Coordination copolymerization of butadiene and isoprene with rare earth chloride-alcohol-aluminum trialkyl catalytic systems

Butadiene and isoprene were copolymerized with LnCl/sub 3/-ROH-AlR/sub 3/ catalytic system. The products obtained were confirmed to be copolymers by their glass transition temperatures and characteristic pyrolytic chromatograms, etc. The equation for copolymerization rate may be expressed as R/sub p/ = K/sub p/(M)/sup 2/(cat). The rate constants of copolymerization, activation energy, and monomer reactivity ratios for catalytic systems containing various rare earth elements in III-B family and different solvents were determined.It was found that the reactivity ratio of butadiene was greater than that of isoprene and r/sub 1/r/sub 2/ near 1, and the composition and microstructure of copolymers were not much affected by variation of polymerization conditions.Both monomer repeat units in the copolymers had cis-1.4 contents above 95%, which is a distinguishing feature of coordination polymerization with the landthanide catalyst system.