Polymer Bulletin, Volume 68, Number 3 (2012), 755-773
Mohammad Taghi Goldani (1)
Reza Sandaroos (2)
Ali Mohmmadi(1)
Maryam Goharjoo(1)
1. Islamic Azad University, Birjand Branch, Birjand, Iran
2. Department of Chemistry, Faculty of Science, Birjand University, P.O.Box 414, Birjand, Iran
Abstract
They conducted ethylene polymerization reactions under various conditions using the prepared catalysts. The activities for ethylene polymerization were significantly dependent on the catalyst structure. The polymerization activity increased with increasing of the both monomer pressure and [MAO]:[Ti] ratio. Unlike the high performance Ti–FI catalysts, bis(aminotropone) Ti catalysts do not require the presence of steric bulk in close proximity to the oxygen moiety. Introduction of the bulky alkyl substitution next to the oxygen moiety decreased the activity of the catalysts. Density Functional Theory (DFT) studies reveal that the active species derived from these catalysts normally possess higher electrophilicity nature compared with those produced using bis(phenoxy-imine) Ti catalysts (Ti–FI catalysts).
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