Polymer Physics

Chapter 7

Polymer Flow

7.1 Introduction to Rheology

7.1.1 What Is Rheology?

Large-enough deformation of solid materials causes fractures, while large-enough
deformation of fluid materials initiates flow.Rheologyis a subject about the flow of
the matter (Morris 2001 ). More specifically, it studies the flow for permanent
deformation, in other words, the ‘molding’ process to re-shape the materials.
The conventional route to process synthetic polymers includes the mixing of raw
materials, molding, performance tests, storage, and applications. At each stage of
the route above, the rheology often takes a determinative role in the final perfor-
mance of polymer materials. In a broad sense, rheology is not only relevant to the
processing of plastics, fibers, rubbers, pigments, coatings, adhesives, lubricants,
composites, but also crucial for the oil pipe-transportation as well as for food
processing. Moreover, it applies in the life sciences of metabolism and blood
circulation, and even in the geological sciences on the formation process of
mountains and underground resources.

7.1.2 Classification of the Flow

The flow can be classified into three types according to their Reynolds numbers.
Assuming the flow in a pipe or a tube, the Reynolds number is defined as
(Reynolds 1883 )

Re

Dvr



(7.1)

W. Hu,Polymer Physics, DOI 10.1007/978-3-7091-0670-9_7,
#Springer-Verlag Wien 2013

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