Investigation of thermal conductivity of graphite flake/poly (p-phenylene sulfide) composite by experimental measurement and non-equilibrium molecular dynamics simulation

Abstract

The thermal conductivities (TC) of graphite flake (GF)/poly (p-phenylene sulfide) (PPS) composites at different GF weight fractions were investigated by experimental measurement and by non-equilibrium molecular dynamics simulation (NEMD). In the experiment, at GF weight fractions lower than 10%, the TC values of samples fabricated by the hot press and injection methods are very close, while the TC values of those from the hot press method are relatively higher at GF weight fractions higher than 20%. From SEM micrographs, it reveals that the GFs distribute uniformly within the PPS matrix for samples prepared by the hot press method, while gradient distributions of GFs are found for the injection method samples. The results of non-equilibrium molecular dynamics simulation confirm the influence of GF weight fractions on the TC value and are in excellent agreement with the results for the hot press method. The enhancement of TC can be attributed to the coupling of GF and PPS vibration modes, which can be seen from our MD simulation results. Finally, an empirical equation, the Maxwell-Eucken model, can be used to predict TC variations at different GF weight fractions once the GF TC value is derived from the MD simulation results. The TC values predicted by the Maxwell-Eucken model agree well with those by experimental and MD simulation approaches.