An investigation into the mechanism of flame retardancy and smoke suppression by melamine in flexible polyurethane foam

Price, Dennis; Liu, Yan; Milnes, G.J.; Hull, T. Richard; Kandola, Baljinder K.; Horrocks, A. Richard

doi:10.1002/fam.810

Cited by 87 publications

(81 citation statements)

References 7 publications

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“…Dick et al used 1 H NMR spectroscopy to find that the melamine additive acts in the condensed phase by promoting the formation of a rigid char at temperatures above 400ºC [25]. Melamine is also believed to act as a heat sink, and the nitrogen content of melamine may partly end up as nitrogen gas, providing a heat sink and diluent in the gas phase [26].…”

Section: Pyrellmentioning

confidence: 99%

The piloted transition to flaming in smoldering fire retarded and non‐fire retarded polyurethane foam

et al. 2008

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The piloted transition from smoldering to flaming, though a significant fire safety concern, has not been previously extensively studied. Experimental results are presented on the piloted transition from smoldering to flaming in non-fire retarded (NFR) polyurethane foam and the fire retarded polyurethane foam Pyrell ® . The samples are small blocks, vertically placed in the wall of an upward wind tunnel. The free surface is exposed to an oxidizer flow and a radiant heat flux. The smolder product gases pass upwards through a pilot. The experiments on NFR foam show that the smolder velocity and peak smolder temperature, which increase with the oxygen concentration and heat flux, are strongly correlated to the transition to flaming event, in that there are minimum values of these parameters for transition to occur. The existence of a minimum smolder velocity for ignition supports the concept of a gaseous mixture reaching a lean flammability limit as the criterion for the transition to flaming. To compensate for the solid-and gas-phase effects of the fire retardants on the piloted transition in Pyrell, it was necessary to increase the oxygen concentration and the power supplied to the smolder igniter and the pilot. The piloted transition is observed in oxygen concentrations above 17% in NFR foam, and above 23% in Pyrell. The results show that although Pyrell is less flammable than NFR foam, it is still susceptible to smoldering and the piloted transition to flaming in oxygen-enriched environments, which is of interest for special applications such as future space missions.

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Section: Pyrellmentioning

confidence: 99%

The piloted transition to flaming in smoldering fire retarded and non‐fire retarded polyurethane foam

et al. 2008

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“…The fire retardants in Pyrell can act in the solid phase to hinder the smolder tendency. Pyrell could include melamine, for example, which is believed to act as a heat sink [21] and forms into thermally stable network structures [19]. The exothermicity of the smolder reaction in Pyrell can further be reduced by other fire retardants such as phosphorus-containing additives that can also act in the solid phase and modify the smolder kinetics.…”

Section: Discussionmentioning

confidence: 99%

“…Dick et al used 1 H NMR spectroscopy to find that the melamine additive acts in the condensed phase by promoting the formation of a rigid char at temperatures above 400ºC [20]. Melamine is also believed to act as a heat sink, and the nitrogen content of melamine may partly end up as nitrogen gas, providing a heat sink and diluent in the gas phase [21]. In addition, the melamine is believed to react with the evolved toluene diisocyanate fraction arising from the decomposition of polyurethane, to form a polymeric structure that reduces the smoke and CO release [21].…”

Section: Pyrellmentioning

confidence: 99%

“…The fire retardants in Pyrell can alter these reactions such that total reaction that is net endothermic, or very weakly exothermic. Pyrell could include melamine, for example, which is believed to act as a heat sink [21] and forms into thermally stable network structures [19]. Other retardants such as phosphorus-containing additives could also modify the kinetic behavior of polyurethane in the solid phase, and hinder the smolder tendencies of the foam.…”

Section: Comparison With Non-fire Retarded Polyurethane Foammentioning

confidence: 99%

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Ignition of Combustion Modified Polyurethane Foam

Putzeys

Fernandez-Pello

Urban

2006

Journal of ASTM International

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ABSTRACT:Results are presented from an experimental study on the ignition of the combustion modified (fire retarded) polyurethane foam Pyrell ® (35.3 kg/m 3 and 64.0 kg/m 3 ) in elevated oxygen concentrations, ranging from 30% to 60%. The samples are exposed to an external flow and variable radiant heat flux on one face, and insulated on the other faces. The experiments show that Pyrell undergoes a weak smoldering reaction that requires significant assistance in the form of external heat input in order to propagate. The results also show that given sufficient oxygen and radiant heat flux, the smoldering reaction can produce enough volatile fuel and heat to trigger a gas phase ignition, i.e. a transition from smoldering to flaming, in pores in the char region. The experiments also indicate that high-density Pyrell is more ignitable than low-density Pyrell, which could be explained by the greater solid surface area for smoldering reactions to take place.

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“…4, the melts of FR-Y-36 and FR-LG-38 shows lower endothermic value than the others and this is believed to be a result of the exothermic char formation from the breakdown of melamine remnants in the melts. The mechanism of melamine as fire retardant additive was studied by Price et al [22] and Denecker et al [23] but their findings were inconclusive. The former reported an exothermic process as a result of char formation by melamine while the latter reported an endothermic process as a result of melamine sublimation.…”

Section: Factors Affecting Heat Of Reaction From Nitrogen Environmentmentioning

confidence: 99%

Sensitivity of Heat of Reaction for Polyurethane Foams

Pau¹,

Fleischmann²,

Spearpoint³

et al. 2014

Fire Saf. Sci.

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The heat of reaction for the decomposition of polyurethane foam and its melt are determined from the heat flow measurements obtained through simultaneous differential scanning calorimetry and thermogravimetric analysis. Under nitrogen environment, the decomposition of foam experiences two endothermic pyrolysis reactions based on the experimental results. Through the investigation on the sensitivity of heat of reaction to heating rate and sample mass, a region where the heat of reaction remains constant is found for the melt samples tested. This consistent region includes heating rate from 5 to 20 °C/min and sample mass between ~20 and ~50 mg. No consistent region is found for the foam samples because of the reduced accuracy in the heat flow measured. For the foams and melts tested, the consistent heat of reaction for the second reaction ranges from endothermic 164 -295 J/g while the recommended heat of reaction for the first reaction ranges from endothermic 610 -1023 J/g.

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An investigation into the mechanism of flame retardancy and smoke suppression by melamine in flexible polyurethane foam

Cited by 87 publications

References 7 publications

The piloted transition to flaming in smoldering fire retarded and non‐fire retarded polyurethane foam

The piloted transition to flaming in smoldering fire retarded and non‐fire retarded polyurethane foam

Ignition of Combustion Modified Polyurethane Foam

Sensitivity of Heat of Reaction for Polyurethane Foams

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