Effect of Hydrogen on Operation of 4th Generation of Ziegler- Natta Catalyst in Slurry Polymerization of Propene

In this paper the influence of hydrogen during propene polymerization with 4th generation of Ziegler-Natta catalyst was investigated in terms of variations in catalyst activity, isotacticity, melt flow index and melting temperature of resulting powder. SEM images, bulk density and particle size distribution were used to analyze the morphology of polymer and catalyst particles. Catalyst activity and isotacticity were found to significantly increase with the addition of hydrogen, but there was a maximum which after that activity and isotacticity decreased. Melting temperature also showed this trend. Melt flow index of polymers was increased by addition of hydrogen which in turn showed the molecular weight of polymers was decreased; therefore hydrogen plays an important role in chain transfer reaction. Particle size of polymers was obviously increased in the presence of hydrogen. Particle size distribution plots of catalyst and resulting polymers illustrated that replication phenomenon had occurred. SEM images demonstrated that there was core-shell structure in all resulting powders. Increase in the polymerization rate in the present of hydrogen caused to improve morphology of polymers