Study on Heterogeneity of Network Structure Formation Using Molecular Dynamics Simulations

We have been intensively studying the network structure formation and rheology of thermosetting polymer epoxy resins by molecular dynamics simulations. Experiments indicated the existence of network structure heterogeneity in epoxy resins depending on the curing temperature, and a detailed rheological molecular picture of this heterogeneity was revealed. We have been also studying the effects of different chemical properties of the adherend surfaces on the curing shrinkage process and adhesive strength. The mechanism of the formation of nanoscale voids (free spaces) where water molecules can enter during the curing shrinkage process has been elucidated. Furthermore, it was found that the absorbed waters diffuse between the free spaces in a hopping manner. In addition, the effects of aggregation state and adsorbed water at the interface with amorphous silica and alumina substrates on the curing process were also investigated.