Molecular dynamics and inverse micromechanical study of thermoelastic properties of epoxy/POSS nanocomposites

A molecular dynamics simulation study was conducted to identify the contributions of polyoligosilsesquioxane (POSS) nanoparticles to the thermoelastic behaviors of cross-linked epoxy nanocomposites. POSS nanoparticles functionalized using pre-cured epoxy were first embedded in an epoxy matrix and the resulting nanocomposites were then cured to a conversion ratio of 87 %. According to the volume fraction of the functionalized POSS nanoparticles, the stress-strain curves, coefficients of thermal expansion (CTEs), and glass transition temperatures of the nanocomposites were determined using a classical molecular potential model. Based on the efficient interfacial load transfer through the epoxy-functionalized structures at the interfaces between the POSS particles and epoxy matrices, the Young’s moduli and volumetric CTEs of the nanocomposites were effectively improved. Additionally, no clear reinforcing effects of the POSS nanoparticles were observed in the glass transition behaviors. Using the multi-inclusion model, the thermoelastic properties of effective POSS nanoparticle were determined from inverse micromechanical method.