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Book Review Chemical Reactions of Natural and Synthetic Polymers. (Ellis Horwood Series in Polymer Science and Technology). By M. Lazr T. Bleha and J

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these systems too the relationships between the spin Hamiltonian parameters for the individual centers and those for
the coupled system are derived; the matrix elements needed
for this derivation are set out in the form of clear tables.
Chapter 5 deals with spin-lattice relaxation processes in magnetically coupled spin systems; the authors limit their discussion almost exclusively to the relaxation behavior of paramagnetic ion pairs (dimers of Ir4+, Fe3+ and CuZf).
The chapters that follow provide a good review of experimental EPR studies on model systems with magnetically
coupled centers that are of importance in physics, chemistry
and biology. Chapter 7 discusses EPR spectra of paramagnetic ion pairs and of diradicals, and Chapter 8 deals with
spectra of systems in which paramagnetic ions and free radicals are magnetically coupled. The application of EPR spectroscopy to studies of magnetically coupled species in biological materials is currently a topic of great importance, and
Chapter 9 therefore deals with EPR spectra and the structural information that they yield for copper and iron proteins
and for exchange coupled species in complexes that are important for photosynthesis. Chapter 10 describes the magnetic properties and EPR spectra of low-dimensional spin
systems consisting of a large number of magnetically coupled
paramagnetic ions. One- and two-dimensional structures are
considered in detail. The final chapter describes the application of EPR spectroscopy to studies of excitons and their
motions in diamagnetic solids.
The book is intended for advanced students and for scientists (physicists, chemists and biologists) involved in work in
the area of EPR spectroscopy or on the magnetic properties
of materials. For these readers the monograph provides a
speedy and thorough introduction to studies of the magnetic
properties and EPR spectroscopy of magnetically coupled
systems, without having to read the widely scattered original
publications. However, in order to understand the theories
treated in the book one must have a knowledge of certain
aspects of quantum mechanics (second-order quantization,
properties of angular momentum operators, irreducible tensor operators). The book concludes with an appendix on
second-order quantization and the properties of the angular
momentum and irreducible tensor operators.
Row Bottcher [NB 11101
Sektion Physik
der Universitat Leipzig (FRG)
Chemical Reactions of Natural and Synthetic Polymers. (Ellis
Horwood Series in Polymer Science and Technology). By
M . Lazar, 7: Bleha and J Rychlj. Ellis Horwood,
Chichester 1989. 250 pp., hardcover, E 35.00.4SBN
0-7458-0193-5
Previous titles in the “Polymer Science and Technology”
series have included “Chromatography of Synthetic and Biological Polymers”, “Polymers and their Properties”, “Cellulose and its Derivatives”, “Wood and Cellulosics”, “Chemical Reactions of Natural and Synthetic Polymers”, “Cellulose
Chemistry and its Applications”, “Polymers as Materials for
Packaging” and “Styrene-Based Plastics and their Modifications”. The declared aim of this series is to cover the field of
natural and synthetic polymers, including the latest developments in basic research and in industry. It is against this
claim that the quality of the present book must be evaluated.
A further question that seems important to me is whether
there is a need for monographs of this kind, which have
recently been published in increasing numbers. In principle I
welcome books of this type, in which experts provide the
Angew. Chem. Int. Ed. Engl. 30 (1991) No. 3
0 VCH
reader with an introduction to a specialized field. There is
hardly a better way of familiarizing oneself with a specialist
topic.
The monograph consists of ten chapters. Chapter 1 discusses the most important aspects of chemical reactions of
polymers, such as the effects of neighboring groups, the influence of the medium, and intra- and intermolecular reactions. These effects are treated in textbook style with wellchosen examples. It is annoying to find it stated (pp. 14, 27)
that the functional groups in a polymer react at rates equal
to those for the same groups in small molecules. If that were
so one would have no need for this monograph. A few lines
later the authors contradict the statement by pointing out
that it is only very rarely the case. The authors’ arguments
are in most cases easy to follow. However, the generalization
that in carrying out reactions on polymers one should choose
a solvent such that the product is precipitated (p. 21) seems
ill-conceived; in many cases the opposite course is more sensible. Apart from these points the chapter is clearly presented, leaving aside the microdiagrams and especially the microcaptions.
The next chapter describes ways of modifying structural
units that are also used in technological applications. These
include fluorinations and chlorinations of hydrocarbon
polymers, reactions at double bonds and cyclizations. In
each case there is a very detailed discussion of mechanisms.
The doping of polymers to increase the electrical conductivity is also described. Three pages are devoted to the many
different reactions of polymers containing aromatic structural units. This section is rather too short in view of importance of such reactions, e.g. for synthesizing ion-exchange
media. In this chapter, of course, one should not omit to
describe such technologically important reactions as the hydrolysis of polyvinylacetates or the modification of natural
polymers, e.g. in the xanthane reaction of cellulose. The rearrangement reaction described on pages 71 -72 is due to A . W
von Hofmann, not to a man named Hoffman.
Chapter 3 deals with branched polymers, and especially
with grafting. Regrettably, the section on “Macromolecular
Initiators” deals only with peroxides and redox systems;
there is no mention of the more than twenty publications on
polymeric azo initiators that have come from the Kerber and
Heitz groups.
Another polymer modification reaction that is certainly of
great importance is crosslinking. Chapter 4 describes the
main methods used for synthesizing network structures.
These are presented very clearly, including modern approaches such as ionomers and the principle of physical
crosslinking. A description of the general principles is followed by detailed accounts of particular systems and the
crosslinkingmethods that can be used in each case. Interpenetrating networks are also briefly touched on. The very short
Chapter 5 deals with polymer-polymer exchange reactions.
Unfortunately the important “urethane exchange” class of
reactions is not mentioned here. However, this chapter does
to some extent live up to the book’s title, as it deals with the
interactions between dissimilar DNA molecules which can
be used, for example, to study genetic defects.
The next chapter, on polymer degradation, is much more
comprehensive; this deals with photooxidative degradation,
thermolysis, thermooxidative degradation, and also the
burning of polymers. Further sections on mechanochemical
degradation, ozonolysis, and radiolytic, ionic and biological
degradation complete this chapter.
The protection of polymers from degradation is an important prerequisite to allow their use as constructional materials. Chapter 7 deals with additives that confer this protec-
Verlagsgesellsehaft mbH, W-6940 Weinheim,1991
OS70-0833/91/0303-0341$3.50+ .2.5/0
342
tion. These include UV stabilizers, antioxidants, quenching
agents and fire-retardants. These are all substances designed
to prevent or hinder reactions of the polymer. In my view,
therefore, this chapter does not quite fit into the overall
theme of the book. Moreover, there exists a considerable
number of fundamental monographs and review articles on
the subject which are not mentioned in the bibliography of
this chapter.
One of the most important aims of polymer modification
is to obtain materials with new combinations of properties,
and to synthesize structures that cannot be obtained in other
ways. This topic is covered in Chapter 8. Methods are described that can be used to alter the crystallinity, solubility,
permeability, and also the mechanical and electrical properties.
The next chapter is concerned with present and future
applications of materials produced by modifying polymers.
Included here are, of course, the cellulose derivatives,
crosslinked polyethylene, crosslinked casein, polyisobutylene copolymers, and various other types of elastomers such
as modified PVC. The principles of manufacturing and using
semipermeable membranes, functionalized polymers, polymeric reagents and polymeric catalysts are also described.
The final chapter describes recent developments such as
the measurement of molecular motions in polymers by introducing fluorescence probes. Theoretical models for energy
conversion processes such as thermal to mechanical, chemical to mechanical and light to chemical energy are at least
briefly mentioned.
This book offers interesting reading both for experts and
for those wishing to begin work in this area. Despite the
weaknesses mentioned, the different aspects of the subject
are covered in a way which gives an impression of uniformity. The book is fluently written and deals with all the important aspects of this highly complex area of polymer research.
In view of the increasing level of activity in the area of polymer modification I consider this to be a useful book.
Oskar Nuyken [NB 1120 IE]
Lehrstuhl fur Makromolekulare Chemie I
der Universitat Bayreuth (FRG)
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