Anionic copolymerization of DGEBA with two bicyclic bis(γ-lactone) derivatives using tertiary amines as initiators

The anionic copolymerization, to form thermosets, of diglycidylether of bisphenol A (DGEBA) with two condensed bis(γ-lactone)s (bisMe and bisPhe) using 4-(N,N-dimethylamino)pyridine (DMAP), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), and 1-methylimidazole (1MI) as initiators was studied by differential scanning calorimetry (DSC). The kinetics was evaluated by isoconversional procedures. The evolution of the typical functional groups that form or disappear during curing was followed by Fourier transform infrared in the attenuated-total-reflection mode (FTIR/ATR) to clarify the reactive processes that takes place. Unexpected processes, which lead to the formation of five-membered lactones, were detected when non-stoichiometric proportions of monomers were used. The stoichiometric DGEBA/bislactone ratio produces the expected alternate poly(ester–ketone) network. The thermal degradability of the materials obtained was evaluated by TGA, and their reworkable character was confirmed. Materials obtained from stoichiometric mixtures were completely soluble in ethanolic KOH.