A Thermal Resistance Network Model for Heat Conduction of Amorphous Polymers

TL;DR

This paper introduces a thermal resistance network model that explains the low thermal conductivity of amorphous polymers by considering chain entanglement, successfully reproducing pressure, temperature, and anisotropic effects.

Contribution

The novel TRN model incorporates chain entanglement effects to accurately predict thermal conductivity in amorphous polymers and their dependence on pressure, temperature, and orientation.

Findings

Model explains low TC in amorphous polymers.

Reproduces empirical pressure and temperature dependence.

Quantitatively explains anisotropic TC in oriented polymers.

Abstract

Thermal conductivities (TCs) of the vast majority of amorphous polymers are in a very narrow range, 0.1 $\sim$ 0.5 Wm$^{-1}$K$^{-1}$, although single polymer chains possess TC of orders-of-magnitude higher. Entanglement of polymer chains plays an important role in determining the TC of bulk polymers. We propose a thermal resistance network (TRN) model for TC in amorphous polymers taking into account the entanglement of molecular chains. Our model explains well the physical origin of universally low TC observed in amorphous polymers. The empirical formulae of pressure and temperature dependence of TC can be successfully reproduced from our model not only in solid polymers but also in polymer melts. We further quantitatively explain the anisotropic TC in oriented polymers.