The anionic polymerization of 4-cyano-α-methylstyrene (1) was carried out in THF at −78 °C with (1,1,4,4-tetraphenylbutanediyl)dipotassium and -dilithium, (diphenylmethyl)potassium, and (triphenylmethyl)potassium and -cesium. All the polymerizations of 1 quantitatively proceeded with each initiator, although the rates of polymerization were quite slow, especially in the case of organolithium initiator. The resulting poly(1)s always possessed narrow molecular weight distributions (M w/M n < 1.13) and predicted molecular weights based on the molar ratios of monomer to initiators. The living nature of the propagating carbanion derived from 1 was demonstrated by the postpolymerization. Novel well-defined block copolymers poly(1-b-styrene-b-1) and poly(1-b-tert-butyl methacrylate-b-1) were successfully synthesized by the sequential addition of 1 and styrene or tert-butyl methacrylate.

The anionic polymerization of 4-cyano-α-methylstyrene 1 was carried out in THF with (diphenylmethyl)potassium (Ph2CHK) as an initiator. At the various temperature ranging from 0 to −78 °C, conversion and equilibrium monomer concentration, [M]e, were obtained from the GLC analysis of the residual monomer. From the plot of ln [M]e against reciprocal temperature, the thermodynamic parameters, ΔH and ΔS, and the ceiling temperature, T c, of the anionic polymerization of 1, were determined to be −7.64 ± 0.5 kcal mol-1, −25.5 ± 1.3 cal mol-1 K-1, and 27 ± 3 °C, respectively. The apparent rate constant and the activation energy of the anionic polymerization for 1 were determined as follows:  ln k p ap = −1.83 × 103/T + 5.74 L mol-1 s-1 and E a = 3.6 ± 0.2 kcal mol-1, respectively. Depolymerization of the living poly(1) proceeded to give a low molecular weight oligomer and starting monomer when the temperature of the polymerization system was raised from −78 to 0 °C. The resulting poly(1)s produced at low temperatures (−30 to −78 °C) possessed narrow molecular weight distributions (M w/M n < 1.1) and controlled molecular weights based on the molar ratios of monomer to initiator. Over −20 °C, after the reaction mixture stood for a period of time, the broadening of the MWD of the poly(1) was apparently observed due to the reversible equilibrium polymerization under the thermodynamic conditions.