Molecular dynamics simulations and experimental studies of the thermomechanical response of an epoxy thermoset polymer

We report a detailed comparison between molecular dynamics predictions and experimental results for a wide range of thermo-mechanical properties of an epoxy resin system: diglycidyl ether of bisphenol A (DGEBA) cured with 3,3′ diamino-diphenyl sulfone (33DDS). A set of carefully designed and characterized experiments provides validation data for the simulations that predict the molecular structure and properties of the thermoset. Our results show that current state-of-the-art molecular dynamics simulations provide quantitative predictions for this epoxy system in its glassy state, including elastic moduli, coefficient of thermal expansion and specific heat. The glass transition temperature is also accurately predicted once a correction is included to account for the difference in cooling rates between the simulations and experiments. Our results also indicate that viscoelastic and thermal properties of the thermoset polymer in its rubbery state are more challenging to predict since the effect of timescales is not well understood.