Dynamic Mechanical Thermal Analyzer
DMTA is a thermoanalytical technique used to study and characterize materials. It is most useful for observing the viscoelastic nature of polymers. Two methods are currently used: One is the decay of free oscillations and the other is forced oscillation. Free oscillation techniques involve applying a force to a sample and allowing it to oscillate after the force is removed. Forced oscillations involve the continued application of a force to the sample. An oscillating force is applied to a sample of material and the resulting displacement of the sample is measured. This method is the most commonly used one today. Samples can be either solids or melts. Most solids are tested by linearly applied strains and melts or liquids are normally tested in shear.