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The dynamics of living polymerization of styrene was studied with alkyllithium/potassium alkoxide as bimetallic initiator and cyclohexane as solvent. It was found that the apparent propagation rate constants ( k ap )increased greatly with little increasing of K/Li ratios and in linear relationships with the concentrations of potassium alkoxide ()when K/Li ratios were lower that 0 1. And the slopes of k ap | lines increased with the decreasing of alkyllithium concentrations. This dynamics feature can not be explained quantitatively by the ordinary association dynamics model which ignored the cross|association between the propagation species with different metallic ion. In this paper, a new dynamics model on cross|association concept was established and the dynamics feature of living polymerization of styrene can be interpreted satisfactorily. The propagation rate constant of potassium species(%k%-k) and the constant group, (%K%-1/2)+{0.5}/%K%-3, of dissociation constants of cross|association species (%K%-3)and lithium species (%K%-1)were derived by curve fitting and led to values of 7 1 ×10 3(mol/L)+{-1}min+{-1} and 67 (mol/L) +{-0.5} respectively at a polymerization temperature of 50℃.
The dynamics of living polymerization of styrene was studied with alkyllithium / potassium alkoxide as bimetallic initiator and cyclohexane as solvent. It was found that the apparent propagation rate constants (k ap) increased greatly with little increasing of K / Li ratios and in linear relationships with the concentrations of potassium alkoxide () when K / Li ratios were lower that 0 1. And the slopes of k ap | lines increased with the decreasing of alkyllithium concentrations. This dynamics feature can not be explained quantitatively by the ordinary association dynamics model which ignored the cross | association between the propagation species with different metallic ion. In this paper, a new dynamics model on cross | association concept was established and the dynamics feature of living polymerization of styrene can be interpreted The propagation rate constant of potassium species (% k % - k) and the constant group, (% K % - 1/2) + {0.5 } / % K % - 3, of dissociation constants of cross | association species (% K % - 3) and lithium species (% K % - 1 ) were derived by the curve fitting and led to values of 7 1 × 10 3 (mol / L). + {- 1 } min + {- 1 } and 67 ) + {- 0.5 } respectively at a polymerization temperature of 50 ° C.