Investigation of Thermal Expansion of Polyimide/SiO₂ Nanocomposites by Molecular Dynamics Simulations

In this paper, an atomistic model for PI/SiO 2 hybrid nanocomposites was designed for the investigation of physical properties of this material on the base of molecular dynamics simulations. The thermal properties of a reference pure PI matrix in the temperature range of 300–650 K were first investigated. The results for the CTE and the glass transition temperature showed good agreement with the experimental data. Then, the thermal expansion of the model of PI/silica composite material with different SiO 2 fractions was investigated at normal conditions. The CTE of the composite model decreases with the increase in the SiO 2 content in agreement with experimental studies. The results show a threshold for the SiO 2 loading beyond which the material model exhibits ultra‐low thermal expansion. magnified image