Spinning a (synthetic) yarn

Krishan Chawla has the happy knack of picking the right topic at the right time - beginning with his general text on fibre-reinforced materials, published in 1987, and his subsequent book on ceramic matrix composites, published in 1993. This new book, Fibrous Materials, deals exclusively with the nature of the reinforcing fibres themselves - ie their processing and properties - without reference to either the matrix material, within which they sit, or the interface, through which they impart their desirable properties (eg stiffness, strength, thermal conductivity) to the composite material as a whole. It will interest all those working in fields related to composite materials science and technology.

The book begins with an explanation of the terminology of fibrous materials. Much of this terminology originates in the garment industry which has had an interest in fibres for a long time. With the increasing use of reinforcing fibres for composite materials in the form of woven, knitted, or braided fabrics, the overlap with the garment industry has become even stronger. Clear definitions of various important terms, as here, are very helpful.

Chawla surveys of all types of fibrous materials, and there are chapters on the experimental determination of fibre properties and the statistics of fibre strength. Although largely concerned with synthetic fibres, the book also deals with natural fibres from the plant and animal kingdoms. There is a fascinating section on spider silk, which has excellent mechanical properties and is spun from aqueous solution - compare the manufacture of some high-performance synthetic fibres, requiring boiling sulphuric acid in the manufacturing process.

The chapter on metallic fibres includes sections on the relationships between microstructure, properties and applications. It is easy to forget, for those usually dealing with composite materials, that some fibres are used in large quantities without a matrix - a bridge cable, for example, can be one metre in diameter and consist of 37,000 individual steel fibres.

Perhaps rather surprisingly, the chapter on glass fibres begins with an introduction to optical fibres, before moving to the less exotic types of glass fibre used to reinforce polymers. Finally, there is a chapter on carbon fibres.

Overall, the only serious quibble I have with this book is that the last chapter, which deals with the statistics of fibre fracture, is somewhat superfluous. Yes, the Weibull distribution is very important for dealing with fibre strength variations, but much of the material here can be found elsewhere. Indeed, about five pages of this chapter are taken almost line-for-line from another book: the excellent Ceramic Matrix Composites - by K. K. Chawla.

Stephen Ogin is senior lecturer in composite materials, University of Surrey.