Thermogravimetric Analysis (TGA) Sample Testing

Thermogravimetric analysis (TGA) measures the change in the mass of a material as a function of temperature. A derivative weight loss curve can be used to determine the point at which the mass loss is most significant. TGA can be used to determine mass loss or degradation temperatures, as well as the absorbed moisture content of a wide range of materials. We have numerous TGA techniques availble.

These include:

TGA/Simultaneous differential thermal analysis (TGA/SDTA)
TGA (Conventional Mode)
Conventional mode TGA
Gas switching TGA
High resolution TGA
Modulated TGA

Thermogravimetric Analysis/Simultaneous Differential Thermal Analysis (TGA/SDTA)

Thermogravimetric analysis/simultaneous differential thermal analysis (TGA/SDTA) combines TGA, which monitors mass change, and DTA, which measures heat flow, to allow concurrent determination of decomposition and transition temperatures. The TGA/SDTA capabilities include a sealed pan piercing kit, which allows volatile samples analysis, and gas switching. Materials may be tested at temperatures up to 1100ºC over a wide range of heating rates.

The unique capabilities of TGA/SDTA allow:

Analysis of hydrophilic samples
Analysis of volatile samples
Collection of thermodynamic mass loss information
Identification of hidden transitions obscured by mass loss



We offer TGAs at up to 1200ºC with a wide range of heating rates. Typical purge gases are nitrogen and zero air. Curie transition analysis can be performed using an internal calibration routine.

In general TGA provides:

Volatiles quantification, including moisture and solvent loss
Decomposition information to establish
Processing parameters
Product use temperature
Effects of fillers
Effects of flame retardants
Comparative thermal or oxidative stability
Residue or filler quantification
Compositional information such as
Water loss from hydrates
Component rations for mixtures of resins
Gas Switching TGA

We have the ability to switch gases during a TGA experiment. Typically this involves heating a sample in an inert atmosphere and then switching to an oxidizing gas, although other types and combinations of gases may be used. Heating to a sufficiently high temperature allows for the decomposition and/or volatilization of an organic matrix, then switching to air allows for a quick burn-off, for the determination of carbon black content. Use of other gases, for example containing additives, can allow for monitoring of specific reactions with the samples being studied. Gas switching is commonly used for:

Carbon black measurement in resins
Adsorption/desorption studies
High Resolution TGA

In high resolution TGA variable heating rates are used to separate closely occurring mass loss events. This technique is especially effective for the quantification of evaporative losses. The high resolution mode applies very high heating rates until mass loss is noted, at which point the rates are automatically reduced. The result is improved separation of overlapping mass loss events, as well as sharper derivative peaks.

High resolution TGA is typically appliied for:

Highly defined hydration losses
Fingerprinting of subtle mass losses
Resolving impurities in polymers, such as monomer and flame retardants
Modulated TGA (MTGA)

Understanding decomposition kinetics is critical for assessing the physical stability of a material with temperature and processing conditions. Kinetic thermal decomposition studies would require several experiments at different heating rates using conventional TGA. Modulated TGA can provide the same kinetic information in a single experiment. As with other modulated techniques, an oscillatory temperature program is applied, which results in a modulated mass loss. Evaluation of the mass loss that responds to the temperature modulation through sequential cycles allows determination of kinetic parameters.

Modulated TGA provides:

Fast kinetic analysis
Determination of activation energy