Molten Polymers

Recent advances in polymer science have made it possible to relate quantitatively molecular structure to rheological behavior. At the same time, new methods of synthesis and characterization allow the preparation and structural verification of samples having a range of branched polymeric structures. This book unites this knowledge to enable production of polymers with prescribed processability and end-product properties. Methods of polymer synthesis and characterization are described, starting from fundamentals. The foundations of linear viscoelasticity are introduced, and then the linear behavior of entangled polymers is described in detail. This is followed by a discussion of the molecular modeling of linear behavior. Tube models for both linear and branched polymers are presented. The final two chapters deal with nonlinear rheological behavior and tube models to describe nonlinearity. In this second edition, each chapter has been significantly rewritten to account for recent advances in experimental methods and theoretical modeling. It includes new and updated material on developments in polymer synthesis and characterization, computational algorithms for linear and nonlinear rheology prediction, measurement of nonlinear viscoelasticity, entanglement detection algorithms in molecular dynamics, nonlinear constitutive equations, and instabilities. Contents: - Structure of Polymers - Polymerization Reactions and Processes - Linear Viscoelasticity - Fundamentals - Linear Viscoelasticity - Behavior of Molten Polymers - Tube Models for Linear Polymers - Fundamentals - Tube Models for Linear Polymers - Advanced Topics - Determination of Molecular Weight Distribution Using Rheology - Tube Models for Branched Polymers - Nonlinear Viscoelasticity - Tube Models for Nonlinear Viscoelasticity of Linear and Branched Polymers

This book shows in detail how rheological properties are related to the molecular structure of polymers. As well, it explains how molecular models based on the tube concept can be used to predict the flow and viscoelastic properties of molten polymers. While data for specially-prepared polymers are vital for model development, the complexities of commercial polymers must be taken into account if these models are to be put to practical use. For this reason, the issues of polydispersity and long-chain branching are dealt with at length. The information provided will be useful in the determination of molecular structure and for predicting how structure affects flow behavior during melt processing

This book, based on lectures given at the Polytechnic of Milan, gives a broad overview of the field of polymer dynamics. In these lectures the aim is to stress the fundamental concepts of the behaviour of polymers without drawing on the more advanced mathematical formalism which often obscures the natural elegance of the subject matter. Professor De Gennes is one of the most distinguished workers in the field of material science. Therefore this book will be welcomed by both the experienced researcher in the area and the interested layman. It will be of particular value to graduate students.

This volume represents a continuation of the Polymer Science and Technology series edited by Dr. D. M. Brewis and Professor D. Briggs. The theme of the series is the production of a number of stand alone volumes on various areas of polymer science and technology. Each volume contains short articles by a variety of expert contributors outlining a particular topic and these articles are extensively cross referenced. References to related topics included in the volume are indicated by bold text in the articles, the bold text being the title of the relevant article. At the end of each article there is a list of bibliographic references where interested readers can obtain further detailed information on the subject of the article. This volume was produced at the invitation of Derek Brewis who asked me to edit a text which concentrated on the mechanical properties of polymers. There are already many excellent books on the mechanical properties of polymers, and a somewhat lesser number of volumes dealing with methods of carrying out mechanical tests on polymers. Some of these books are listed in Appendix 1. In this volume I have attempted to cover basic mechanical properties and test methods as well as the theory of polymer mechanical deformation and hope that the reader will find the approach useful.

Bioresorbable implants can be processed via conventional polymer processing methods such as extrusion, injection and compressing moulding, solvent spinning or casting. This book addresses issues and highlights recent advances in the use of biodegradable polymers. It is intended for researchers utilizing biodegradable polymers in areas from tissue engineering to controlled release of active pharmaceuticals, as well as industrial processors.

Extrusion is by far the most important and the oldest processing and shaping method for thermoplastic polymers. This process concerns almost all synthetic polymers, as well as elastomers or food materials. Single-screw extrusion is mainly used nowadays to manufacture finished goods or semi-finished products. More than 90 million tons of thermoplastics are therefore processed every year. Twin-screw extrusion may be divided into two systems: contra-rotating systems used within the context of PVC extrusion, for the manufacture of pipes or profiles; and co-rotating systems experiencing nowadays a very significant development, because of their significant adaptability and flexibility, which enables the manufacture of specific materials (polymer alloys, thermoplastic elastomers, filled polymers, nanocomposites). Extrusion is carried out by passing molten polymer through a tool called die that will give the product its final shape (films and sheets, rolled products, and electric cables). Thanks to the design of dies, we obtain at the output a product with controlled dimensions, uniform speeds and homogeneous temperatures. The book will discuss the same production types, but only in the case of coextrusion flows, i.e. multilayer stratified products. First of all, we will present in this book the physics of the mechanisms at stake, then propose more or less complex models in order to describe these mechanisms and then go forward in the interpretation of results and the control of condition flows.

Polymer Processing Instabilities: Control and Understanding offers a practical understanding of the various flows that occur during the processing of polymer melts. The book pays particular attention to flow instabilities that affect the rate of production and the methods used to prevent and eliminate flow instabilities in order to increase product