Michael addition reaction kinetics of acetoacetates and acrylates for the formation of polymeric networks

2-Ethylhexyl acrylate and ethyl acetoacetate were reacted in a Carbon - Michael addition reaction as a model for subsequent studies of polymer networks. A statistical design of reactions was conducted in the presence of an in-situ ATR FTIR spectrometer to determine the effect of solvent, base, base concentration, and reactant stoichiometry on the observed rate constant. In particular, a central composite statistical design of experiments analysis was performed for model reactions that were catalyzed using either l,8-diazbicyclo[5.4.0]undec-7-ene (DBU) or K ₂CO ₃ at various concentrations. Poly(propylene glycol) bisacetoacetate (PPG BisAcAc) and poly(propylene glycol) diacrylate (PPGDA) networks were then prepared in the absence of solvent at 23°C based on optimized conditions in the presence of DBU and K ₂CO ₃. In a similar fashion to model studies, in-situ FTIR spectroscopy was utilized, and observed rate constants were determined. The influence of PPG BisAcAc molecular weight on dynamic mechanical properties was determined and gel fraction analysis was conducted. It appears that the selection of base significantly altered the rate of the reaction, but had an insignificant effect on mechanical properties.