Palygorskite clay supported Cp2TiCl2 catalyst system was developed and evaluated by ethylene slurry polymerization.The inorganic carrier was thermally activated at 500℃ to generate surface Lewis acidity

which was confirmed by pyridine adsorption experiment and subsequent FTIR spectra analysis.Two types of supported catalysts were prepared: immobilizing the metallocene catalyst directly on the carrier (Cat-A) and also on the carrier with methylaluminoxane(MAO) modification (Cat-B).Polymerization was carried out in toluene at 40℃ and 60℃ with the supported Cp2TiCl2 catalyst and homogeneous analogue.Cat-A gave higher catalyst activity compared with Cat-B

and was even more robust than corresponding homogeneous catalyst.This specifically high activity of Cat-A was attributed to the surface Lewis acidity of the thermally activated clay.Models of active surface species were discussed in comparison with silica supported metallocene catalyst.With the directly supported catalyst

molecular weights and melting points of the polymer products were lower than those of the polymer products obtained with Cat-B

and the polymer properties were much more affected by the polymerization temperature.By analyzing the SEM photographs of polymers at different polymerization stages

morphological replication of the single fiber of palygorskite was revealed and a final polyethylene “fiber cluster” structure was formed.This interesting evolution of polymer morphology was further discussed in relation to polyethylene/clay composite and the method of improving the final polymer morphology.