Thermal conductivity of aligned CNT‐polyethylene nanocomposites and correlation with the interfacial thermal resistance

Abstract

AbstractCarbon nanotube (CNT) reinforced polymer composites have higher thermal conductivity than polymers themselves, so they have wide application prospects in many thermodynamic applications. It is of great significance to deeply understand the thermal conductivity of polymer nanocomposites and its creations, especially with the CNT‐polymer interface. In this article, for CNT‐polyethylene (PE) nanocomposites, the temperature distribution and thermal conductivity, and its correlation with the CNT volume fraction, the interfacial thermal resistance caused by interfacial defects in the CNT‐PE interface region, and mechanical strain were comprehensively studied through molecular dynamics simulation. The results show that the CNT volume fraction and mechanical stretches have remarkable effects on the thermal conductivity of the nanocomposite, and comparatively the influence of the interfacial defects is weak just in the range of the CNT volume fraction <0.3. The thermal conductivity rapidly increases when the volume fraction of CNTs changes from 0 to 0.20. Under tensile strain, the thermal conductivities κ∥ and κ⊥ (being parallel to and perpendicular to the stretching direction, also the direction of nanotubes) display quite different rules. The κ∥ increases linearly with the tensile strain, while the κ⊥ decreases linearly. After the CNT‐PE interfacial defect degree fd of assessing the defect extent was introduced, its dependence on the interfacial thermal resistance Ri was analytically given, and further the influence of the fd on the thermal conductivity was obtained through comparative studies of with/without interfacial defects. We found that the thermal conductivity has a sharply deduce when the fd is in the range of 30% to 60%.