Copolymerization of styrene and isoprene with Ni(acac)2‐methylalumoxane catalyst

Copolymerization of styrene (St) and isoprene (IP) with nickel(II) acetylacetonate [Ni(acac)2] and methylalumoxane (MAO) catalyst was investigated. It was found that the Ni(acac)2‐MAO catalyst is effective for the copolymerization of St and IP. From the copolymerization of St (M1) and IP (M2) and IP (M2) with the Ni(acac)2‐methylalumoxane catalyst, the monomer‐reactivity ratios were determined to be r1 = 1,18 and r2 = 0,88, i.e., ideal copolymerization was found to proceed to give perfectly random copolymers without formation of any homopolymer. The microstructure of IP units in the copolymers exhibits high cis‐1,4 contents.