
%A Khosh Sefat, Mostafa
%A Saeid Ahmadjo
%A Mohammad Mehdi Mortazavi
%A Zohuri, Gholamhossein
%A Haghpanah, Meisam
%D 2016