Anionic polymerization of acrylates. III. Polymerization of 2‐ethylhexyl acrylate initiated by lithium‐tert‐butoxide

Abstract

AbstractThe polymerization of 2‐ethylhexyl acrylate (EtHA) initiated with lithium‐tert‐butoxide (t‐BuOLi) in tetrahydrofuran (THF) and in the temperature range between −60 and 20°C was investigated. The reaction rate is distinctly temperature‐dependent and at −60°C is already very low, similarly to the polymerization of methacrylates. Molecular weights of the polymers thus formed, particularly at higher temperatures, are inversely proportional to conversion of the monomer due to the slow initiation reaction. This is documented by the low consumption of alkoxide even at long reaction times, which also depends on the reaction temperature. At higher temperatures the polymerization stops spontaneously, due to the greater extent of autotermination reactions. The weak initiating efficiency of the alkoxide decreases still more with decreasing concentration of the monomer during the polymerization, as confirmed by the concentration dependence of the reaction rate in toluene at −20°C. The results suggest a negligible initiating effect of alkoxides in complex bases, particularly at lower polymerization temperatures. © 1992 John Wiley & Sons, Inc.