Dual-cured thermosets based on eugenol derivatives and thiol chemistry

Abstract

This paper aims to increase sustainability in thermosetting polymeric fields using bio-based monomers and environmentally friendly processing technologies based on dual-curing. Eugenol has been transformed into acrylate epoxy eugenol (AEEU) that can participate in thio-Michael additions and thiol-epoxy reactions. These reactions constitute the first and second steps of the sequential dual-curing process. A basic catalyst has been added to favor the kinetics of the curing process. We have selected three thiols with functionalities 3, 4, and 6, the first is derived from eugenol, and the others are derived from pentaerythritol, all can be obtained from renewable resources. To tailor and improve the intermediate material characteristics in the dual-curing process, we have added the triacrylate of glycerol. By changing its proportion, a liquid or a rubbery solid can be obtained as an intermediate, which allows a significant number of application technologies. Rheology, DSC, and FTIR were used to follow the evolution of both curing steps and to confirm the sequential character of the dual-curing. The thermal characteristics of intermediate and final materials have been evaluated by TGA and DMTA. Tensile tests at break were performed to evaluate the mechanical properties.