Thermal Analysis:Methods, Applications, and Insights in Material Research

Thermal analysis is a method used to accurately record the relationship between the physical and chemical properties of a substance and its temperature under programmed temperature control. It studies the physical changes, such as polymorphic transformations, melting, evaporation, and dehydration, as well as chemical changes like thermal decomposition and oxidation, which occur during heating. These changes are accompanied by alterations in temperature, energy, or weight.

Differential Thermal Analysis (DTA)

Figure 1:Characteristics of DTA curve

The sample and a reference material are subjected to the same heating or cooling conditions, and the temperature difference between them is measured over time. By analyzing the relationship between the temperature difference and time, physical or chemical changes occurring in the sample can be identified.

Differential Scanning Calorimetry (DSC)

Figure 2:DSC thermograms from both failed and passing adhesives.Image from VERYST

The sample and the reference material are placed in two separate cells and heated or cooled within the same temperature range. The heat flow between the two is recorded over time. By analyzing the relationship between heat flow and time, the physical or chemical changes occurring in the sample, as well as the associated thermal effects, can be determined.

Thermogravimetric Analysis (TGA)

Figure 3:Thermogravimetric analysis (TGA) of nanocapsules and Urea-formaldehyde.

Under programmed temperature control, the sample's mass is measured over time. By analyzing the relationship between mass change and time, physical or chemical changes in the sample and their corresponding mass changes can be identified.

Thermomechanical Analysis (TMA)

Figure 4:Schematic diagram of the thermal curve for cyclic TMA testing.Image from tainstruments

Under programmed temperature control, the expansion coefficient of the sample is measured as a function of temperature. By analyzing the relationship between expansion and temperature, the volume changes in the sample during heating or cooling can be determined.

Wide Applications of Thermal Analysis

Thermal analysis plays a critical role in the research and development of various materials. In the polymer industry, it is used to evaluate the thermal properties of plastics and rubbers, such as glass transition temperature and melting behavior. In the pharmaceutical field, these techniques help study drug crystallization, stability, and potential thermal reactions during formulation processes. Additionally, thermal analysis is used in food science to monitor the thermal stability of food and phase changes during processing.

In battery and electronic materials research, thermal analysis is also extensively applied. For instance, TGA assesses the decomposition behavior of battery materials at high temperatures, while DSC tests the thermal stability of electrolytes. The ceramic, metal, composite, and construction material industries also rely on these techniques during research and quality control, allowing for the measurement of key properties such as expansion, stress, and heat resistance at high temperatures.

Conclusion

In summary, thermal analysis is a core tool in materials science that not only helps researchers deeply understand the physical and chemical properties of materials but also provides essential technical support for the development, performance optimization, and quality control of materials. Comprehensive thermal analysis allows for the prediction of material behavior in specific applications, improving functionality and reliability.