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International Journal of Polymer Science
Volume 2016, Article ID 6289326, 9 pages
http://dx.doi.org/10.1155/2016/6289326
Research Article

A Comparative Study of AlCl3 and FeCl2-Modified TiCl4/MgCl2/THF Catalytic System in the Presence of Hydrogen for Ethylene Polymerization

Center of Excellence on Catalysis and Catalytic Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand

Received 28 April 2016; Revised 6 July 2016; Accepted 14 July 2016

Academic Editor: Atsushi Sudo

Copyright © 2016 Thanyathorn Niyomthai et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Ethylene homopolymerization over TiCl4/MgCl2/THF catalysts modified with different metal halide additives (AlCl3 and FeCl2) with and without hydrogen was investigated based on catalytic activity and polymer properties. Lewis acid modification can improve activity because it can remove the remaining THF in the final catalyst, which can poison the catalyst active sites via the ring-opening of THF that was confirmed by XRD measurements. Moreover, the activity enhancement was due to the formation of acidic sites by modifying the catalysts with Lewis acids. Thus, FeCl2 doped catalyst (Fe-THF) exhibited the highest activity followed by AlCl3 doped catalyst (Al-THF) and undoped catalyst (None-THF). In H2/C2H4 molar ratio of 0.08, Fe-THF showed a better hydrogen response than Al-THF due to more titanium cluster distribution. Fe-THF is considered to have more clustered Ti species than Al-THF. As a consequence, it led us to obtain more possible chances to precede chain transfer reaction by hydrogen. The molecular weight, melting temperature, and crystallinity of obtained polymers were investigated by GPC and DSC measurement, respectively.