This part of ISO 11358 specifies general conditions for the analysis of polymers using thermogravimetric techniques. It is applicable to liquids or solids. Solid materials may be in the form of pellets, granules or powders. Fabricated shapes reduced to appropriate specimen size may also be analysed by this method.

Thermogravimetry can be used to determine the temperature(s) and rate(s) of decomposition of polymers, and to measure at the same time the amounts of volatile matter, additives and/or fillers they contain.

The thermogravimetric measurements may be carried out in dynamic mode (mass change versus temperature or time under programmed conditions) or isothermal mode (mass change versus time at constant temperature).

Thermogravimetric measurements may also be carried out using different testing atmospheres, e.g. to separate decomposition in an inert atmosphere from oxidative degradation.