Viscosity of entanglement network solutions

Newtonian flow. This is called the infinite shear or upper Newtonian viscosity, denoted as T]. This flow behaviour can be accurately modelled using the Cross equation [11]  

Entanglement solutions of the various polysaccharides differ greatly in the magnitude of their zero shear viscosity and in the shear rate at which shear thinning commences 

The shear-thinning region of flow can be conveniently modelled with a power law equation of the form  

This expression can be finther simplified for random coil polysaccharide solutions above C since the fitting of equation 2.6 to the master curve of 77/770 versus j/% where /= 0.1 yields the values of 18 and 0.76 for k and n, respectively. Therefore  

Using equation (2.7) the shear-thinning behaviour of any entanglement polysaccharide solution can be characterised by two parameters, the zero shear viscosity and the shear rate required to reduce viscosity to some fraction of 770. This can be conveniently set to in [7]- 

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