Dynamic mechanical analyzer storage modulus

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.

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 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 the ratio of loss modulus to storage modulus?

This is illustrated in Figure 2. The ratio of the loss modulus to the storage modulus is also the tan of the phase angle and is called damping: Damping is a dimensionless property and is a measure of how well the material can disperse energy. Damping lets us compare how well a material will absorb or loose energy.

What is dynamic mechanical analysis?

Dynamic mechanical analysis is an essential analytical technique for determining the viscoelastic properties of polymers. Unlike many comparable methods, DMA can provide information on major and minor transitions of materials; it is also more sensitive to changes after the glass transition temperature of polymers.

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.