Some Flame Retardants Make Fires More Deadly

Released: 14-Mar-2012 11:45 PM EDT
Embargo expired: 27-Mar-2012 12:30 PM EDT
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Newswise — SAN DIEGO, March 27, 2012 — Some of the flame retardants added to carpets, furniture upholstery, plastics, crib mattresses, car and airline seats and other products to suppress the visible flames in fires are actually increasing the danger of invisible toxic gases that are the No. 1 cause of death in fires. That was the finding of a new study presented here today at the 243rd National Meeting & Exposition of the American Chemical Society (ACS), the world’s largest scientific society.
Anna A. Stec, Ph.D., led the research, which focused on the most widely-used category of flame retardants, which contain the chemical element bromine. Scientists term these “halogen-based” flame retardants because bromine is in a group of elements called halogens.

“Halogen-based flame retardants are effective in reducing the ignitability of materials,” Stec said. “We found, however, that flame retardants have the undesirable effect of increasing the amounts of carbon monoxide and hydrogen cyanide released during combustion. These gases, not the thermal effects of burns on the body, are the No. 1 cause of fire deaths.” Stec, who is with the University of Central Lancashire, Centre for Fire and Hazards Science, Lancashire, U.K., spoke at an ACS symposium on “Fire and Polymers,” which included 60 presentations.

Almost 10,000 deaths from fires occur in industrialized countries worldwide each year, including about 3,500 in the U.S. Contrary to popular belief, inhalation of toxic gases released by burning materials –– not burns –– causes the most deaths and most of the serious injuries. Stec’s team set out to determine the effects of flame retardants on the production of those gases. The scientists tested brominated flame retardants with antimony synergists, mineral-based flame retardants and so-called intumescent agents, which swell when heated, forming a barrier that flames cannot penetrate.

Unlike the halogen-based retardants, mineral-based fire retardants have little effect on fire toxicity. Most intumescent fire retardants reduce the amount of potentially toxic gases released in a fire.

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Abstracts from other presentations in the symposium appear below.

Abstracts




Influence of fire retardants on fire toxicity
Anna A. Stec1, University of Central Lancashire, Centre for Fire and Hazards Science, JBF 108, Preston, Lancashire, PR1 2QF, United Kingdom , 44-1772-893759, stec_anna@yahoo.co.uk
The fire toxicity of a range of commercial fire retarded materials as, a function of ventilation condition, or equivalence ratio, has been investigated, showing how different forms of fire retardant action have different effects on the toxicity. The study includes halogenated, mineral filler, nanocomposite and phosphorus based fire retardants in a number of different polymer matrices.

Characteristics of sustainable flame retardants
Susan D. Landry1 , Albemarle Corporation, 451 Florida Street, Baton Rouge, LA, 70820, United States, 225-388-7565, susan.landry@albemarle.com
We are currently experiencing a shift in chemical regulations and regulatory programs that impact many materials, including flame retardants. Emerging chemical regulations are focusing on characterizing the environmental and human health impacts of all substances. A goal for many companies is sustainability. Industry is responding to market driven and regulatory challenges to ensure that flame retardants are safe, effective, sustainable, and meet evolving marketplace demands. A crucial aspect of sustainability is to understand the life-cycle implications of chemicals and even polymer formulations. Life-Cycle Assessments can determine if the substitution of one flame retardant or technology for another can result in unforeseen consequences that can impact society or the ecosystem. Programs are in place to drive all members of the supply chain to reduce or eliminate chemical emissions to the environment, understand human health and environmental characteristics, and make transitions to more environmentally preferred products.

Towards evidence-based development of flame retarded polymers
Bernhard Schartel1, BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, Berlin, 12205, Germany , +49 30 8104 1021, bernhard.schartel@bam.de
Competence in polymer research and development is founded not only on methodical components such as know-how, knowledge and communication, but also on scientific components. According to many sources the latter can be identified as a) identifying tasks, opportunities, challenges, etc. b) describing/understanding phenomena and c) using evidence. Accepting this basic background, this contribution demonstrates how a, b and c can be fulfilled in the development of flame retarded polymeric materials. Based on different examples of our work over the last 10 years, it is shown that innovation and co-operation are used to tackle actual tasks, and that multi-methodical approaches and key experiments are sufficient to generate a deep understanding of phenomena as well as systematic investigations and comprehensive assessments. What is more, the examples shown demonstrate how guidelines are deduced for future material developments, which is, of course, the ultimate benefit of using evidence in applied polymer science and engineering.

Durable nanoparticle coatings to reduce polyurethane foam flammability
Yeon Seok Kim1, 100 Bureau Drive, MS-8665, Gaithersburg, MD, United States , 301-975-6481, yeonkim@nist.gov
This research involves fabricating nanoparticle-filled thin coatings as an innovative approach to reduce the flammability of polyurethane foam typically used in residential home furnishings. The coatings are typically constructed of four oppositely charged bi- or tri-layers, are 350 nm thick, and contain 50 mass-% carbon nanofibers, multi-walled carbon nanotubes, or sodium montmorillonite clay. Compared to 17 commercial foam fire retardants, these nanoparticle fire retardant (nanoFR) coatings are 300-1100% more effective at reducing the heat generated from the highly flammable foam. In a real fire, the impact may be even greater as these nanoFR coatings prevent the foam from generating flaming melt drips, which are responsible for pool fires and significant fire spread. Additionally, these coatings appear durable when exposed to simulated wear and tear and chewing conditions releasing nanoFRs in the range of a few milligrams per simulated year.

Comparison of fiber reinforced polymers in global fire performance tests
Michael G. Stevens1, Ashland Performance Materials, 5200 Blazer Parkway, Dublin, OH, 43017, United States , 614-790-3483, mgstevens@ashland.com
The fire code requirements for building, construction and mass transit applications are not the same across the world. Even the tests within the same country are different for these market areas. Materials used in these areas may be similar, but must be tested to all of the different standards. It is known that very little correlation exists between the various tests. This makes it difficult for a material supplier or a fabricator to determine what fire retardant system to use for the different applications. In the past each European country had its own fire codes and employed its own fire test procedure. This required that materials meet different qualifications for the same application in each nation. The European Union has begun harmonizing the fire code tests. The standard for building and construction applications has been issued and is starting to be used. EN45545 is the proposed standard for the European rail industry that should be finalized in the near future. This will make it easier to have materials qualified for use all across Europe without having to tests to every country's specifications. As companies sought attractive labor pools and expanded globally, the need to find other economies of scale also became of paramount importance. With this there is a desire to sell the same product in the United States, Europe, Asia and South America. It would be helpful to know how the same FRP will perform in the standard tests used for qualifying them for applications in the different countries. This study was set up to look at how typical FRP systems from the United States will perform in the new EU standard tests and also how FRP systems designed for the European market will perform in the EU tests as well as in the standard U.S. tests for buildings and mass transit.

Small scale flammability testing of phosphonate and boronate + polyurethane blends
Alexander B. Morgan1, 300 College Park, Dayton, OH, 45469-0160, United States , 937-229-3079, alexander.morgan@udri.udayton.edu
In this paper we outline our work with the Pyrolysis Combustion Flow Calorimeter (PCFC) to use it as a screening tool for the development of new non-halogenated flame retardant chemistry for polyurethane foams. We report on the use of a thermoplastic polyurethane (TPU) as a mimic for a polyurethane foam, as well as the effects of phosphonate and boronate compounds as flame retardants in this polymer.

Study of intumescent flame retardant PES hot melt adhesive
Jianxin Du1, Beijing Institute of Technology, Department of Materials, Beijing, 5 South Zhongguancun Street, China , 0086-010-68913075, tonydjx@bit.edu.cn
Halogen-free flame retardant PES hot melt adhesive was prepared by using intumescent flame retardant (IFR) consisting of ammonium polyphosphate (APP), pentaerythritol (PER) and melamine (MEL) as flame retardants and Zeolite 4A as synergistic agent. The effect of IFR on flame retardancy of PES and synergistic effect between IFR and Zeolite 4A were studied. It was found that a small quantity of Zeolite 4A could promote flame retardant effect of IFR to PES. When IFR were 30wt%, PES/IFR achieved LOI value of 30.7%, UL-94 V-0 rate, and significantly reducing the maximum heat release rate; LOI value increased to 35.1% by adding extra 3wt% Zeolite 4A. TGA, SEM and XPS research showed that Zeolite 4A could catalyze esterification reaction of IFR, and facilitate to form much denser char; Zeolite 4A decomposed and participated into carbon reaction at high temperature, which stabilized the carbon residue and increased the amount.

Polymer pyrolysis modeling based on moving mesh
Daoyun Song1, 1701 Century Circle, Apartment 113, Woodbury, Minnesota, 55125, United States , 304-685-3608, dysong@gmail.com
Polymers and polymer composites have been increasingly used in construction, infrastructure, automobile, aircraft and aerospace applications, etc. In particular, both the residential and commercial construction markets have been identified as one of the largest markets for implementation of composites in the field. The reasons for high popularity of composites in the construction industry should be attributed to their excellent properties such as light weight, the ability to produce complex shapes, corrosion, thermal, sound and electrical resistance, and lower maintenance costs. However, a major drawback of polymers and composites is their susceptibility to heat and fire. In the literature, a vast number of papers have addressed the pyrolysis modeling. This paper applies a commercial software package, COMSOL (3.5a) to solve the non-Arrhenius type pyrolysis modeling based on the moving mesh technique and compare our data with the literature. Two examples were excerpted from the literature. Present simulations are in excellent agreement with those reports using different numerical methods in the literature as shown in Figures

Novel biomass-based “eco-FR” styrenic blends
Rakesh K. Gupta1, West Virginia University, Department of Chemical Engineering, P.O. Box 6102, Evansdale Drive, Morgantown, WV, 26506, United States , 304-293-9342, 304-293-4139, rakesh.gupta@mail.wvu.edu
Flame retardant (FR) additives are commonly used in polymeric materials, with non-halogenated variants being preferred for environmental, health and safety reasons. Developing non-halogenated FRs for styrenic polymers such as acrylonitrile-butadiene-styrene (ABS) is a challenge since these polymers burn very easily and produce minimal char. This talk describes a novel technical approach to increase char formation in ABS by utilizing sustainable natural fibers and ammonium polyphosphate (APP) to provide V-0 burn ratings in UL –94 testing. The effects of various phosphates and natural ingredients on flame retardancy and other properties will be presented. These types of ABS blends were found to suffer from lower impact strength, darker base color and lower thermal stability versus tradition formulations. Technical strategies for resolving these issues will be described. It will be shown that a good balance of mechanical properties, flow and flame retardancy in these formulations can be achieved in a cost effective manner.

Fire safety requirements for interior wall and ceiling finish in US codes
Marcelo M. Hirschler1, GBH International, 2 Friars Lane, Mill Valley, CA, 94941, United States , 415-388-8278, mhirschler@gbhinternational.com
The most important code requirements on reaction-to-fire safety for building products involve testing of interior finish (namely coverings for walls and ceiling). Traditionally this testing was conducted in the US by using the Steiner tunnel fire test (ASTM E84). However, increasingly requirements are trending towards the assessment of heat and smoke release rate with room-corner tests. In fact, in US codes the default fire test used for interior wall and ceiling is now NFPA 286 (a room-corner test). In both Steinertunnel testing and room-corner testing, significant differences in fire test results can be obtained by variations in specimen preparation techniques and in mounting methods. This has resulted in the development of many standard mounting practices for a variety of products. This paper will present an update and indicate areas where added work is still needed.

Quantitative approach of intumescence by numerical simulation
Serge Bourbigot1, ENSCL, ISP/UMET, Av Mendeleiev, BP 90108, Villeneuve d Ascq, Nord, 59652, France , 33320434888, serge.bourbigot@ensc-lille.fr
The purpose of this paper is to investigate quantitatively the intumescence mechanism by a numerical simulation using the finite element method. It is not our intention to describe all phenomena involved in intumescence but we have tried to make a simple model gathering the fundamental parameters. Our goal is to quantify the effects of heat conductivity, porosity and swelling on intumescence performance. A model describing the intumescence phenomenon has been developed and has been used to quantify the effects of heat conductivity and the swelling on its efficiency; the main results are: (i) large heat gradients take place in the expanded coating, (ii) low heat conductivity is necessary and (iii) high swelling rate permits to achieve the best performance.

Application of carbon nanotube as flame retardant of polymers
Zhengping Fang1,2, Zhejiang University, Ningbo Institute of Technology, Lab of Polymer Materials and Engineering, 1 Xuefu Road, Ningbo, Zhejiang, 315100, China , 86-574-88130132, 86-574-88130140, zpfang@zju.edu.cn
Carbon nanotube has shown significant flame retardancy in cone calorimetric tests. The network structure can improve the melt viscosity of polymer nanocomposites and confine the thermal movement of polymer chains. Besides, the network structure can efficiently improve the barrier character to the evolution of flammable volatiles and the ingress of oxygen to the condensed phase. Therefore, flame retardancy of the nanocomposites is significantly improved. However, they often fail traditional flammability tests such as limited oxygen index (LOI) and UL-94. The combination of carbon nanotube with conventional flame retardants or other nano-fillers lead to synergistic effects on flame retardancy. Very promising developments in the synergy aspects are then expected and efforts should be made in this direction.

Synthesis of new boronated and phosphonated aromatic flame retardants
Vladimir Benin1, University of Dayton, Chemistry, 300 College Park, Dayton, OH, 45469-2357, United States , 937-229-4762, vladimir.benin@notes.udayton.edu
We have prepared new substituted terephthalic esters and acids with one or two boronic or phosphonic ester (or acid) groups. The target structures are designed for potential use as reactive flame retardants. The syntheses were accomplished by introduction of boronate or phosphonate ester unit(s) via transition metal-catalyzed coupling reactions of dimethyl iodoterephthalate and dimethyl 2,5-diiodoterephthalate (Pd- or Ni-containing catalysts).


Facile hydrolysis of all ester functionalities in 3M HCl afforded the corresponding borono- or phosphonoterephthalic acids.

Completely renewable flame retardant thin films
Galina Laufer1, 1331 Harvey Mitchell Parkway, Apartment 1306, College Station, TX, 77840, United States , 979-862-8065, galina2405@tamu.edu
In an effort to create an environmentally-friendly flame retardant (FR) system for foam and fabric, layer-by-layer (LbL) thin films were assembled using “green” materials obtained from completely renewable sources. Positively- charged chitosan paired with anionic montmorillonite clay nanoplatelets was deposited on open-celled polyurethane foam. This coating completely stops the melting of a flexible polyurethane foam, when exposed to direct flame from a butane torch, with just 10 bilayers (~ 30 nm thick and only 4 wt% addition to the foam). Cone calorimetry confirms that this coated foam exhibited a reduced peak heat release rate, by as much as 52%, relative to the uncoated control. These results demonstrate the first truly “green” LbL flame retardant and set the stage for a new class of FR nanocoatings.

Layer-by-layer assembly of water-based, environmentally-friendly flame retardant nanocoatings for fabric and foam
Jaime C. Grunlan1,2,3, Texas A&M University, Department of Mechanical Engineering, 3123 TAMU, College Station, TX, 77843-3123, United States , 979-845-3027, jgrunlan@tamu.edu
By treating cotton with intumescent nanocoatings, composed of polyallyamine and polysodium phosphate, prepared via layer-by-layer (LbL) assembly, no ignition occurs (i.e., the fabric did not burn when exposed to direct flame). With a 20-bilayer nanocoating, total heat release is reduced 65% compared to the uncoated fabric, with only 4 wt% added. On open-celled polyurethane foam, ten bilayers of pH 6 chitosan and pH 10 montmorillonite were deposited (~ 30 nm thick). Only the outermost surface of the foam was charred after being exposed to direct flame from a propane torch for 10 seconds. This work demonstrates the first intumescent and fully renewable FR treatments, made via layer-by-layer assembly, and provides environmentally benign alternatives to commonly used halogenated materials for rendering foam and fabric flame retardant.

Carbon nanotubes: New approach for innovative flame retardant solutions
Michael Claes1, NANOCYL SA, Department of Research and Development, rue de l'essor, 4, Sambreville, Namur, Belgium , +32476432830, mclaes@nanocyl.com
For the past few years fire retardant polymers market is changing following two major drivers: harmonisation of regulation and standards in European Community and Health-Safety and Environmental concerns. Those actions cause increase of fire tests severity and banishment of most hazardous substances. As a consequence plastic industry is requested to develop new Fire Retardant polymer solutions to foresee those regulations modifications. In this frame, although some early results were not very convincing regarding the ability of CNTs to prevent fire, new approaches have been developed to use the best of the CNTs actions. Benefits of CNTs on flame retardant properties of polymer are now under strong investigation as a new solution for a more demanding market. Working on this topic from the early beginning, collaborations with universities, companies and fire test centres have led rapidly, for instance, to interesting results for Ethylene Vinyl Acetate and Polypropylene solutions. Cone calorimeter and UL94 results showed an improved and strengthened charring effect, a drastic reduction of dripping and flame spread rate as well as an additional synergist effect with phosphorus based flame retardant. In particular we have developed a Halogen Free Flame Retardant PP which passes UL 94 V0 @ < 2 mm. Nowadays, an even deeper work is ongoing in order to develop new HFFR solutions in Thermoplastic PolyUrethane and PolyEthylene. These products should comply with UL94 V0 and more severe standards. These studies investigate how CNT can increase fire performances of plastics in order to reach new fire class rank and how CNT can be used to achieve a high level of fire properties as well as improve global functionality of polymer solutions. During this conference, we will present our the latest developments in the field and an overview of the potential applications for carbon nanotubes in the fight against fire.

Flexible polyurethane foam with well characterized and reproducible smoldering
Mauro Zammarano1, National Institute of Standards and Technology, Engineering Laboratory, 100 Bureau Drive, Gaithersburg, MD, 20899-8665, United States , 301-792-4982, mzam@nist.gov
Smoldering is a self-sustaining heterogeneous oxidation reaction that induces a slow, low temperature, flameless combustion. Flexible polyurethane foams (PUF) are particularly prone to smoldering due to their high air permeability and low density. In this study we investigate the effect of PUF cell structure and morphology on smoldering. Our preliminary results show that above a threshold value of air permeability, the specific surface area of PUF might be used to assess smoldering.

Self-extinguishing non-toxic layer-by-layer coating on flexible polyurethane foam
Yu-Chin Li1, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD, 20899, United States , 301-975-6692, yu-chin.li@nist.gov
Flexible polyurethane foams were treated with two flame retardant coatings, branched polyethylenimine (PEI)/montmorillonite (MMT)/poly (acrylic acid)(PAA) and poly allylamine (PAAm)/poly (sodium phosphate) (PSP), prepared via layer-by-layer (LbL) assembly. The thickness of the coatings and coverage on PU foam were examined by scanning elecron microscope. MMT-coated foam prevented the melt-dripping, but had a faster burning and more vigorous flame during an open flame test. PSP-coated foam delayed the burning but melt-dripped. By combining two coatings together, flame size and spread rate were improved compared to the MMT-coated foam, and there was no melt-dripping problem. Foam shape was also retained. The preliminary results gave us ideas of how these coatings behave during a real fire scenario, and more studies are under investigation. These results show that LbL assembly is a relatively simple method for imparting environmentally-friendly flame-retardant behavior to polyurethane foam.

Flammability of polymer/clay aerogels
Hongbing A. Chen1, Case Western Reserve University, Department of Macromolecular Science and Engineering, 2100 Adelbert Road, Cleveland, OH, 44106, United States , 216-368-4243, 216-358-4202, hongbing.chen@case.edu
Foam-like polymer/clay aerogels are produced using an environmentally-friendly freeze drying process, generally from aqueous mixtures. These materials typically have bulk densities in the 0.05-0.2 g cm-3range, and exhibit useful compressive properties (1-20 MPa), typical of commercial foams. It is possible to produce inorganic loadings of 40-80% in the polymer matrix, values that are generally higher than can be obtained using traditional compounding operations, leading to a significant decrease in overall flammability of the material, and enhanced dimensional stability of the structure under flame conditions. Typical polymer/clay aerogels exhibit gasification mass loss rates of less than 7 g/m2s which compare favorably with FR polystyrene. Similarly, 50% clay filled poly(vinyl alcohol) and casein aerogels were measured to release 400-460 kW/m2per gram of material, comparing favorably with 1300 kW/M2per gram of expanded polystyrene (EPS) foam.

Measurement of the thermodynamics of polymers degradation
Stanislav I. Stoliarov1, University of Maryland, Department of Fire Protection Engineering, 3104C J.M. Patterson Bldg., College Park, MD, 20742, United States , 301-405-0928, stolia@umd.edu
Recently, significant advances have been made in modeling of pyrolysis and burning of polymers. A number of comprehensive numerical models have been developed including Gpyro, solid phase model in the NIST Fire Dynamics Simulator, and ThermaKin. These models have similar capabilities; they solve transient conductive and radiative energy transfer (usually in a one-dimensional form) coupled with simplified decomposition chemistry. The models compute the mass fluxes of combustible volatiles, which, together with the corresponding heats of combustion, define material flammability. The key issue that remains unresolved is how to determine the parameters of these models, which are formulated in terms of fundamental physical and chemical properties. This work is a part of the ongoing effort to develop a systematic procedure for the model parameterization. The focus is on the parameters that describe the thermodynamics of material heating and degradation. Early results suggest that these parameters can be obtained from mg-scale experiments conducted in a simultaneous thermal analyzer, which combines a heat-flux differential scanning calorimeter and a microbalance. An accurate determination of the heat of decomposition reaction requires a careful accounting for all components that comprise the heat flow baseline. In addition to the mg-scale experiments, this work involves exploration of a possibility of using relatively large, 10-25 g, samples to determine the overall energy required to heat and degrade a unit mass of a given material (starting from the room temperature). This energy, which may serve as a checksum on the parameters determined from the mg-scale experiments, is frequently referred to as the heat of gasification. The first prototype of the gasification device has been built and shown to be able to measure the heats of gasification of simple liquids, such as water or ethylene glycol, with the uncertainty of ±6%. The experiments on polymers are currently underway.

Textile flame retardancy through assembled nanoarchitectures: From single-step to multi-step nanoparticle adsorption
Federico Carosio1, Politecnico di Torino, Alessandria Branch, Department of Materials Science and Chemical Engineering, Alessandria, Viale Teresa Michel 5, Italy , 00390131229303, federico.carosio@polito.it
Nowadays fabric flammability still represents a severe threat to people safety. This work focuses on different approaches to improve the flame retardancy of natural and synthetic fibres (namely cotton, polyester and their blends). Fabrics have been treated with single step nanoparticle adsorption in a finishing-like process; afterwards nanoparticle adsorption has been improved using plasma surface activation. As an evolution of single-step adsorption, multi-step adsorption (namely layer by layer assembly) has been developed in order to build complex hybrid organic-inorganic or inorganic nanoarchitectures on the fabric surface. The treatments are able to increase fabric flame resistance (polyester dripping is prevented) in a vertical flame test; by cone calorimeter, treated fabrics have shown an increased time to ignition (104% for plasma activated fabrics) and a reduced heat release rate as well as a limited production of toxic smoke during combustion (25% and 30% respectively for layer by layer treated fabrics).

Flammability of polymer nanocomposites
Takashi Kashiwagi1, National Institute of Standards and Technology, Fire Research Division, Gaithersburg, MD, 20899, United States , 301-975-6699, takashi.kashiwagi@nist.gov
Polymer nanocomposites have attracted a great deal of interest due to their ability to improve physical properties of polymers such as mechanical and thermal properties. Furthermore, an improvement in the flammability properties of polymers has been achieved with polymer nanocomposites, which could provide an alternate to conventional flame retardants. This presentation briefly summerizes current flammability research of polymer nanocomposites and provides key properties which control their flammability properties.

Decomposition of polyesters influenced by phosphorus-containing substituents
Oliver Fischer1, Hohe Straße 6, Dresden, Saxony, 01069, Germany , +49-351-4658-556, fischer-oliver@ipfdd.de
To investigate the influence of the structure of phosphorus-containing polymeric flame retardants on their decomposition, four different aromatic aliphatic polyesters were synthesized. Three of them have organophosphorus substituents and one, taken as a reference, contains no phosphorus. The substituents belong to different classes of phosphororganic compounds: DOPO (9,10-dihydro-9-oxa-10-phospha-phenanthrene-10-oxide) phosphinate, DPPO (9,10-dihydro-3,6-dimethyl-9-oxa-10-phospha-anthracene-10-oxide) and DPhPO (diphenylphosphine oxide) phosphine oxides). Additionally, DOPO and DPPO are cyclic compounds, while DPhPO is non-cyclic. By using TGA, TGA-FTIR, pyrolysis-GC/MS and microscale combustion flow calorimetry (PCFC), it was found that all four polyester types decompose via different routes. The backbone degradation proposed for the non-substituted reference was not observed in the phosphorus polyesters. Results of decomposition under oxygen-containing atmosphere (air (TGA), N2/O2-mixture (PCFC)) demonstrated char oxidation for all polymers. Compared to pyrolysis under nitrogen, DPPO exhibited a significant change of the main decomposition step towards higher stability. This was not observed for the other polymers.

Fire retardancy of emulsion polymerized PMMA/CeO2 and PS/CeO2 composites
Guipeng Cai1, P.O. Box 1881, Milwaukee, Wisconsin, 53201, United States , 414-306-1736, guipeng.cai@marquette.edu
In situ emulsion polymerization was employed to obtain PMMA/CeO2 and PS/CeO2 composites with two different CeO2 loadings. Atomic force microscope (AFM) results indicated homogeneous dispersion of CeO2 in the polymer matrix. Both PMMA and PS based nanocomposites exhibited lower thermal stability than the neat polymers. Microscale combustion calorimeter (MCC) test was conducted to evaluate the fire retardancy of the polymer nanocomposites. PMMA/CeO2 showed greater heat release rate (HRR) reduction which may due to better compatibility than in PS/CeO2 nanocomposites.

Effect of structural morphology of silicates on the thermal and fire retardancy of polyurea
Thirumal Mariappan1, Marquette University, Department of Chemistry and Fire Retardant Research Facility, Toddwehr Chemistry, 110, 535 North 14 Street, Milwaukee, Wisconsin, 53201, United States, 414-288-7772, mariappan.thirumal@marquette.edu
The thermal and fire retardant property of polyurea, formed by the poly-addition reaction of a modified diisocyanate with an oligomeric diamine, has been studied using the thermogravimetric analysis and microscale combustion calorimeter (MCC). The effect of morphology of silicates such as layered (organoclay), tubular (halloysite) and particulate (nanosilica) on the thermal and flame retardant properties of polyurea was studied. The results showed that the addition of nanofillers with ammonium polyphosphate (APP) to polyurea improved the thermal as well as fire retardant properties. Synergistic and additive effect has also been found with the combination of nanofillers with APP.

Ammonium polyphosphate/montmorillonite nanocompounds in polypropylene
Deqi Yi1,2, Marquette University, Department of Chemistry, 535 North 14th Street, Milwaukee, WI, 53233, United States , 414-288-7772, deqiyi@gmail.com
Composites of polypropylene (PP)/clay nanocomposites and ammonium polyphosphate (APP)/montmorillonite (MMT) nanocompound were prepared by melt blending in two steps. Their morphologies were assessed by X-ray diffraction, while the thermal stability and flammability properties were characterized by thermogravimetric analysis and cone calorimetry. The char structure was carried out by Fourier transform infrared spectroscopy. Synergistic effects between PP/clay nanocomposites and APP/MMT nanocompound were observed; enhanced flame retardancy compared to other PP composites was observed.

Thermal degradation and fire performance of silicone-based coatings
Bastien Gardelle1, ENSCL, ISP/UMET, Av. Mendeleiev, BP 90108, Villeneuve d'Ascq, Nord, 59652, France, 33320434925, bastien.gardelle@hotmail.fr
In recent decades, disastrous accidents caused by damage of steel structure in fire have reminded people of the risk of fire in buildings. One of the most used systems to protect metallic structures is intumescent paint. This paper investigates the fire performance of phenyl silicone coating to protect steel against fire using two lab-scale tests : one based on the torch test (convective heat) and a heat radiator test (radiative heat). It was shown that the performance of the silicone based coating can be improved incorporating a siloxane modifier and reaches that of intumescent paint in convective fire test. The thermal conductivity of the coatings was measured versus temperature (from ambient to 500°C). The low values obtained (0.14 ± 0.01 W/K.m at 300°C) associated to the high expansion were attributed to be responsible of the good fire protective properties of the coating.

Role of dispersion of LDH in fire retardancy
Zvonimir Matusinovic1, Marquette University, Departemnt of Chemistry and Fire Retardant Research Facility, 535 14th Street, Milwaukee, Wisconsin, 53233, United States , 414-306-2034, zvonimir.matusinovic@marquette.edu
In order to clarify whether dispersion has influence on fire retardant properties or those properties are the result of other processes, including glass formation and/or endothermic decomposition, layered double hydroxides with three different M2+cations (Ca2+, Zn2+and Mg2+) were prepared and organically modified by the intercalation of benzoate anions (CaAlLDH-B, Zn-AlLDH-B and Mg-AlLDH-B). Nanocomposites were prepared in a two-stage process by the in situ bulk polymerization using polystyrene, poly(methyl-methacrylate) and poly(styrene-co-methyl methacrylate) matrices. Nanocomposites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and Transmission electron microscopy (TEM) and tested on the Microscale combustion calorimeter (MCC).

Synergistic and antagonistic effect in intumescent epoxy resin
Gaëlle Fontaine1, ENSCL, ISP/UMET, Av Mendeleiev, BP 90108, Villeneuve d'Ascq, Nord, 59350, France , 00 33 3 20 46 83, gaelle.fontaine@ensc-lille.fr
The fire retardancy effect of nanoparticles in epoxy resin is studied. Incorporation of Polyhedral Oligomeric Silsesquioxane (POSS) or carbon nanotubes alone in epoxy resin provides a little enhancement of the reaction to fire. The combination between a phosphorus-based flame-retardant (APP) and carbon nanotubes reveals an antagonistic effect between these two fillers, whereas POSS in combination with APP provides a synergy. The Investigation of the mechanism supports the hypothesis that the main action of the different systems takes place in the condensed phase.

Relation between the barrier and flammability properties of polymer nanocomposites
Pingan Song1, Zhejiang Agriculture and Forestry University, Department of Materials, North Huancheng Road 88, Hangzhou/Linan, Zhejiang, China , +086 6374 3599, pingansong@gmail.com
Despite of many studies on the barrier and flammability properties of polymer nanocomposites, the relationship between them remains not to be investigated in detail so far. We created polymer nanocomposites with a 1.0 wt% of nanofillers loading by employing three types of nanoparticles, namely, chemical reduced graphene (RGO), carbon nanotubes (CNTs), and layered silicates (Clay) through a melt-compounding method. The oxygen permeation tests show that RGO perform better than CNTs and clay due to its higher aspect ratio creating a longer and tortuous path for gas molecules. CNTs performs worst among them because it reduces the gas permeation only by forming a network. Cone calorimeter test results demonstrate that RGO leads to a biggest reduction in the peak heat release rate (PHRR) of polymer, followed by CNTs, and then clay. Thus, the better the barrier property, generally, the lower the flammability of polymer materials.

Flame retardants for flexible polyurethane foams: Structure-property-relationship studies
Nicloas M. Neisius1, EMPA, Laboratory of Advanced Fibers, Lerchenfeldstrasse 5, St. Gallen, Switzerland , +41 58 7657 846, +41 58 7657 862, matthias.neisius@empa.ch
In order to investigate the structure-property-relationship of different organophosphorus compounds on the flame retardant behavior of flexible polyurethane foam, a series of model compounds were synthesized. Within this series of compounds we systematically varied the substituents of different classes of as well as the classes of compounds keeping the substituent the same. The different classes of compounds we investigated were namely phosphoramidates, phosphates and phosphonates. With several different compounds in hand we prepared different foams with different concentrations of flame retardant subsequently evaluated the flame retardant behavior by limiting oxygen index (LOI), BKZ-VB and UL94-HB test methods. It was found that the phosphonates and analogous phosphoramidates were more effective than corresponding phosphates in rendering FPF flame retardant. Among these phosphoramidates, mono secondary phosphoramidates were shown to have better flame retardant action than mono tertiary and triphosphoramidates. In addition, dimethyl phosphoramidates exhibited better flame retardant efficacy than the corresponding diphenyl derivatives.

Exploring halogen free flame retardant flexible polyurethane foams via a combined effect of flame retardants
Gordon L. Nelson1, Florida Institute of Technology, Department of Academia Affairs, 150 West University Boulevard, Melbourne, Florida, 32901, United States , 321-674-8480, nelson@fit.edu
The combined use of phosphorus flame retardant with smoke suppression agents, as well as reactive silicone, in flexible polyurethane foams was studied. Cone results of the obtained flexible foams strongly support “synergism”. With 25 pbw of phosphorus FR, Antiblaze® 230, and 10pbw of zinc stannate in the PUR formulation, the peak heat release rate was reduced by as much as 52%. Furthermore, the combined use of phosphorus FR with reactive silicone in flexible PUR foams also exhibited significant reduction in PHRR. The addition of Antiblaze® 230 increases smoke production of PUR foams, but the combined use of ZS or ZHS with Antiblaze® 230, as well as reactive silicone with Antiblaze® 230, significantly reduces smoke generation. It is also found that RDP with low volatility and high heat stability characteristics leads to the absence of gas phase inhibition, and has no flame retardant effect when used in PUR foams.

High temperature mechanical properties of thermoplastic polyurethane nanocomposites
Preejith V. Ambuken1, Tennessee Technological University, Department of Chemical Engineering, 1020 Stadium Drive, Prescott Hall, Room 214, Box 5013, Cookeville, TN, 38505-0001, United States , 409-273-2918, preejith.ambuken@gmail.com
Incorporation of nanoparticles into a polymer can result in enhancement of electrical, thermal and mechanical properties. This work describes the modulus enhancement of thermoplastic polyurethane (TPU) nanocomposite chars at high temperature (up to 300oC) using Dynamic Mechanical Analysis. Different compositions of TPU nanocomposites were prepared on a pilot scale twin-screw extruder using a Montmorillonite organo-clay, carbon nanofiber and multiwall carbon nanotubes. The dynamic mechanical properties of different TPU nanocomposite chars have been correlated with their fire retardance properties, including UL-94. The onset of softening was found to increase with loading at 1 Hz for all nanocomposites, and overall MWNT were found to produce the optimal reinforcement response in the char for TPU-based nanocomposites heated to 300°C.

Synergistic flame retardant mixtures in epoxy resins
Manfred Doering1, Karlsruhe Institute of Technology, Department of Catalysis Research and Technology, Hermann-von-Helmholtz-Platz 1, Eggenstein-Leopoldshafen, Baden-Wuerttemberg, 76344, Germany , 0049-721-608-24385, manfred.doering@kit.edu
Phosphorous compounds can be used to impart flame retardancy on epoxy resins. Depending on the grade of crosslinking, a gas-phase active species (e.g. 9,10-dihydro-9-oxa-phosphaphenanthrene-10-oxide (DOPO), for highly cross-linked resins) or a compound that acts in the condensed phase (e.g. phosphorous acid esters, for weakly cross-linked resins) is required. We used a phenolnovolac resin cured with DICY as a highly cross-linked test-system and DGEBA cured with either dimethyldicycane or DICY as a weakly cross-linked test-system. The efficiency of phosphorous flame retardants in epoxy resins can be enhanced by the incorporation of additives that provide a synergistic effect.[1] Melaminpolyphosphate, different boehmites (distinguishable from their specific surface areas) and elementary sulfur as well as organic disulfides (e.g. dicaprolactam disulfide) were applied as synergists. These were combined with different phosphorous compounds (additive and reactive DOPO derivatives, phosphorous containing salts, phosphates) and examined for their flame retardant properties in the above-mentioned resins.

Ferrocene-β-cyclodextrin inclusion compound used in polystyrene intumescent flame retardant system
Jin Zhu1, Chinese Academy of Sciences, Ningbo Institute of Material Technology and Engineering, 519 Zhuangshi Road, Zhenhai District, Ningbo, Zhejiang, 315201, China , 086-0574-86685925, jzhu@nimte.ac.cn


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