Spherical MgCl 2 ⅐nEtOH was prepared by adducting ethanol to MgCl 2 using melt quenching method. Effect of molar ratio of [EtOH]/[MgCl 2 ] ϭ 2.8 -3.05 on the morphology and particle size of the MgCl 2 ⅐nEtOH were studied. The best adduct of spherical morphology was obtained when 2.9 mol ethanol to 1 mol MgCl 2 was used. An emulsion of dissolved MgCl 2 in ethanol was prepared in a reactor containing silicon oil. Stirrer speed of the emulsion and its transfer rate to quenching section that work at Ϫ10 to Ϫ40°C are affected by the particle size of the adduct particle. The adducted ethanol was partially removed with controlled heat primary to catalyst preparation (support). Treatment of the support with excess TiCl 4 increased its surface area from 13.1 to 184.4 m 2 /g. Heterogeneous Ziegler-Natta catalyst system of MgCl 2 (spherical)/TiCl 4 was prepared using the spherical support. Scanning electron microscopy studies of adduct, support, and catalyst obtained shown spherical particles, however, the polyethylene particles obtained have no regular morphology. The behavior indicates harsh conditions used for catalyst preparation, prepolymerization, and polymerization method used.

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A novel binary homogeneous catalyst system based on (I): rac-Me 2 Si(2-Me-4-PhIn) 2 ZrCl 2 and (II): (2-PhIn) 2 ZrCl 2 catalysts at various molar ratios was utilized for the synthesis of polypropylene (PP) reactor blends with bimodal molecular weight distribution (MWD). The results of gel permeation chromatography analyses revealed that the catalyst (I) was responsible for the production of i-PP with high molecular weight (MW) while the individual use of catalyst (II) led to the production of an elastomeric PP with relatively low MW. However, application of the binary catalyst system led to high MW bimodal MWD products being highly dependent on the catalysts' molar ratios. Increasing the molar ratio of catalyst (II) to catalyst (I) resulted in a notable enhancement of the products' complex viscosity due to the increased MW, a higher level of chains' entanglements and formation of amorphous blocks along the polymer chains. All products exhibited a single relaxation that shifted towards longer times upon changing the catalysts' molar ratios. Scanning electron microscopy results revealed that the fracture surface of the blends, synthesized by the binary catalyst system, became more heterogeneous in comparison with the products obtained by the individual use of the catalyst (I). The observed heterogeneity was found to increase by increasing the amount of catalyst (II). Such morphological change was further corroborated by the dynamic rheological data, indicating a promising correlation between the linear rheological results and the morphological features of the synthesized PP reactor blends.

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