ABSTRACT
Thermal analysis embraces all methods in which measurements are made of a physical property that changes as the temperature is varied. Measurements of the variation in physical properties such as the modulus in dynamic mechanical thermal analysis and electrical permittivity in dielectric thermal analysis are both useful methods for characterizing polymers and can provide valuable information on the molecular dynamics. In the dynamic mechanical thermal analysis the sample is deformed cyclically, usually under forced vibration conditions. Techniques such as differential scanning calorimetry, or differential thermal analysis, primarily measure the thermal properties of the material and allow calculation of the enthalpy or entropy changes that occur when transformations such as crystal melting occur. Thermomechanical analysis is the name given to a method capable of measuring the thermal expansion coefficient of materials in their most refined form, but which is sometimes used simply to determine the location of the glass transition temperature.
