|94. Schmitt, B.; Schlaad, H.; Müller, A.H.E.: Mechanism of anionic polymerization of (meth)acrylates in the presence of aluminium alkyls, 6. Polymerization of primary and tertiary acrylates, Macromolecules 31, 1705 (1998)|
The kinetics of the polymerization of n-butyl acrylate initiated by lithiated ester enolates in the presence of aluminum alkyls was investigated in toluene and in toluene/Lewis base mixed solvents at -78 °C. In pure toluene, curved time-conversion plots, incomplete monomer conversion, and broad molecular weight distributions (Mw/Mn > 2) are observed-in the absence of aluminum alkyls the molecular weight distributions are significantly broader (Mw/Mn > 14). High monomer conversions and narrower molecular weight distributions (Mw/Mn < 1.5) are obtained when using Lewis bases (e.g., methyl pivalate) as cosolvents. The polymerization of tert-butyl acrylate rapidly reaches full monomer conversion with rather broad molecular weight distributions (Mw/Mn > 2); the addition of a Lewis base, however, does not have a pronounced effect on these values.