Joule heat treatment on carbon nanotube films at different elevated temperatures

The temperature response and material changes of Joule heat on carbon nanotube (CNT) films are studied at different elevated temperatures. The results indicate that Joule heating causes rapid rise of temperature up to 300^oC/s for the CNT film. Meanwhile, the steady temperature shows an approximate linear relationship with the power. Under long-term Joule heating the resin impregnated CNT film turns into a well cured CNT composite film. However, uneven temperature distribution of the film is recognized during the Joule heating process, and the temperature distribution can’t be changed by simple pressing, stretching and impregnation on the CNT film. It reveals that the square resistance is the main factor affecting the temperature distribution of the film. In addition, the Joule heat treatment below 250^oC results in an increase of the thickness by 10% and a decrease of the electrical conductivity by 15% for the CNT film.