Thermogravimetric Analysis (TGA)

What is it?

Thermogravimetric Analysis (TGA) is the measurement of the weight loss or gain as a function of temperature or time. It can be used to calculate the components in a polymer or material: the amount of solvents or extenders, amount of polymer, percent filler, and ash content.  In addition, it can also be used to measure the amount of coke on catalysts, the Curie point of a metal, or the progress of a condensation polymerization.  Measurement of materials losing or gaining mass like residual solvent in a dried pharmaceutical or the amount of gases lost on decomposition or curing can be performed. Coupling to a FTIR in TG-IR  increases the ability to determine the off-gases.

We offer the following up to 1000°C:

*Not all specific testing methods may be listed here 

  • Compositional Analysis is the basic technique done in TGA.
    • Most products today are not made up of one exclusive material. Many of these have different decomposition temperatures and from this one can determine the component percentage of the sample. A commonly used example is rubber, where it may contain oil, polymers, and various fillers. Switching gases in the run can also be of use depending on the application.
    • While one method is to simply perform a test at a set rate per minute, another is to insert an isothermal step above each individual decomposition point, and hold at that temperature until that component has burned off. This would be repeated for each component and give a more accurate compositional analysis. This can be automated by several software methods like Autostep, High Res, or MaxRes TGA.
    • The coupling of the TGA to an FT-IR system can provide greater detail in to substance composition. This method allows analysis of the components that burn off, and determining the component by IR spectra.
    • Methods:
      • ASTM E1131, E2105, E2402, D6375
      • IPC-TM-650: TM
  • Curie Point Determination
    • The Curie point is the temperature where a material changes from magnetic to non-magnetic. Specific alloys are used throughout various industries, particularly electronics, and knowing the produced alloy’s true Curie point can determine if it has been correctly made or if it will be suitable for use. This test is preferable to taking the sample to the melting point as many of the widely used materials have extremely high melting points and in some cases different alloys have similar melting points but drastically different Curie points.
    • A NOACK test is important in most lubricating oils. These generally are used in machinery that operates at high temperatures, and many oils have components that will evaporate at higher temperatures. After this evaporation, the remaining oils properties can change dramatically and lead to increased wear, reduced lifetime, etc. As there is generally a maximum allowable evaporation amount, this test can give an idea of when the lubricant needs to be replaced.
    • Methods:
      • ASTM D5800, D6375
      • IPC-TM-650: TM
  • Residual Solvents
    • This can also be referred to as off-gassing. Small amount of solvents that were not totally removed in processing can cause problems from either a performance or compliance perspective.
    • Methods:
      • ASTM E1131, E2402
  • TGA Kinetics
    • Kinetics can be studied on the degradation of polymers by various approaches to allow predication of behavior under different conditions.  Several standard methods are available.

Rubber Composition by TGATGA