Effect of the Reaction Temperature on the Polymerization of 2-Ethylhexyl Acrylate Initiated by Lithium Ester Enolate-Lithium tert-Butoxide Complex

Abstract

The effect of reaction temperature in the range from -72 to 0 °C on the course of the anionic polymerization of 2-ethyhexyl acrylate in 9 : 1 (v/v) toluene THF was studied. In the polymerization tert-butyl 2-lithioisobutyrate and Li tert-butoxide were used as initiator and active centre stabilizer, respectively; the alkoxide at two different concentrations. From conversion curves and number-average molecular weights of the polymers, the rate constants of the propagation and autotermination reactions were calculated. The rate constant of autotautomerization rises more rapidly with temperature than that of propagation. Consequently, at temperatures higher than -60 °C polymerization autoterminates before reaching quantitative monomer conversion. The limiting monomer conversion was higher at the higher alkoxide concentration but did not reach 100%.