488 Book Reviews

survey of the basic chemistry and economic perspectives of large-scale production of organic chemicals, many of which are used as the precursors of polymers. Economic data are provided up to about 1994, and important innovations, such as the development and application of metallocene catalysts for polyolefin production, and novel methyl methacrylate pro- cesses which avoid production of ecologically undesirable by- products, are also considered.

Basically, the technology of the organic chemicals industry is discussed in a form suitable for new entrants and for experi- enced workers. It does not describe applications of the chemi- cals. Since the last edition many things have not changed-the same basic building blocks are used for polymers, but there is more emphasis on lesser volume chemicals and specialities. More production has shifted away from Europe, US and Japan to the Middle East and South-east Asia. This conclu- sion is well documented, with many notes and references, and detailed and informed commentary on the points raised.

Readers interested in aspects of the economics of chemicals for polymer production will find this book interesting and stimulating. It should be available to all students involved in chemical studies in any aspect.

C. A. Finch

Solvent crazing of polymers Studies in polymer science 13 Edited by A. L. Volynskii and N. F. Bakeev. Elsevier Science, Amsterdam, 1995. pp. xiii + 410, price US$250.00, Df1425.00. ISBN 0-444-81848-0

One of the benefits of the changing East-West political situ- ation has been the opening up of interactions between scien- tists and engineers who previously could have been unaware of each other’s existence. The previous barriers were partly caused by restrictions on travel, partly by limitations on publishing and often by language barriers which in particular meant that the Russian academic journals were inaccessible to western scientists. The authors of this volume have the major aim of covering, in general, recent knowledge and understand- ing of solvent crazing in polymers, and, in particular, a desire to publicize some of the work of their Russian colleagues. This latter aim alone will, I believe, make the volume a very useful addition to the library shelves. Many of the 344 references are from the original Russian journals; enough detail is given to summarize the main findings.

Of course, the main purpose of the book is to give both an overview and a detailed, up-to-date picture of the crazing of polymers, The phenomenon is unique to polymers and is important in many applications. Starting from the viewpoint that crazing is, in effect, just one mode of plastic deformation, the authors develop their theme through chapters on struc- ture, dynamics, mechanical properties during crazing, and the properties after crazing. After dealing with classical crazing in considerable detail (with both theoretical and phenomenologi- cal explanations of extensive experimental data), the authors go on to discuss delocalized solvent crazing in crystalline polymers, in particular as a mechanism for the preparation of polymer blends. At this stage the volume becomes more of a review of recent (Russian) research literature. The final chapter is devoted to a summary of applications of solvent crazing as

a method either of preparing porous materials or of intro- ducing additives into a polymer matrix.

Overall the volume provides a very detailed overview of an important technological field. It is not a beginner’s intro- duction, and has a distinctly Russian flavour, but neither of these factors is to its detriment. It is certainly worth having on the shelf for reference to a complex and important field.

J. S. Higgins

Excipients and delivery systems for pharmaceutical formula- tions Edited by D. R. Karsa and R. A. Stephenson. The Royal Society of Chemistry, Cambridge, 1995. pp. viii + 192, price E39.50. ISBN 0-85404-715-8

Chemical aspects of drug delivery systems Edited by D. R. Karsa and R. A. Stephenson. The Royal Society of Chemistry, Cambridge, 1996. pp. viii + 162, price f49.50. ISBN 0-85404-706-9

These two camera-ready volumes overlap in the sense that they both discuss aspects of the use of speciality polymers in pharmaceutical systems. Both volumes originate from con- ferences held in Manchester.

The first volume is mainly concerned with use of excipients, which are subject to many differing regulatory arrangements in different parts of the world. Most chapters discuss the selec- tion and application of different polymers, including cross- linked acrylic acid polymers, polymethacrylates, gelatin, triglycerides and water soluble cellulose ethers, including hydroxypropylmethyl cellulose (mainly in matrix systems), starches, xanthan gums, alginates and chitosan.

The second volume reviews novel materials for drug delivery systems, including both natural and synthetic poly- mers, notably polyethylene oxides and derivatives, and other selected water-soluble polymers and hydrogels. Some carbo- hydrate derivatives (including starch, lactose, microcrystalline cellulosspace of 3.9 and 4.7 A of the Fourier transforms func- tion (Fig. 5C2), corresponding to higher-shell Co-Co neigh- bours, is evidence of the formation of large cobalt particles, possibly on the external surface. However, EXAFS evidence is lacking for any higher-shell Co atom in [Co,],,,~ redmay sample, which is likely a consequence of the limited sensitivity of the EXAFS technique.,,

The [Cox],,,, J N a Y species obtained from mild oxidaticones) in transdermal drug delivery systems indicates the complex requirements required of the adhesive-apart from low irritancy and non-sensitivity to skin, low acute and chronic toxicity, such adhesives must have good adhesion to oily, wet, wrinkled and hairy skin, they should be resistant to, but be water-permeable. They should also leave no residues on removal from the skin.

Both of these volumes describe the selection and applica- tion of polymers for specific applications from a viewpoint not normally considered by polymer scientists. For this alone, they are worth studying.

C. A. Finch

POLYMER INTERNATIONAL VOL. 41, NO. 4, 1996