Styrene‐butadiene copolymerization initiated by organopotassium compounds in hydrocarbon medium

Abstract

AbstractThe following values of monomer reactivity ratios were found: rS = 3,3 ± 0,3; rB = 0,12 ± 0,02 (cyclohexane, 25 °C). The comparison of the kinetic parameters obtained with Li, Na and K counter‐ions shows that the great difference between coordination polymerization with Li and “typically anionic” polymerization with K is mainly determined by the variation of the cross‐propagation rate constant kBS with the nature of the counter‐ion. No evidences for the specific role of the solvation of Li counter‐ion with butadiene monomer were found.