Interfacial thermal transport properties of polyurethane/carbon nanotube hybrid composites

摘要

Although polymers have been used in a wide range of applications in everyday life, their extremely low thermal conductivity severely impedes their applicability in the fields of energy-efficient buildings and microelectronics. Pioneering researchers have proposed carbon nanotubes (CNTs) that can remarkably improve the overall thermal transport properties of polymers by functioning as great thermally conductive fillers. However, the interfacial thermal transport mechanisms between CNT and polymer are complex and not fully understood. To clarify this issue, the interfacial thermal conductance (G) of a representative single-walled CNT (SWCNT)/polymer interface, specifically CNT/polyurethane (PU), was studied in detail by molecular dynamic simulation. Two different hybrid CNT/PU structures were constructed and the corresponding G values were 0.163 MW m~(-2) K~(-1) and 1.062 MW m~(-2) K~(-1). This significant enhancement in the G value can primarily be attributed to the increase in the length of SWCNTs and in the number of PU molecular chains. The vibrational densities of states of phonon spectrum indicate that the carbon and oxygen atoms in the PU molecular chains are favorable for interfacial thermal transport. The radial distribution function and interaction energy demonstrate the distribution characteristics of the PU molecular chains and also verify the accuracy of the simulation.