III International Conference

PP-II-144from the surface of sample for the investigation and comparison of these aluminoxancomposition and structure. It was shown, that the most part of alkylaluminoxane molecules isbonded with the support surface by the donor-acceptor interaction, with the retention of themost reactivity СН 3 -groups. Such groups are necessary for the alkylation of transition metal atthe formation of catalytic complexes. The differences in the thermal behavior of the surfacemethyl- and isobutylaluminoxanes were found, which were, obviously, connected with thedifferences of their steric and electronodonor properties. These properties, apart the others,define the behavior of aluminoxanes as metallocene activators-cocatalysts in olefinpolymerization. The investigation of the ethylene and propylene polymerization in thepresence of elaborated ММТ-Н 2 О/AlR 3 /Zr-cene catalysts showed that ММТ-Н 2 О/AlR 3 arethe high-effective activators for zirconocenes. They do not demand the use of the commercialMAO or the other aluminumorganic cocatalysts. It was revealed the dependence of thecatalytic properties of investigated heterogeneous systems (kinetics, activity, microstruture ofthe synthesized macromolecules) on the design of zirconocene pre-catalyst (nature ofη-ligands and substitutions in η-ligands, symmetry type) and the aluminoxan nature.Isobutylaluminoxane synthesized on ММТ-Н 2 О formes with all investigated ancazirconocenesmore active in propylene polymerization catalytic complexes, thanmethylaluminixane in ММТ-Н 2 О/AlMe 3 The stereospecificity of ММТ-Н 2 О/AlR 3 /Zr-cenecatalysts depends on the composition and the type of symmetry of zirconocene compound anddoes not depend on the activator nature. The data concerning the influence of catalyticcomplex immobilization on the stereocontrol of polymer chain propagation in the process ofpropylene polymerization were obtained. The character of this influence depends on thezirconocene structure. Thus, the immobilization of С 2 -symmetric rac-Me 2 Si(Ind) 2 ZrCl 2 on theММТ-Н 2 О/AlR 3 surface leads to the increase of the catalyst stereospecificity in thecomparison with the compatible homogeneous system. In the case of С S –symmetric rac-[1-(Flu)-2-(5,6-Cp-2-Me-Ind)Et]ZrCl 2 immobilization the catalyst stereospecificity decreases. Atthe same time the immobilization of the stereospecific catalyst on the base of С 2 -symmetricrac-Me 2 Si(2-Me-4-Ph-Ind) 2 ZrCl 2 leads only to the slight decrease of the heterogeneoussystem stereospecificity.This work was supported by the Russian Foundation of Basic Research,Grant № 04-03-32884429