Thermomechanical analysis

What is thermomechanical analysis used for?

Thermomechanical analysis measures the physical changes a sample undergoes across a temperature range, thus helping to investigate the mechanical properties of polymers and novel materials in different environmental conditions. The parameters that can be studied through TMA include the coefficient of thermal expansion, phase transition temperatures, and crystalline vs. amorphous characteristics of polymers at specific temperatures. 

The wide array of properties that TMA can measure gives the technique applications across a range of industries for quality control and the development of new materials. For example, the method can be used to ensure that the properties of novel biobased plastics are comparable to those of traditional plastic.

How does thermomechanical analysis work?

In general terms, thermomechanical analysis is any process that measures the changes in the physical properties of a sample as it undergoes a temperature change. In most cases, this will involve heating the sample through a temperature regime as a constant, external force is applied.

Typically, the sample is attached to a probe and set inside the testing chamber. The probe is coupled to a force generator and a length detector, which will respectively apply a constant force and measure the distance that the probe moves as a result. A variety of different forces can be introduced, such as pulling for tensile testing or pushing for compression or bend testing. The detector measures how the sample moves or deforms as the temperature is cycled, which in turn provides information about how the mechanical properties of the sample are tied to its thermal characteristics.

Suitable samples and sample preparation

TMA is most commonly carried out on a range of solids, such as polymers, ceramics, or composites. Sample preparation will depend on the type of TMA analysis that is carried out and may include cutting into strips for pull testing or casting a solid block for bend testing.

TMA vs. DMA & DSC

During TMA, a constant force can be applied to the material as it is cycled through a temperature regime, allowing the user to monitor how it deforms or undergoes changes based primarily on the temperature. In dynamic mechanical analysis (DMA), oscillating or varying force is applied, which means that the focus is more on determining the effects of the applied force, although the temperature can also be varied. Both DMA and TMA can be used to determine some of the same properties, such as the glass transition temperature.

During differential scanning calorimetry (DSC), on the other hand, a sample is heated with a specific amount of energy, and its temperature change is monitored. This can provide information on the thermal characteristics, such as the specific heat capacity or the phase transition temperatures of the sample, but does not provide information on mechanical changes in the same way that TMA does. To gather a full set of information, TMA, DMA, and DSC can all be used in conjunction.

Questions?

Polymer testing expert Ville Roininen is happy to help with selecting the most suitable thermal analysis method for your testing need.

ville.roininen@measurlabs.com+358 40 752 5289

Need an analysis?

Measurlabs offers high-quality testing services with a variety of thermal analysis methods, including TMA, DMA, DSC, dilatometry, and thermogravimetric analysis (TGA). Do not hesitate to contact us to request an offer or ask for more information.

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