Alternating copolymerization of 2,4-dicyanobut-1-ene and α-methyl styrene

The copolymerization reaction between the comonomers 2,4-dicyanobut-1-ene and a-methyl styrene in the bulk has been shown to result in a highly alternating copolymer. The existence of a charge-transfer complex between the two monomers was established with an equilibrium constant K(323°K) = 0.14 dm³ mol^-1. The compositions of the copolymers obtained at low % conversions were used to determine the likely mechanism of alternation. Four models were tested: the terminal; the terminal-depropagation; the penultimate; and the complex-participation models. Statistical analysis of the results indicate that the complex-participation model can be discounted and that the best descriptions of the data are obtained using the terminal-depropagation and penultimate models. Discrimination between the latter two, however, is much more subjective and was not attempted. © 1989.