Influences of secondary and tertiary amines in epoxy resins on water dynamics by all-atomic molecular dynamics simulations

Abstract

All-atomic molecular dynamics simulations were conducted to elucidate the water dynamics around amines in epoxy resins. The rotational relaxation and translational diffusion of water molecules were slow in an epoxy resin based on a secondary amine, compared with those in one based on a tertiary amine. This qualitatively agrees with experimental quasielastic neutron scattering results, demonstrating the validity of the simulations. For the tertiary amine, water cluster formation accelerated the rotational relaxation of water, while the secondary amines attracted water molecules slightly more strongly than tertiary amines, preventing water from forming large clusters and slowing down translational diffusion.