3. Dynamic mechanical analysis

3.1 Principle

In dynamic mechanical analysis (DMA), dynamic stress replaces or is superimposed on static stress. Analyses in which dynamic stress is applied to the sample enable us to characterize relaxation phenomena associated with glass transition-type transitions (primary relaxation) or without thermal manifestation (secondary relaxations).

Depending on the temperature range, on which the polymer's viscosity depends, and on the sample's dimensions, different stress modes are used: three-point bending, longitudinal stress, torsion, shear between parallel plates ( T > T _g ), single or double embedding... [23] . Recording the elastic and anelastic...