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Reviews Polymer science I The third polymer revolution
like to think of the current era as the ‘third polymer revolution’ – the first being the appearance on Earth of carbohydrates, proteins and polynucleotides, and the second dating from the time of Wallace Carothers to the late 1950s when all the main synthetic polymer classes that we are familiar with started to appear.
But now polymers are turning up in places that would have been surprising even 20 years ago – including jet aircraft bodies, photovoltaic devices, and displays for hand-held devices. Polymer architectures made by specialist synthetic routes that used to be academic curiosities are likewise now turning up in the market place. In my own area of adhesives, we are now seeing monodisperse block copolymers made by living radical polymerisation and/ or organic or inorganic nanoparticles as additives in structural products with fracture toughness an order of magnitude higher than what could be achieved a generation ago. And yet, polymers are also facing challenges in terms of sustainability – use of renewable resources, recyclability and biodegradability – along with rapidly variable raw material prices. These challenges can be met, and they add to the excitement.
So it is not surprising that polymer
chemistry, whether industrial or academic, has flourished in the past 15 years or so, as has the design of precisely tailored advanced materials with a significant polymer content. After years of decline, demand for places on undergraduate chemistry courses and polymer masters courses is on the increase. I strongly suspect that there would be considerable interest in something that combined the two, along the lines of a BSc in chemistry with polymer & materials science. Certainly similar requirements from the pharmaceutical industry have led many universities and colleges to offer medicinal chemistry as an option. Indeed, these tailored courses with an often illusory half-promise of an industrial
job at the end have proved so popular in Ireland – and I imagine much the same is happening in the UK – that advertisements for general chemistry positions – for university lecturers and for researchers in the non-pharmaceutical chemical industry – summon up a deluge of applications from medicinal chemists. It’s time the materials chemistry community fought back. Fortunately, high-quality up-to-date books that address this side of chemistry are starting to appear, and this book is a welcome addition to the field. It is very much a polymer synthesis text, and alongside the traditional addition and condensation polymerisations covers all the recent or relatively recent advances in synthetic techniques: polymers of controlled architecture via atom transfer radical polymerisation (ATRP) or reversible addition-fragmentation chain transfer (RAFT); novel polyolefins via ring-opening metathesis or via metallocene catalysis; and coupling reactions to generate conducting polymers. There is, in my opinion, however, an unfortunate omission, which is the interesting reaction related to anionic polymerisation: the nucleophilic polymerisation of cyanoacrylates – it is the nitrogen in our skin that causes us
to stick our fingers together with these products if we are not careful. Otherwise I can certainly recommend the book. Ever since blue-green algae started pumping oxygen into the Earth’s atmosphere, the very existence of polymers has been a triumph of kinetics of thermodynamics. For instance, the strength of adhesives varies in a complicated way with the environment to which they have been exposed, and I have often been asked by design engineers what the ‘final’ strength of our products will be. I have to reply ‘zero’ because – even though it may take thousands of years – all polymers in the presence of oxygen, water and ultraviolet light will end up as small molecules again.
But the new synthetic techniques that Mandal describes are also being used to make products where this is exactly what you want – microcapsules for controlled drug delivery. And other polymers for implants are being made that can survive the conditions inside the body. The third polymer revolution is starting to impinge on the products of the first – ourselves.
David Birkett is a senior scientist at Henkel Adhesive Technologies, Dublin, Ireland
Fundamen-
tals of poly- merisation
Author Broja M. Mandal
Publisher World Scientific Books Year 2013 Pages 468 Price £79 ISBN 978-981- 4322-461
Chemistry&Industry • November 2013 51
David Parker/Science Photo Library
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