INTRODUCTION TO VISCOUS FLOW AND THE RHEOLOGICAL BEHAVIOR OF POLYMERS

INTRODUCTION TO VISCOUS FLOW AND THE RHEOLOGICAL BEHAVIOR OF POLYMERS 

Fundamental Principles of Polymeric Materials, Third Edition. Christopher S. Brazel and Stephen L. Rosen. 2012 John Wiley Sons, Inc. Published 2012 by John Wiley Sons, Inc. 

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The Newtonian constitutive equation is the simplest equation we can use for viscous liquids. It (and the inviscid fluid, which has negligible viscosity) is the basis of all of fluid mechanics. When faced with a new liquid flow problem, we should try the Newtonian model first. Any other will be more difficult. In general, the Newtonian constitutive equation accurately describes the rheological behavior of low molecular weight liquids and even high polymers at very slow rates of deformation. However, as we saw in the introduction to this chapter (Figures 2.1.2 and 2.1.3) viscosity can be a strong function of the rate of deformation for polymeric liquids, emulsions, and concentrated suspensions. 

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