Decreased Thermal Conductivity of Polyethylene Chain Influenced by Short Chain Branching

Abstract

In this paper, we have studied the effect of short branches (side chains) on the thermal conductivity (TC) of a polyethylene (PE) chain. With a reverse nonequilibrium molecular dynamics (RNEMD) method, TCs of the pristine PE chain and the PE-ethyl chain are simulated and compared. It shows that the branch has a positive effect to decrease the TC of a PE chain. The TC of the PE-ethyl chain decreases with the number density increase of branches, until the density becomes larger than about eight ethyl per 200 segments, where the TC saturates to be only about 40% that of a pristine PE chain. Because of different weights, different branches will cause a different decrease of TCs, and a heavy branch will lead to a lower TC than a light one. This study is expected to provide some fundamental guidance to obtain a polymer with a low TC.