PREPARATION OF POLYPROPYLENE/CLAY NANOCOMPOSITES BY in situ POLYMERIZATION WITH TiCl4/MgCl2/CLAY COMPOUND CATALYST

TiCl4/MgCl2/clay compound catalyst was prepared by chemical reaction. Exfoliated polypropylene (PP)/clay nanocomposites were synthesized by in situ polymerization with this compound catalyst. Effects of polymerization temperature, polymerization time, propylene pressure, solvent consumption and pre-treat time of catalyst on catalyst activity and catalytic stereospecificity were studied. Under optimal conditions, activity of the nano-compound catalyst is about 88.3 kg/(mol Tih). Isotacticity of PP obtained in the nanocomposites is in the range of 89%-99%, and its melting temperature is about 159C. The weight-average molecular weight of PP can reach 6.7 105 -7.8 105, and the molecular weight distribution is between 7.7 and 7.9.