HIGH ACTIVITY AND GOOD HYDROGEN RESPONSE SILICA-SUPPORTED ZIEGLER-NATTA CATALYST FOR ETHYLENE POLYMERIZATION

A silica-supported Ziegler-Natta catalyst with dimethyldichlorosilane （DMDS） as modifier and small silica as support was successfully prepared and characterized. Results from pilot screen showed that the new catalyst exhibited higher catalytic activity, better hydrogen response ability and better copolymerization ability than the commercial M catalyst. Pilot screen in ethylene gas phase fluidized bed polymerization, the catalytic activity of the new catalyst was up to 8000 g PE/g cat, which was twice of that of the commercial M catalyst. The bulk density of polyethylene obtained with the new catalyst was 0.38 g/cm^3. The new catalyst is suitable for condensed and super-condensed process in fluidized bed ethylene polymerization.