Anionic Copolymerization of Butadiene and 1,1-Diphenylethylene

The anionic copolymerization of butadiene (M1) and 1,1-diphenylethylene was investigated in tetrahydrofuran (THF) and benzene, using n-butyllithium (n-BuLi), Na-naphthalene, and Na-and K-dispersions as initiators. An alternating copolymer was formed in THF, where the reaction proceeded without termination and chain-transfer reactions. The monomer reactivity ratios, r1 were 0.13 (Li+), 0.09 (Na+), and 0.09 (K+) in THF at 0°C. The r1 values in benzene at 40°C were 54 (Li+), 0.71 (Na+), and 0.10 (K+). The order of rate constants in THF was k12>k11>k21; the last of these was 0.27m−1 sec−1, with n-BuLi at 0°C.