Table Of ContentFire Retardancy of Polymers
The Use of Intumescence
Fire Retardancy of Polymers
The Use of Intumescence
Edited by
M. Le Bras
LCAPCS, Ecole Nationale Supkrieure de Chimie de Lille, France
G. Camino
Department of Chemistry, University of Torino, Italy
S. Bourbigot
LCAPCS, Ecole Nationale Sup6rieure de Chimie de Lille, France
R. Delobel
CREPIM, Bruay la Bussikre, France
THE ROYAL
CHEMISTRY
Information
Services
Papers presented at the 6th European Meeting on Fire Retardancy of Polymeric Materials
(FRPM’97) organised jointly by the ‘Laboratoire de Chimie Analytique et de Physicc-Chimie
des Solides’ de 1’E.N.S.C. de Lille and the ‘Centre de Recherche et d’Etude des ProcMts
d’Ignifugation des Mattkiaux’ at the University of Lille (France) on 24-26th September 1997.
Special Publication No. 224
ISBN 0-85404-738-7
A catalogue record for this book is available from the British Library
0 The Royal Society of Chemistry 1998
All rights reserved.
Apart from any fair dealing for the purpose of research or private study, or criticism or
review as permitted under the terms of the UK Copyright, Designs and Patents Act, 1988,
this publication may not be reproduced, stored or transmitted, in any form or by any means,
without the prior permission in writing of The Royal Society of Chemistry, or in the case of
reprographic reproduction only in accordance with the terms of the licences issued by the
Copyright Licensing Agency in the UK, or in accordance with the terms of the licences
issued by the appropriate Reproduction Rights Organization outside the UK. Enquiries
concerning reproduction outside the terms stated here should be sent to The Royal Society of
Chemistry at the address printed on this page.
Published by The Royal Society of Chemistry,
Thomas Graham House, Science Park, Milton Road,
Cambridge CB4 4WF, UK
For further information see our web site at www.rsc.org
Printed by Athenaeum Press Ltd, Gateshead, Tyne and Wear, UK
An exponential development such as that of synthetic polymers in the last forty years has
never previously happened in the history of mankind’s use of materials. Indeed, it has been
proposed that this Century be named the ‘Plastic Age’.
Polymer chemists and engineers can now design and produce synthetic materials of an
almost unlimited variety of properties which strongly affect our technological and socio-
economic progress. However, in many fields such as electrical, electronic, transport, building,
etc., the use of polymers is restricted by their flammability, whatever the importance of the
advantages their use may bring. Polymers may indeed initiate or propagate fires because,
being organic compounds, they decompose to volatile combustible products when they are
exposed to heat.
Attempts to prevent polymer materials from burning are already reported in the earliest
historical records available, that is Roman war chronicles in which wood treatment with
inorganic compounds is described. Similar so called ’fire retardant’ or ’flame retardant’
treatments of natural polymer materials and textiles have been reported in the literature
throughout the centuries.
The present diffusion of synthetic polymers has greatly increased the ‘fire risk’ and the
‘fire hazard’, i.e. respectively the probability of fire Occurrence and its consequence either on
humans or on structures. Thus, there is now an increasing demand for fire retardant systems
capable of reducing both these risks whereas in earlier developments the reduction of fire risk
was the major target. Moreover, the ‘sustainable development’ concept applied to this field
implies that fire retardants should involve a low impact on health and environment during the
entire life cycle including recycling and disposal.
For all these reasons , the versatile and effective class of halogen-based fire retardants
is somewhat unsatisfactory. Indeed, while they perform a fire retardant action, they may
increase optical density, corrosiveness and toxicity of smoke produced in fires, which have
been shown to be major hazards in the experience acquired in fires occurring in the past
vi Fire Retardancy of Polymers: The Use of Intumescence
decades. Furthermore, super-toxic products were detected when some aromatic halogenated
fire retardants were exposed to heat. Thus, the halogen-based fire retardant can effectively
reduce fire risk but may increase fire hazard as compared to the non-retarded material.
Among alternatives currently actively investigated, the ‘intumescent’ systems which
undergo charring and foaming upon thermal degradation, forming a blown protective cellular
char, are considered a particularly promising environmentally friendly approach. The first fire
retardant system likely to show intumescent behaviour was reported in the literature by Gay
Lussac for cellulosic fibres [Gay Lussac, J. L., Annales de Chirnie, 18(2) (1821) 21 I] and
intumescent coatings for fire protection of wood or metal structures from the effect of fire
have been in industrial use for about fifty years now. However, the regular use of additives to
induce the intumescent behaviour in polymer materials is more recent. In particular,
mechanistic studies on the process of intumescence, which are indispensable to develop
effective fire retardants, have been carried out only in the last twenty five years.
These studies are particularly difficult because of the superposition of several chemical
and physical processes concurring in the intumescent effect. A consistent progress in the
understanding of the mechanisms involved was due to the relatively recent availability of new
effective techniques for the characterisation of the molecular structure of intractable solids
such as charred intumescent materials.
The evolution of this area of fire retardancy is well documented by the increasing
number of papers concerning intumescence presented at the series of European Conferences
on fire retardant mechanisms, materials and environmental-regulation aspects, regularly
organised in Europe in the last fifteen years. It was then thought useful to collect these papers
in this volume which is the first attempt ever to appear in the literature to supply a
comprehensive updated view of this field. I hope that this effort may produce a useful tool for
further research and development work in this field and I wish to thank the organisers of the
Lille Conference and, in particular, Dr. Michel Le Bras for having made this possible.
Giovanni Camino
Preface vii
At the last edition of the European Meeting on Fire Retardancy of Polymeric Materials
(FRPM’97) held in Lille, France, in 1997, a large number of papers dealt with the
intumescence fire retardant approach (33 of the 96 contributions). They covered the most
recent studies on intumescence mechanisms, new intumescent polymeric materials or textiles
and comparative ecological reviews.
This book presents the reviews and the original work presented at FRPM’97, to which
the Editors have added three invited reviews.
In all, twenty seven Research Teams (Academic Laboratories, Institutes or Industrial
Groups) have contributed to this book and proposed different chemical, chemical engineering,
or physical approaches of intumescence and some industrial applications. A comparatively
short last section asks researchers the question: ‘Is intumescence of polymeric materials an
environmentally friendly process?’.
The location of papers in the sections of the book has not been easy. In practice, works
dealing with mechanisms present new formulations and, of course, works on new materials
propose a mechanism discussion as well.
Michel Le Bras
Acknowledgements
The Editors would like to thank:
Professor C. CazC (E.N.S.A.I.T.,R oubaix, France), Dr J. Gilman (N.I.S.T., Gaithersburg,
U.S.A.),P rofessor A. R. Horrocks (Bolton Institute of Higher Education, U.K.), Dr B. K.
Kandola (Bolton Institute of Higher Education, U.K.), Dr T. Kashiwagi (N.I.S.T.,
Gaithersburg, U.S.A.),D r S. Levchik (Byelorussian State University, Minsk, Belarus), Dr B.
Mortaigne (D.G.A.K.R.E.A.,A rcueil, France), Professor G. Montaudo (Dipartimento di
Chimica, Catania, Italy), Professor E. M. Pearce (Polytechnic University of New York,
U.S.A.),D r D. Price (University of Salford, U.K.), Professor J. Wang (Beijing Institute of
Technology, China) and Professor E. D. Weil (Polytechnic University of New York, U.S.A.),
for their invaluable help with refereeing the papers included in this Volume.
Contents
Fire Retardancy of Polymeric Materials: Strategies
Physical and Chemical Mechanism of Flame Retarding of Polymers.
M. Lewin 3
Intumescence: Mechanism Studia
Char-Forming Additives in Flame Retardant Systems.
E. D. Weil, W. Zhu, H. Kim, N. Pate1 and L. Rossi di Montelera 35
Mechanistic Study on Intumescence.
G. Camino and M P. Luda 48
Fire Retarded Intumescent Thermoplastics Formulations, Synergy and Synergistic
Agent+ A Review.
M. Le Bras and S. Bourbigot 64
Mechanism of Action of Halogen-Free Fire Retardants and Developmental Approaches
to Design of New Fire Retardants with Reduced Environmental and Health Concerns.
L. Costa, J.-M. Catala, K. M. Gibov, A. V. Gribanov, S. KLevchik
AndN. A. Khalturinskij 76
Intumescent Chars.
IS. Reshetnikov, M. Yu. Yablokova and N. A. Khalturinskij 88
Some Aspects of Mechanical Stability of Intumescent Chars.
Al. AI, Berlin, N. A. Khalturinskij, I. S. Reshetnikov and M. Yu. Yablokova 104
Modelling Fire Retardant Intumescent Polymeric Materials.
V. Sh, Mamleev and K. M. Gibov 113
Modelling of Thermal Diffusivity during Combustion - Application to Intumescent
Materials.
S. Bourbigot and J. -M.L eroy 129
X Fire Retardancy of Polymers: The Use of Intumescence
Special Features of Bubble Formation During Intumescent Systems Burning.
I. S. Reshetnikov, M. Yu. Yablokova and N. A. Khalturinskij 140
The Role of Radiation over Intumescent Systems Burning.
I. S. Reshetnikov and N A. Khalturinskii 152
Studies on Thermal Degradation and Chamng of Polymers by XPSRGA - to Re-examine
the Transition Temperature TGRoLf the Graphite-like Structure for Polymers on Heating
J. Wang 159
New Intumescent Polymeric Materials
Polymer Combustion and New Flame Retardants.
T. Kashiwagi, J. W. Gilman, M.R . Nyden and S. M.L omakin 175
Nanocomposites:Radiative Gasification and Vinyl Polymer Flammability.
J. W. Gilman, Takashi Kashiwagi, E. P. Giannelis, E. Manias, S. Lomakin,
J. D. Lichtenhan and P. Jones 203
Synergy in Intumescence: the Use of Zeolites.
S, Bourbigot and M.L e Bras 222
Influence of High Energy Radiation on the Thermal Stability of Polydde-6
A. I. Balabanovich, W. Schnabel, G. F. Levchik, S. V. Levchik and C. A. Wilkie 236
The Use of Organophosphorus Functionality to Modlfy the Thermal and Fire Retardant
Behaviour of Polyamides.
J. W. Wheeler, Y. ZhangandJ. C. Tebby 252
-
Comprehensive Study of Protection of Polymers by Intumescence Application to
Ethylene -Vinyl Acetate Copolymer Formulations.
M.L e Bras, S. Bourbigot, C. Siat and R. Delobel 266
Polyamide-6 Fire Retarded with Inorganic Phosphates.
G .F. Levchik, S. V. Levchik, A. F. Selevich, , A. I. Lesnikovich, A. V. Lutsko
and L. Costa 280
MicroencapsulatedF ire Retardants in Polymers.
A. Antonov, E. Potapva, T. Rudakova, I. Reshetnikov, N. Zubkova,
M.T uganova and N Khalturinskii 290
