Cationic copolymerization of DGEBA with two bicyclic bis(γ-lactone) derivatives using rare earth metal triflates as initiators

The thermal cationic curing of mixtures in different proportions of diglycidylether of bisphenol A (DGEBA) with two differently substituted condensed bis(γ-lactone)s (BisMe and BisPhe) initiated by scandium, ytterbium and lanthanum triflates or a conventional BF3·MEA initiator was investigated. Non-isothermal differential scanning calorimetry (DSC) experiments at a controlled heating rate were used to evaluate the evolution of the reactive systems. BF3·MEA and rare earth metal triflates initiated curing systems follow a different evolution. Among rare earth metal triflates tested, the scandium was the most active initiator. The phenomenological changes that take place during curing were studied and represented in time-temperature-transformation (TTT) diagrams. The improvement in the reworkable character of the materials prepared was confirmed by thermogravimetry. The thermomechanical characteristics were also evaluated.