POLYMERIZATION OF 1,3-DIENES WITH METHYLALUMINOXANE-TRIACETYLACETONATOVANADIUM

Various 1,3-dienes (1,3-butadiene, isoprene, 2-ethyl-1,3-butadiene, (E)- and (Z)-1,3-pentadiene, (E)-2-methyl-1,3-pentadiene) were polymerized with the soluble catalyst system methylaluminoxane/V (acac)3 (acac: acetylacetonato). Butadiene and (Z)-1,3-pentadiene gave trans-1,4 polymers, at low and room temperature. Isoprene, 2-ethyl-1,3-butadiene and (E)-2-methyl-1,3-pentadiene gave trans-1,4-polymers at low temperature (< -20-degrees-C), but polymers of mixed cis/trans structure at room temperature. (E)-1,3-pentadiene gave polymers of mixed 1,2/trans-1,4 structure either at low or room temperature. An interpretation of the results is reported.