ORIGINAL PAPER FI Zr-type catalysts for ethylene polymerization Saman Damavandi & Griselda Barrera Galland & Gholam Hossein Zohuri & Reza Sandaroos Received: 22 December 2009 / Accepted: 29 August 2010 / Published online: 1 October 2010 # Springer Science+Business Media B.V. 2010 Abstract Two FI-type catalysts of Bis[N-(3,5-dicumylsali- cylidene)-naphthylaminato]zirconium(IV) dichloride (catalyst (a)) and Bis[N-(3,5-dicumylsalicylidene)-anthracylaminato] zirconium(IV) dichloride (catalyst (b)) were prepared and used for ethylene polymerization comparatively. Methylalu- minoxane (MAO) was used as cocatalyst. Polymerization reactions of ethylene using the prepared catalysts at the different conditions of polymerization were carried out. Plurality of the fused aromatic rings on the N atom of the imine in the catalyst structure affected the polymerization activity and molecular weight of the resulting polymer as well. Productivity of the prepared catalysts increased with the addition of [Al]/[Zr] molar ratio. The highest activity was observed at about 35–40 °C for the catalysts. The catalyst (b) produced higher viscosity average molecular weight (M v ) of the obtained polyethylene, while generally the activity of the catalyst (a) was higher than the catalyst (b). Similar behavior was observed for the polymerization carried out at the monomer pressure of 2 to 6 bars using the catalysts. The higher the pressure the more activity of the catalysts obtained, in the range studied. Crystallinity and melting point of the obtained polymer were between 55–65% and 120–135 °C respectively. Higher pressure increased both the crystallinity and the M v values of the resulting polymer. The polymerization was carried out using different amounts of hydrogen. Higher amount of hydrogen could increase the activity of the catalysts. A linear dependence between the polymerization time and the molar weight was observed, however the polydispersity was broadened with the time. Keywords Catalytic polymerization . FI catalyst . Zr-based catalyst . Olefin polymerization . Polyethylene Introduction Ziegler-Natta catalysts have been developed to achieve higher productivities and better stereoselectivity. The current state-of- the-art Ziegler-Natta catalyst comprises of MgCl 2 support, TiCl 4 , aluminium alkyl(s) and internal- and/or external-donor (s) [1–3]. Even though the performance of Ziegler-Natta catalysts have been greatly improved, they have an inherent characteristic of being “multisite” catalysts, i.e. the environ- ment around the active sites varies resulting in broad molecular weight distributions as well as variations in stereoselectivity. Well-defined, homogeneous, “single- site” catalysts provide a solution for this drawback of heterogeneous Ziegler-Natta catalysts. Following the great success of the metallocene catalysts, significant efforts have been directed towards the discovery and application of new, highly active, single-site catalysts (post-metallocene catalysts) [4, 5]. These research efforts have led to the introduction of quite a few high-activity, single-site catalysts based on both early and late transition metal complexes with various ligand environments [6– 14]. A new series of non metallocene FI catalysts have been reported by researchers from Mitsui Chemicals which polymerize ethylene and propylene in conjunction with methylaluminoxane (MAO) as an activator at ambient temperature [15]. FI catalysts are very versatile. They are S. Damavandi (*) : G. H. Zohuri : R. Sandaroos Department of Chemistry, Ferdowsi University of Mashhad, Mashhad, Iran e-mail: Saman_Damavandi@yahoo.com G. B. Galland Instituto de Química, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil J Polym Res (2011) 18:1059–1065 DOI 10.1007/s10965-010-9507-0