Measurement of the glass transition temperature of polymers by Dynamic Mechanical Analysis (DMA) (CAT#: STEM-ACT-0076-WXH)

DMA works by applying a sinusoidal deformation to a sample of known geometry. The sample can be subjected by a controlled stress or a controlled strain. For a known stress, the sample will then deform a certain amount. In DMA this is done sinusoidally.
Thermomechanical Analysis, or TMA, applies a constant static force to a material and watches the material change as temperature or time varies. It reports dimensional changes. On the other hand, DMA applies an oscillatory force at a set frequency to the sample and reports changes in stiffness and damping. DMA data
is used to obtain modulus information while TMA gives coefficient of thermal expansion, or CTE. Both detect transitions, but DMA is much more sensitive.

DMA is a technique used to study and characterize materials. It is most useful for studying the iscoelastic behavior of polymer. It is widely used in thermoplastic and thermosetting plastics, rubber, coatings, metals and alloys, inorganic materials, composite materials, etc.
DMA is used for measurement of various types of polymer materials using different deformation modes. There are tension, compression, dual cantilever bending, 3-point bending and shear modes, and the most suitable type should be selected depending on the sample shape, modulus and measurement purpose.

1. The sample is clamped in the measurement head of the DMA instrument.
2. During measurement, sinusoidal force is applied to the sample via the probe.
3. Deformation caused by the sinusoidal force is detected and the relation between the deformation and the applied force is measured

Dynamic Mechanical Analyzer (DMA)