Basic Rheology Concepts

M. Joly, Rheological Properties of Monomolecular Films, in Surface and Colloid Science, E. Matljevic, M., Vol. 5 Wiley (1972), Part I Basic Concepts and Experimental Methods, p. 1 Part II Experimental Results. Theoretical Interpretation, Applications, p. 79. (Extensive review with several illustrations further reading to secs. 3.6 and 3.7e.)... 

The transport of momentum, heat and mass, or in simpler terms the phenomena of flow, convection, heat conduction, and diffusion, are primarily studied by process engineers and in some aspects also by rheologists. Important though these topics are for the food technologist, they are not the subject of this book. However, some basic concepts are needed in various chapters this includes aspects of rheology and hydrodynamics. Furthermore, transport phenomena inside solidlike foods often are rather intricate, and this subject is also introduced in this chapter. 

Having attempted to delineate what this book is, it may be well to remind the reader what it is not. First of all, it is not a complete treatment -lacking among other topics discussions of crystalline polymers, solution behavior, melt rheology, and ultimate properties. It is also not written from the continuum mechanics approach and thus is not mathematically sophisticated. Finally, it is not a primer of polymer science. Familiarity with the basic concepts of the field is presumed. 

In order to illustrate these approaches, we need to consider some basic concepts of melt rheology. 

Section II conlains a review of the basic concepts of viscosity, rheology, rheological behavior, and well-known and proven evaluation techniques. The discussion will be focused exclusively on shear flow, excluding elongationai flow and nonlinear viscoelasticity which, despite their importance, are not often used in product formulation and for this reason will not be discussed. In fact, elunga-tional effects are more often negligible in suspensions and emulsions. 

A basic appreciation of slurry rheology, or flow behaviour, is in oitant in many solid-liquid separations, e.g. when feeding pressure filters, punq)ing thickener underflow, hydrocyclone feed and exit streams and during cross-flow filtration. This Appendix is designed to introduce some of the terminology and basic concepts. A more thorough text such as Wilkinson [1960] should be referred to for further details, if necessary. 

Except for a brief review of the basic concepts of viscosity, steady shear flow and dynamic flow, the details of rheological measurements and analysis wiU be left to the noted references. 

Rheological Properties of Polyelectrolyte Dispersions 6.1 Basic Concepts on Reology of PE... 

Abstract The basic concepts, formulations, and test methods of pressure-sensitive adhesives are presented. The importance of interfacial interactions, viscous loss, and extensibility are stressed. The common rheological tests are described and the equivalence of deformation rate and test temperature is emphasized. The much longer time scale for bond formation versus the rate of deformation upon debonding in peel or tack is exploited by the formulator to optimize properties. The formulation principles and common ingredients for preparing acrylic- and rubber-based adhesives are described, and the performance capabilities of these two types of pressure-sensitive adhesives are contrasted. 

Basic concepts of surface chemistry are outlined in this chapter to understand the mechanisms that can be applied to optimize the dispersion and rheological behavior of advanced refractory castables. The modes of action of some dispersants are described to illustrate the effects of some of their molecular features (chain length, functional groups, charge density) on the dispersion state of matrix... 

DMA is also known as mechanical spectroscopy. It is a nondestructive rheological characterization technique practiced extensively by material scientists, especially polymer physicists, to probe the viscoelastic state of various samples. Since the basic concept of DMA as a rheological characterization technique is well known, only a brief description pertinent... 

Covers all the basics of experimental rheology and includes a brief section on constitution equations and other theoretical concepts. 

Although the aim of the book is to provide an introduction to the field, it does so in a very applications-oriented manner. Thus, the focus of the book is practical rather than theoretical. In a systematic progression, beginning with the fundamental principles of petroleum emulsions, the reader is soon introduced to characterization techniques and fiow properties, and finally to industrial practice. Chapters 1-4 present the fundamental concepts and properties involved in emulsions within the context of their occurrence in the petroleum industry. Chapter 1 sets out the basic foundation for all subsequent chapters. Selected areas of special importance are then expanded in Chapter 2 on emulsion stability. Chapter 3 on characterization techniques, and Chapter 4 on rheological properties. All of these use petroleum emulsion examples for illustration, and in most cases cover the latest useful techniques available. 

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