Preface

This text is an outgrowth or organized compilation of the notes the authors have used to teach an introductory course on the viscoelasticity of polymers for more than thirty years for the senior author and about fifteen years for the junior author. Originally, the course was taught only to graduate students but in recent years an effort has been made to teach a modification of the course to senior level mechanical engineering students. The authors have long held the view that the lack of knowledge of the fundamental aspects of the time and temperature behavior of polymer materials is a serious shortcoming in undergraduate as well as graduate engineering education. This is especially important in our present society because the use of polymeric materials pervades our experience both in our daily lives and in our engineering profession. Still the basic thrust of undergraduate education and even graduate education to some degree in the areas of mechanical and civil engineering is toward traditional materials of metal, concrete, etc. Until about twenty five years ago, elementary undergraduate textbooks on materials contained little coverage of polymers. Today many elementary materials texts have several chapters on polymers but, in general, the thrust of such courses is toward metals. Even the polymer coverage that is now included treats stress analysis of polymers using the same procedures as for metals and other materials and therefore often misleads the young engineer on the proper design of engineering plastics. Thus, it is not surprising that some structural products made from polymers are often poorly designed and do not have the durability and reliability of structures designed with metallic materials.

For the above reasons, the view of the authors is that specific courses on polymer materials as well as associated stress analysis and engineering design need to be offered to every engineer. The present text has been devel-oped with this in mind. The intent is to have sufficient coverage for a two semester introductory sequence that would be available to upper class undergraduates and first year graduate students. The level is such that only basic knowledge of solid mechanics and materials science are needed as prerequisites. The book is intended to be self sufficient even for those that have little formal training in solid mechanics and therefore chemical engineers, materials, forestry, chemistry, bio-engineering, etc. students as well as mechanical and civil engineering students can use this text successfully. Similarly, because chemistry background is often weak for non-chemical engineers, introductory material is provided on the chemical basis of polymers, which is essential for proper appreciation of the thermomechanical response. 

Another major objective is for the text to be readable by recent engineering graduates who have not had the advantage of a formal course on polymer science or viscoelasticity. The reason, of course, is that today’s engineering curricula, both undergraduate and graduate, have few extra hours such that new courses can be accommodated in degree plans. Therefore, a book such as this one should be of great value to the young engineer who finds him/herself in a position heavily involved with the engineering design and use of polymer based materials. In addition a text such as this should be invaluable to those cross-disciplinary scientists such as biologist, biochemist, etc. that need to understand the basic background to rigorous mechanics approaches to the design of structures made with polymer based materials.

The first chapter gives insight to the historical aspects of the subject. A review of basic mechanics of materials (strength of materials) and materials science is given in Chapter 2. Chapter 3 gives an introduction to the mechanical properties of polymers and how they are determined as well as general information on optical, electrical and other properties. Chapter 4 is an introduction to the general character of polymers from a molecular viewpoint and is valuable in assessing the mechanisms associated with viscoelastic deformations. Chapters 5 and beyond speak to the formal mathematics and experimental methods associated with the relationship between stress and strain in viscoelastic solids, both linear and nonlinear, as well as stress analysis and failure.