TGA or thermogravimetric analysis allows for a determination of the change in a material, both in physical as well as chemical properties, which occurs with increasing temperature with a constant rate of heating as well as over time.
This is very helpful in providing mass change, temperature change and temperature throughout the process, which can then be used to identify the material. TGA analysis is often used when there is a need to determine inorganic filler materials in an unknown sample for reverse engineering or other processes.
There are many different analysis possibilities using this method. In addition to inorganic materials, it is can also be used to determine plastics and polymers as well as metals, glass and even composite materials.
The Process
Sample sizes can be very small with TGA analysis, with the possibility to work with samples as small as 1mg, although larger sample sizes of up to 10mg make the testing process less complicated.
The sample is loaded onto the balance pan in the machine. Then, a computer controls the heating process to create either a specific heating rate or to produce a consistent mass loss of heating time.
The computer continually weighs the sample as well as records the weight over time and with the temperature. In some cases, a reference sample will also be simultaneously tested, providing a specific set of results from a known sample exposed to the same process.
Applications
While TGA analysis can be used to identify unknowns in a polymer or resin, it can also be used to measure and evaluate the thermal stability of a sample. This is done with known samples to ensure that the polymer is stable to use in specific temperatures and environments.
It is also an option for determining if there is water content or specific types of solvents present in the sample. In some applications, it is also the best option for evaluating the volatile emissions of a material as evaporation occurs.
