A kinetic study of copolymerization of styrene and ff-methylstyrene initiated by n-butylli-thium in cyclohexane with tetrahydrofuran as a polar additive has been carried out. Through the investigation of kinetics and mechanism of copolymerization in the presence of multiple active species accompanied with depropagation

the propagation rate constants and depropaga-tion rate constants of the two monomers with regard to different species as well as the cotn-plexation equilibrium constants between various type of active species were obtained.