Thermodynamic simulations of SrTiO3/epoxy nanocomposites with different mass fractions

Abstract

Molecular dynamics simulations have been used to study the thermomechanical properties of SrTiO3/epoxy nanocomposites with different mass fractions. The calculation results revealed that thermal conductivity increased with mass fractions and temperature, which was consistent with the measured experiment value. Motion of molecular chain segment of pure epoxy resin became intense with temperature increase. With the increase in mass fractions of incorporated SrTiO3 nanoparticles, the mobility of molecular chain segment was significantly weakened below 500 K compared with pure epoxy resin model and the model of nanocomposite with a mass fraction of 25 wt% SrTiO3 showed best structure stability. Dipole autocorrelation functions (DACF) of pure epoxy resin fluctuated slightly under 350 K, but substantial fluctuation happened over 500 K. With the incorporation of SrTiO3 nanoparticles, the fluctuation of DACF of nanocomposites decreased drastically, maintaining a small value of 0.004 Debye, which demonstrated that structure stability of nanocomposites was strengthened under 500 K. Based on interface model between epoxy resin macromolecular ligands and crystal plane (110) of SrTiO3, interface interaction energy was calculated to be − 235.9 kcal/mol. To sum up, incorporation of SrTiO3 nanoparticles could significantly improve the thermomechanical properties of epoxy resin and enhance structure stability of nanocomposites.