Non-porous submicron silica particles (250 and 500 nm) with high monodispersity were agglomerated to form spherical agglomerates via spray drying. As a binder, 25 nm sized monodisperse silica spheres were selected from a variety of colloidal systems including Levasil-type and Aerosil-type silica nanoparticles. The use of such binders led to an increase of the specific surface area of the agglomerated carriers. All materials were characterised by nitrogen sorption, mercury intrusion and scanning electron microscopy. The silica agglomerates, with highly defined geometrical and pore structural parameters, were employed as model carriers in the heterogeneous polymerization of ethylene using a conventional methylaluminoxane (MAO)/eta(5)-dicyclopentadienyl zirconiumdichloride metallocene catalyst system. The activity of these model carriers was evaluated, as was the influence of MAO impregnation on the carriers' physico-chemical properties. The activity of the presented catalyst systems depended heavily on the percentage of binder. Due to skin formation, high contents of binder resulted in agglomerates with a smoother, more rigid surface. These carriers did not fragment during polymerization, and displayed low catalytic activity. Less binder gave more readily fragmented agglomerates displaying higher catalytic activities. Despite their small specific surface areas in comparison to commercially available polymerization carriers, e.g. SYLOPOL 948 from W.R. Grace, these model carriers possess similar activities, with the polymerization process depending more on the geometrical and structural aspects of the beads rather than on their specific surface areas. (C) 2004 Elsevier B.V. All rights reserved.