The intrinsic viscosity concentration and molecular weight relationships

1 The intrinsic viscosity concentration and molecular weight relationships 

The viscosity of a polymer solution is related to the size and extension of the polymer molecule in that particular solution larger molecular species are generally associated with higher solution viscosities. In this section, the issue of the molecular size of the polymer is discussed mainly in the light of viscosity-related properties of the polymer solution. Relationships are developed that apply to both random coil molecules, such as HPAM, and more rigid macromolecules like xanthan. A number of other quantities are related to viscosity these include the relative viscosity, specific viscosity, reduced viscosity and inherent viscosity, which are defined in Table 3.1. (Billmeyer, 1971 Rodriguez, 1983). Clearly, all of these quantities are related to the polymer concentration in solution, and a more fundamental quantity which will be defined is the intrinsic viscosity, [ ]. The intrinsic viscosity is the limit of the reduced viscosity or inherent viscosity as the solution concentration of polymer tends to zero as shown below. 

Newtonian fluid viscosity cP (centipoise) P (poise) Pas (Pascal second)  

Polymer solution viscosity n rjQ at very low shear rj limiting value at high shear cP P Pas 

In the formulation of Huggins (1942), the relationship between the specific viscosity and concentration is as follows for low-concentration solutions  

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