Supported metallocene catalysts prepared by impregnation of MAO modified silica by a metallocene/monomer solution

Effect of MAO silica surface loading on (nBuCp)2ZrCl2 anchoring, on catalyst activity and on polymer properties

“…Kanjford et al [15] also modified silica surface (460 m 2 g −1 -calcinated at 723 K for 6 h) with MAO, but they employed the wetness incipient impregnation method, i.e. the solution volume is just enough to fill the pores of the support.…”

Heterogeneous Single-Site Catalysts for Olefin Polymerization

“…As an alternative to prepolymerizing with a gaseous monomer such as ethylene, Brant added hydrocarbon-soluble poly(4-methyl)styrene or low molecular weight waxes to the supported catalyst to fill the pores of the support . Using a pore-filling technique to add ( n -BuCp) 2 ZrCl 2 in 1-hexene, 1-octene, or styrene to MAO on silica at low temperatures, then warming to ambient temperatures fills the pores of a silica support with polymer . Melting paraffin wax with a Me 2 Si(2-Me-4,5-BenzoInd)ZrCl 2 −MAO catalyst on silica and pouring the mixture into pentane produces a solid which not only polymerizes propylene with high activity, but also is essentially air-stable…”

Silica-Grafted Borato Cocatalysts for Olefin Polymerization Modeled by Silsesquioxane−Borato Complexes

“…For these processes only heterogeneous catalysts allow polymer morphology control and narrow particle size distribution and avoid reactor fouling . Besides traditional heterogeneous olefin polymerization catalysts (Ziegler−Natta, Phillips), immobilization of well-defined homogeneous metallocene catalysts is receiving increasing interest. , The most common immobilization technique consists of adsorption of a combination of methylalumoxane (MAO) and the metallocene precursor onto a silica support …”