COPOLYMERIZATION OF ETHYLENE AND 1-OCTADECENE WITH THE CP(2)ZRCL(2) MAO AND CP(2)HFCL(2)/MAO CATALYST SYSTEMS/

The comparison of the copolymers obtained with the Cp(2)ZrCl(2)/MAO an d Cp(2)HfCl(2)/MAO catalyst systems showed that the catalyst having ha fnocene was much more reactive towards 1-octadecene than zirconocene. The comonomer concentration had to be three times higher in the zircon ocene copolymerization than in the hafnocene copolymerization when the level of 6 mol-% was reached. Although the hafnocene catalyst was mor e reactive towards 1-octadecene, the molecular weights were higher tha n in the copolymers obtained with the zirconocene catalyst. The total activity of the zirconocene was 10 times higher than with the hafnocen e catalyst. With the zirconocene catalyst the activity towards ethylen e was constantly increasing by increasing the comonomer concentration but stayed nearly constant with the hafnocene catalyst. It seemed that there is no rate enhancement effect upon comonomer addition with the hafnocene catalyst.