Studying the fire hazard properties of multi-walled carbon nanotubes by the method of synchronous thermal analysis

Abstract

The present paper considers oxidation of multi-walled carbon nanotubes at different heating rates and temperatures to ensure the process in the kinetic region. The nanotubes were analyzed by the method of synchronous thermal analysis. Experiments were carried out at different heating rates: 5, 10 and 20 °C/min. As a result, the character of thermogravimetric and differential thermogravimetric curves was determined, and thermograms were constructed, thereby allowing to define weight loss stages and establish exact weight loss values at a programmed temperature increase. Besides, the temperature characterized by the maximum weight loss rate was established. Differential scanning calorimetry revealed the maximum temperature of endothermic and exothermic peaks, as well as changes in thermal effects (enthalpy changes). The most important indicators of fire hazard of the multi-walled carbon nanotubes – ignition and self-ignition temperature – were determined. The ignition temperature was approximately equal to the temperature of the beginning of the thermal distortion of the sample in the air – 553.7, 578.6 and 584.3 °C for the heating rates of 5, 10 and 20 °C/min, respectively. The self-ignition temperature corresponded to the temperature of the maximum yield of volatiles – 627.5, 651.9 and 670.8 °C for the heating rates of 5, 10 and 20 °C/min, respectively.