What is the difference between storage modulus and dynamic loss modulus?

The storage modulus is often times associated with “stiffness” of a material and is related to the Young’s modulus, E. The dynamic loss modulus is often associated with “internal friction” and is sensitive to different kinds of molecular motions, relaxation processes, transitions, morphology and other structural heterogeneities.

What is storage modulus?

The storage modulus, either E’ or G’, is the measure of the sample’s elastic behavior. The ratio of the loss to the storage is the tan delta and is often called damping. It is a measure of the energy dissipation of a material. Figure 2.

What is storage modulus in tensile testing?

Some energy was therefore lost. The slope of the loading curve, analogous to Young's modulus in a tensile testing experiment, is called the storage modulus, E '. The storage modulus is a measure of how much energy must be put into the sample in order to distort it.

Why is dynamic loss modulus important?

The dynamic loss modulus is often associated with “internal friction” and is sensitive to different kinds of molecular motions, relaxation processes, transitions, morphology and other structural heterogeneities. Thus, the dynamic properties provide information at the molecular level to understanding the polymer mechanical behavior.

How do you calculate a complex modulus from a dynamic mechanical test?

s = so sin(wt) cos d + so cos(wt) sin d. Equation (7) shows that the complex modulus obtained from a dynamic mechanical test consists of “real” and “imaginary” parts. The real (storage) part describes the ability of the material to store potential energy and release it upon deformation.

What is a dynamic modulus of a polymer?

These properties may be expressed in terms of a dynamic modulus, a dynamic loss modulus, and a mechanical damping term. Typical values of dynamic moduli for polymers range from 106-1012 dyne/cm2 depending upon the type of polymer, temperature, and frequency.