双金属引发体系苯乙烯活性聚合活性种的交互缔合动力学  

CROSS-ASSOCIATION DYNAMICS OF LIVING SPECIES OF BIMETALLIC INITIATING SYSTEM IN LIVING POLYMERIZATION OF STYRENE

作　　者：范赤 应圣康[1] 刘青[2] 

机构地区：[1]华东理工大学活性聚合实验室,上海2000237 [2]北京燕山石油化工公司研究院,北京102500

出　　处：《高分子学报》2000年第4期486-488,共3页Acta Polymerica Sinica

摘　　要：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 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℃.

关 键 词：双金属引发体系 交互缔合 苯乙烯 活性聚合 

分 类 号：O631[理学—高分子化学]