Fire retardancy of a reactively extruded intumescent flame retardant polyethylene system enhanced by metal chelates

Wang, De‐Yi; Liu, Yun; Wang, Yu‐Zhong; Artiles, C. Perdomo; Hull, T. Richard; Price, Dennis

doi:10.1016/j.polymdegradstab.2007.04.015

Cited by 166 publications

(82 citation statements)

References 25 publications

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“…These problems have driven the search for alternative "halogenfree" fire retardants, which include metal hydroxide 7,8 and carbonate fillers 9 , phosphorus compounds 10 , low melt glasses 11 , as well as a range of more esoteric materials, such as clay and silica nanoparticles 12,13 , carbon nanotubes 14 , expandable graphite 15 and metal chelates 16,17 . In general, halogen-free fire retardants are much more polymer-specific -while one fire retardant will work well in one polymer, it may not work at all in another.…”

Section: Fire Retardants and Flammabilitymentioning

confidence: 99%

Fire retardant action of mineral fillers

Hull

Witkowski

Hollingbery

2011

Polymer Degradation and Stability

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292

144

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Endothermically decomposing mineral fillers, such as aluminium or magnesium hydroxide, magnesium carbonate, or mixed magnesium/calcium carbonates and hydroxides, such as naturally occurring mixtures of huntite and hydromagnesite are in heavy demand as sustainable, environmentally benign fire retardants. They are more difficult to deploy than the halogenated flame retardants they are replacing, as their modes of action are more complex, and are not equally effective in different polymers. In addition to their presence (at levels up to 70%), reducing the flammable content of the material, they have three quantifiable fire retardant effects: heat absorption through endothermic decomposition; increased heat capacity of the polymer residue; increased heat capacity of the gas phase through the presence of water or carbon dioxide. These three contributions have been quantified for eight of the most common fire retardant mineral fillers, and the effects on standard fire tests such as the LOI, UL 94 and cone calorimeter discussed. By quantifying these estimable contributions, more subtle effects, which they might otherwise mask, may be identified.

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Section: Fire Retardants and Flammabilitymentioning

confidence: 99%

Fire retardant action of mineral fillers

Hull

Witkowski

Hollingbery

2011

Polymer Degradation and Stability

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292

144

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“…The cone calorimeter provides detailed information on burning behaviour and can be used to predict the behaviour of materials in a real fire [16,17] . At the same time, the flow behaviour of a polymeric matrix containing IFR during heating is a key parameter needed to determine the fire retardant mechanism, since the viscosity of the molten matrix will affect the flow of fuel to the flame zone, the swelling of the intumescent layer, and the properties of the char layer, all of which will affect the heat release rate.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

“…Table 4 shows the weight of PP/25APP+PER/1MnAc residue increased to 27.4 wt% as expected, 8 Moreover, Table 4 shows that the t ign of most PP/25APP+PER/MnAc materials were shortened with the increase loading of MnAc. Unlike PP can melt and be cooled by liquid phase convection, the loading of MnAc in the intumescent flame retarded PP increases the viscosity of the matrix reducing heat transfer between the exposed sample surface and the bulk of the sample, then results the surface getting hotter more quickly [17,30] . The surface of the samples with more MnAc may easily reach the critical surface temperature for ignition more quickly than the sample with less MnAc, thus probably causes the increase in the t ign .…”

Section: Cone Calorimetrymentioning

confidence: 99%

Mechanism of enhancement of intumescent fire retardancy by metal acetates in polypropylene

Zhang

Fang

et al. 2017

Polymer Degradation and Stability

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The effects of cobalt acetate (CoAc), manganese acetate (MnAc), nickel acetate (NiAc) and zinc acetate (ZnAc) as fire retardant additive in intumescent polypropylene (PP) formulations containing PP/ammonium polyphosphate (APP)/pentaerythritol (PER) are reported. The limiting oxygen index (LOI) and vertical burning (UL94) tests and cone calorimetry were used to quantify the enhancement. Environmental chamber rheometry, thermal gravimetric analysis and the morphology of the residual char were used to investigate the mechanism of enhancement. The incorporation of small quantities of metal acetates had a significant influence on the fire behaviour. As an example, 0.7 wt% MnAc improved the UL 94 rating of PP/APP+PER (mass ratio 100/25, with APP/PER=3/1) sample from V-2 to V-0, while 1 wt% MnAc reduced the peak heat release rate and the total heat release by 18% and 12% in the cone calorimeter. Rheological data, cone calorimetry, and photographs of the residual char showed how the fire retardancy of the systems were affected by the melt viscosity, which depended on the loading of metal acetate. During thermal decomposition, the metal acetates promote the crosslinking of the polymer and the fire retardant, reinforcing the protective intumescent layer. While, the effect is most potent at the optimal metal loadings. At higher MnAc loadings, the benefit of a stronger char is overwhelmed by the adverse effect of crosslinking on the transition char layer. Thus, this paper offers a new insight into the mechanism of the intumescent fire retarded PP system.

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“…However, adding a large amount will adversely affect the mechanical properties of the polymeric material 6 . In recent years, intumescent flame retardants (IFRs) have attracted more and more attention in flame-retarding polypropylene (PP) because of their halogen-free, environmental-friendly, low smoke, and low toxicity properties [7][8][9][10][11][12] . IFR usually consists of three ingredients: acid source, carbonization agent and blowing agent.…”

Section: Introductionmentioning

confidence: 99%

Dual Fire Retardant Action: The Combined Gas and Condensed Phase Effects of Azo-Modified NiZnAl Layered Double Hydroxide on Intumescent Polypropylene

Wang

Liao

et al. 2017

Ind. Eng. Chem. Res.

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Ternary nickel-substituted layered double hydroxide (C-LDH) was synthesized. It was intercalated with azobenzene-4,4'-dicarboxylic acid, using an ion exchange method to obtain organically modified NiZnAl-LDH (O-LDH). Both LDHs were melt-blended into polypropylene (PP) with intumescent fire retardant (IFR). The structure, morphology, thermal stability and combustible properties of intercalated LDH and its hybrid composite have been comprehensively characterized. SEM and EDX mapping show O-LDH exhibits better dispersion than ZnNiAl-CO3 LDH (C-LDH). Cone calorimetry shows the addition of IFR and LDH significantly reduced smoke and heat release rate. The composite with 1 wt% O-LDH, which showed dual gas phase and condensed phase fire retardant action, exhibited the lowest flammability with an LOI value of 29.3 % and achieved a UL-94 V-0 rating. In addition, incorporation of LDH improved the mechanical properties compared to PP/IFR composites. UV absorption showed that O-LDH could significantly improve the ultraviolet stability of PP composites.

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Fire retardancy of a reactively extruded intumescent flame retardant polyethylene system enhanced by metal chelates

Cited by 166 publications

References 25 publications

Fire retardant action of mineral fillers

Fire retardant action of mineral fillers

Mechanism of enhancement of intumescent fire retardancy by metal acetates in polypropylene

Dual Fire Retardant Action: The Combined Gas and Condensed Phase Effects of Azo-Modified NiZnAl Layered Double Hydroxide on Intumescent Polypropylene

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