Basic concepts of rheological behaviour

It is beyond the scope of this chapter to consider in detail the many issues related to the theoretical and practical aspects of the non-Newtonian behaviour of polymer solutions. A large amount of published literature is available for readers requiring more detailed information ranging from the introductory to the advanced level [25-28]. One author [29] includes a chapter listing a comprehensive library of books on rheology, categorised into both theoretical and practical aspects of the science. 

However, it is worthwhile considering some of the underlying principles on which the science and measurement of rheology is based, in order to understand how the different polymer types discussed in this chapter behave in end-use environments. 

The outcome of applying this force to the cube can be described by two extremes. 

In practise, aqueous systems containing synthetic polymers of this type exhibit complex behaviour that shows elements of both these effects. Consequently, the term viscoelastic is commonly used when referring to such systems. These effects arise in the entangled mass of chains present in a true solution of polymer, as well as in the interlinked polymer chain network present within the water swollen micro-particles of cross-linked polymers. 

---