Synthesis of Stereodiblock Polybutadiene Using Cp*Nd(BH4)2(thf)2 as a Catalyst

Butadiene polymerization, in both a highly cisand trans-specific manner, was achieved by using a Cp*Nd(BH4)2(thf)2–Bu2Mg system as an initiator. The cis-/transratio can be tuned by the amount of trialkylaluminum-depleted modified methylaluminoxane (dMMAO). The cis-regularity of the polymer was much higher than those obtained by Nd(BH4)3(thf)3. The molecular weight of cis-regular polymer was increased according to polymer yield, showing that there was no termination or chain transfer reaction during the polymerization. Synthesis of stereodiblock polybutadiene, which showed a high melting temperature (Tm) compared with stereodiblock polyisoprene, was also performed by the addition dMMAO during the polymerization.