Fire-retardant fillers polymers

FIRE RETARDANT FILLERS. The next major fire retardant development resulted from the need for an acceptable fire retardant system for such new thermoplastics as polyethylene, polypropylene and nylon. The plasticizer approach of CP or the use of a reactive monomer were not applicable to these polymers because the crystallinity upon which their desirable properties were dependent were reduced or destroyed in the process of adding the fire retardant. Additionally, most halogen additives, such as CP, were thermally unstable at the high molding temperatures required. The introduction of inert fire retardant fillers in 1965 defined two novel approaches to fire retardant polymers. 

Marosi, G., Keszei, S., Marton, A., Szep, A., Le Bras, M., Delobel, R., and Hornsby, P. Flame retardant mechanisms facilitating safety in transportation. In Fire Retardancy of Polymers New Applications of Mineral Fillers, M. Le Bras, C.A. Wilkie, S. Bourbigot, S. Duquesne, and C. Jama (Eds.), pp. 347-360. Cambridge, U.K. The Royal Society of Chemistry. 

A major drawback to the industrial use of fire-retardant fillers is the high addition levels needed in most polymers to confer adequate fire retardancy. This can detrimentally influence processability and melt rheology, and, when used in load-bearing situations, the presence of the filler generally... 

Hornsby, P.R. and Watson, C.L., Mechanistic aspects of smoke suppression and fire retardancy in polymers containing magnesium hydroxide filler, Plast. Rubber Process. Appl., 11,45-51, 1989. 

FIGURE 8.10 Rate of heat release curves of TPU, TPU/DP-POSS, and TPU/FQ-POSS as coating of woven PET fabrics at heat flux 35kW/m2. (From Bourbigot, S. et al., Fire Retardancy of Polymers New Applications of Mineral Fillers, Bras, M., Bourbigot, S., Duquesne, S., Jama, C., and Wilkie, C.A., Eds., The Royal Society of Chemistry, Cambridge, MA, 2005, 189. With permission.)... 

Since the decomposition reaction occurs at a specific temperature, the performance of these fillers depends on the properties of the polymers in which they are used. For example, Mg(0H)2 performs better in polyethylene than AlfOI I) because it remains stable during compounding and decomposes at a temperature closer to the decomposition of PE (300-400 C). In unsaturated polyesters, Al(0H)3 starts to release water at 200°C. The major endothermic peak occurs at 300°C with a heat of decomposition of 300 kJ/mol. About 90% of the water is released between 200 and 400 C. A considerable amount of heat is absorbed before the polymer is affected. The water also dilutes combustible gases and hinders the access of oxygen to the polymer surface. Figure 12.8 shows the difference between talc and a fire retardant filler in PP." Talc causes an increase in the combustion rate as its concentration increases, whereas Mg(OH)2, used at a sufficient concentration (above 20%), decreases the rate of combustion. 

Methods of filler pretreatment coating with thermoplastic polymer zinc hydroxystannate coating of fire retardant fillers increases their performance... 

Bras ML, Camino G, Bourbigot S, Delobel R (1998) Fire retardancy of polymers the use of intumescence. Royal Society of Chemistry, Cambridge, ISBN 0-85404-738-7 Fina A, Tabuani A, Boccaleri E, Camino G (2005) Fire retardancy of polymers new application of mineral filler. Royal Society of Chemistry, Cambridge Grand AF, Wilkie CA (2000) Fire retardancy of polmeric materials. Marcel Dekker, New York Horrocks AR et al (eds) (2001) Fire retardant materials. CRC Press, Boca Raton, FL Prager FH, Rosteck H (2006) Polyurethane and Fire Fire performance testing under real conditions. Weinheim, Wiley VCH... 

Resin A term which is generally u.sed to designate a polymer, a basic material for plastic products. It is somewhat synonymously used with "plastic," but "Resin" (and polymer) most often denotes a polymerized material, while "plastic" refers to a resin which also includes additives such as plasticizers, fire retardants, fillers or other compounds. 

M. Le Bras, C.A. Wilkie, and S. Bourbigot, Fire retardancy of polymers New applications for mineral fillers. Royal society of chemistry, Cambridge (2005). 

Intrinsically fillers can be divided into two types, reactive and inert. Reactive fillers will react with their environment. A good example of this is gibbsite (aluminium hydroxide), which will react with both acidic and basic substances. Aluminium hydroxide also loses its water of crystallisation at around 200 °C and this enables it to provide fire retardancy in polymer formulations. The silicate minerals (kaolin, mica, talc, quartz, etc.), are, in classical chemical terms, virtually inert, only being attacked by very strong acids and alkalis. The carbonate minerals and the hydroxide minerals are very reactive to acids. 

Ecological considerations and investigations of fire hazards such as CO and smoke production target the inert filler characteristics of nanocomposites. The rather physical mechanisms proposed for nanocomposites are advantageous for such considerations. Nanocomposites appear to be a promising eco-friendly approach to fire retardancy in polymers. 

Fire Retardancy of Polymers New Applications of Mineral Fillers. Royal Society of Chemistry, London, 2005, pp. 3-15. 

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