Intrinsic viscosity and storage modulus

What is intrinsic viscosity of a polymer solution?

The intrinsic viscosity, [η], of a polymer solution is defined as the zero concentration limit of the reduced viscosity, \ (\eta _ {red} = \eta _ {sp} /c\), where c is the polymer concentration and \ (\eta _ {sp} \) is the specific viscosity.

What is the difference between viscosity and modulus?

The difference is that viscosity looks at the variation of strain with time. Nevertheless, modulus in solids is roughly analogous to viscosity in liquids. We can use this parallel plate geometry to obtain values for storage modulus and loss modulus, just like we can via an extensional geometry. The values we get are not quite the same.

What is the'sum' of loss and storage modulus?

The ‘sum’ of loss and storage modulus is the so-called complex modulus G*. The complex viscosity h* is a most usual parameter and can be calculated directly from the complex modulus. This viscosity can be related to the viscosity measured in a steady shear test by a relation known as the Cox-Merz rule.

How to determine intrinsic viscosity?

To determine the intrinsic viscosity [η], the polymers contribution to the solutions viscosity, a multi-concentration method was used with the dilute samples from 0.8 to 0.1 wt%. The importance of model fitting from the previous section arises from the necessity for the measured viscosity values used in the calculations to be at zero shear.

What is a storage modulus?

The storage modulus is a measure of how much energy must be put into the sample in order to distort it. The difference between the loading and unloading curves is called the loss modulus, E ". It measures energy lost during that cycling strain. Why would energy be lost in this experiment? In a polymer, it has to do chiefly with chain flow.

Can moduli be used to describe viscoelastic properties?

However, it is often acceptable to use the moduli extracted from the first-harmonic component of the stress as measures of energy storage and dissipation for the description of the viscoelastic properties of the system .