Effects of chemical modifications on the thermal conductivity of carbon nanotube composites

Interfaces and close proximity between carbon nanotubes (CNTs) and the matrix are very important for their thermal conductance of CNT composites. Chemical modifications to the CNTs are a possible approach to manage the interfacial interactions. In this study, the nanocomposites of the polydimethylsiloxanerubber with 2 wt % chemical-treated CNTs loading were prepared to investigate the influence of chemical modifications and defects on the thermal conductivity of CNT composites. The CNTs treated in concentrated nitric acid showed remarkable changes which could be seen directly by their morphologies. The thermal conductivities kappa of the composites were measured carefully in comparison with that by the raw CNT loading. The kappa varied somewhat up and down with the treatment level. This study reveals that moderate chemical modifications are beneficial to improve the thermal conductivity of the CNT composites. However, their negative effects to the thermal conductance are more remarkable than the theoretical anticipation. (C) 2005 American Institute of Physics.