thermogravimetrie

Thermogravimetrie, also known as thermogravimetric analysis (TGA), is an analytical technique that measures the change in mass of a sample as a function of time or temperature under a controlled atmosphere. It is used to determine moisture content, volatile components, decomposition behavior, and thermal stability of materials.

In a TGA experiment, a small sample is placed on a microbalance inside a furnace. The temperature is raised according to a programmed profile or held at specific temperatures, and the sample mass is recorded continuously. The resulting mass‑loss curve (TG) can be complemented by the derivative curve (DTG) that shows the rate of mass loss.

The atmosphere can be air, nitrogen, argon, or reactive gases, chosen to promote or prevent specific reactions. The technique uses a high‑resolution balance that detects microgram changes to typical sample masses of 1–20 mg and heating rates from roughly 1 to 20 °C per minute.

Applications span polymers, pharmaceuticals, catalysts, ceramics, biomass, and soils. TGA is used to quantify moisture or solvent content, determine ash yield, evaluate thermal stability, estimate composition, and study decomposition pathways. Coupled methods with infrared spectroscopy, mass spectrometry, or differential scanning calorimetry provide insight into evolved gases and related transitions.

Interpretation relies on assigning mass‑loss steps to physical or chemical processes. Kinetic analyses and model fitting can estimate activation energies, but results require appropriate models and careful baseline correction. The method is destructive, requires representative samples, and may be complicated by overlapping reactions.

Thermogravimetric analysis is a standard tool in materials science and chemistry, widely available as commercial instruments and integrated into quality control and research workflows.