of the isotherms. Samples were handled and packed to the analysistubes under dry nitrogen atmosphere.The morphology of the catalysts and resulting polymers wasexamined by scanning electron Microscopy (SEM) technique. AJEOL 6700F scanning electronmicroscope at the accelerating volt-age of 5 kV was used. Samples were Pt-coated before investigation.The melting temperature of polymers as well as enthalpy offusion was measured by differential scanning calorimeter (DSC)using a Perkin-Elmer DSC-7 instrument controller operating from50 to 180◦C with a heating rate of 10◦C min−1. The data werecollected on the second heating cycle. The molecular weight andmolecular weight distribution of PP polymers produce were deter-mined by gel permeation chromatography (GPC) using a WatersAlliance GPC 2000 instrument equipped with a refractive index(RI) detector and a set of u-Styragel HT columns of 106, 105, 104,and 103pore size in series. The measurement was performed at150◦C with 1,2,4-trichlorobenzene as the eluent with a flow rateof 1.0 ml min−1. Narrow-molecular-weight PS samples were usedas standards for calibration. Viscosity-average Molecular weightof PP polymers produced was determined according to a visco-metric method using a LaudaUbbelohde viscometer in decalin at135 ± 0.1◦C. The Mark–Houwink equation ([] = KM˛v) was appliedwith K = 1.58 × 10−4and ˛ = 0.77 [22].