Anionic Copolymerization of Styrene and 1, 1-Diphenylethylene

The anionic copolymerization of styrene (M1) and 1, 1-diphenylethylene (M2) was investigated. 1, 1-Diphenylethylene, which can not homopolymerize by itself, was copolymerized with styrene by means of an anionic initiator. The copolymerization reaction seemed to proceed without termination or chain transfer, and gave a high molecular alternating copolymer under appropriate reaction conditions. The monomer reactivity ratio, r1, was obtained from the copolymer composition at the complete consumption of M1, assuming the rate constant k22=0. The monomer reactivity ratio was affected by the solvent (n-hexane, benzene, toluene, or THF), but not by the catalyst (n-BuLi, Na-dispersion, Na-naphthalene, or K-dispersion) or the reaction temperature. It was 0.4 in toluene at 30°C.