Dynamical Mechanical Analysis (DMA)

DMA curves used to measure glass transition temperature (Tg) in CFRP polymeric composites using 3 different metrics: Storage modulus, Loss modulus, and Temperature. Broadening of the range of measured Tg values (as shown in this sample) can be indicative of polymer crosslinking.

Dynamical mechanical analysis (DMA) is used to study changes in the mechanical properties of a material under periodic stress as the temperature is varied. DMA results are used to assess: glass transitions, melting points, elastic modulus, strain-to-break, toughness, creep, and numerous other thermal and mechanical properties.

Strengths

Ultra-high sensitivity to deformation and displacement
Improved detection threshold for thermal transitions (vs. Differential Scanning Calorimetry)
High flexibility in experiment design
Rapid and straightforward data collection
Particularly well-suited for high-stiffness polymers

Limitations

Data quality is impaired by rough, asymmetric, and irregularly-shaped samples
Analysis is destructive

Technical Specifications:
Example Outputs Instruments Used Sample Requirements

Learn More:
How DMA Works Additional Resources Related Techniques

Example Outputs

DMA curves used to measure glass transition temperature (Tg) in CFRP polymeric composites using 3 different metrics: Storage modulus, Loss modulus, and Temperature. Broadening of the range of measured Tg values (as shown in this sample) can be indicative of polymer crosslinking.

DMA curve of moduli as functions of time. Curve shape is characteristic of epoxy resin material during the cross-linking reaction (G’, G” cross-over).

Instruments Used for DMA

Anton Paar MCR702 DMA

The MCR 702 MultiDrive is a combination DMA / Rheometer with the flexibility and precision to facilitate a huge array of test mode options.

Maximum Torque: 230 mNm
Normal Force Range: 0.005 N to 50 N
Maximum Temperature: 1000 °C

View Instrument Brochure

Sample Requirements

Solid phase
Smooth, symmetric, and regularly shaped for best data
Sample Dimension Limits:
- For 3-point Bending Test:
  thickness ≥ 4mm, length ≥ 40 mm;
- For Tension Test:
  thickness ≥ 200 µm, length ≥ 30 mm;
- For Compression Test:
  thickness 5 – 10 mm, diameter ~ 50 mm;

How DMA Works

In a DMA measurement, an oscillating force is applied with a set frequency to a sample suspended in a near-frictionless environment. This force can be set to bend, stretch and compress, torque, or maintain tension directionally within the sample.

While the dynamic stress is applied to the sample, the whole system is simultaneously subjected to set temperature change: either constant or iterated heating / cooling at fixed or variable rates. The material’s stress response over time is measured both through its dimensional changes and its damping of the oscillating force.

DMA systems detect dimensional changes with hypersensitive optical sensors, and track damping through the applied force probe. These two metrics, recorded as a function of time and temperature, are used to produce DMA curves which provide robust, quantitative analysis of the sample’s thermomechanical characteristics.

Additional Resources