The Elements of Polymer Science and Engineering, Third Edition

Book Preface

Since the publication of the last edition in 1999, the field of polymer science and engineering has advanced and changed considerably. The advances come from our increasing abilities to make a wide variety of polymers with tailor- made structures and/or molecular weight distribution using sophisticated polymerization techniques and to characterize the structures of such polymers at different length scales and the corresponding properties by modern analytical techniques. This trend is somewhat driven by the fact that polymers with tailor-made structures are an integral part of the solution to key societal challenges facing us such as energy, water, environment, and health care areas. It is also interesting to note that highvolume polymers (e.g., polyethylene) are also made with tailor-made structures to improve their performance. The other emerging front of the field of polymer is the desire to use materials derived from renewable resources (less than 1% of the total market nowadays) due to the increasing awareness of the substantiality of using polymers derived from petroleum sources. Therefore, we added a new chapter (Chapter 13) to introduce the new trend of using biopolymers for various applications and what types of biopolymers have been investigated. Nevertheless, to make polymers with tailor-made structures, a deeper understanding of the molecular structureproperty relationship is needed. Therefore, the writing of this edition stresses the molecular-level understanding of phenomena and processes involving the use of polymers. In this regard, throughout the textbook, if applicable, we explain concepts related to and/or behavior of polymers in terms of their molecular structure, particularly their conformation. In fact, a new section was added to Chapter 1 to elaborate the concept of conformation and various theoretical models associated with the concept. A new chapter (Chapter 6) on the diffusion in polymers was added as such a topic is at the heart of many modern technologies (e.g., separation of gases using polymer membranes).

In this edition, we decided not to include additional topics on polymer processing and polymer degradation given the expectation that the book is used for a one semester introductory polymer course. The students should consult more specialized textbooks on these topics. The book has been substantially restructured to fit the pedagogical requirement that the first six chapters mainly cover the basic concepts and models of polymer conformation (Chapter 1), definition of molecular weight averages and their measurements (Chapters 2 and 3), physical and mechanical properties of polymers (Chapter 4), and polymer solutions and blends (Chapter 5). As mentioned, Chapter 6 covers an old but important topic: diffusion in polymers. The second half of the book (Chapters 7 to 13) mainly focuses on the polymerization techniques. In particular, Chapter 12 deals with polymerization reaction engineering. We put Chapter 13 in the second half of the book simply because use of biopolymers requires chemical modification of natural polymers and/or polymerization of renewable monomers.

Another motivation for the third edition of the book is to improve its style to make it more comprehensible to undergraduate students studying in a variety of disciplines such as chemistry, physics, pharmacy, chemical engineering, as well as materials science and engineering. To this end, we include additional inchapter numerical examples and new figures to illustrate the concepts involved and additional end-of-the-chapter practice problems. Most of the practice problems were made using published research data and/or relevant industrial data. We believe in this way students can see how they can apply research results and industrial data to solve practical problems. A student who understands the material in the chapter should not find these problems time consuming. The problems have been formulated to require numerical rather than essay-type answers, as far as possible, since “handwaving” does not constitute good engineering or science.

The units in this book are not solely in SI terms, although almost all the quantities used are given in both SI and older units. Many active practitioners have developed intuitive understandings of the meanings and magnitudes of certain quantities in non-SI units, and it seems to be a needless annoyance to change these parameters completely and abruptly.

The only references included here are those dealing with particular concepts in greater detail than this book. This omission is not meant to imply that the ideas that are not referenced are our own, any more than the concepts in a general chemistry textbook are those of the author of that book. We lay full claim to the mistakes, however.