On the effective thermal conductivity of carbon nanotube reinforced polymer composites

In this paper, a theoretical model has been developed for predicting the effective thermal conductivity of an aligned multi-walled nanotube polymer composite. This model is based on an effective medium theory that has been developed for composites containing aligned spheroidal inclusions with imperfect interfaces. To incorporate the nanotube structure into this theory, a continuum model of the nanotube geometry is developed by considering its structure and the mechanism of heat conduction through it. Results show that the overall conductivity will be much lower than expected due to the fact that in the composite, the outer nanotube layer carries the bulk of the heat flowing through the nanotube. It is also seen that the high nanotube–matrix boundary resistance does not significantly affect the overall conductivity. The effective conductivity was also found to be highly sensitive to the nanotube diameter.