High activity Ziegler-Natta catalyst made from Mg powder

Abstract

A series of novel high activity Ziegler-Natta catalysts were manufactured with spherical magnesium powder as the raw material. The morphology and properties of the catalysts and the prepolymer thereof were analyzed and characterized by scanning electron microscope (SEM) and laser particle size analyzer. The results indicate that the spherical Mg powder is favourable for the preparation of catalyst; the prepolymer prepared with the catalyst exhibit an improved morphology and fluidity, compared with catalyst made from laminar Mg powder. The activity of the catalyst manufactured with Mg powder in the particle size ranging from 30 to 70 μm can reach 313 mg/(mol·h·Pa). As the iodine amount is reduced, bulk density of the prepolymer decreases from 0.28 g/cm3 to 0.25 g/cm3 while the average particle size of the prepolymer increases gradually from 155.42 μm to 186.50 μm, in addition, the content of fine powder of the prepolymer lowered from 27.1% to 14.8%. The observation of the prepolymer under SEM demonstrates that the shape of the prepolymer particle approaches sphere and its fluidity reaches class II (high class) after introducing SiO2 into the catalyst system.