Author/Authors :
Nejabat، Gholam-Reza نويسنده Dapartment of Catalyst, Iran Polymer and Petrochemical Institute (IPPI), Tehran, Iran , , Nekoomanesh، Mehdi نويسنده Polymerization Engineering Department, Iran Polymer and Petrochemical Institute (IPPI), P.O. Box 14975/112, Tehran, Iran. , , Arabi، Hassan نويسنده , , Salehi-Mobarakeh، Hamid نويسنده , , Zohuri، Gholam-Hossein نويسنده Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, P.O. Box 1436, Mashhad, Iran , , Mortazavi، Seyed Mohammad Mahdi نويسنده Dapartment of Catalyst, Iran Polymer and Petrochemical Institute (IPPI), Tehran, Iran , , Ahmadjo، Saeid نويسنده , , Miller، Stephen A. نويسنده ,
Abstract :
Several types of hybrid catalysts are made through mixing of 4th generation Ziegler-Natta (ZN) and (2-PhInd)2ZrCl2
metallocene catalysts using triethylaluminum (TEA) as coupling agent. Response surface methodology (RSM)
is used to evaluate the interactive effects of different parameters including amounts of metallocene and TEA and
temperature on metallocene loading. Analyzing the amounts of Al and Zr elements in the hybrid catalysts through
ICP-OES and EDXA reveals that temperature plays a crucial role on anchoring of the metallocene catalyst on ZN
while TEA has the least determining effect. The ICP analysis shows that as the concentration of Al goes up in the
hybrid catalyst the concentration of Zr passes a maximum, while EDXA shows a direct relationship between the Al
and Zr contents. Using triisobutylaluminum (TIBA) and methylaluminoxane (MAO) as the coupling agents, almost
similar metallocene loadings are observed. Finally, the performance of hybrid catalysts is investigated in propylene
polymerization and the obtained polymers are characterized using DSC and DMTA through which the presence of two
types of polymers in the final product are confirmed.
