Novel Methylaluminoxane‐Activated Neodymium Isopropoxide Catalysts for 1,3‐Butadiene Polymerization and 1,3‐Butadiene/Isoprene Copolymerization

The homo‐ and copolymerizations of 1,3‐butadiene and isoprene are examined by using neodymium isopropoxide [Nd(O i ‐Pr) 3 ] as a catalyst, in combination with a methylaluminoxane (MAO) cocatalyst. In the homopolymerization of 1,3‐butadiene, the binary Nd(O i ‐Pr) 3 /MAO catalyst works quite effectively, to afford polymers with high molecular weight ( ≈ 10 5 g mol ‐1 ), narrow molecular‐weight distribution (MWD) ( / = 1.4–1.6), and cis ‐1,4‐rich structure (87–96%). Ternary catalysts that further contain chlorine sources enhance both catalytic activity and cis ‐1,4 selectivity. In the copolymerization of 1,3‐butadiene and isoprene, the copolymers feature high , unimodal gel‐permeation chromatography (GPC) profiles, and narrow MWD. Most importantly, the ternary Nd(O i ‐Pr) 3 /MAO/ t ‐BuCl catalyst affords a copolymer with high cis ‐1,4 content in both monomer units (>95%). image