1. 1 Preamble The science to which this work is appended is termed rheology and rheology means the study of flow and deformation of liquids and solids with emphasis on the underlying physical processes. Characteristic for solids is that they respond to a force by deforming, and, on removal of the force, by returning to their original shape. This type of re sponse is termed elastic. Characteristic for liquids is that they deform and continue to deform as long as the force is present. This type of response is termed viscous. The two definitions just given for viscous and elastic response represent ~wo extremes of response to an external force. Materials do not always fall readily into one or the other of the above-mentioned categories. An additional parameter is needed to describe material response more fully. The extra param eter is time. As a general rule the faster the deformation the closer the re sponse is to being elastic, the slower the deformation the closer the response is to being viscous. Slow and fast . are factors relative to some natural time, T, of the material. This natural time may be thought connected with the rates of spontaneous diffusion of its molecular and atomic constituents. For every day fluids as water, the natural time is very short, of the order of 10-10s 1) and hence for most purposes is considered as being viscous.

1. 1 Preamble The science to which this work is appended is termed rheology and rheology means the study of flow and deformation of liquids and solids with emphasis on the underlying physical processes. Characteristic for solids is that they respond to a force by deforming, and, on removal of the force, by returning to their original shape. This type of re sponse is termed elastic. Characteristic for liquids is that they deform and continue to deform as long as the force is present. This type of response is termed viscous. The two definitions just given for viscous and elastic response represent ~wo extremes of response to an external force. Materials do not always fall readily into one or the other of the above-mentioned categories. An additional parameter is needed to describe material response more fully. The extra param eter is time. As a general rule the faster the deformation the closer the re sponse is to being elastic, the slower the deformation the closer the response is to being viscous. Slow and fast . are factors relative to some natural time, T, of the material. This natural time may be thought connected with the rates of spontaneous diffusion of its molecular and atomic constituents. For every day fluids as water, the natural time is very short, of the order of 10-10s 1) and hence for most purposes is considered as being viscous.

The present monograph is intended as an introduction into a field which certainly did not receive proper attention in the past. It is one of the aims of this book to verify this suppo sition. The author hopes to show that the technique of the measurement of flow birefringence can fulfil an important com plementary task in polymer melt rheology. From this point it is expected that the present monograph will attract the atten tion of polymer scientists in general, and of rheologists and process engineers in particular. Certainly, the fourth chapter will appeal to the latter group. As a teacher in polymer science and technology the author wants to address also the group of the graduate students. In fact, the standard knowledge acquired during usual university studies in chemistry, physics or engineering does not enable a quick start of research activities in the field of polymer melt rheology. Certainly, in this typically interdisciplinary field everyone can lay emphasis on matters which are familar to hirn because of his preceding education. Significant research activities, however, can only be generated on the basis of a more universal knowledge. In the absence of this knowledge beginners have to rely upon the guidance of their supervisors for an unduly long period. Otherwise they take the risk of losing too much of their costly time. This holds in particular for the experimentalists who cannot be dispensed from being familiar with the necessary theoretical background.

This book explores the ways in which melt flow behaviour can be exploited by the plastics engineer and technician for increased efficiency of processing operation, control of end product properties and selection and development of polymers for specific purposes. (reissued with minor corrections 1994)

An analysis of polymer and composite rheology. This second edition covers flow properties of thermoplastic and thermoset polymers, and general principles and applications of all phases of polymer rheology, with new chapters on the rheology of particulate and fibre composites. It also includes new and expanded detail on polymer blends and emulsions, foams, reacting systems, and flow through porous media as well as composite processing operations.

In many cases rheological measurements are carried out in the simplest of geometries, but the interpretation involved in obtaining the rheological parameters of the test fluids from these measurements is surprisingly complex. The purpose of this book is to emphasise the points on which most workers in the field agree, and to let the authors deal with the contentious points according to their own beliefs and experience. This work represents a summary of the current thought on rheological meas urement by experts in the various techniques. When making measurements and obtaining from them parameters that describe the flow behaviour of the test fluids, it is essential that the experimentalist understands the underlying theory and shortcomings of the measurement technique, that he is aware of the likely microstructure of the fluid, and that from this he can appreciate how the fluid and the measuring system will interact with each other. It is this interaction that gives both the required rheological parameters of the fluids and the artefacts that confuse the issue. This book covers the main rheological measurement techniques from capillary, slit and stretching flows to rotational and oscillatory rheometry in various geometries including sliding plate measurements. These topics are backed up by chapters on more practical aspects, such as commercial instruments, and on computer control and data acquisition. The chapters deal with the basic methods, how the measurements are taken, and what assumptions and interpretations are made to obtain valid data on the test fluids.

Provides the basic background needed by engineers to determine experimentally and interpret the rheological behavior of polymer melts--including not only traditional pure melts but also solutions and compounds containing anisotropic (fiber or disc) or colloidal particles--and apply it to analyze flow in processing operations. Experimental foundations of modern rheology and rheo-optics and the interpretation of experimental data are covered, which also develops the fundamentals of continuum mechanics and shows how it may be applied to devise methods for measurement of rheological properties, formulation of three-dimensional stress-deformation relationships, and analysis of flow in processing operations. Also discusses the structure of polymers and considers rheological behavior in terms of structure. Constitutive equations relating stress to deformation history in non-Newtonian fluids and their applications are discussed. Each chapter presents an overview of the subject matter and then develops the material in a pedagogical manner.

Rheology: Concepts, Methods and Applications, Third Edition provides a thorough historical and theoretical grounding in the field, and introduces rheology as the method of solving many practical problems in materials science and engineering. The book is practical and relevant for industry, but is also consistent with rheology courses in academia, making it relevant to both academics and accomplished rheologists in industry. The first four chapters discuss various aspects of theoretical rheology and, through examples from numerous studies, show how particular theories, models, or equations can be used in solving different problems. The shared experience and insight contained in these chapters assists practitioners carrying out rheological studies in generating relevant data. This helps to avert costly errors in analysis which are common when data are generated under the wrong conditions, or are incorrectly used. The fifth chapter covers methods of measurement and treatment of raw data—eight groups of methods are discussed in this chapter, providing the reader with many options for experimentation, along with guidance on where and how to use them properly. The final chapter demonstrates how to use rheological methods for different groups of products and manufacturing methods. The usefulness of chemorheological (rheokinetical) measurements is also emphasized. The chapter has a particular emphasis on real-world applications of rheology, and gives practical guidance to enable materials scientists to gather data and solve problems using these methods. This book is a systematic presentation of the subject of rheology—written by two of the foremost researchers in the field—showing the subject as an interrelated system of concepts, principal phenomena, experimental methods, and directions of their application. It also links with other branches of theoretical and applied sciences. - Provides substantial experience and insight to assist rheologists working in a range of industries to generate relevant data, avoiding costly errors in analysis - Includes eight groups of measurement methods, providing the reader with options so they can choose the most effective for their situation - Offers thorough coverage of different applications of rheology, demonstrating how to use rheological methods for different products—from polymeric materials to food products, biological fluids, and electro and magnetic materials