Thermal Conductivity of Single-Walled Carbon Nanotube/PMMA Nanocomposites

Single-walled carbon nanotubes (SWNTs) are considered as promising filler materials for improving the thermal conductivity of conventional polymers. We carefully investigated the thermal conductivity of SWNT poly(methylmethacrylate) (PMMA) nanocomposites with random SWNT orientations and loading up to $9vol%$ using the comparative technique. The composites were prepared by coagulation and exhibit $∼250%$ improvement in the thermal conductivity at $9vol%$⁠. The experimental results were analyzed using the versatile Nielsen model, which accounts for many important factors, including filler aspect ratio and maximum packing fraction. In this work, the aspect ratio was determined by atomic force microscopy (AFM) and used as an input parameter in the Nielsen model. We obtained good agreement between our results and the predictions of the Nielsen model, which indicates that higher aspect ratio fillers are needed to achieve further enhancement. Our analysis also suggests that improved thermal contact between the SWNT network and the matrix material would be beneficial.