Apparent Viscosity in Non-Newtonian Flow

Several mblecular theories for non-Newtonian flow have been ad-vanced 2-i04 jjjg earlier ones have been reviewed in detail by Graessley.  

Dependence of non-Newtonian viscosity on shear rate log tj/ijo plotted against log 7t,. (A) Theory of Graessley (B) theory of Williams.  

Logarithmic plot of against 7T /2 for narrow-distribution polystyrene with = 180,000. Different symbols refer to five different temperatures from 142° to 174.5°C. Curve drawn from Graessley theory. (Penwell, Graessley, and Kovacs. ) Reproduced, by permission, from the Journal of Polymer Science. 

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