9:30 AM - 9:45 AM
[11a-N323-3] Protonation and Weakening of Epoxy Resin Adhesive Under Wet Conditions: First-Principles Free Energy Calculations
Keywords:epoxy resin, adhesion, weakening
A significant challenge facing adhesive bonding is the weakening or lost of adhesion under wet conditions. In this study, we investigated the protonation of the amine group in epoxy resins prepared using amine-based curing agents by theoretical methods. The density functional theory (DFT)-based free-energy calculations of the corresponding deprotonation sub-reactions showed that the amine group of the epoxy resin is protonated at equilibrium depending on the location of the amine group when the epoxy resin is embedded in water under standard conditions. Comparing the transition state energies for breaking principal groups calculated with DFT, we predict that the bond breakage of the protonated amine groups is the principal process causing the weakening of epoxy resins under wet conditions.