Applied Catalysis A: General, Vol.327, No.2, 270-277, 2007
Characteristics and catalytic properties of [t-BuNSiMe(2)Flu]TiMe2/dMMAO catalyst dispersed on various supports towards ethylene/1-octene copolymerization
In the present study, the characteristics and catalytic properties of [t-BuNSiMe(2)Flu]TiMe2/dMMAO catalyst dispersed on various supports towards ethylene/1-octene copolymerization were investigated. First, the dMMAO was impregnated onto various supports, such as SiO2, SiO2-TiO2, and TiO2. Then, copolymerization of ethylene/1-octene was conducted with and without the presence of supports in different solvent mediums. The SiO2-TiO2 support exhibited the highest activity among all the supports. The high activity observed for the SiO2-TiO2 support can be attributed to fewer interactions between the support and dMMAO, as confirmed by XPS and TGA results. The different solvents can alter the nature of the catalyst in two ways: (i) changing the interactions between the support and cocatalyst and/or (ii) changing the form of active species i.e., active ion-pair and solvent-separated ion)-pair, as seen in the homogeneous system. However, there was no effect with regards to activity of the solvent mediums employed for the homogeneous system. It is worth noting that the Ti-complex made possible high incorporation of I-octene having the triblock (OOO) and diblock (EOO) copolymers. The properties of copolymers by means of GPC, DSC, and C-13 NMR were further discussed in more detail. C) 2007 Elsevier B.V. All rights reserved.