A highly active supported metallocene catalyst for propylene isospecific polymerization was prepared by immobilization of SiO2 with precontacted compounds of rac Me2Si(Ind)2ZrCl2 and methylaluminoxane (MAO).The influence of [Al]/[Zr] ratio and polymerization temperature on the activity

molecular weight (Mw) and polymerization kinetics was investigated.The behavior of this catalyst was also compared with its corresponding homogeneous catalytic system.It was demonstrated that the active site of heterogeneous systems was more stable

and the Mw of catalysts was determined by 13C-NMR spectra.It was found that the isotacticity of iPP obtained by heterogeneous systems was higher

ist pentad sequence [mmmm] increased to 86.3% from 82.0% for homogeneous systems. Moreover

the regioselectivity of polmers produced by heterogeneous systems was also improved

the 2

1-insertion and 1

3-insertion decreased to 3.7%。and 0.5%。 from the values of 4.4%。and 1.9%。

respectively for those produced by homogeneous systems.