Thermal Analysis of Coatings
Published Online: 15 SEP 2006
Copyright © 2000 John Wiley & Sons, Ltd. All rights reserved.
Encyclopedia of Analytical Chemistry
How to Cite
Meyer, E. F. 2006. Thermal Analysis of Coatings. Encyclopedia of Analytical Chemistry.
- Published Online: 15 SEP 2006
The thermal analysis of coatings involves measuring the response of a material when subjected to a thermal stimulus, sometimes in combination with a mechanical stress. The thermal stimuli used in the thermal analysis of coatings include linear temperature ramps, a sinusoidal modulation around a fixed temperature, the superposition of a linear ramp and a sinusoidal modulation, and a simple isotherm in which some property of the material is monitored as a function of time. The responses measured by the thermal analyst include: melting, crystallization, evaporation, degradation, stress relaxation, softening point, and glass transition, as well as physical properties such as the elastic and viscous moduli. These responses aid in the development, characterization, and determination of the proper application and bake conditions for a wide range of coatings.
In general, thermal analysis techniques are very sensitive and, for many applications, a sample mass of the order of 10 mg is sufficient. However, the assignment of a thermal event to a particular chemistry or morphology requires knowledge of the system being analyzed or another analytical technique. For example, thermal analysis can accurately determine the temperature and enthalpy of a crystalline polymer melt but it does not provide any other information as to the chemistry of the polymer. Assigning a cause to a thermal event becomes increasingly difficult as the nature of the material becomes more complicated. Such is the case with a fully formulated coating which contains a wide range of polymeric and oligomeric materials, as well as various additives. To determine which chemistry is responsible for a particular thermal transition, other analytical techniques are used, frequently in direct combination with the thermal analysis technique.