Synthesis of block copolymer of ethylene with styrene and isoprene by means of active site transformation from anionic to coordination route

Synthesis of block copolymer consisting of ethylene with styrene (St) and isoprene (IP) by active site transformation from anion to coordination route was investigated. The active site transformation was achieved by adding VCl4 to the living polymers initiated with butyllithiums. The block copolymer consisting of IP and ethylene segments was synthesized by means of active site transformation using VCl4 and the poly(IP) with lithium chain end. When the living poly(St) with lithium chain end was used instead of the poly(IP), the block copolymer of St and ethylene was not obtained. This may be explained by the β-hydride elimination reaction from polystyryl chain.