Simultaneous Thermal Analysis (TGA-DSC)

Simultaneous Thermal Analysis (STA) is a thermoanalytical technique which simultaneously measures two or more thermal properties on a single sample. Generally, this refers to the simultaneous recording of mass changes and caloric data in the sample; i.e., the combination of thermogravimetry (TGA) and differential thermal analysis (DTA) or differential scanning calorimetry (DSC).

During the measurement, the sample is subjected to a freely selectable temperature program under a defined atmosphere.  By simultaneously recording mass changes and caloric data on exactly the same sample and under identical conditions, the measuring time is decreased (by half), among other things. Another significant advantage is that uncertainties resulting from possible differences in sample preparation and the use of different instruments (TGA, DSC) can be ruled out. By employing an STA, the comparability of the characteristic temperatures obtained by means of TGA and DSC measurements is guaranteed. For inhomogeneous sample materials, problems due to differing sample compositions for TGA and DSC measurements can thus be eliminated.

The advantages are obvious: The test conditions are perfectly identical for the TGA and DSC signals (same atmosphere, gas flow rate,vapor pressure on the sample, heating rate, thermal contact to the sample crucible and sensor, radiation effect, etc.).

Furthermore, it improves sample throughput as more information is gathered from each test run.

DSC Analysis Possibilities

  • Melting/crystallization behavior
  • Solid-solid transitions
  • Polymorphism
  • Degree of crystallinity
  • Glass transitions
  • Cross-linking reactions
  • Oxidative stability
  • Purity Determination
  • Specific heat
  • Thermokinetics

TGA Analysis Possibilities

  • Mass changes
  • Temperature stability
  • Oxidation/reduction behavior
  • Decomposition
  • Corrosion studies
  • Compositional analysis
  • Thermokinetics

Problem: Oxidation of Samples due to residual O2

Prerequisite for lowest O2 concentrations: Vacuum-tight instrument!

Evacuation and filling of the instrument (several times)

Residual O2 level depends on:  

  • Vacuum tightness of the instrument  
  • Desorption of O2 from the walls  
  • Vacuum tightness of the gas supply  
  • Purity of the purge gas

Solution: OTS® for in-situ Reduction of Oxygen

Recommended Literature

Application literature
Application literature

Evolved gas analysis (EGA) from thermal analyzers such as thermogravimetry (TG) or simultaneous thermal analysis (STA) which refers to simultaneous TG–DSC is well established since it greatly enhances the value of TG or TG–DSC results.

Application Literature

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