The thermal conductivity of pyrolytic char obtained by ultrahigh temperature decomposition of polyethylene specimen via molecular dynamics simulations is investigated as a function of temperature and microstructural characteristics. We find that the simulated thermal conductivity dependence on the average coordination number is modified by formation of graphene-like microtopological features in carbonaceous char. The dependence of thermal conductivity on temperature and average coordination number is explained in terms of an analytical model, based on the Einstein's theory of heat transport. The deviations due to the formation of graphene sheet-like units are taken into consideration by introducing corresponding corrections in the elastic properties of char.
Bibliographical noteFunding Information:
M.A.M. and D.S. gratefully acknowledge support from NASA through the Hypersonics project of the Fundamental Aeronautics program (Grant No. NNX07AC41A).