Thermal Analysis

Thermal analysis includes a group of analytical methods by which a physical property of a substance is measured as a function of temperature while the substance is subjected to a controlled temperature and atmosphere. With differential scanning calorimetry (DSC) a small sample is heated or cooled using a controlled temperature program in a controlled atmosphere and the heat flow to or from the sample in comparison to a reference is determined. With DSC the melting temperature and melting enthalpy, the glass transition temperature and specific heat change, the temperature and enthalpy change of other phase transitions and related variables like the degree of cystallinity of a polymer sample can be determined. Thermogravimetric analysis (TGA) permits the continuous determination of sample weight as a function of a temperature / time program and in various atmospheres. Typically, only a few milligrams of a polymer sample is heated with 10 or 20 kmin^-1 in N₂ or O₂ to determine its decomposition onset temperature, or the loss of low molecular weight components like residual solvent, plasticizer, etc. The TGA coupled mass spectrometry allows for the direct analysis of the species driven out of the sample in the course of a TGA program.