Towards the control of the reactivity in high temperature bulk anionic polymerization of styrene, 1. Influence of n,s-dibutylmagnesium on the reactivity of polystyryllithium species

• Published in: Macromolecular chemistry and physics Vol. 200; no. 3; pp. 621 - 628
• Main Authors: Desbois, Philippe, Fontanille, Michel, Deffieux, Alain, Warzelhan, Volker, Lätsch, Stephan, Schade, Christian
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag GmbH 01.03.1999; WILEY‐VCH Verlag GmbH
• DOI: 10.1002/(SICI)1521-3935(19990301)200:3<621::AID-MACP621>3.0.CO;2-K
• ISSN: 1022-1352

The influence of n,s‐dibutylmagnesium on the kinetics of styrene polymerization initiated by s‐butyllithium was investigated in cyclohexane at 50°C. The presence of n,s‐dibutylmagnesium, in molar ratios ranging from 0 to 20 with respect to polystyryllithium, leads to a drastic and continuous reduction of the reactivity of the propagating species. The living character of the polymerization, especially the control of the molar mass is preserved over the entire range studied. The experimental molar masses are in agreement with the formation of one polystyrene chain per lithium and 0.5 to 0.8 chains per magnesium atom, indicating that both alkyllithium and dialkylmagnesium species are involved in the polymerization process through the formation of “ate” complexes. The UV‐visible study of the PSLi/n,s‐dibutylmagnesium systems shows that several types of “ate” complexes with different stoichiometry are formed depending on the proportion of the two metal derivatives.