List of contributors
Dean, Faculty of Technology Bolton Institute Deane Road Bolton BL3 5AB UK Tel 01204 903831 Fax 01204 381107 E-mail arh1 bolton.ac.uk Tel 0161 295 4262 Fax 0161 295 5222 E-mail d.price salford.ac.uk Professor D Price, Fire Chemistry Research Group, School of Sciences, University of Salford, Salford, Manchester M5 4WT, UK Dr Geoff Anthony, Great Lakes Chemicals Tenax Road, Trafford Park, Manchester M17 1WT, UK Dr P Carty, Department of Chemical and Life Sciences, University of Northumbria at...
Conclusion
Polymer-layered silicate nanocomposites may be considered to be environmentally friendly alternatives to some traditional flame retardants. Not only does this fact give rise to a promising means of producing flame-retarding polymers, but it does not have the usual drawbacks associated with other additives. For instance, relatively low concentrations of silicates are necessary compared with the amounts used for conventional additive flame retardants in order to achieve similar or indeed,...
Info Kst
The intercalated nanocomposites showed much higher char yields than any of the other polymer, immiscible and delaminated systems. The residual weights after different times at different temperatures from isothermal TGA experiments for PEI and PEI-intercalated nanocomposites are given in Table 6.1. There was, however, no difference between the montmorillonite- and fluorohectorite-based nanocomposites containing the same nanostructure, suggesting that the particle size of the silicates is not an...
References Rtf
1 Wilkie C A, Pettegrew J W and Brown C E, 'Pyrolysis reactions of poly methyl methacrylate and red phosphorus an investigation using cross polarization, magic angle NMR spectroscopy', J Polym Sci Poly Lett Ed, 1981 19 409-14. 2 Brown C E, Wilkie C A, Smulkalla J, Cody R B and Kinsinger J A, 'Inhibition by red phosphorus of unimolecular thermal chain-scission in poly methyl methacrylate investigation by NMR, FT-IR and laser desorption Fourier transform mass spectroscopy', J Polym Sci Polym Chem...
Mode of action of ammonium bromide
Ammonium bromide was recently found to have a high FR-effectivity of bromine, i.e. 1.24 for NH4Br encapsulated in PP as compared to 0.6 for aliphatic bromine compounds. It has been explained by the low dissociation energy of NH4Br to HBr and NH3 which is much lower than the dissociation energy of the C-Br bond. The degree of dissociation is 38.7 at 320 C, so that sizable amounts of HBr are readily available when PP begins to decompose. The radical trap activity of the HBr as well as the...
Direct application methods
Successful flame retardant finishes are those which combine acceptable levels of flame retardancy at an affordable cost and are applicable to textile fabrics using conventional textile finishing and coating equipment. Such established techniques are well-documented in the general textile literature, so excessive detail here is superfluous. Figure 4.10 attempts to present an overall summary of four basic processes shown schematically and as they would be used on open-width textile fabrics. Each...
The bromine antimony question
However, notwithstanding the above, considerable concern has been shown regarding the possible formation of polybrominated dioxins associated with incineration of organobromine compounds, especially those based on poly-brominated diphenyl oxides PBDPO .40 Without wishing to enter into very great detail, following the initial concern in Germany in 1986, the EU published in 1991 a draft amendment to EC Directive 76 769 EEC, which would essentially ban use of all polybrominated diphenyl oxides or...
Crosslinking and char formation
It was early recognised that cross-linking promotes char formation in pyrolysis of celluloses.21 Cross-linking has been assumed to be operative in P-N synergism.22 Cross-linking reduces in many cases, albeit not always, the flammability of polymers. Although it increases the OI of phenolics, it does not markedly alter the flammability of epoxides.23 A drastic increase in char formation is observed when comparing cross-linked polystyrene PS , obtained by copolymerising it with vinylbenzyl...
mechanism dehydration and char formation
The varying effectivity of phosphorus compounds in different polymers has been related to the polymers susceptibility to dehydration and char formation this explains the decreasing activity with decreasing oxygen content of the polymer. Whereas cellulosics are adequately flame retarded with around 2 of phosphorus, 5-15 of it is needed for polyolefins.18 The interaction of phosphorus derivatives with the polymers not containing hydrox- yls is slow and has to be preceded by an oxidation. It has...
Smoke measurement
Smoke formation during burning or smouldering is not an inherent property of a material as are heats of combustion, melting points or densities. The level of smoke actually measured in a test depends on the burning conditions i.e. heat flux, oxidant supply, specimen geometry, the presence or absence of flame as well as the test conditions ambient temperature, test chamber volume, ventilation, etc. . As a result, no single smoke test or even a set of smoke measurements from different tests is...
Info Dhe
Park H, Keun J and Lee K, 'Synthesis and physical properties of two-component polyurethane flame-retardant coatings using chlorine-containing modified polyesters', J. Polym. Sci., Part A, Polym. Chem., 1996, 34 8 , 1455-64. Park H S, Ha K J, Keun J H and Kim T O, 'Preparation and physical properties of two-component polyurethane flame-retardant coatings using trichloro modified polyesters', J. Appl. Polym. Sci., 1998, 70 5 , 913-20. Lin R K, Way T F, Huang L C, Liou R J, Sheng C C, Hwang S K...
Polyhaloalkenes
Organophosphorus and nitrogen-containing monomeric or reactive species e.g. Proban CC Rhodia formerly Albright amp Wilson , Pyrovatex CP Ciba , Aflammit P and KWB Thor , Flacavon WP Schill amp Seilacher Antimony-organo-halogen systems e.g. Flacavon F12 97 Schill amp Seilacher , Myflam B F Goodrich, formerly Mydrin Zirconium hexafluoride complexes, e.g. Zirpro IWS Pyrovatex CP Ciba , Aflammit ZR Thor Organophosphorus and nitrogen sulphur-containing species e.g. Sandoflam 5060 Clariant, formerly...
References
1 Little R W, Flameproofing Textile Fabrics, Reinhold, London, 1947. 2 Rosser W A, Wise H and Miller J, 'Mechanism of combustion inhibition by compounds containing halogen' in Proc. 7th Symposium on Combustion, Butterworth, London, 1959, 175. 3 Van Krevelen D W and Hoftyzer P J, Properties of Polymers, Elsevier Scientific Publishing Co., New York, 1976, pp 523-6 Van Krevelen D W, 'Flame Resistance of Polymeric Materials', Polymer, 1975,16 8 , 615-20. 4 Minkoff G I and Tipper C F H, Chemistry of...
Fabrics and yarn structures
The burning behaviour of fabrics comprising a given fibre type or blend is influenced by a number of factors including the nature of the igniting source and time of its impingement, the fabric orientation and point of ignition e.g. at the edge or face of the fabric or top or bottom , the ambient temperature and relative humidity, the velocity of the air and last but not least fabric structural variables. Fabric orientation, point of ignition source and time and the atmospheric variables are...
Flameretardant finishes for synthetic fibres
Polyamide, polyester, polyacrylic and polypropylene are also candidates for semi-durably and durably flame retarding if suitable finishes are available. Table 4.13 lists examples of those currently available for polyester, polyamide and blends. In the case of acrylics, because of the difficulty in finding an effective flame retardant finish, modacrylic fibres are preferred, unless a back-coating is considered as an acceptable solution, as it would be for finishing fabrics to be tested to BS...
Flameretardant cottons
It is most important that effective flame retardants are also effective afterglow retardants.36 All flame-retardant cottons are usually produced by after-treating fabrics chemically as a textile finishing process which, depending on chemical character and cost, yields flame-retardant properties having varying degrees of durability to various laundering processes. These may be simple soluble salts to give non-durable finishes e.g. ammonium phosphates, polyphosphate and bromide borate-boric acid...
O Och
Second step Scheme 10.3 Ester pyrolysis mechanism in competition with other processes the final products are obtained by some random combination of polymerisation, Diels-Alder condensation, aroma-tisation, etc. Ester pyrolysis supplies the chemical structures which build up the charred material through relatively simple reactions Scheme 10.3 . These schemes give a better account of the charring reactions than that previously proposed in the literature37 for similar compounds, based on the...
Inherently flameretardant synthetic fibres
The conventional synthetic fibres may be rendered flame retardant during production by either incorporation of a flame retardant additive in the polymer melt or solution prior to extrusion or by copolymeric modification. Synthetic fibres produced in these ways are often said to be inherently flame retardant. However, problems of compatibility, especially at the high temperatures used to extrude melt-extruded fibres like polyamide, polyester and polypropylene, have ensured that only a few such...
Flameretarded wool and blends
The dyeing and finishing of wool continues to pose a challenge for textile and protein chemists because the complexity of its chemical and physical structure and the need to find effective processes are in competition in recent years with its almost constant world tonnage production and diminishing share of world fibre markets and textile economy. Within the area of flammability of all so-called conventional fibres, wool has the highest inherent non-flammability and for some end-uses, where...
The structure and properties of layered silicates
Layered silicate clays, because of their chemically stable siloxane surfaces, high surface areas, high aspect ratios and high strengths are most widely used for the formation of organic-inorganic nanocomposites.4 Their high aspect ratios and high strengths make them very good reinforcing elements as well. Their two particular characteristics exploited for the formation of nanocomposites are The rich intercalation chemistry used to facilitate exfoliation of silicate nanolayers into individual...
Some comments on interaction of phosphorus retardants with other flame
2.6.4.1 Further aspects of the mode of action of halogen-phosphorus combinations Synergism has been discussed earlier in this chapter. Some problems of defining synergism, with particular attention to the question of halogen-phosphorus synergism, were critically reviewed with reference to real and dubious examples in flame retardancy.163 Phosphorus-halogen synergism, unlike antimony-halogen synergism, does not appear to be general. Formation of phosphorus oxyhalides, while possible, lacks any...
Menachem Lewin And Edward D Weil 1
Polymer Research Institute Polytechnic University, Brooklyn, New York Some basic mechanisms of flame retardancy were recognised as early as 1947 when several primary principles were put forward.1 These included the effect of the additive on the mode of the thermal degradation of the polymer in order to produce fuel-poor pyrolytic paths, external flame retardant coatings to exclude oxygen from the surface of the polymer, internal barrier formation to prevent evolution of combustible gases, inert...
References Hmm
1 Eckold G, Design and Manufacture of Composite Structures, Cambridge, Woodhead, 1994. 2 Phillips L N ed , Design with Advanced Composite Materials, London, SpringerVerlag, 1989. 3 Vasiliev V V, Jones R M and Man L I eds , Mechanics of Composite Structures, Washington, Taylor amp Francis, 1988. 4 Kandola B K and Horrocks A R, 'Flame retardant composites, a review the potential for use of intumescents', in Bras M L, Camino G, Bourbigot S and Delobel R eds , Fire Retardancy of Polymers - The Use...
ABS Yye
Halogen Melting content soft. range C TGAa 5 Main weight applications loss C Phenoxy-terminated carbonate oligomer of TBBA Phenoxy-terminated carbonate oligomer of TBBA Pyrocheck 68 PB Ferro HP-7010 Albemarle BC-52 amp 58 GLCC FG 7 8000 series Teijin Pyrocheck 68 PB Ferro HP-7010 Albemarle BC-52 amp 58 GLCC FG 7 8000 series Teijin
Halogenantimony synergism
Formulations based on the halogen-antimony synergism are being widely used and have been described for a variety of polymers cellulosics,1 polyesters, polyamides, polyolefins, polyurethanes, polyacrylonitrile and polystyrene.24 The mode of action responsible for this synergism appears to depend both on condensed-phase as well as vapour-phase activities.3637 It is believed that during the pyrolysis, first, some hydrogen halide is released in the self-decomposition of the halogenated compound or...
Polycarbonate and polyphenylene oxide
Polycarbonate PC is a mechanically tough and strong thermoplastic which, even though partly crystalline, is transparent. It is widely used for making impact-resistant mouldings and sheet glazing materials. Where transparency is not required, PC can be used blended with acrylonitrile -butadiene-styrene ABS terpolymers to give cheaper materials, still with good mechanical performance. PC and its blends can be flame retarded by the addition of conventional brominated flame retardants, such as...
Intumescent application to textiles
Clearly any enhancement of the char barrier in terms of thickness, strength and resistance to oxidation will enhance the flame and heat barrier performance of textiles. Generation or addition of intumescent chars as part of the overall flame retardant property will also reduce the smoke and other toxic fire gas emissions. The application of intumescent materials to textile materials has been reviewed33 and is exemplified in the patent literature by the following fibre-intumescent structures...
Model study of char formation in ammonium polyphosphate pentaerythritol system
In order to understand better the chemical reactions that are responsible for the intumescent behaviour of APP-PER mixtures, a thorough study of the thermal degradation of pentaerythritol diphosphate PEDP was undertaken.30 PEDP is a model compound for structures identified in ammonium polyphosphate-pentaerythritol mixtures heated below 250 C. Using TGA five major degradation steps between room temperature and 950 C have been identified and volatile products are evolved in each step. The...
Info Fdr
Kashiwagi T, Gilman J W and Nyden M R, 'New Flame Retardant Additives' in 6th European Meeting on Fire Retardancy of Polymeric Materials, Lille, Sept. 24-6,1997. Basch A, Nachumowitz S, Hasenfrath S and Lewin M, 'The chemistry of THPC-urea polymers and relationship to flame retardancy in wool and wool-polyester blends. II. Relative flame retardant efficiency', J. Polym. Sci., Polym. Chem. Ed., 1979,17, 39. Basch A, Zwilichowski B, Hirschman B and Lewin M, 'The chemistry of THPC-urea polymers...
Flame retardants containing phosphorus and nitrogen
Phosphorus and nitrogen compounds and systems are a small but rapidly growing group of intumescent flame retardants which are in the focus of public interest concerning environmentally friendly flame retardants. Today their main applications are melamine for polyurethane flexible foams, melamine cyanurate in nylons, melamine phosphates, ammonium polyphosphate-pentaerythryol or ethylene-urea formaldehyde polymers in polyolefins, melamine and melamine phosphates or dicyandiamide in intumescent...
Condensedphase modes of action
There is very convincing evidence, especially in oxygen-containing polymers such as cellulose and rigid polyurethane foam, that phosphorus compounds can increase the char yield. Formation of char means that less material is actually burned. Secondly, char formation is often accompanied by water release, which dilutes the combustible vapours. Moreover, the char can often protect the underlying polymer and the char-forming reactions are sometimes endothermic. The pyrolysis behaviour of cellulose...
Conclusions
The majority of fire injuries and deaths result from exposure to toxic products. The extent of such exposure toxic risk depends upon the probability that fires will occur and the extent of the subsequent toxic fire hazard. Fire retardant systems are used in a wide range of materials and products to control fire risk and fire hazard. They achieve this by improving ignition resistance and in some cases by improving the rate of fire growth once defined levels of ignition resistance are overcome....
Bromine content
The bromine content is generally closely related to flame-retardant efficiency and therefore should be as high as possible in order to reduce the loading required and hence limit changes in properties of the substrate. In Table 8.5, a comparison in high impact polystyrene HIPS is made between ethylene bis-tetrabromophthalimide 67 of bromine and Applications of halogen flame retardants 283 Table 8.5 Bromine content and properties of UL 94 V-0 HIPS Applications of halogen flame retardants 283...
Amino and phenolic resins
Cured amino and phenolic resins are above averagely flame retardant owing to the extensive cross-linking and to the high nitrogen contents, in the case of amino resins, and significant aromatic content, in the case of phenolic resins. Also, amino and phenolic resins tend to be used in materials containing high concentrations of non-flammable fillers and laminating agents, such as kaolin, glass powder and glass fibre. Amino resins, which themselves are used as components of flame retardants for...