Thermogravimetry in an inert atmosphere

The series of n-alkanes from n-decane up to n-hexacontane (Table 3-1) and some chemicals mentioned in ASTM D 2887-84 (Table 3-2) were used for modelling purposes. 

Carbon Number Boiling Point CC) Carbon Number Boiling point CC) 

The model substances tested mostly exhibit only one maximum in the curve of weight (mass) loss rate versus temperature (DTG). The maximum temperature will be determined by the boiling behavior of the sample. The same is valid for the DTA curves measured by the Simultaneous Thermal Analyzer (STA 780). Each of the temperatures, which describe the thermal behavior in an inert atmosphere, can be repeated within relatively nan ow limits as shown in Table 3-3 by the example of four n-alkanes, and in Table 3-4 for five aroma- 

Nevertheless there are differences in the temperatures of equal evaporated portions, and in the DTG maximum temperatures between the two thermobalances TG 750 and STA 780  

Even if the ratio surface volume seems to be nearly equal for equal sample sizes, the higher walls of the STA pan cause a difference in the removal of the evaporated portions. Nor did the use of TG 750 pans in the STA 780 yield identical results, because the geometric conditions of the two ovens are different. 

---