SUPPORTED METALLOCENE COMPLEXES FOR ETHYLENE AND PROPYLENE POLYMERIZATIONS - PREPARATION AND ACTIVITY

Important research is currently underway to develop supported metalloc ene-based catalysts that could be widely used in the polyolefin indust ry. Recent developments concerning these systems are reviewed. The mai n preparation methods for metallocene immobilization on various suppor ts are first systematized and described. Then, the nature and structur e of active sites as well as their formation mechanism are analyzed. T he performances for ethylene and propylene polymerizations of various supported metallocene systems are compared and discussed on the basis of the different catalyst preparations and of the operational polymeri zation conditions. Finally, the influence of metallocene heterogenizat ion on the final polymer properties is examined.