Simultaneous Thermal Analyzer

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-... 

The experiments described in this section were performed using a Simultaneous Thermal Analyzer STA 780 (Stanton-Redcroft Ltd.). This instniment supplies the measuring signals temperature (T), weight (TGA), first derivative of weight with respect to time... 

One cannot be certain about the beginning of oxidation of the blown bitumens, their dispersion medium, or their petroleum resins, because this type of bitumen contains relative low boiling flux oils. There are only small, statistically insignificant, differences between the means of the DTG maximum temperatures of the blown bitumens, their dispersion medium and their petroleum resins in air and in argon. Thermogravimetry cannot determine whether evaporation or oxidation takes place. Use of a simultaneous thermal analyzer might prove whether the reaction is exo- or endothermic. 

The software of the Simultaneous Thermal Analyzer, STA 780 (STA 1000) also allows the ASTM E 698-79 method to be used. Unfortunately there is no computer program to process data from simultaneous TGA/DTA (TGA/DSC) test runs. For computation according to ASTM E 698-79 only separately sampled DTA (DSC) data can be used, so the advantage of a simultaneous measuring instrumentation cannot be fully realized. The conversion levels at peak maximum temperatures are also unknown, and the total conversion can only be ascertained after termination of the test run. The installed software version C 4.20 offers plots similar to those of the DSCASTMKin vl.OO ... 

The kinetic parameters computed according to ASTM E 698-79 from DTA data of the Simultaneous Thermal Analyzer are presented in Table 4-203 No. 1 and No. 2. 

Table 4-203 Pyrolysis kinetics according to ASTM E 698-97, experiments with Simultaneous Thermal Analyzer.

The standard evaluation program of the Simultaneous Thermal Analyzer STA 750 supplies the plots of TGA and DTA versus temperature. In addition, the curve of the first differential quotient of the weight loss with respect to time dG/d/ (DTG) may be plotted (Fig. 4-194). The peak maximum temperatures from both DTA and DTG may be determined quite easily and used to calculate the activation energy and frequency factor. There is no program to process such data, so the calculation is done on an external computer. The... 

Software only for the Simultaneous Thermal Analyzer STA 780 was available for kinetics according to Borchardt and Daniels. Similarly to the kinetics program according to ASTM E 698-79, only separately sampled DTA data can be processed using the Borchardt and Daniels program. The DTA data from simultaneous TGA/DTA experiments cannot be... 

Table 4-206 Pyrolysis kinetics of bitumen B80 according to McCarty and Green. Experiments with Simultaneous Thermal Analyzer...

Comparison of commercial computer programs 467 4.10.2.1.2 Experiments using Simultaneous Thermal Analyzer... 

DSC instruments can be used as well as thermobalances. The use of a Simultaneous Thermal Analyzer (TGA/DSC or TGS/DTA) makes sense only if the software permits evaluation of the DSC (DTA) data using the ASTM E 698-79 method, and evaluation of thermogravimetric data by the Flynn and Wall method. Otherwise using a cheaper instrument will be just as good. 

For investigation of the kinetics of p)Tolysis and oxidation reactions a Simultaneous Thermal Analyzer is preferred, provided that the incorporated software permits the evaluation according both to ASTME 689-79 and Flynn and Wall. In this way the kinetic parameters can be obtained and at the same time the peak maxima (minima) of the curves of energy against temperature can be examined to decide whether they really appear at equal conversion levels independent of the heating rates. All the requirements for the thermoanalysis of petroleum and its products would be fulfilled if such an instrument could... 

Schematic Diagram of the Simultaneous Thermal Analyzer STA 409EP (Netzsch Geratebau GmbH)...

STA Simultaneous Thermal Analyzer (TGA/DSC or TGA/DTA) DMTA Dynamic Mechanical Thermal Analyzer TMA Theimomechanical Analyzer DETA Dielectric Thermal Analyzer... 

TGA and DTA were performed in argon or in air flow under dynamic (5 °/min) heating. A simultaneous thermal analyzer STA-781 (Stanton Redcroft) was used. 

The TGA and DSC were carried out using simultaneous thermal analyzer apparatus of Rheometric Scientific Company (STA 1500+ Model, England) under a flow of dry air. The temperature was raised from 25°C to 800°C using a linear programmer at a heating rate of 10°C/min. The sample weight was between 10 and 20 mg. 

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