This lecture will focus on the role of magnesium and aluminum compounds as additives to alkali metal, onium salts, or simple alcohols to either retard the living polymerization of styrene and dienes or activate the anionic ring-opening polymerization of cyclic ethers.<br/>To produce economically polystyrene-based materials via an anionic route, and therefore to compete with a free radical process, bulk and high temperatures experimental conditions are required. The addition of Lewis acids such as magnesium or aluminum alkyls to an anionic initiator (Li or Na derivatives) permits to adjust the reactivity of the active centers and to control the copolymerization of styrene and dienes with peculiar issues in terms of reactivity ratios and microstructure.<br/>A similar and unique approach was then applied to different cyclic ether monomers. The addition of Lewis acids such as trialkylaluminum to alkali metal alkoxides or onium salts showed a strong increase of the polymerization rates of epoxides and glycidyl ethers as well as a consequent decrease of transfer reactions allowing the controlled synthesis of (co)polymers with various molar masses. A specific focus will be given to simple Grignard reagents and diakylmagnesium, in the presence of protic compounds, for the polymerization of epoxides and the synthesis of polyethers.<br/>

From retarded to activated anionic polymerization: A focus on magnesium and aluminum derivatives

251st National Meeting (2016)

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