Thermogravimetric analysis (TGA) records the weight of a sample under controlled environmental (temperature, purge gas) conditions. Residual solvent or water content may be evaluated by TGA by monitoring weight loss in a sample as it is heated through the boiling point of the compound of interest. More broadly, total volatile, semi-volatile, and medium volatile content in a sample can be characterized using standard test methods, such as those listed below. Accelerated aging studies can also be conducted using TGA to determine the Arrhenius activation energy of a material.
When coupled with FTIR, TGA can be used to analyze the chemical composition of materials. Evolved gases are transported to a flow cell within the FTIR for real time analysis of composition. The kinetic FTIR data is synced with the TGA data, allowing for the weight percentage of individual components (that evaporate or degrade at distinct temperatures) to be determined. Such analyses are useful for analyzing the bulk components in unknown systems. If a more in-depth analysis of minor components/trace additives is needed, pyrolysis GC-MS may be a good alternative.