Polymerization of propylene using isospecific rac-Me2Si(2-Me,4-PhInd)2ZrCl2 catalyst immobilized on polyethylene with grafted poly(acrylic acid)

The catalytic behavior of the highly isospecific catalyst rac-Me2Si(2-Me,4-PhInd)(2)ZrCl2 immobilized on the surface of a polymer support, PE with grafted poly(acrylic acid) that was preliminarily treated by poly(methylaluminoxane), was studied. The immobilized catalyst was activated by triisobutylaluminum. The molecular masses, melting temperatures, and isotacticity of the produced PP were examined. It was shown that the modification of the catalyst by the boron salt Me2NHPhB(C6F5)(4) leads to a change in the kinetics of polymerization and in the isotacticity of the resulting PP. Factors affecting the rate and stability of the catalytic behavior of the studied supported catalysts such as the content of immobilized zirconocene, the concentration of triisobutylaluminum, and the reaction temperature were analyzed. It was demonstrated that the catalyst is not washed out from the support surface in the course of polymerization and that PP is produced in the form of granules with a bulk density of 0.2-0.3 g/cm(3).