Recent developments in the chemistry of halogen-free flame retardant polymersAbstractAn overview of recent developments of the chemistry of halogen-free flame retardant polymers is presented in this paper. The polymers or reactive monomers that are inherently flamed retarding contain P, Si, B, N and other miscellaneous elements. They can be used on their own or added to current bulk commercial polymers to enhance flame retardancy. The synthetic chemistry of these molecules is discussed along with their thermal stabilities and flame-retardant properties.

Thermal decomposition of polymer mixtures of PVC, PET and ABS containing brominated flame retardant: Formation of chlorinated and brominated organic compounds

The thermal decomposition of various mixtures of acrylonitrile butadiene styrene copolymer (ABS), ABS containing brominated epoxy resin flame retardant and Sb2O3, poly(ethylene terephthalate) (PET) and poly(vinyl chloride) (PVC) has been studied in order to clarify the reactions between the components of mixed polymers. More than 40 halogen-containing molecules have been identified among the pyrolysis products of mixed samples. Brominated and chlorinated aromatic esters were detected from the mixtures containing PET and halogen-containing polymers. A series of chlorinated, brominated and mixed chlorinated and brominated phenols and bisphenol A molecules have been identified among the pyrolysis products of polymer mixtures containing flame retarded ABS and PVC. It was established that the decomposition rate curves (DTG) of the mixtures were not simple superpositions of the individual components indicating interactions between the decomposition reactions of the polymer components. The maximal rate of thermal decomposition of both ABS and PET decreases significantly if the mixture contains brominated epoxy flame retardant and Sb2O3synergist. The dehydrochlorination rate of PVC is enhanced in the presence of ABS or PET.

Highlights The ABS, PET, PVC and brominated epoxy flame retardant influence the decomposition of each other. A series of brominated, chlorinated and both chlorinated and brominated phenols and bisphenol A molecules forms if both PVC and brominated epoxy oligomer flame retardant are present in the mixture. The PET decomposition radicals are ready to stabilize with both Clor Brradical in the presence of PVC or brominated epoxy flame retardant. The brominated epoxy flame retardant and Sb2O3synergyst initiates the decomposition of ABS, this effect intensifies in the presence of PET.

New Thinking on Flame RetardantsKellyn S. Betts

No one wants their bed, couch, chair, computer, or TV to catch on fire. If an ordinary upholstered chair in your home gets ignited, it can essentially take your whole house down, says Richard Gann, a senior research scientist at the U.S. National Institute of Standards and Technologys (NIST) Building and Fire Research Laboratory. The most flammable part of a mattress or couch is its plastic polyurethane foam cushioning, he explains. Once a fire gets through a chair or mattresss fabric covering and into this cushioning, it can start a catastrophic reaction that quickly leads to flashover, in which nearly everything combustible inside a room ignites simultaneously.Until very recently, brominated flame retardants, especially polybrominated diphenyl ethers (PBDEs), were one of the main materials used to reduce the speed with which the plastic components of consumer goods including beds, couches, chairs, and electronics could be consumed by fire. However, growing evidence shows that PBDE compounds are escaping from the products they protect and making their way into the products users. Moreover, the chemicals may disrupt human thyroid hormone functioning and cause other health effects, prompting many nations to ban or suspend their use in new consumer goods. [For more information on the health effects of PBDEs, see Unwelcome Guest: PBDEs in Indoor Dust, p. A202 this issue.]Although bromine- and chlorine-containing flame retardants are still used in some products, the need for new alternatives is being driven by a confluence of policy, standards, and pressure from environmental groups. Europe banned the use of two formulations, PBDE pentaBDE and octaBDE, in 2004, the same year they were withdrawn from the North American market. A third compound, decaBDE, was banned 1 April 2008 by the European Court of Justice. Stateside, Maine has banned the use of decaBDE, the only PBDE still on the market in North America, in mattresses and residential upholstered furniture produced and sold in that state, and will extend the ban to electronics in 2010. Washington prohibits the use of decaBDE in mattresses and sets a process for a future ban in furniture and electronics if the state can identify a safer and feasible alternative that meets fire safety standards. Asian countries and other U.S. states have similar legislation in the works.Instead of adding new fire retardant chemicals that ultimately may be shown to cause health problems, we should be asking whether we need to use these chemicals or if there are other ways to achieve equivalent fire safety, contends Arlene Blum, a biophysical chemist and visiting scholar at the University of California, Berkeley. So many of the chemicals we have banned in the past were flame retardantsthink about asbestos, polychlorinated biphenyls, polybrominated biphenyls, tris(2,3-dibromopropyl) phosphate, PBDEs[and] they all ended up in the environment and in people, she points out. We need to think carefully about adding these sorts of chemicals to consumer products before there is adequate health information.Go to:Policy DriversTwo new standards from the U.S. Consumer Product Safety Commission (CPSC) are opening the door for innovative approaches for protecting consumer goods containing polyurethane foam from fire. The first took effect last year for mattresses. This standard is innovative in being the first in the United States to focus on the rate of heat release, which fire safety experts recognize is the main determinant of how quickly a fire can spread out of control to the flashover point, Gann says.The mattress industry worked with NIST to develop the new standard test method to meet the CPSC regulation, which stipulates that no mattress may generate a peak heat release rate greater than 200 kilowatts when subjected to gas burners that mimic burning bedding. The CPSC estimates the new standard will prevent as many as 270 fire-related deaths and 1,330 injuries every year. Since this is a performance standard rather than a prescribed mattress design, it allows manufacturers to choose how to fabricate mattresses that comply with the regulation, Gann says.One approach mattress manufacturers are using to meet the standard is to employ what is known in the industry as a barrier material, says Tom Ohlemiller, who was the project leader for the NIST team that developed the mattress test method. The barrier materials themselves may be inherently nonflammable, such as polyamides like Kevlar. Flammable barriers may be protected with proprietary fire retardant treatments such as decaBDE. However, Ohlemiller says the standard does not require such treatments for the polyurethane foam padding beneath the barrier, which some scientists believe is the source of some of the PBDE flame retardants that have escaped into peoples homes. Over the past year, scientists have reported detecting other flame retardants used in polyurethane foam in household dust.The second new standard, which affects upholstered furniture, is still wending its way through the regulatory process. According to Nancy Nord, acting chairman of the CPSC, the new rule will address upholstered furniture fires without requiring the use of fire retardant chemicals. Under the new proposal, furniture manufacturers could meet the performance standard by using smolder-resistant cover fabrics or interior fire-resistant barriers to protect the furnitures internal filling material. The standard was put out for public comment in theFederal Registeron 4 March 2008 and is open for comment until May 19.The furniture standard focuses on cigarettes as a source of fires because they are responsible for 90% of the fires involving upholstery, says Russell Batson, vice president of government affairs for the American Home Furnishings Alliance, an industry group. You can get smolder resistance without relying on chemicals, he says. However, Gann points out that cigarette ignition resistance is going to be improved significantly anyway due to the passage over the past four years of laws mandating that Canada and 24 U.S. states can sell only fire-safe cigarettes, which self-extinguish if left unattended. These laws affect nearly 60% of the North American population, according to the nonprofit Coalition for Fire-Safe Cigarettes.Additionally, Alexander Morgan, a group leader at the University of Dayton Research Institute, says there is a lot of concern about barriers failing against ignition sources stronger than a cigarette, especially since smoking rates are declining in many developed nations, according to the World Health Organization. He says candles, hot electrical equipment, and short-circuiting laptops could easily penetrate these protective barriers.This is a fundamental weakness of the barrier approach in light of several decades of fire safety data for furniture from the United Kingdom, which Morgan says has the worlds toughest flammability standards for polyurethane foam. Yes, they do use flame retardants, but the level of fire safety of their products is very good and fire losses in the UK due to furniture fires are quite low or non-existent. When and if flashover occurs due to a furniture fire, the amount of pollution and carcinogens released from this one fire far overwhelms the production of potentially dangerous products from a flame retardant foam, he says. Morgan argues that the solution may be to devise flame retardants that are less likely to escape from the materials that they protect, together with better product reclamation and recycling programs for flame retardant products so that the chemicals dont end up into the environment.Despite such concerns, Batson says the proposed standard is inspiring furniture manufacturers to investigate how barriers can be used to insulate the interior cushioning materials inside upholstered furniture. Recent innovations in materials science, together with concerns about flame retardant toxicity and ecotoxicity have convinced people in the industry to try to design effective barrier materials for the market, he says. The furniture industry is looking carefully at how mattress manufacturers construct fire-blocking barrier layers of fabric or high-loft materials such as batting rather than chemically loading the outer fabric layer, he says. That approach and some of the technologies that are emerging in response to it is probably going to be useful in the furniture [industry], as well, he says.Go to:NanomaterialsOne promising approach is to incorporate flame retardants into the materials themselves. A new company called G3 Technology Innovations (G3i) is pursuing that line of reasoning with its GreenShield FR treatment for polyester fabrics. Such fabrics are the basis of 90% of the products used in the contract textile industrywhich produces all furniture, floor coverings, wall coverings, and window treatments used in commercial buildings and institutionssays Alex Qiao, G3is co-founder and president.The technology, which G3ico-founder and chief operating officer Suresh Sunderrajan and his business partners developed for different applications while previously employed at Eastman Kodak, revolves around the ability to attach different functional groups onto nanoparticles. We are able to attach multiple sets of these [functional molecules] onto the particles, he explains. For example, he says one set of the molecules might encompass the particles needed to allow the molecules to attach themselves to a fabrics fibers, a second set might provide water and stain repellency, and a third set could involve flame retardancy. All of this is built onto a [silica-based] backbone which is inherently nonflammable, he explains. The GreenShield FR treatment goes into the [polyester] fiber and becomes a permanent part of it, Qiao says.The company has also worked with a textile finisher called Preferred Finishing to develop new barrier materials that Qiao says can become integral parts of the fabric they protect because both are made of polyester resin. This confers an additional advantage of avoiding the use of melamineformaldehyde resin, which is often used to bind other barriers to decorative fabrics, Sunderrajan points out. When the resin degrades, he explains, it releases formaldehyde, which the International Agency for Research on Cancer classifies as a known human carcinogen. The company says all of its technologies are based upon commercially available materials that have been tested individually for toxicity. Several furniture makers are now testing the G3iproducts.Nanoclays are another material that could change the way consumer products are protected from combustion. Flame retardants made with naturally occurring clay called montmorillonite are poised to have a huge influence on future fire safety, Gann says. Scientists at NIST and Cornell University have been investigating how this clay can help reduce the amount of energy released during fires for more than a decade, says Jeffrey Gilman, a research chemist at NIST.When things burn, contrary to how it looks, it is not the solid that is burning. The solid breaks down to give you small fragments of molecules. These vaporize and mix with the air, and they burn there, Gann explains. The nano-network formed by the nanoclays impedes this from happening, he says. If the [nanoclay] particles are appropriately spread out and dispersed through the host [material], they form sort of a gauze inside the material. It slows down significantly or even prevents the breakdown of material and the release of gas-phase combustible molecules, he says.The potential of nanoclays isnt just theoretical. A company called Nanocor sells nanoclay-based flame retardants that are used in electronics, wires, cables, and decorative wallpapers, says Tie Lan, general manager for the companys U.S. operations. The fundamental nature of the nanoclay will make the material burn slower [and] lower the temperature of the flame, he says, adding that the same clays are also used in nonclumping kitty litters.Both Nanocor and Albemarle Corporation, one of the major flame retardant makers, sell flame retardants combining nanoclays with another major class of flame retardants based on metal hydroxides. The nanoclays synergistically improve how the metal hydroxide retardants perform, Gilman says. Combining the two flame retardants also improves how the plastics are processed, as well as their material properties. Nanoclays are appealing to plastics manufacturers because they can be added in relatively small amounts, on the order of a few percent by weight. This means both that they are unlikely to negatively affect the functionality of the plastic material to which they are added and that they are relatively inexpensive, Gann says.More recently, the NIST researchers have also begun to look at other nanomaterials, including carbon nanotubes, layered hydroxides, and polyhedral oligomeric silsesquioxane nanocomposites that also contain silicon, says Gilman. Some nanomaterials, especially carbon nanofibers, appear to have promise for use in polyurethane foam, says Mauro Zammarano, a guest researcher from Italy evaluating these materials at NIST. Testing at NIST suggests carbon nanofibers are able to reduce the rate at which heat is released when polyurethane foam is burned.However, Andrew Maynard, chief science advisor of the Project on Emerging Nanotechnologies, a nonprofit group associated with the Woodrow Wilson International Center for Scholars, cautions that the same properties that make the nanoparticles effective could also make them toxic. With any sort of nanotechnology . . . [the] potential for harm is associated with the size and shape of the particles, as well as what theyre made of. That applies whether youre looking at sunscreen, impregnated fabrics, or flame retardants, he says. Scientists need to look carefully to determine if there is any way the nanomaterial-based flame retardants escape from the fabric or material in which theyre used and enter the environment, and whether people could be exposed to the nanoparticles, he says.NIST has begun to work with the CPSC and Scripps Institution of Oceanography to evaluate whether any of these nanomaterial-based fire retardants are toxic, Gilman says. Dimitri Deheyn, a marine biologist at Scripps Marine Biology Division, is conducting some of this testing using brittle stars, which Deheyn says have nervous systems that function very similarly to mammals, including humans. He says the testing he has conducted to date suggests the surfactants used to ensure the nanomaterials disperse throughout the materials to which they are added may be more toxic than the nanomaterials themselves.Go to:Halogen-Free ElectronicsThe electronics industry is under pressure from environmental groups to remove potentially toxic compounds from their products, including the brominated flame retardants that were once widely used in electronics housings and cases and are still used extensively in printed circuit boards. At least nine leading electronics companies have pledged to remove brominated and/or halogenated flame retardants from some or all of their products, according to the Environmental Working Group.The main way that companies are doing this is by using phosphorus-based flame retardants for casings and circuit boards, and using minerals such as nanoclays in combination with aluminum and magnesium hydroxide for the machinerys wiring and cabling, says Morgan. However, he points out that companies and environmental watchdogs are scrutinizing some of these phosphorus-based retardants for potential health problems of their own; for example, some are suspected to be neurotoxicants when they break down in the environment, he points out. He says his experience testing how well different nonhalogenated flame retardants work suggests that reactive phosphorus-based retardants appear to be the best nonhalogenated flame retardants for printed circuit boards at this time, in terms of their effectiveness, long-term durability, sustainability, and environmental impact.Trying to find halogen-free alternatives for electronic circuit boards involves significant trade-offs, stresses Fern Abrams, the director of government relations and environmental policy for IPC, an electronics industry association for manufacturers of printed circuit boards and other electronics components. She says the holy grail would be to develop materials for building and housing electronics that are inherently flame-resistant.Morgan agrees. He says the aerospace industry currently uses some inherently non-flammable plastics, but they are too expensive for commodity-type applications such as electronics housings, given the industrys profit margins. More recently, scientists have begun trying to develop plastic polymers that are inherently nontoxic and nonflammable.One team involved in this effort is at the University of Massachusetts Amherst, where researchers have developed a new plastic polymer based on bishydroxydeoxybenzoin (BHDB) that releases water vapor rather than hazardous gases when it breaks down in a fire. The great thing about BHDB is that . . . it is extremely fire-safe and does not contain halogenated additives, says Bryan Coughlin of the universitys Polymer Science and Engineering Department, one of the new materials co-inventors.The Amherst researchers believe BHDB may prove to be cost-effective for use in some consumer products, including home furnishings and electronics. We are currently trying to determine how well BHDB works in a variety of plastics formulations . . . including polyurethane foam, says Todd Emrick, another co-inventor at the University of Massachusetts Amherst Polymer Science and Engineering Department. The fire safety experts at NIST say that they believe the material has a great deal of promise. But the biggest challenge, as Morgan points out, may be finding a company willing to make the investment needed to bring such an innovative technology to the marketplace.

Although house dust is known to be a predominant source of exposure to PBDEs, its not yet clear which part of the dust these chemicals bind to. The dust pictured above contains pet hair (rust brown), pollen (yellow), plant fibers (green), dead...Go to:Suggested Reading Kashiwagi T.Flame retardant mechanism of the nanotubes-based nanocomposites.Gaithersburg, MD: National Institute of Standards and Technology; 2007. Final report. NIST GCR 07-912. Morgan AB, Wilkie CA, editors.Flame retardant polymer nanocomposites.Hoboken, NJ: John Wiley & Sons; 2007. Nelson GL, Wilkie CA, editors.ACS Symposium Series #797.Washington, DC: American Chemical Society; 2001. Fire and polymers: materials solutions for hazard prevention. U.S. EPA. Washington, DC: U.S. Environmental Protection Agency; 2005. Environmental profiles of chemical flame-retardant alternatives for low-density polyurethane foam, volume 2: chemical hazard reviews. EPA 742-R-05-002B.

Overview of Flame Retardants IncludingMagnesium HydroxideMatthew D. WalterMark T. WajerMARTIN MARIETTA MAGNESIA SPECIALTIES LLC8140 Corporate Drive, Suite 220Baltimore, MD 21236There are many classes of compounds which are useful as flame retardants. Inorganic minerals, organo-phosphates, and halogenated compounds are all commonly used for their ability to inhibit combustion and smoke generation in plastics and other materials. In 1993, United States industries consumed 810 million pounds of flame retardant additives, and demand is projected to be over one billion pounds in 19981. While currently a small part of this large market, Magnesium Hydroxide is attracting attention because of its performance, price, low corrosiveness, and low toxicity. The current market for magnesium hydroxide in flame retardants is about ten million pounds per year, with the potential to surpass thirty million pounds per year in the near future.Basic Fundamentals of Various Flame RetardantsATH, Magnesium HydroxideLike ATH* (Al2O33H2O), magnesium hydroxide (Mg(OH)2), is an acid- and halogenfree flame retardant for various plastics. Both hydroxides decompose endothermically when heated according to the reactions:2Al(OH)3 ---> Al2O3 + 3H2OMg(OH)2 ---> MgO + H2OThe gaseous water phase is believed to envelop the flame, thereby excluding oxygen and diluting flammable gases.2Similar to the function of char formed by phosphorouscontaining flame retardants, a heat insulating material may form on the surface of the plastic in contact with the flame, reducing the flow of potentially flammable decomposition products to the gas phase where combustion occurs." In both of the reactions, the decomposition products are non-toxic and the mineral phases, especially MgO, are alkaline, reducing the likelihood of acidic, corrosive gases exiting the plastic.The physical and chemical properties of magnesium hydroxide and ATH are shown in Table One. Magnesium hydroxide has a 100C higher decomposition temperature than ATH, allowing a higher processing temperature in compounding and extruding the plastic. Also, magnesium hydroxide adsorbs more energy during the decomposition process.Table One: Comparison of Properties of Mg(OH)2 and ATHMg(OH)2 ATHBound Water, % 31.0 34.6Specific Gravity 2.36 2.42Mohs Hardness 2.5 3.0Refractive Index 1.56 - 1.58 1.57Initial Decomposition Temperature 330C 230CEnthalpy of Decomposition 328 cal/g 280 cal/gTable One: Comparison of Properties of Mg(OH) and ATH.Phosphorous-Containing Flame RetardantsPhosphorous-containing flame retardants mainly influence name retardancy in the condensed phase. They are particularly effective in materials having a high oxygen content, such as cellulose and some oxygen-containing plastics. The basic flame retarding mechanism involves thermal conversion of the phosphorous-containing name retardant to phosphoric acid in the condensed phase of the plastic. The phosphoric acid extracts water from the burning plastic, causing it to char. The char insulates the plastic from flame and heat, preventing volatile, combustible gases from exiting the bulk.3Since phosphoric acid is formed in the burning plastic, there is increased likelihood that the smoke will be corrosive. Halogenated organophosphates are sometimes used as a flame retardant.3The halogens, as will be shown in the next section, interfere with the radical chain reaction, while the phosphorous forms a char.Halogenated Flame RetardantsHalogenated name retardants are organo-halides selected to vaporize in a similar temperature range as that of the plastic resin. Once in the gas phase, the halogen, typically chlorine or bromine, decreases the concentration of high energy free radicals that are involved in the combustion process.3Eliminating these free radicals reduces flame intensity, decreases the amount of heat transferred to the plastic, consequently slowing or eliminating the burning of the plastic. A mechanism for this action has been proposed as follows:3In the gas phase, a radical chain reaction occurs involving OH and H radicals formed by high energy decomposition of the plastic:H.+ O2 ---> OH.+ O..O.. + H2 ---> OH.+ H.To remove these high-energy free radicals, the halogenated flame retardant first breaks down as shown:RX ---> R.+ X. where X is either Cl or Br.The halogen radical reacts to form the hydrogen halide:X.+ RH ---> R.+ HXwhich in turn interferes with the radical chain mechanism:HX + OH.---> H2O + X.The high energy H.and OH.radicals involved in combustion of the plastic are thus removed by the flame retardant and replaced with lower energy X.radicals. These radicals react with the plastic hydrocarbons to produce the hydrogen halide, regenerating the flame retardant.Since halogenated flame retardants are regenerative, much lower loadings (typically ~10% by weight) are required compared to ATH or magnesium hydroxide (typically ~50% by weight). Brominated flame retardants are typically more effective than those utilizing chlorine because of a narrower vaporization temperature leading to higher concentration of the flame retardant in the flame zone.3Synergistic agents, such as antimony oxides, further increase the effectiveness of both brominated and chlorinated flame retardants by enabling the halogen to stay in the flame zone for longer periods.4While halogenated flame retardants and halogen-antimony combinations provide better name retardance in most systems, use of these compounds has given rise to some concern.5,6 In particular, much attention has been focused on the corrosiveness and toxicity of smoke and other emission products generated during the combustion of plastics utilizing these materials. In recent years there has been much speculation that legislation will arise restricting the use of these compounds as flame retardants. Some brominated flame retardant producers have voluntarily agreed to put restrictions on production, export, and import of their products in European countries in advance of such legislation.7In contrast to the potentially hazardous halogenated flame retardants, magnesium hydroxide is considered a nuisance dust and is not volatilized during combustion of the plastic. Table Two shows toxicity data for brominated and chlorinated compounds.Additionally, as landfill space declines, or becomes unpopular, incineration and recycling of used plastics will become more widespread. Plastics formulated with halogenated flame retardants pose problems for incinerators in design, operation and maintenance, as well as a danger to public health from the incineration product gases.8Table Two: Range of Toxicity Values for Flame Retardant TypesCompound Class Toxicity, LD50 ReferenceNumberBrominated, (inhalation) 2.49-200 mg/L 9Chlorinated, (inhalation) 2.25-203 mg/L 10Magnesium Hydroxide, (inhalation) None published, Mg(OH), is considered a nuisance dust 11Table Two: Toxicity Values for Flame Retardant TypesUse of Magnesium Hydroxide as a Flame Retardant in PlasticsThere are many producers of magnesium hydroxide for flame retardants.12 Martin Marietta Magnesia Specialties, LLC, the Solem Division of J.M. Huber, and Morton International are the larger domestic producers with Dead Sea Periclase (Israel), Kyowa (Japan), and Magnifin (Austria) being some of the foreign producers. Grades of magnesium hydroxide range from coated, micronized powders (for higher end, higher loading applications) to uncoated magnesium hydroxide as a direct replacement for ATH. Kyowa and Magnifin specialize in the more expensive coated, high-end grades of magnesium hydroxide while Martin Marietta Magnesia Specialties, LLC produces MagShieldTM S in uncoated form as a direct ATH replacement.Several studies13,14,15,16 illustrating the effectiveness of magnesium hydroxide as a flame retardant in plastics have been performed. These have concluded that magnesium hydroxide is effective at reducing smoke emissions from burning plastics. A summary of the more important factors determining the performance of magnesium hydroxide as a flame retardant follow:1. The endothermic decomposition commencing at about 330C for magnesium hydroxide (versus about 230C for ATH) withdraws heat from the substrate, slowing the rate of thermal degradation of the plastic.2. The release of water vapor upon decomposition of magnesium hydroxide dilutes the fuel supply present in the gas phase.3. The relatively high heat capacities of both magnesium hydroxide and the decomposition products formed upon decomposition of magnesium hydroxide reduce the thermal energy available to degrade the plastic.4. The decomposition products provide increased insulation of the plastic from the heat source through char formation.5. The high filler content usually associated with magnesium hydroxide-treated plastics acts as a solid phase dilutent.Figure 117 shows typical results of smoke emission testing (ASTM E662, under flaming conditions) on various plastics with and without 40% by weight of magnesium hydroxide. The magnesium hydroxide in this study significantly lowers the overall level of smoke produced. Furthermore, the use of magnesium hydroxide causes a considerable delay in the onset of smoke evolution and markedly slows the rate of smoke release. Clearly, these factors have major implications in real life.Another study18 showed the results of UL 94 testing (Ignitability of Plastics by a Small Flame, or Vertical Burn Test) where polyamide and polypropylene plastics were compounded with Mg(OH)2 at 60% by weight loading. These compositions attained a VO classification representing a high resistance to ignition, according to the UL 94 test.For a flame retardant to be useful in compounded plastics, it must not degrade the physical properties of the plastic. In a typical flexible wire PVC formulation, Martin Marietta Magnesia Specialties LLC's MagShieldTM S was found to slightly improve the physical properties of the PVC formulation compared to ATH and a competing, higher grade magnesium hydroxide. The compounded PVC utilized a 30 PHR loading of each flame retardant and resulted in a plastic with the properties19 shown in Table Three.Table Three: Physical Properties of a Typical Flexible Wire and Cable PVC Formulation with Magnesium Hydroxide and ATHMagShieldTM S ATH Competitive Mg(OH)2Elongation, % 139 118 136Tensile Breaking Strength, psi 2610 2365 2499Tensile Modulus, psi 20330 19173 20116Melt Flow Index, (g/10 min) 0.90 0.43 1.00Table Three: Data from Martin Marietta Magnesia Specialties LLC testingPlastics requiring higher loadings, such as polypropylene and polyamides, typically require the use of specialty magnesium hydroxide grades having fatty acid coatings or specific physical properties. The special properties of these materials allow for highloadings with little to no degradation of the physical properties of the plastic. New work underway with metallocene catalyzed polymers indicates that coating of the magnesium hydroxide may be reduced or eliminated for various plastics.20ConclusionsMagnesium hydroxide acts as a flame retardant and smoke suppresser in plastics mainly by withdrawing heat from the plastic during its decomposition into magnesium oxide and water. The water vapor that is generated dilutes the fuel supply to the flame. Decomposition products insulate the plastic from heat and produce char that impedes the flow of potentially flammable gases to the flame.Increasing legislation and concern about the use and recyclability of halogenated flame retardants make magnesium hydroxide more attractive to plastics producers. Magnesium hydroxide offers flame retardance and smoke suppression from a substance that is acidand halogen-free and has low toxicity values. In most cases, with proper selection of the grade of magnesium hydroxide, no compromise need be made for physical properties and name retardancy of the plastic. For high-loading applications where the use of highend or coated magnesium hydroxide is dictated, legislation maybe the dominant driving force for specifying magnesium hydroxide as opposed to halogenated flame retardants. The more economical route for lower loading applications may be the use of lower-priced grades of magnesium hydroxides such as MagShield TM S.*Also known as aluminum hydroxide, Al(OH)31. HAIRSTON, D.W., Chemical Engineering, 9 (1995), 65.2. HORNSBY, P.R. and WATSON, C.L., Polymer Degradation and Stability, 30 (990), 74.3. KIDDER, R.C., TROITZSCH, J.H., NAUMANN, E., and ROUX, H.J., From Course Work Materials in New Developments and Future Trends in Europe and the United States for Fire Retardant Polymer Products, (1989).4. HASTIE, J.W., High Temperature Vapors, Academic Press, LLC, New York, 1975, p. 353.5. WOOLEY, W.D. and FARDELL, P.J., Fire Safety Journal, 5 (1982), 29-48.6. REINKE, R.E. and REINHARDT, C.F., Modem Plastics, 50 (1983), 94-98.7. From Industrial Minerals, 336 (1995), 17.8. GANN, R.G., from Kirk-Othmer Encyclopedia of Chemical Technology, 4th Ed., Volume 10, 935.9. Material Safety Data Sheets from Ethyl Corporation for hexabromcyclododecane and dibromoneopentylglycol.10. Material Safety Data Sheets from Velsicol Chemical Company for chlorendic anhydride and Occidental Chemical Corporation for bis(hexachlorocyclopentadieno)-cycloocta11. Sax's Dangerous Properties of lndustrial Materials, 8th Edition, R.J. Lewis, Sr., Vol. 111 (992), 2150.12. From Industrial Minerals, 318 (1994), 23-45.13. ZIEGAN, G. and HONGESBERG, H., from Flame Retardants '92, 5th Conference, 120-132.14. HORNSBY, P.R., Fire and Materials, 18 (5), (1994), 269-276.15. LEVESQUE, J.L. and HASTBAKA, M.A., from RETEC Additive Approaches to Polymer Modification Conference Papers, (9/1989), R89-190.16. HORNSBY, P.R. and WATSON, C.L., Polymer Degradation and Stability, 30 (990) 73-87.17. From Reference 14, p. 272.18. From Reference 14, p. 275.19. Taken from MagShieldTM 98 Product Literature, Martin Marietta Magnesia Specialties, LLC20. HUGGARD, M., Flame Retardant Polyolefins: Impact and Flow Enhancement Using Metallocene Polymers, Conference Proceedings (Additives for Metallocene Catalyzed Polymers, June 24-26, 1996), Intertech Conferences, 411 U.S. Route One, Portland, MA 04105, p. 9.NOTICE The data and test results referred to herein are based on tests defined by flammability safety regulations and performed under laboratory conditions. This should not be construed as a representation or warranty of performance under actual fire conditions. The information contained herein is, to the best of our knowledge and belief, accurate. Any recommendations or suggestions made are without warranty or guarantee of results since conditions of use are beyond our control. Before using, the customer should determine the suitability of the product for the customer's intended application. We warrant only that this product will meet the specifications set forth herein. ANY OTHER REPRESENTATION OR WARRANTY, EITHER EXPRESS OR IMPLIED, IS SPECIFICALLY DISCLAIMED INCLUDING WARRANTIES OF FITNESS FOR A PARTICULAR PURPOSE AND MERCHANTABILITY. Our only obligation is to replace nonconforming product or to refund purchase price at our option. In no event shall we be liable in tort, contract or otherwise for any incidental or consequential damages.MagShield is a trademark ofMartin Marietta Magnesia Specialties LLC

Use of flame retardant polymer grades on the rise in electric/electronic & building industries

Plastics materials are used in large volumes in major applications such as buildings, vehicles and electronic appliances. In each of these areas fire safety is critical. Fire is a big menace. As per estimates from USA, there are approximately 400,000 residential fires each year, 20% involving electrical distribution and appliances; another 10% concerning upholstered furniture and mattresses. These fires kill about 4,000 people, injure another 20,000 people and result in property losses amounting to about US$4.5 bln. The use of flame retardant plastics can reduce deaths by 20%. Flame retardants can act in a variety of ways: by raising the ignition temperature, reducing the rate of burning, reducing flame spread and reducing smoke generation. Hence flame retardants have been developed to improve the properties of plastics under the different conditions of processing and use. Flame retardants are an important part of fire protection as they not only reduce the risk of a fire starting, but also the risk of the fire spreading. The increasing demands in the electrical and electronic sector for miniaturisation and faster injection moulding cycles exerts additional demand on flame retardant technology. The faster injection speeds require higher processing temperature stability and increased flow performance; while miniaturisation leads to increasing property performance for a given resin system as less material is used in each part. Flame retardants in commodity polymers are growing exceptionally well since the inherent flame retardant polymers are relatively more expensive. Environmental, health and technical concerns and regulations like REACH, RoHS, WEEE will change the market of flame retardants along with other additives used in polymers.

In all, over 175 different types of FRs exist, commonly divided into four major groups: inorganic FRs, organophosphorus FRs, nitrogen-containing FRs and halogenated organic FRs.Inorganic FRs comprise metal hydroxides (e.g. aluminium hydroxide and magnesium hydroxide), ammonium polyphosphate, boron salts, inorganic antimony, tin, zinc and molybdenum compounds, as well as elemental red phosphorous. Inorganic FRs are added as fillers into the polymers and are considered immobile, in contrast to the organic additive FRs. Organophosphorous FRs are primarily phosphate esters that may also contain bromine or chlorine. Organophosphorous FRs are widely used both in polymers and textile cellulose fibers. Nitrogen-containing FRs inhibit the formation of flammable gases and are primarily used in polymers containing nitrogen, such as polyurethane and polyamide. The most important nitrogen-based FRs is melamine and melamine derivatives.The main flame retardant systems currently in use are polymeric based brominated solutions which have a range of performance characteristics offering a choice of solutions depending on specific critical performance requirements. Brominated additives will continue to lead the flame retardant additive market in total value. Phosphorus-based flame retardants will grow at the fastest pace, driven by increasing trends towards non-halogenated products. Rapid gains are also expected in inorganic flame retardants such as aluminum hydroxide and magnesium hydroxide which are finding more use in polyolefins. Halogen-free and phosphorous-free route is the most difficult, and also the most environment friendly, with a limited choice of FR additives. The newer technologies being developed include flame retardants combining nanoclays with another major class of flame retardants based on metal hydroxides. The nanoclays synergistically improve how the metal hydroxide retardants perform, improve how the plastics are processed, as well as their material properties. Nanoclays are appealing to use because they can be added in relatively small amounts. Some nanomaterials, especially carbon nanofibers, appear to have promise for use in polyurethane foam.Flame retardants can interfere, inhibit or even suppress the combustion process during a particular stage of the fire: heating, decomposition, ignition or flame spread. There are two types of action, chemical or physical. Generally chemical actions are more efficient than physical ones. The chemical actions can be:Reaction in the gas phase: The radical gas phase combustion process is interrupted by the flame retardant, resulting in cooling the system, reducing and eventually suppressing the flammable gas flux.Reaction in the solid phase: The flame retardant builds up a char layer protecting the polymer against oxygen and heat.The physical actions can be:Cooling: Endothermic processes cool the polymer to a temperature inhibiting the fire.Formation of a solid or gaseous protective layer against heat and oxygen needed to sustain the combustion.Dilution effects: Inert fillers reduce the combustible carbon content, and additives releasing inert gases dilute the fuel in the solid and gaseous phases.Organic and inorganic phosphorous compounds have a good fire safety performance and are fast developing to meet halogen free requirements. Nitrogen-containing flame retardants are of lower efficiency and are combined with phosphorous compounds to boost their efficiency. Inorganic compounds, particularly aluminum and magnesium hydroxides, must be used at high levels to compensate for their lower efficiency and meet high fire safety performances. HFFR polymers with increasing oxygen index values are Polysulfones, PEEK, Liquid crystal polymers (LCP), Melamines (MF), Polyamides (PI), Polyamide-imide (PAI), Polyetherimide (PEI), Polyphenylenesulfide (PPS), Polybenzimidazole (PBI).US demand for flame retardants will rise 3.8% pa to 1 bln lbs in 2013, reflecting more stringent fire codes and flammability requirements, especially in building materials and consumer products, as per Freedonia. Additionally, an improved economic outlook in key applications, such as wire and cable insulation and jacketing, and motor vehicles, will fuel demand. Nonetheless, overall gains will be limited by cost sensitivity in price-competitive markets such as motor vehicles and textiles, as well as environmental and health concerns over several flame retardant chemicals. In value terms, flame retardant demand will advance nearly 4% pa to US$1.1 bln in 2013. This represents a deceleration from the 2003-2008 period, which was characterized by rapid price increases for flame retardants as a result of high raw material and energy costs. Phosphorus-based flame retardants will grow at the fastest pace, driven by increasing trends toward non-halogenated products. However, brominated compounds will continue to lead the market in total value, as the regulatory climate in the US is unlikely to undergo dramatic changes in the near future. Rapid gains are also expected for smaller-volume flame retardants, such as magnesium hydroxide, which is finding increased use in polypropylene and engineering resins. Alumina trihydrate (ATH) will remain the largest volume flame retardant through 2013, comprising 46% of demand and growing slightly faster than the overall market

Flame retardantsare chemicals used in thermoplastics, thermosets, textiles and coatings that inhibit or resist the spread of fire. These can be separated into several different classes of chemicals: Minerals such asaluminium hydroxideATH,magnesium hydroxideMDH,huntiteandhydromagnesite,[1][2][3][4][5]varioushydrates,red phosphorus, andboroncompounds, mostlyborates. Organohalogen Compounds. These includeorganochlorinessuch as,chlorendic acidderivatives andchlorinatedparaffins;organobrominessuch asdecabromodiphenyl ether(decaBDE), decabromodiphenyl ethane (a replacement for decaBDE), polymeric brominated compounds such as brominated polystyrenes, brominated carbonate oligomers (BCOs), brominated epoxy oligomers (BEOs), tetrabromophthalic anyhydride,tetrabromobisphenol A(TBBPA) andhexabromocyclododecane(HBCD). Most but not all halogenated flame retardants are used in conjunction with a synergist to enhance their efficiency. Antimony trioxide is widely used but other forms of antimony such as the pentoxide and sodium antimonate are also used. Organophosphorus compounds such asorganophosphates,tris(2,3-dibromopropyl) phosphate, TPP, RDP, BPADP,tri-o-cresyl phosphate, phosphonates such as DMMP and phosphinates. There is also an important class of flame retardants that contain both phosphorus and halogen, examples of such are the chlorophosphates like TMCP and TDCP.Mineral flame retardants are typically additive while organohalogen and organophosphorus can be either reactive or additive. The basic mechanisms of flame retardancy vary depending on the specific flame retardant and the substrate. Additive and reactive flame-retardant chemicals can function in the vapor or condensed phase.The annual consumption of flame retardants is currently over 1.5 million tonnes per year, which is the equivalent of a sales volume of approx. 1.9 billion Euro (2.4 billion US-$).[6]Contents 1Mechanisms of function 1.1Endothermic degradation 1.2Thermal shielding 1.3Dilution of gas phase 1.4Gas phase radical quenching 2Environmental prevalence 2.1Health concerns 2.2Sudden infant death syndrome 3See also 4References 5External links

Mechanisms of functionEndothermic degradationSome compounds break downendothermicallywhen subjected to high temperatures. Magnesium and aluminium hydroxides are an example, together with various carbonates andhydratessuch as mixtures ofhuntiteandhydromagnesite.[1][4][5]The reaction removes heat from the substrate, thereby cooling the material. The use of hydroxides and hydrates is limited by their relatively low decomposition temperature, which limits the maximum processing temperature of the polymers (typically used in polyolefins for wire and cable applications).Thermal shieldingA way to stop spreading of the flame over the material is to create a thermal insulation barrier between the burning and unburned parts.Intumescentadditives are often employed; their role is to turn the polymer into a char, which separates the flame from the material and slows the heat transfer to the unburned fuel.Dilution of gas phaseInert gases (most oftencarbon dioxideandwater) produced by thermal degradation of some materials act as diluents of the combustible gases, lowering their partial pressures and the partial pressure of oxygen, and slowing the reaction rate.[3][5]Gas phase radical quenchingChlorinated and brominated materials undergo thermal degradation and releasehydrogen chlorideandhydrogen bromideor if used in the presence of a synergist like antimony trioxide antimony halides. These react with the highly reactive Hand OHradicalsin the flame, resulting in an inactive molecule and a Clor Brradical. The halogen radical has much lower energy than Hor OH, and therefore has much lower potential to propagate the radical oxidation reactions ofcombustion.As of 2008 the United States, Europe and Asia have a annual consumption rate for flame retardants at 1.8 million metric tons and valued at $4.20-4.25 billion dollars. According to the Ceresana Research, the market for flame retardants is increasing due to rising safety standards worldwide and the increase use of flame retardants. It is forecasted that the global flame retardant market will generate $5.8 billion dollars (US). As of 2010, the Asia-Pacific region was the largest market for flame retardants which was approximately 41% of global demand followed by North America, and Western Europe.Environmental prevalenceIn 2009, the U.S.National Oceanic and Atmospheric Administration (NOAA)released a report on polybrominated diphenyl ethers (PBDEs) and found that, in contrast to earlier reports, they were found throughout the U.S. coastal zone.[7]This nationwide survey found that New Yorks Hudson Raritan Estuary had the highest overall concentrations of PBDEs, both in sediments and shellfish. Individual sites with the highest PBDE measurements were found in shellfish taken from Anaheim Bay, California, and four sites in the Hudson Raritan Estuary. Watersheds that include the Southern California Bight, Puget Sound, the central and eastern Gulf of Mexico off the Tampa-St. Petersburg, Fla. coast, and Lake Michigan waters near Chicago and Gary, Ind. also were found to have high PBDE concentrations.Health concernsBrominated flame retardants have faced renewed attention in recent years. The earliest flame retardants,polychlorinated biphenyls(PCBs) were banned in 1977 when it was discovered that they are toxic.[8]Industries shifted to usingbrominated flame retardantsinstead, but these are now receiving closer scrutiny. The EU has banned several types ofpolybrominated diphenyl ethers(PBDEs) as of 2008, 10 years after Sweden discovered that they were accumulating in breast milk.[9]As of December 2009, negotiations between EPA and the two U.S. producers of DecaBDE (a flame retardant that has been used in electronics, wire and cable insulation, textiles, automobiles and airplanes, and other applications), Albemarle Corporation and Chemtura Corporation, and the largest U.S. importer, ICL Industrial Products, Inc., resulted in commitments by these companies to phase out decaBDE for most uses in the United States by December 31, 2012, and to end all uses by the end of 2013.[10]The state of California has listed the flame retardant chemical chlorinated Tris (tris(1,3-dichloro-2-propyl) phosphate or TDCPP) as achemical known to cause cancer. In December 2012, the California nonprofit Center for Environmental Healthfiled notices of intent to sue several leading retailers and producers of baby productsfor violating California law for failing to label products containing this cancer-causing flame retardant. The demand for brominated and chlorinated flame retardants in North America and Western Europe is declining, it is rising in all other regions.[6]Nearly all Americans tested have trace levels of flame retardants in their body. Recent research links some of this exposure to dust on television sets, which may have been generated from the heating of the flame retardants in the TV. Careless disposal of TVs and other appliances such as microwaves or old computers may greatly increase the amount of environmental contamination.[11]A recent study conducted by Harleyet al.2010[12]onpregnant women, living in a low-income, predominantly Mexican-immigrant community in California showed a significant decrease in fecundity associated with PBDE exposure in women.Another study conducted by Chevrieret al.2010[13]measured the concentration of 10 PBDE congeners, free thyroxine (T4), total T4, and thyroid-stimulating hormone (TSH) in 270 pregnant women around the 27th week of gestation. Associations between PBDEs and free and total T4 were found to be statistically insignificant. However, authors did find a significant association amongst exposure to PBDEs and lower TSH during pregnancy, which may have implications for maternal health and fetal development.A prospective, longitudinal cohort study initiated after 11 September 2001, including 329 mothers who delivered in one of three hospitals in lower Manhattan, New York, was conducted by Herbstmanet al.2010.[14]Authors of this study analyzed 210 cord blood specimens for selected PBDE congeners and assessed neurodevelopmental effects in the children at 1248 and 72 months of age. Results showed that children who had higher cord blood concentrations of polybrominated diphenyl ethers (PBDEs) scored lower on tests of mental and motor development at 14 and 6 years of age. This was the first study to report any such associations in humans.A similar study was conducted by Roze et al. 2009[15]in Netherlands on 62 mothers and children to estimate associations between 12 Organohalogen compounds (OHCs), including polychlorinated biphenyls (PCBs) and brominated diphenyl ether (PBDE) flame retardants, measured in maternal serum during the 35th week of pregnancy and motor performance (coordination, fine motor skills), cognition (intelligence, visual perception, visuomotor integration, inhibitory control, verbal memory, and attention), and behavior scores at 56 years of age. Authors demonstrated for the first time that transplacental transfer of polybrominated flame retardants was associated with the development of children at school age.Another interesting study was conducted by Rose et al. 2010[16]to measure circulating PBDE levels in 100 children between 2 to 5 years of age from California. The PBDE levels according to this study, in 2- to 5-year-old California children was 10 to 1,000 fold higher than European children, 5 times higher than other U.S. children and 2 to 10 times higher than U.S. adults. They also found that diet, indoor environment, and social factors influenced childrens body burden levels. Eating poultry and pork contributed to elevated body burdens for nearly all types of flame retardants. Study also found that lower maternal education was independently and significantly associated with higher levels of most flame retardant congeners in the children.San Antonio Statement on Brominated and Chlorinated Flame Retardants 2010:[17]A group of 145 prominent scientists from 22 countries signed the first-ever consensus statement documenting health hazards from flame retardant chemicals found at high levels inhome furniture,electronics,insulation, and other products. This statement documents that, with limited fire safety benefit, these flame retardants can cause serious health issues, and, as types of flame retardants are banned, the alternatives should be proven safe before being used. The group also wants to change widespread policies that require use of flame retardants.A number of recent studies suggest that dietary intake is one of the main routes to human exposure to PBDEs. In recent years, PBDEs have become widespread environmental pollutants, while body burden in the general population has been increasing. The results do show notable coincidences between the China, Europe, Japan, and United States such as dairy products, fish, and seafood being a cause of human exposure to PBDEs due to the environmental pollutant.A February 2012 study genetically engineered female mice to have mutations in the x-chromosome MECP2 gene, linked to Rett Syndrome, a disorder in humans similar to autism. After exposure to BDE-47 (a PDBE) their offspring, who were also exposed, had lower birth weights and survivability and showed sociability and learning deficits.http://www.ucdmc.ucdavis.edu/publish/news/newsroom/6164A January 2013 study of mice showed brain damage from BDP-49, via inhibiting of the mitochdrial ATP production process necessary for brain cells to get energy. Toxicity was at very low levels. The study offers a possible pathway by which PDBEs lead to autism.http://www.ucdmc.ucdavis.edu/publish/news/mindinstitute/7378This checklist is cited from the Department of Health in Washington state. Cleaning - PBDEs in indoor dust is one of the primary sources of people's exposure. Reduce your exposure to indoor dust. Use a damp cloth to dust indoor living and working areas. Avoid stirring the dust into the air. Use a vacuum with a HEPA filter. Open windows and doors while you clean. Wash hands after dusting and cleaning. Foam products - New foam items that you purchase today are unlikely to contain PBDEs.[citation needed]However, mattresses, mattress pads, couches, easy chairs, foam pillows, carpet padding, and other foam products purchased before 2005 likely contain PBDEs. Replace older foam products that have ripped covers or foam that is misshapen or breaking down. If you can't replace the item, try to keep the covers intact. When removing old carpet foam, keep the work area sealed from other areas of the house, avoid breathing in the dust, and use a HEPA-filter vacuum for cleanup. Electronics - Deca-BDE has been used in electronics for years but is now being phased out of most electronics. When purchasing electronics, request products that contain no Deca-BDE or other bromine-containing fire retardants. Foods - PBDEs can concentrate in the fat of poultry, red meat, fish and other fatty meats. See how to reduce the fat when preparing and cooking fish (these tips can be applied to other meats). Wash hands before preparing and eating food. Disposal and recycling - PBDEs will continue to pollute the environment unless flame retardant products are disposed of properly. To keep PBDEs out of the environment, dispose of foam containing products and electronics such as TVs and computers at your nearest hazardous waste collection site.Sudden infant death syndromeMain article:Sudden infant death syndrome#Toxic_gasesUK scientist Barry Richardson claimed in 1989 that a fungus in bedding broke down the antimony, phosphorus, and arsenic flame retardants in infant bedding to form toxic gases. This research was taken up by New Zealand scientist Jim Sprott, who published a book on the topic, and eventually aired onThe Cook Reportin 1994. A 1998 UK government-sponsored study called the Limerick Report found that toxic gases were not created.[18]Based on the Limerick report, position papers publicized by US SIDS organizations[19]say there is not enough evidence to support the toxic gas theory, and that parents should continue to put their babies to sleep on vinyl-covered crib mattresses. However, Sprott maintains that his findings were not refuted

Read more:http://www.answers.com/topic/flame-retardant#ixzz2PQmV3vh3

Over the past few years, the use of certain types of halogenated flame retardant additives such as decabromodiphenylether has come under intense scrutiny due to their toxicity, environmental persistence and bio-accumulation. There is an immediate need for the development of non-toxic alternative flame retardant materials and fire resistant polymers with comparable or better efficacies, obtained using benign synthetic approaches. Enzymatic polymerization is being used increasingly as an environmentally friendly alternative method for the synthesis of functional materials including polymers and additives. Here, we report a biocatalytic synthesis of a new class of thermally stable, ultra-fire resistant polyphenols based on deoxybenzoins. In calorimetric studies, these polyphenols exhibit very low heat release capacities (comparable to Nomex) and form a large amount of carbonaceous char rendering them suitable for flame retardant applications.

Huntiteis acarbonate mineralwith the chemical formula Mg3Ca(CO3)4

383.4 Nitrogen-based flame retardantsMelamine is a thermally stable crystalline product characterized by amelting point as high as 345 C that contains 67 wt% nitrogen atoms [23].Melamine sublimates at about 350 C. Upon sublimati on, a significantamount of energy is absorbed, decreasing the temperature. At hightemperature, melamine decomposes with the elimination of ammonia, whichdilutes oxygen and combustible gases and leads to the formation of thermallystable condensates, known as melam, melem and melon (Fig. 15) [63].These reactions compete with melamine volatilization and are morepronounced if melamine volatilization is impeded, e.g. by the formation of aprotective layer. The formation of melam, melem and melon generatesresidues in the condensed phase and results in endothermal processes, alsoeffective for flame retardancy. In addition, melamine can form thermallystable salts with strong acids: melamine cyanurate, melamine phosphate,and melamine pyrophosphate. Melamine and melamine salts arecharacterized by various flame retardant mechanisms. Upon heating,melamine-based salts dissociate and the re-formed melamine volatilizes, likeneat melamine, but a large proportion of the melamine undergoes moreprogressive condensation than in the case of pure melamine [63]. The actionof salts in the condensed phase is therefore significantly higher.The thermal decomposition of melamine phosphate (Fig. 16) leads tothe formation of melamine polyphosphate, with the release of melamine andphosphoric acid [43]. The phosphoric acid released is known tophosphorylate many polymers and produce flame retardant effects similar tophosphorus-based flame retardant additives.

How Flame Retardants Are Used in Transportation

A wide variety of plastics, textiles and composite materials are used extensively in the mechanical, structural and decorative parts of todays transport, including airplanes, trains and cars. These materials are: (i) highly adaptable to new designs; (ii) lighter weight, making them more energy efficient; (iii) less labor intensive; and (iv) more cost effective. Flame retardants are often used to ensure these materials can meet flammability standards.To make materials fire-resistant, flame retardants act to help stop or slow the spread of fire. They can be used alone, or in combination with other flame retardants that act as synergists to enhance fire retardant properties. If a fire does start, flame retardant solutions work in different ways to help stop or minimize its effects.Learn more about how flame retardants work.Different classes of flame retardantswork to reduce the threat of fire hazards in different ways, and must be matched to the specific material being used and the performance specifications of the final product. There is no one-size-fits-all solution when essential fire-protection benefits must be balanced with ensuring optimal performance.Today, travel is safer than ever before, regardless of the mode of transportation. Thousands of people take to the highways, railways and air daily, and they do so with the expectation of reaching their destinations safely. Flame retardants play an important role in helping to meet that expectation of safety.The August 2005 fiery crash of a passenger jet in Toronto, Canada, in which all 309 people aboard survived, is a prime example of how flame retardants can contribute to passenger safety. Safety officials considered the fire-retardant material now required in airplane cabins to be a factor in slowing the spread of the fire and allowing passengers to escape safely.As the transportation industry evolves, and more emphasis is put on the production of lighter weight, more fuel-efficient modes of transportation, technologically advanced materials will increasingly be used, and fire protection will remain a public safety priority.NAFRA memberswill continue to innovate and develop new and sustainable flame retardant solutions to keep pace with advances in transportation and public safety standards.

Electrical & Electronic Equipment Key Role of Flame RetardantsSHARE Key Role of Flame Retardants

Plastic componentsare a part of almost all of todays electrical and electronic equipment (EEE).The characteristics of plastic (i.e. versatile, flexible, and easy to mold into complicated shapes and small sizes) make it the material of choice for EEE.But, this material also must meet important fire safety standards. Miniature components in high-powered computers, for example, generate a high concentration of heat sources that can lead to rapid overheating of internal components. Electrical and electronic products are also subject to fire risks from electrical short circuits that can cause ignition within a product, or external ignition sources such as candles close to heat-generating equipment. Without the use of flame retardants to help protect materials and components against fire, the potential for fire dangers increases as the number of electronic productsand the cables, wires and electronic chargers to power themincreases in households, offices and commercial buildings.Incorporating flame retardants into the materials used in electrical and electronic components lets manufacturers meet fire safety standards, while also ensuring a product meets key technical requirements, including weight, durability, flexibility and performance specifications. Flame retardants provide specific and critical fire protection properties. They increase a products resistance to both internal and external heat sources that, potentially, could turn into sources of fires. They also provide EEE with fire resistance characteristics so that internal electrical and electronic components do not fuel a fire that has started outside of the equipment.As new and more sophisticated material technologies emerge, and requirements for fire resistant materials evolve, the flame retardant industry must keep pace. Flame retardant manufacturers will continue to innovate and develop effective and sustainable flame retardants that meet new product demands for fire resistance, high performance and cost-effectiveness, and address environmental health and safety concern

There are no U.S. federal standards regulating upholstered furnishings. However, the Consumer Products Safety Commission (CSPC) is in the process of drafting federal safety standards for these products.In 1975, with the implementation of Technical Bulletin 117 (TB 117), California became the first state to set some flammability requirements for upholstered furniture paddings, and it is still the only state with fire safety regulations for upholstered furniture. Californias TB 117 requires upholstered furniture paddings to withstand 12 seconds of an open flame without spreading the flame.In the United States, fire codes set by the International Fire Code and the National Fire Protection Association (NFPA), and the NFPAs Life Safety Code require that upholstered furniture in health care facilities and university and college dormitories without building sprinkler systems, and all detention facilities must meet the requirements of California Technical Bulletin 133. This standard requires upholstered furniture to meet certain thresholds for heat release. Those same locations are required by these codes to comply with a test for cigarette smoldering.For residential upholstered furniture, manufacturers, who are members of the Upholstered Furniture Action Council (UFAC), voluntarily comply with the UFAC smoldering test, which tests upholsterys resistance to ignition from smoldering cigarettes.Mattresses used in homes, including youth and crib mattresses, must meet two federal flammability standards set by the CPSC. The first, 16 CFR 1633, is a test that measures heat release when mattresses are exposed to an open flame. The second, 16 CFR 1632, tests mattress components to ignition from smoldering cigarettes and it applies to all mattresses.In 1988, the UK enacted the Furniture and Furnishings (Fire) (Safety) Regulations, a strict set of regulations requiring all upholstery fabrics and polyurethane foams used in upholstered furniture (domestic and commercial) to meet fire tests. In 1989, the requirements were extended to other filling materials and in 1993 to mattresses. The regulation set flammability requirements based on both smoldering (cigarette) and flaming ignition tests. Fabrics had to meet a match ignition test while foams had to meet a test with a larger ignition source: a wood crib. The tests required no ignition or very low flame spread.A December 2009 report, commissioned in the U.K. by the Consumer and Competition Policy Directorate of the Department for Business, Innovation and Skills (BIS), examined the effectiveness of that nations flammability standards for furniture and furnishings. An analysis of fire data offered a strong endorsement of the regulations and the use of flame retardants they require. The report found: Both the number and lethality of F&F (furniture and furnishings regulations) fires rose before the introduction of the regulations and fell afterwards. According to BIS, the reduction in the rate and lethality of F&F fires was estimated to equate to 54 lives saved per year, 780 fewer casualties per year and 1065 fewer fires per year in the period 2003-2007. Learn more about theprotective benefits of flame retardants.SHARE TOPIC

From residential homes to commercial buildings, and from hospitals to schools, architects and designers rely on plastics to help maximize energy efficiency, durability and performance. In addition to potentially lightening a structures environmental footprint, properly installed plastic building products can help reduce energy and maintenance costs over many years. In todays cars and trucks, a key driver in boosting fuel efficiency, reducing emissions and lowering costs for motorists is plastic. And in the kitchen plastic packaging helps keep food fresh and safe until were ready to use it. Plastics have a proven track record of helping to save livesbut not before they are rigorously evaluated for safety.Automotive

In automotive design, plastics have contributed to a multitude of innovations in safety, performance and fuel efficiency. Todays plastics make up 50 percent of the volume of new cars but only 10 percent of the weight, which helps make cars lighter and more fuel efficient, resulting in fewer CO2 emissions. Tough, modern plastics also help improve passenger safety and auto designers rely on the versatility of plastics when designing todays cool cars.Food Safety

Plastics play an important role delivering a safe, healthy and abundant food supply that families rely on everyday. In the store, clear plastic overwrap protects food while allowing consumers to see through the packaging. In the home, sealable plastic bags, wraps and containers can contribute to a longer, fresher shelf life for perishable foods.Child Safety

At every turn, plastics are there to help parents protect their children. Moldable plastics allow safer, rounded corners on everything from toys to high chairs and car seats. Plastics strength, light weight and shape-shifting versatility also contribute to child-resistant medicine bottles, easy-to-install safety latches and gates, and many other handy devices to help keep little explorers out of trouble.Sports Safety

Sports are a great way to keep active and stay healthy, but they can also lead to injuries. Fortunately, innovations in plastics have helped to make essential safety geartems like plastic helmets, mouth guards, goggles and protective paddinglighter and stronger to help keep sports enthusiasts of all ages safe. Molded, shock-absorbent plastic foam helps keep feet stable and supported, while the rugged plastics shells covering helmets and pads help protect heads, joints and bones.Plastics Myth BustersHeard Something About Plastics? Get the Facts Here

Determining fact from fiction on the Internet can be harder than you think. We know because people often contact us with questions about rumors concerning plastics. And since many of these might sound scientific or seem like good common sense, it's only natural to be concerned. Visit this site if you've heard a rumor about plastics and want to know more.Bisphenol-A (BPA)/Polycarbonate

A comprehensive resource for environmental, health and safety information about bisphenol A (BPA), an industrial chemical used primarily to make polycarbonate plastic and epoxy resins.

Flame retardants are an important component in reducing the devastating impact of fires on people, property and the environment.Their areas of application in electrical and electronic equipment (EEE) vary depending on the materials being used, the function of the product, and the level of fire resistance that must be achieved based on fire safety standards. Flame retardants have unique characteristics, and, as a result, need to be matched appropriately to the materials used.In wires and cables, for example, the flame retardants used must meet fire safety requirements developed specifically for these products because they have the potential for spreading a fire to the electrical socket, and to walls and curtains. The level of flame retardancy required for printed wiring boards used in consumer mobile phones is different than that of wiring boards used in computer servers or in telecommunications or aerospace applications. Higher electrical and mechanical performance demands must be met with flame retardants that can achieve higher flammability and fire resistance standards, without affecting a products performance specifications.When it comes to fire safety, one size does not fit all. Specific flame retardants must be selected carefully to meet fire safety standards, electrical and mechanical requirements.The following classes of flame retardants used in EEE include: Bromine-based flame retardants, predominantly TBBPA (help prevent fires from starting or slow down a fire) Chlorine-based flame retardants (work to stop flame formation) Nitrogen-based flame retardants (stop the decomposition process and prevent the release of flammable gases) Phosphorus-based flame retardants (promote charring and prevent the release of flammable gases; provide a barrier between the material and heat source Metal hydroxide and oxide flame retardants (slow down the decomposition process and the release of flammable gases; can be used alone or as synergists to boost other flame retardants benefits Combinations of flame retardants are also used for maximum efficiency in specific material applications

Find out more abouttheclasses of flame retardants.Flame retarding requirementsand the choice of flame retardant solutionswill vary with the properties of the materials used for each specific product and the level and type of mechanical and electrical functions the product must perform.SHARE TOPIC

POLLUTIONEnvironmental contaminants are a serious concern for many marine species. The main environmental toxins that are currently a concern for populations of marine mammals are known as persistent organic pollutants (POPs) and include PCBs, PBDEs and dioxins and furans. Many of these human produced chemicals are bioaccumulated, meaning that organisms absorb these chemicals at a rate faster than they are lost. Predatory animals acquire the lifetime accumulation of POPs of the animals they eat. This leads to biomagnification, whereby the concentration of POPs increases greatly at every step in the food chain, and top predators, such as killer whales, end up with extremely high levels.The chemicals:Polychlorinated biphenyls (PCBs)Polychlorinated biphenyls (PCBs) were first introduced into the environment in the early 1900s where they were used in a variety of adhesives, sealants, paints, hydraulic fluids, coolants and electric transformer insulating fluids. PCBs were banned in Canada and the US in the 1970s but persist in the environment. They are still produced and used in some parts of the world.According to Dr Peter Ross at the Institute of Ocean Sciences, PCBs are considered of highest concern to marine life. PCBs have been associated with toxic effects in marine mammals such as endocrine disruption, which can cause impairment of reproduction, development, and other hormonally mediated processes, and immunotoxicity, giving rise to an increased susceptibility to infectious diseases and cancers.Polybrominated diphenyl ethers (PBDE)PBDEs are a relatively new class of flame retardants that have been added to a variety of plastic products, including fabrics, furniture, and especially electronics such as computers. PBDEs are present in increasing concentrations in the environment and are still produced and used in North America. PBDEs are chemically similar to PCBs and the metabolites of PBDEs (the chemical that forms when the body attempts to break down PBDEs) are likely to interfere with hormones, uptake of Vitamin A, neurological development and the immune system.Dioxins and FuransDioxins and furans are closely related chemicals that are produced when organic material is burned in the presence of chlorine. Common sources include coal-fired generators, municipal waste incinerators, metal smelting, pulp and paper mills, diesel engines, sewage sludge, and the burning of preservative-treated wood and trash. Dioxins and furans persist in the marine environment and are extremely toxic in minute amounts the most toxic dioxin is ten times more toxic than the most toxic PCB.POPs and CetaceansPOPs are stored in the fat of animals that consume them, which makes marine mammals particularly vulnerable as contaminants will accumulate in their thick layer of blubber. Endocrine system disruption and immunotoxicity are the two serious issues that arise from POP exposure, and these toxins are difficult to metabolize and eliminate in long-lived species such as killer whales. In fact, recent studies have shown that killer whales of the Pacific Northwest are some of the most contaminated marine mammals in the world. Killer whales are top predators in the oceans food chain and therefore receive high contaminant loads from their prey. Research by Dr. Peter Ross has shown that Biggs killer whales (transients), being mammal predators, feed highest up the food chain and therefore have the highest level of POPs.Where the animals forage may also affect the contaminant load they receive. For example, the difference in northern and southern resident killer whales POP accumulation is significantly different. While both populations have the same preference for chinook salmon, the southern residents killer whales, who spend the summer months around the Puget Sound area of Washington and in the southern Strait of Georgia in British Columbia, have accumulated toxin levels four times higher than the northern resident population, found along the central and northern coasts of British Columbia during the summer and fall. Cullonet al found that the cause of this discrepancy is the Chinook that these populations eat. The salmon consumed by southern resident killer whales is exposed to higher toxin levels in more urbanized areas. Southern residents also need to eat more of this contaminated prey, as Chinook nearing the end of their migrations in the south are less fatty.POPs are not only acquired by consuming contaminant-laden prey, but are also passed from female to calf during gestation and nursing. They are mainly transferred via the rich, fatty milk produced by the mother. A females first calf receives the largest contaminant load compared to the load received by subsequent calves. While this transfer of contaminants from female to calf may be very harmful for the calf, it does mean that females reduce their contaminant load significantly every time they rear young. This release of toxins through lactation means that the POP load of adult females is roughly 30% less than that of adult males.The Arctic is a region that appears seemingly untouched by modern human existence, but sadly this is not the case. POPs from all over the world arrive in the Arctic via atmospheric and ocean circulation. The result is that animals at the top of the food chain, such as belugas, narwhals and polar bears, accumulate tremendous amounts of contaminants the way killer whales and other marine mammals do in more southern latitudes, closer to direct pollution sources. Research by Desforgeset al. attests to the issue of Arctic pollution and female POP offload to offspring, although in this case it was via transplacental transfer and not lactation. This study found that female belugas transferred 11.4% of their PCBs and 11.1% of their PBDE blubber burden to their fetuses in utero.Oil SpillsOil spills are also a major threat to marine life and cetaceans do not appear to avoid areas affected by oil. They have little if any sense of smell and are unable to detect oil vapour in the air. While they do have excellent eye sight, they dont appear to recognize surface oil as a hazard. Oil vapour is very toxic and causes respiratory distress when inhaled. Whales are also in danger if they eat oiled prey.Biggskiller whales (transients)can consume oil adhering to the bodies and fur of their mammalian meals, and ingestion of oil can cause serious long-term damage to internal organs. Baleen whales are also particularly vulnerable to oil while feeding, as oil may stick to their baleen while they filter feed near oil slicks.The 1989 Exxon Valdez disaster in Alaska sadly illustrated the damaging effects of oil on killer whale groups. One resident pod (AB) was photographed in an oil slick shortly after the spill and suffered the loss of 33% of its members within a year. Its rate of reproduction has been lower than average ever since, and the pod fractured following the death of a matriarch. Members of the AT1 transient population were also photographed in oil from the Exxon Valdez, and 41% of its members were lost in the following year. There has been zero reproduction in this group since the spill and this genetically distinct transient population is on the verge of extinction with almost no chance of recovery.WHAT YOU CAN DO Use your consumer power to demand PBDE-free products. Choose furniture, carpet and electronic products that do not use these hazardous chemicals. Reduce the use of hazardous chemicals by choosing household cleaners, pesticides and fertilizers which are not toxic to your surroundings. If chemicals are toxic to the oceans, they are also a danger to you and your family. Support companies that make clean products and consume less pesticide-dependant foods thereby reducing the amount of pesticides used. Compost your household, kitchen and yard wastes, which makes an excellent fertilizer. Never burn treated wood and trash. This releases POPs into the environment. Recycle all electronic equipment responsibly. Never pour any oil or other chemicals onto the ground or into drains. Many of these chemicals make their way to the ocean. Even if you live far from the ocean, the chemicals from your area can be transported to the ocean in streams and rivers. Maintain your vehicles to prevent oil from leaking onto the road which will then go down a drain and into the water. Recycle all oil and chemicals. Most communities have recycling centers that will accept used oil and other chemicals for recycling. Your Voice counts. Citizens can also petition their governments to restrict the emission / dumping of toxic contaminants into the environment.ReferencesCullon, D.L., M.B. Yunker, C. Alleyne, N.J. Dangerfield, S. ONeill, M.J. Whiticar, P.S. Ross. 2009. Persistent organic pollutant in chinook salmon (Oncorhynchus tshawytscha): Implications for resident killer whales of British Columbia and adjacent waters. Environmental Toxicology and Chemistry 28(1): 148-161Desforges, J.P., Ross, P.S., Loseto, L.L. 2012. Transplacental transfer of polychlorinated biphenyls and polybrominated diphenyl ethers in arctic beluga whales (Delphinapterus leucas). Environmental Toxicology and Chemistry 31(2): 296-300.Ross, P.S., De Swart, R.L., Reijnders, P.J.H., Van Loveren, H., Vos, J.G., and Osterhaus, A.D.M.E. 1995. Contaminant-related suppression of delayed-type hypersensitivity and antibody responses in harbor seals fed herring from the Baltic Sea. Environ. Health Perspect. 103: 162167.Ross, Peter S. 2006. Fireproof killer whales (Orcinus orca): flame retardant chemicals and the conservation imperative in the charismatic icon of British Columbia, Canada. Can. J. Fish. Aquat. Sci. 63: 224234

Killer whales swim off Harmac pulp mill in Nanaimo. (photo Graeme Ellis)

Concentrations of polychlorinated biphenyls (PCB's) in killer whales and humans.

Arctic narwhals. (photo John Ford)http://www.dow.com/PublishedLiterature/dh_004e/0901b8038004ee63.pdf

PCB and PBDE concentrations in different killer whale populations and sexes.

http://flameretardants.americanchemistry.com

http://www.environmentalhealthnews.org/ehs/news/2012/burning-irony

http://es.farnell.com/images/en/pdf/flame_retardants.pdf