Fire retardant composite materials

Using this concept, it has been shown by cone calorimetry that over a 3 min combustion period, 3 and 6 mm thick laminated structures, made with different fire-retardant skin and unfilled core combinations can give similar resistance to ignition and comparable HRR and smoke extinction area (SEA) results to fully fire-retardant compositions (Table 7.4). Mechanical properties, in particular impact strength, were also found to be greatly enhanced by this approach, since less fire-retardant filler is present in the material. Whereas this approach has been demonstrated to be effective with hydrated fillers, it is applicable to all fire-retardant types. 

The different methods of obtaining the fire resistance of the polymers have been discussed in previous chapters (Chapters 4 through 13). Fire codes and fire tests relevant to FRPs have also been discussed in previous chapters (Chapters 14 through 16 and 20 through 22), but there will be some discussions of tests solely relevant to composites in this chapter. This chapter will focus primarily on some methods for preparing FRPs, some of the factors that have to be considered when designing an FRP part and typical applications where fire retardant FRP materials are used. 

The common matrix materials in FRP composites are flammable. However, FRP composites in buildings must meet the relevant fire regulations. The requirement of FRP composite components to be fire-resistant can generally be met by applying a gel coat, by putting appropriate additives in the matrix, or through the inclusion of fire-retardant core materials... 

Oxygen Concentration to Support the Candle-Like Combustion of Plastics (Oxygen Index), and internationally as ISO 4589-2 Plastics—Determination of Burning Behavior by Oxygen Index—Part 2 Ambient-Temperature Test. The test does not correlate well with other fire and flammability tests nor does it provide a reliable indication of material performance in real fires. However, the results appear to be very sensitive to the composition of the material and the test is therefore ideally suited to serve as a quality assurance tool of fire-retardant-treated materials. 

Pentaerythritol is used in self-extinguishing, non dripping, flame-retardant compositions with a variety of polymers, including olefins, vinyl acetate and alcohols, methyl methacrylate, and urethanes. Phosphoms compounds are added to the formulation of these materials. When exposed to fire, a thick foam is produced, forming a fire-resistant barrier (see Elame retardants) (84—86). 

Sodium borate solutions near the Na20 B202 ratio of maximum solubihty can be spray-dried to form an amorphous product with the approximate composition Na20 4B202 4H20 commonly referred to as sodium octaborate (64). This material dissolves rapidly in water without any decrease in temperature to form supersaturated solutions. Such solutions have found apphcation in treating ceUulosic materials to impart fire-retardant and decay-resistant properties (see Cellulose). 

Poly(phenylene sulfide) (PPS) is another semicrystalline polymer used in the composites industry. PPS-based composites are generally processed at 330°C and subsequently cooled rapidly in order to avoid excessive crystallisation and reduced toughness. The superior fire-retardant characteristics of PPS-based composites result in appHcations where fire resistance is an important design consideration. Laminated composites based on this material have shown poor resistance to transverse impact as a result of the poor adhesion of the fibers to the semicrystalline matrix. A PPS material more recently developed by Phillips Petroleum, AVTEL, has improved fiber—matrix interfacial properties, and promises, therefore, an enhanced resistance to transverse impact (see PoLYAffiRS containing sulfur). 

Uses. Dicyandiamide is used as a raw material for the manufacture of several chemicals, such as guanamines, biguanide and guanidine salts, and various resias. Siace 1975, it has also been used ia the manufacture of potassium or sodium dicyanamide which are used as iasecticides and ia chemotherapy. Melamine has extensive appHcations ia the resia and plastic iadustry guanamines are used as copolymers (qv) ia many resia compositions. Guanidine phosphate [1763-07-1] is employed as a fire retardant ia appHcations where water solubiHty is not a drawback. 

An obvious utility for the type of modeling described is to evaluate the effect of exchanging one material for another in a composite or an assembly or even the addition of a new material, perhaps one of high toxicity but with a low burning rate. It can be used to evaluate the contribution of a material that does not become involved until the later stages of a fire. The model has the potential of assessing the trade-offs of flammability vs. toxicity often encountered with the use of fire retardants. 

Most research on chemical modification of lignocellulosic materials has focused on improving either the dimensional stability or the biological resistance of wood. This paper reviews the research on these properties for wood and other lignocellulosic composites and describes opportunities to improve fire retardancy and resistance to ultraviolet degradation. 

The book opens with a paper on the structure and composition of wood to define the material under discussion and then considers molds, permeability, wood preservation, thermal deterioration and fire retard-ance, dimensional stability, adhesion, reconstituted wood boards such as fiberboard and particleboard, plywood, laminated beams, wood finishes, wood-polymer composites, and wood softening and forming. A final paper treats the common theme of wastewater management. Only one of the papers presented at the meeting is not included in this volume, and its subject of conventional wood preservation methods is adequately treated in detail elsewhere (e.g., Nicholas, D. D., Ed Wood Deterioration and Its Prevention by Preservative Treatments, 2 vols., Syracuse University Press, 1973). 

E. Kandare, D. Hall, D.D. Jiang, and J.M. Hossenlopp, Development of new fire retardant additives based on hybrid inorganic-organic nanodimensional compounds Thermal degradation of PMMA composites, in Fire and Polymers IV, Materials and Concepts for Hazard Prevention, C.A. Wilkie and G.L. Nelson (Eds.), ACS Symposium Series, American Chemical Society, 922, 2005. 

Small heat source ignition tests generally appear to be very sensitive to the composition of the material and some are therefore ideally suited to serve as a tool for formulation development and quality assurance of fire-retardant-treated products and materials. The equipment is inexpensive, only a small quantity of material is needed, the results are usually reasonably repeatable and reproducible, and a qualified laboratory technician can run many tests in a short time. 

The materials included in this chapter for illustration are nanocomposite polymers combined with intumescent commercial phosphorous fire retardants. In this chapter, different base polymers (e.g., PA6, PBT, PP, and EVA) are mentioned for illustrating the methodology but the focus will be on PA6. For the present purpose, the composition of a PA6 nanocomposite is described next to make the development of the present methodology more clear. 

Mutmansky, J.M., Brune, J.F., Calizaya, F., Mucho, T.P., Tien, J.C., and Weeks, J.L., The final report of the Technical Study Panel on the utilization of belt air and the composition and fire retardant properties of belt materials in underground coal mining, 2007. http //www.cdc.gov/niosh/mining/mineract/pdfs/... 

Kandola, B.K. and Kandare, E. 2008. Composites having improved fire performance. In Advances in Fire Retardant Materials, Horrocks, A.R. and Price, D. (Eds.), Woodhead Publishing Ltd., U.K., Chapter 16. 

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