Thermal mechanical analysis (TMA) works by measuring the dimensional changes (expansion or contraction) of a material as it is subjected to a controlled temperature program and a defined mechanical force. During the analysis, a sample is placed in the sampling area, and a small force is applied to the material while it is being heated or cooled. The sample is then heated or cooled while the force is applied, causing the material to expand or contract.

A sensor measures the dimensional changes in the sample and plots the displacement against temperature or time. The resulting data is used to calculate the linear expansion, shrinkage, coefficient of thermal expansion (CTE), glass transition temperature, softening point, and other properties related to the behavior of materials under different thermal conditions.

Measurement modes: The METTLER TOLEDO TMA instrument provides a range of different measurement modes, depending on the type of sample and investigation:

• Compression or dilatory
• Penetration
• Film and fiber extension
• 3-point bending
• Swelling in a solvent
• Volume expansion

More information on the different measuring modes can be found in the TMA brochure or by watching the free, on-demand TMA webinar.

The theory behind TMA, or thermomechanical analysis, is based on the principle that when a material is subjected to a controlled temperature program, it undergoes thermal expansion or contraction. This causes a change in its dimensions. By measuring these dimensional changes under different conditions, valuable information about the mechanical behavior of a material can be obtained using a thermomechanical analyzer.

Thermomechanical behavior is the mechanical response of a substance (e.g. expansion or contraction) to a change in temperature. This field of study examines the interconnected effects of temperature and mechanical stress or force on a material's properties. Understanding these interactions is essential for predicting material performance in real-world applications where both thermal variations and mechanical loads are present. A thermomechanical analyzer is a powerful tool used to study these effects.

TMA (thermal mechanical analysis) is a valuable tool in materials science, engineering, research, and quality control. It offers several advantages over other thermal analysis techniques. Some of the advantages of using TMA are:

• Efficient material characterization: TMA allows you to simultaneously measure multiple properties (e.g. expansion, glass transition), saving time and sample material.
• Small sample size: TMA requires only tiny amounts of material, making it ideal for precious or limited quantities of sample.
• Accuracy: The vertical measurement setup in TMA minimizes errors due to bending or sagging, providing precise data.
• Versatility: TMA can be used for the comprehensive analysis of many different materials. It is particularly useful for investigating the behavior of polymers, composites, ceramics, and metals.

Discover an array of additional advantages with the METTLER TOLEDO TMA/SDTA instrument. This advanced instrument boasts a wide temperature range (-150 to 1600 °C) for analyzing a range of materials. Its SDTA capability allows the simultaneous measurement of thermal effects alongside dimensional changes, providing a more holistic picture of the material. The innovative One Click™ feature streamlines sample measurement, while nanometer resolution detects even the subtlest dimensional shifts.

Thermomechanical analysis (TMA) has numerous applications in many different fields, including materials science, engineering, and manufacturing. It is used to characterize materials by measuring the linear thermal expansion, coefficient of thermal expansion (CTE), softening, and glass transition temperature. A thermomechanical analyzer is an instrument used to perform these measurements.

TMA can be used to study the thermal stability of materials, perform quality control tests, develop new products, analyze material failures, and conduct research and development of new materials. By measuring samples under different conditions, TMA allows researchers and engineers to gain insights into the mechanical changes of materials, to optimize their performance, and develop new materials with improved properties.

Explore the TMA technique and its industry applications in this free, on-demand TMA webinar.

TMA (thermal mechanical analysis) and DMA (dynamic mechanical analysis) are thermal analysis methods used to examine the thermal and mechanical properties of materials. However, they differ in methodology and the type of information provided.

TMA focuses on dimensional changes under a small static force. It provides data on how materials expand or contract with a change in temperature. It is used to investigate linear thermal expansion, coefficient of thermal expansion (CTE), glass transition temperature, and softening.

DMA focuses on viscoelastic behavior and mechanical properties under a small oscillatory (dynamic) force of variable frequency. It provides insights into stiffness and damping behavior. It is mainly used to study the viscoelastic properties of polymers, elastomers, and composites.

In summary, TMA evaluates dimensional changes and DMA assesses mechanical behavior. Both techniques are complementary and are often used together to provide a comprehensive understanding of the thermal and mechanical behavior of a material.

TGA (thermogravimetric analysis) and TMA (thermomechanical analysis) are both thermal analytical techniques used to study the properties of materials. However, there are significant differences between them.

TGA measures changes in sample mass as a function of temperature, often with a change of atmosphere from inert to oxidizing conditions. This technique is especially useful for studying the composition, thermal stability, and decomposition of materials. It is also used to determine the amount of volatile components in a sample.

TMA measures changes in the physical dimensions of a material as a function of temperature or time. This technique provides information on the mechanical properties of materials, such as linear expansion, coefficient of thermal expansion (CTE), as well glass transition temperature, and softening behavior.

Thermal mechanical analysis (TMA) is a technique used to measure the dimensional changes in a material as a function of temperature. It is used to characterize materials by determining expansion, shrinkage, coefficient of thermal expansion (CTE), damping, viscoelastic behavior, softening, creep, swelling in solvents, and glass transition (Tg).

It can aid the development and optimization of materials for various applications. For example, thermal mechanical analysis can be used to assess the dimensional stability of electronic components at high temperatures. Another example is to identify the optimal processing temperature for manufacturing polymers and polymer products. The study of degradation behavior of composites is also carried out using TMA techniques.

Here are some examples of thermal mechanical analysis in use:

• Measuring the Coefficient of Thermal Expansion (CTE) allows us to understand how much a material expands or contracts in response to temperature changes. It is vital in assessing the suitability of materials for their intended purpose, such as safeguarding pipes from cracking, or railway lines from bending, due to thermal expansion in a limited space.
• Evaluating Glass Transition Temperature (Tg) enables us to pinpoint the temperature at which a polymer transitions from a rigid solid to a more rubbery state. This understanding is crucial in determining the suitability of a polymer for specific applications at different temperature ranges.
• Determining the Softening Point of Metals helps us assess a metal's capacity to endure deformation under heat and pressure. It is instrumental in selecting metals for applications such as welding or hot forging.
• Analyzing Stress Relaxation in Polymers allows us to measure how the internal stress of a polymer evolves under constant strain. It provides invaluable insights into predicting the long-term performance of polymer components under a fixed load.

Thermomechanical analysis (TMA) of polymers is a technique for analyzing the thermal mechanical properties of polymers. It explores how polymers react to controlled temperature changes by measuring their dimensional responses.

Typically, a small force is applied to the sample by a probe, and its response is tracked using a sensor. TMA analysis can determine important properties such as the thermal expansion, glass transition temperature (Tg), and thermal stability of polymers. Additionally, it can be used to investigate the viscoelastic behavior of polymers, as well as softening temperature and creep.

TMA is a useful technique to characterize polymers and composites when you need to understand their behavior under both temperature and stress. This is crucial for applications where both factors are present, such as predicting how a polymer gear will perform under engine heat and load.

Download our free handbook Thermal Analysis of Polymers – Selected Applications to learn more about important TMA applications, specifically focusing on techniques used to characterize thermoplastics, thermosets, and elastomers.

You can also register to watch our free on-demand webinar, Thermal Analysis of Composites, to better understand how thermal analysis is used to analyze composite materials.

TMA is a powerful technique for analyzing the thermal and mechanical properties of materials, offering high sensitivity. However, it does have some limitations to consider:

• Small sample size: Due to the small size of the sample, TMA may not capture the full material complexity, especially for irregular or inhomogeneous samples.
• Limited detail provided: TMA reveals the dimensional changes but not the underlying molecular reasons for the change. Therefore, consider using additional, complementary techniques for a deeper understanding.
• External factors: Vibrations, ambient temperature, and humidity can affect results. Careful control of ambient conditions is essential.

When used appropriately, TMA provides valuable insights into material properties and behavior, particularly when combined with other techniques.

The METTLER TOLEDO TMA/SDTA 2+ is a robust thermal analysis system designed to give you a comprehensive understanding of your materials' behavior under changing temperatures. Download the full brochure to explore the key benefits that make the TMA/SDTA 2+ an invaluable tool for researchers and engineers.

For METTLER TOLEDO’s TMA instruments, we offer the STARe™ Excellence software. This software is compatible with all our thermal analysis instruments, providing nearly limitless evaluation possibilities. The modular design allows you to choose the functionalities you need, while its flexibility empowers you to customize experiments for any material. With this feature-rich software, you can automate routine tasks as well as ensure regulatory compliance.

The formula for the coefficient of thermal expansion (CTE) relates the change in dimension of a material to the change in temperature and is given by:

CTE = (ΔL / L₀) / ΔT
where:

• CTE is the coefficient of thermal expansion
• ΔL is the change in the length of the material
• L₀ is the original length of the material
• ΔT is the change in temperature

The coefficient of thermal expansion is usually expressed in units of parts per million per degree Celsius (ppm/°C) or per Kelvin (ppm/K). It measures how much a material expands or contracts when subjected to a defined change in temperature.