Principles of Polymer Engineering

Abstract Polymers are important engineering materials. This book introduces the reader to what polymers are and how they are structured, provides understanding of their engineering properties, and explains how products are designed and manufactured from them. It is a substantial revision of the previous edition. The new Introduction reviews the range of industrial applications of polymers and also addresses problems for the environment that can arise, and how these are managed sustainably. Chemical structures and physical microstructures of polymers are explained, especially aspects of special interest to the engineer: melting, crystallization, and the glass transition. Distinctive mechanical properties of polymers are highlighted—rubber elasticity and viscoelasticity—and analytical tools provided for predicting such responses. The reader also learns of polymer failure mechanisms under load, including their pressure-dependent yield and the distinctive crazing that sometimes accompanies fracture. Reinforced polymers contain stiffer, stronger fibres or other particles: the engineer must then be able to anticipate resulting mechanical properties. The reader is introduced to this task using an approximate but consistent three-dimensional approach to the micromechanics required. During product manufacture, polymers are shaped by flow in the liquid state followed by solidification by cooling or crosslinking. The principles of polymer processing are explained, together with the distinctive features of numerous forming processes, including extrusion, injection moulding, and the newer additive manufacturing processes. Finally, the reader learns how product design with polymers takes account of all the above, with the aim to achieve products that perform as required and are sustainable.