KINETICS OF COPOLYMERIZATION OF ETHYLENE WITH ALPHA-OLEFINS INITIATEDBY SUPPORTED TITANIUM-MAGNESIUM AND VANADIUM-MAGNESIUM CATALYSTS

Copolymerization of ethylene with higher alpha-olefins initiated by ne w modifications of highly active supported titanium-magnesium and vana dium-magnesium catalysts was studied. It was established that the reac tivities of linear alpha-olefins in the copolymerization with ethylene decrease in the sequence propylene > 1-butene > 1-hexene > 1-octene. The reactivities of branched alpha olefins are determined by the posit ion of a substituent with respect to the double bond and the length of chain branching and the decrease in the sequence 4-methyl-1-pentene > 3-methyl-1-butene > 3-methyl-1-pentene. The data on high relative rea ctivity of 2-norbornene in copolymerization with ethylene, which is cl ose to that of linear alpha-olefin (1-hexene), were obtained. For all the studied comonomers, the vanadium-magnesium catalyst shows higher a ctivity in copolymerization than the titanium-magnesium catalyst. It w as shown that, in the range 40-70 degrees C, the temperature of polyme rization affects the reactivity ratio of ethylene r(1). In the copolym erization of ethylene with alpha-olefins, the initial acceleration per iod sharply decreases, and the maximum activity is observed on the kin etic curves.