POLYMERIZATION OF DIENES WITH TITANIUM-MA GNESIUM CATALYSTS

It is shown that titanium-magnesium catalysts (TiCl4/MgCl2 and TiCl4/M gCl2/SiO2) in combination with triisobutylaluminum are highly effectiv e in the polymerization of butadiene and isoprene. The rate of polymer ization and the microstructure of the polymer are controlled by the Al : Ti molar ratio in the catalytic system and the reaction temperature ; polymerization of butadiene proceeds with a noticeable rate even at temperatures below O degrees C. Polymerization of the studied dienes l oad's to the predominant formation of trans-isomers and is not accompa nied by the oligomerization. According to the data of DSC and X-ray di ffraction, the resulting polybutadiene is a mixture of trans-1,4-homop olymer with a small amount of the polymer of mined structure.