- Email: [email protected]
Mechanics of Polymer Processing
Journal of Non-Newtonian Fluid Mechanics, 21 (1986) 271-272 Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands
271
Book Review
Mechanics of Polymer Processing, by J.R.A. Pearson, Applied Science lishers, London, 1985, pp xv + 712, ISBN 0 85334 308 X, E75.00.
Pub-
Polymer processing operations are very difficult to analyze because of two reasons. First, polymers have peculiar rheological behavior, which needs to be described with mathematically complex constitutive equations. Second, polymer processing operations involve complicated geometries, in many of them there are free surfaces, and heat transfer plays an important role, so that the analysis is very complex even if one is willing to regard the polymers as Newtonian fluids. Therefore, books on polymer processing either have to abandon any hope of rigorous analysis and be of the cook-book variety, or they have to include a rather large amount of complex mathematics. The intended goal of this book, as stated in the preface, is to provide a rigorous mathematical analysis of polymer processing operations, and this goal is beautifully achieved. The book is divided into four parts. The first part (108 pages) deals with polymer mechanics and rheology. It does not attempt to give the basic theory of continuum mechanics, and hence readers who are not familiar with nonlinear continuum mechanics will need a companion book. The notation and kinematic description chosen by Pearson is that of the text by myself and Marrucci, which in this sense constitutes the most useful companion book. The first part includes the discussion of the basic flow fields of interest in rheometry, of the experimentally observed rheological behavior of polymers, and of the most useful constitutive equations. Nonisothermal constitutive equations are discussed in some detail. The second part (94 pages) deals with the analysis of complex flow fields. Here, as well as in the last two parts, one can appreciate how rigorous theory and approximate methods are not mutually exclusive; indeed, the only way of sensibly making approximations is to fully understand what is being approximated. The ability to make sensible and yet sweeping approximations is one of the best features of the book. This part includes a section on the thin sheet approximation, a subject familiar to workers in solid mechanics but not to those in fluid mechanics. The last two parts deal with continuous and cyclic polymer processing operations. Each specific operation is clearly described and lucidly analyzed. Great importance is rightly attached to the role of heat transfer and to the problems of stability-the latter often represent the upper bound to the productivity obtainable from any given piece of machinery. Attention is not restricted to shaping operations (those whose aim is to produce a manufact
272 of a given shape), and problems for which solid mechanics is relevant are not left out. The only operation which is left out is the reaction injection molding (RIM) of thermoset materials (with or without fillers). Crosslinking of elastomers in the mold is analyzed, but this bears only a superficial analogy to RIM. This is a very goodsbook, but it is not an easy one. It has many examples and problems, but it would be difficult to cover the whole book in a graduate course. These difficulties are connected with the subject matter itself, and there is nothing one could do about them. The wealth of material covered in the book, and the elegant quality of the analysis, make it an indispensable addition to the library of any serious worker in the field. The only (minor) fault I could find in the book is that it is written in an extremely concise style, so that every sentence needs to be read very carefully and thought about in depth; algebraic derivations, also when quite lengthy and involved, are generally skipped entirely. (A pearl appears on page 241: “On further investigation we get. . . “. About three hours worth of further investigation.) This style adds to the difficulty in using the book as a textbook for a graduate course. The literature references are adequate and the choice of what to include is not parochial. Only works which are very significant to what is discussed in the text are included, and thus the number of references is not very large. This book should not be used as an exhaustive source to the relevant literature; with available computerized literature searches, books are not any more required to be that. There are very few typographical errors; the book is well printed and pleasing to the eye. Figures are well drawn and provide great help in understanding the text. GIANNI ASTARITA
271
Book Review
Mechanics of Polymer Processing, by J.R.A. Pearson, Applied Science lishers, London, 1985, pp xv + 712, ISBN 0 85334 308 X, E75.00.
Pub-
Polymer processing operations are very difficult to analyze because of two reasons. First, polymers have peculiar rheological behavior, which needs to be described with mathematically complex constitutive equations. Second, polymer processing operations involve complicated geometries, in many of them there are free surfaces, and heat transfer plays an important role, so that the analysis is very complex even if one is willing to regard the polymers as Newtonian fluids. Therefore, books on polymer processing either have to abandon any hope of rigorous analysis and be of the cook-book variety, or they have to include a rather large amount of complex mathematics. The intended goal of this book, as stated in the preface, is to provide a rigorous mathematical analysis of polymer processing operations, and this goal is beautifully achieved. The book is divided into four parts. The first part (108 pages) deals with polymer mechanics and rheology. It does not attempt to give the basic theory of continuum mechanics, and hence readers who are not familiar with nonlinear continuum mechanics will need a companion book. The notation and kinematic description chosen by Pearson is that of the text by myself and Marrucci, which in this sense constitutes the most useful companion book. The first part includes the discussion of the basic flow fields of interest in rheometry, of the experimentally observed rheological behavior of polymers, and of the most useful constitutive equations. Nonisothermal constitutive equations are discussed in some detail. The second part (94 pages) deals with the analysis of complex flow fields. Here, as well as in the last two parts, one can appreciate how rigorous theory and approximate methods are not mutually exclusive; indeed, the only way of sensibly making approximations is to fully understand what is being approximated. The ability to make sensible and yet sweeping approximations is one of the best features of the book. This part includes a section on the thin sheet approximation, a subject familiar to workers in solid mechanics but not to those in fluid mechanics. The last two parts deal with continuous and cyclic polymer processing operations. Each specific operation is clearly described and lucidly analyzed. Great importance is rightly attached to the role of heat transfer and to the problems of stability-the latter often represent the upper bound to the productivity obtainable from any given piece of machinery. Attention is not restricted to shaping operations (those whose aim is to produce a manufact
272 of a given shape), and problems for which solid mechanics is relevant are not left out. The only operation which is left out is the reaction injection molding (RIM) of thermoset materials (with or without fillers). Crosslinking of elastomers in the mold is analyzed, but this bears only a superficial analogy to RIM. This is a very goodsbook, but it is not an easy one. It has many examples and problems, but it would be difficult to cover the whole book in a graduate course. These difficulties are connected with the subject matter itself, and there is nothing one could do about them. The wealth of material covered in the book, and the elegant quality of the analysis, make it an indispensable addition to the library of any serious worker in the field. The only (minor) fault I could find in the book is that it is written in an extremely concise style, so that every sentence needs to be read very carefully and thought about in depth; algebraic derivations, also when quite lengthy and involved, are generally skipped entirely. (A pearl appears on page 241: “On further investigation we get. . . “. About three hours worth of further investigation.) This style adds to the difficulty in using the book as a textbook for a graduate course. The literature references are adequate and the choice of what to include is not parochial. Only works which are very significant to what is discussed in the text are included, and thus the number of references is not very large. This book should not be used as an exhaustive source to the relevant literature; with available computerized literature searches, books are not any more required to be that. There are very few typographical errors; the book is well printed and pleasing to the eye. Figures are well drawn and provide great help in understanding the text. GIANNI ASTARITA