Carbon Nanotube | Purity | Evaluation of Purity and Heat Resistance


Evaluation of Purity and Heat Resistance

When carbon nanotubes (CNTs) are heated in air, their mass reduces due to combustion. This mass reduction can be used to evaluate the purity of CNTs. The decomposition temperature can also be used to evaluate the heat resistance of CNTs, and this is applied to investigating the conditions of CNT formation.
Thermogravimetric analyzers offer qualitative and quantitative measurements of thermal decomposition and dehydration of various samples. Using a simultaneous thermogravimetric/differential thermal analyzer (TG/DTA), differential thermal analysis can be simultaneously conducted.

The DTG-60 Thermal Analyzer simultaneously performs measurements of changes in mass and DTA measurements of the exothermic peak temperatures and calorific values, which allows detailed determination of the ratio of amorphous carbon and CNTs.
Fig. 1 shows the thermogravimetric (TG) curve and differential thermal analysis (DTA) curve of single-walled carbon nanotubes (SWNTs) created by arc discharge. The largest exothermic peak in the DTA curve is near 683 ºC, which indicates the combustion of SWNTs. As the 322 ºC peak in the DTA curve is thought to be the combustion of amorphous carbon, the content ratio of SWNTs and amorphous carbon can be determined from their mass loss ratios in the TG curve.

Fig. 2 shows the results of thermogravimetric analysis (using a TGA-50 thermogravimetric analyzer) of SWNTs produced by the HiPco method. The TGA-50 is a dedicated thermogravimetric instrument that uses a highly sensitive vibration-resistant, suspension-type balance to achieve high-sensitivity measurements of less than 1 mg CNT samples. It offers good repeatability, even with less than 0.5 mg samples.

Fig. 1 TG/DTA Measurements (by DTG-60) of SWNTs Produced by Arc Discharge (Samples supplied by Ando Laboratory, Faculty of Science and Technology, Meijo University)

Fig. 2 TG Measurements (by TGA-50) of SWNTs Produced by HiPco Method (Samples supplied by Ando Laboratory, Faculty of Science and Technology, Meijo University)

DTG-60 Thermal Analyzer

This instrument offers improved basic performance, as required for simultaneous thermogravimetric/differential thermal analysis (TG-DTA), and flexibly accommodates a diverse range of atmosphere gases. The TA-60WS thermal analysis workstation compiles and analyzes data to make measurements simple.

TGA-50 Micro Thermogravimetric Analyzer

Offers excellent performance for all items, including vibration resistance, stability, noise, and resistance to temperature fluctuations.
Clearly detects mass fluctuations in the order of several micrograms.