Thermal decomposition of carbon nanotube/Al2O3 powders by DSC testing

Concerns over unsafe or unknown properties of carbon nanotubes (CNTs) have been raised by many researchers. The thermal stability characteristics, which may represent potential hazards during the production or utilization stage, could be determined by calorimetry testing for various thermokinetic parameters. In this study, differential scanning calorimetry (DSC) was employed to analyze thermal decomposition and to calculate thermodynamic characters and dynamic parameters for activated carbon powder (C), commercial CNT (CBT), and an innovative composite of CNT on Al2O3 powders (CCNT) during the time-effective experiments.The higher heating temperature revealed a “thermal delay effect” that increased the exothermic onset temperature and decreased the heat of decomposition for C, CBT and CCNT. The temperature shifts were irregular at exothermic onset temperatures and at about 25 °C for peak exothermal temperatures of C, CBT, and CCNT as heating rate increased from 2 to 4 °C min−1. From a comparison of results on C, CBT, and CCNT, CCNT had medium exothermic onset temperature, lowest heat of decomposition, and is a safer material (less thermal hazard) than C and CBT. In addition, the heating exothermic reaction was the first order for CCNT and the activation energy increased as the heating rate increased. Our results also implied that different types of carbon contained in C, CBT, and CCNT could yield different energies during thermal decomposition.