THE ATTEMPTED COPOLYMERIZATION OF STYRENE AND ETHYLENE WITH MONOCYCLOPENTADIENYLTITANIUM TRICHLORIDE METHYLALUMINOXANE CATALYST - EFFECT OF POLYMERIZATION CONDITIONS

The copolymerization of styrene and ethylene was attempted in the presence of the catalytic system CpTiCl3-methylaluminoxane. Polymerizations were carried out at different polymerization temperatures and Al/Ti mole ratios. The structure of the polymer was investigated with FTIR, DSC, GPC, and C-13-NMR techniques. The polymerization product ws composed of polyethylene and syndiotactic polystyrene. No ethylene-styrene copolymer was detected. The composition of the product was dependent on the polymerization conditions. The catalyst activity was highest at polymerization temperature 30 degrees C and Al/Ti ratio 1500. Styrene concentration of the product was highest at polymerization temperature 50 degrees C and Al/Ti ratio 1500. The melting temperature of the polyethylene fraction ws dependent on the styrene content of the product, suggesting some interaction between the monomers in the polymerization reaction. The formation of separate polymer fractions may indicate a different polymerization mechanism for the two monomers, or the presence of more than one active species in the catalyst, one producing polyethylene and the other syndiotactic polystyrene.