Computational modeling and evaluation of the thermal behavior of randomly distributed single-walled carbon nanotube/polymer composites

A three-dimensional computational model is developed using the finite element method based on continuum mechanics to evaluate the thermal behavior of randomly distributed single-walled carbon nanotube (SWCNT)/polymer composites. The model is validated with the experimental data of two composites, SWCNT/polyolefin and SWCNT/epoxy. The effects of SWCNT–matrix interfacial thermal resistance (Rksm), volume fraction (Vf), thermal conductivity (k) and diameter of SWCNTs on the k of composites are quantified using this model. The results show that the k of the composite is lower than that of the pure polymer matrix at an Rksm larger than the critical value (Rksmc). The effect of the Vf of SWCNTs on the value of k depends on the Rksm of the SWCNT–matrix. The k of the composite increases with the Vf of SWCNTs when the Rksm is lower than the Rksmc and, in contrast, the value of k decreases as the Vf of SWCNTs increases when the Rksm is higher than the Rksmc. SWCNTs with a large diameter can increase the k of composites more efficiently than is the case with a small diameter. When the k of SWCNTs is higher than 1000 W/m K, it has little influence on the k of composites.

► A finite element model of thermal conductivity (k) of SWCNT composites. ► The role of SWCNTs and interfaces change with the interfacial thermal resistance. ► SWCNTs with a larger diameter are more efficient to conduct heat in composites. ► The k of SWCNTs (above 1000 W/m K) has little effect on the k of composites.