An empirical model to predict temperature-dependent thermal conductivity of amorphous polymers

Thermal conductivity in polymers has been theoretically and experimentally studied in good detail, but there is a need for more accurate models. Polymeric thermal conductivity exhibits a plateau-like transition at temperatures around 10 K, which is not well accounted for by existing models. In this work, an empirical model that can predict temperature-dependent thermal conductivity of amorphous polymers is developed. The model is based on kinetic theory and accounts for three sets of vibrational modes in polymers, and is developed using classical expressions, results of previous simulations, and experimental data. Fundamental material properties like density, monomer molecular weight, and speed of sound are the only input parameters. The model provides estimates for the locations of transitions between different sets of vibrational modes, an upper limit for the thermal conductivity, and temperature-dependent thermal conductivity, which are in good agreement with experimental data. (c) 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 1160-1170