Abstract: Bulk polymerization technique so far has not been successfully realized for cis-1,4 polybutadiene synthesis. In this research a type of rare earth based catalyst was developed for the synthesis of gel free polybutadicne(PB) with high cis-1,4 content. The results show that the catalyst has a higher activity than in solution polymerization and the molecular weight distribution of PB obtained in bulk polymerization is more narrow than those obtained in solution polymerization. It is also found that when the ratio of Cl/Ln is between 1.0 and 7.0 the conversion of monomer is 70% and more.

Key words: Butadiene, Coordination polymerization, Rare earth, catalyst, Bulk polymerization