Anionic equilibrium polymerization of α‐methylstyrene initiated by butyllithium/dimethoxyethane and glyme‐1

Abstract The kinetics and mechanism of anionic equilibrium polymerization of α‐methaylstyrene in cyclohexane with butyllithium (BuLi) as initiator and dimethoxyethane (DME) and glyme‐1 (bis(2‐methoxyethyl)) ether; (1G) as polar additives were investigated. The apparent constant of propagation kap and of depropagation kad were evaluated over a wide concentration range of DME (or 1G). The kinetic equations of the equilibrium polymerization as mole ratios of [DME]/[BuLi] < 1,66, [DME]/[BuLi] > 33,3 and 1,66 < [DME]/[BuLi] < 33,3 were established. The mathematic equations of the equilibrium monomer concentration [M]e deduced from the kinetic measurements, at the above mentioned ratios [DME]/[BuLi], were used to control the polymerization process. The rate constants of different active species and the equilibrium constants between active species were calculated by the curve fitting method for the DME system. The fact that free ions exist in the polymerization system when the concentration of 1G was about 40 vol.‐% was proved by conductance measurements. Finally, the reaction features of the anionic polymerization of α‐methylstyrene with various polar additives are compared.