Comparative investigation of thermal and mechanical properties of cross-linked epoxy polymers with different curing agents by molecular dynamics simulation

Molecular dynamics (MD) simulations were carried out to predict the thermal and mechanical properties of the cross-linked epoxy system composed of DGEBA resin and the curing agent TETA. To investigate the effects of curing agents, a comprehensive and comparative study was also performed on the thermal and mechanical properties of DGEBA/TETA and DGEBA/DETDA epoxy systems such as density, glass transition temperature (T-g), coefficient of thermal expansion (CTE) and elastic properties of different cross-linking densities and different temperatures. The results indicated that the glass transition temperature of DGEBA/TETA system calculated through density-temperature data, similar to 385-395 degrees K, for the epoxy system with the cross-linking density of 62.5% has a better agreement with the experimental value (T-g, similar to 400 degrees K) in comparison to the value calculated through the variation of cell volume in terms of temperature, 430-440 K. They also indicated that CTE related parameters and elastic properties including Young, Bulk, and shear's moduli, and Poisson's ratio have a relative agreement with the experimental results. Comparison between the thermal and mechanical properties of epoxy systems of DGEBA/TETA and DGEBA/DETDA showed that the DGEBA/DETDA has a higher T-g in all cross linking densities than that of DGEBA/TETA, while higher mechanical properties was observed in the case of DGEBA/TETA in almost all cross linking densities. (C) 2015 Elsevier Inc. All rights reserved.