A method to assess downward flame spread and dripping characteristics of fire‐retardant polymer composites

Wen, Chuchu; Zhang, Jiyue; Levendis, Yiannis A.; Delichatsios, Michael

doi:10.1002/fam.2498

Cited by 5 publications

(2 citation statements)

References 51 publications

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“…Wen et al investigated the downward flame spread of low‐density polyethylene containing different micron and nano‐sized particles, including carbon black, soot particulate, multi‐wall carbon nanotube, bituminous coals and calcium‐based compounds. From the mass loss and change in sample height, the melting and dripping rates were quantified.…”

Section: Existing Experimental Studies On Melting and Dripping Behavimentioning

confidence: 99%

Apparatus for investigating the burning and dripping of vertically oriented polyurethane foams

2019

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The burning and dripping behaviour of polyurethane (PU) foam is crucial for upholstered furniture fires due to the melting and dripping behaviour of the foam that results in a pool fire under the furniture, which enhances the combustion. The sample feeding vertical cone is developed to investigate the two-dimensional small-scale burning and dripping behaviour of vertically oriented PU foams where a constant irradiance is maintained at the exposed surface by means of automatic sample compensation. Seven different PU foams were investigated and classified as conventional foam or char-forming foam according to the observed surface phenomena during exposure to heat fluxes. The burning and dripping behaviour is found to depend on the foam density as well as the solid-phase char formation by the presence of fire retardant additives. The total mass loss rate and the dripping rate increase with higher foam density and with the presence of char formation. In contrary, the vaporisation rate is favoured at lower foam density and with the absence of char formation. Flexible foams of low density without the ability to form char tend to achieve low dripping rate where majority of the mass loss is via vaporisation, contributing directly to the gas-phase combustion. K E Y W O R D S burning and dripping behaviour, fire retardant additives, polyurethane foam, sample feeding vertical cone 1 | INTRODUCTION Flexible polyurethane (PU) foam is a synthetic thermosetting polymer 1,2 that is commonly found in bedding and upholstered furniture. The flexible foam's expansive range of hardness and densities allows the material to be incorporated into different types of mattress and different paddings of the upholstered furniture. The end use of mattresses and upholstered furniture means that these products are often intimate with the users where life safety in event of fire is paramount. Non-fire retardant (NFR) flexible PU foams have relatively poor performance in fire, in terms of ignitability, flammability and toxicity, which challenge the occupants survival in the room of origin and beyond. 3,4 A number of researchers have focused on improving the understanding on the decomposition and burning behaviour of flexible PU foams. 5,6 Despite being a thermosetting polymer, flexible PU foams exhibit melting behaviour upon thermal decomposition, which resembles the characteristic of most thermoplastic polymers. The amount of melt produced depends on the type of flexible foams, and according to Ohlemiller et al, 2 this can be as high as 70%-90% of the original mass for certain foams, which is comparable to common thermoplastic polymers such as polypropylene and polystyrene. Flexible PU foam is formed by the polycondensation of polyfunctional isocyanates commonly diisocyanates, with polyfunctional alcohols or polyols commonly polyestherols or polyetherols. 3,7,8 The manufacturing process also includes a number of additives such as blowing or foaming agent, coupling agent, catalyst, chain extender, neutralizer, surfactant and cell opener. 1,7-10 Ch...

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Section: Existing Experimental Studies On Melting and Dripping Behavimentioning

confidence: 99%

Apparatus for investigating the burning and dripping of vertically oriented polyurethane foams

2019

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“…Kim et al [24] simulated the melting dripping behaviors of polypropylene (PP) under external radiation and simplified many influencing factors in the simulation process. Additionally, Wen et al [25] simulated the melting dripping of flame retardant polyethylene (PE); the results showed that the carbon particle additives could effectively reduce the dripping rate. These previous studies validate that the present study is meaningful to some extent for the safety evaluation of polymers.…”

Section: Introductionmentioning

confidence: 99%

Research on the Fire Behaviors of Polymeric Separator Materials PI, PPESK, and PVDF

Huang,

Li,

Han

et al. 2023

Fire

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Certain polymers, such as polyvinylidene fluoride (PVDF), polyimide (PI), and poly (phthalazinone ether sulfone ketone) (PPESK), are commonly used separator materials in batteries. However, during the thermal runaway (TR) processing of batteries, significant heat is released by the combustion of the polymer separator. Therefore, analysis of the fire behaviors of polymer separator materials will facilitate a more comprehensive quantitative evaluation of battery thermal risk. This paper investigated the combustion properties of three types of polymers, namely, PVDF, PI, and PPESK, as potential separator materials by cone calorimetry and thermogravimetry (TG). A series of characteristic parameters, including ignition time (TTI), heat release rate (HRR), smoke production rate (SPR), and total heat release (THR), were evaluated for three polymers and blends (PI/PVDF, PPESK/PVDF) under an external heat flux of 45 or 60 kW/m2, respectively. The combustion characteristics and fire hazards of the three polymers and corresponding mixtures were analyzed through the comparative analysis of experimental data and phenomena. Under 60 kW/m2, the HRR curves of all polymers presented two peaks, while PI/PVDF and PPESK/PVDF mixtures exhibited one obvious peak. Moreover, the peak HRR (pHRR) for the mixed polymers was higher, indicating a relatively higher fire risk. However, in the application scenario, the mixed state represents the main polymer form as the active separator materials in batteries. The results showed that the specific coupling behaviors were related primarily to the component type. This work will help evaluate the fire risk of polymeric separator materials based on the combustion characteristics to predict the safety of mixtures in batteries and develop new methods for fire suppression.

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Melt dripping behavior in the process of flame spread over energized electrical wire at different pressures

Wang

Wei

et al. 2019

Fire and Materials

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SummaryMelt dripping of polymer insulation in electrical wires is impacted by some factors, such as ambient pressure and electric current. The motivation of this paper is to investigate and discuss the effect of these factors on melt dripping characteristics in the process of flame spread over electrical wire. The results show that the number of dripping times and dripping frequency generally increase with ambient pressure reduced. No dripping phenomenon occurs when the ambient pressure is below 40 kPa at any electric current or is above 70 kPa without electric current applied. There is a good parabolic correlation between the ambient pressure and dripping frequency. The equilibrium temperature of conductor resulted by electric current increases with electric current. A critical electric current found to divide the temperature rate into two regimes is about 8 A. The dripping period and dripping frequency depend on the electric current. The dripping frequency fits well with electric current using a power‐law function. The numerical data are consistent with the experimental data. Besides, the decrease in dripping frequency is greater with ambient pressure at reduced electric current, whereas at larger electric current, the electric current, rather than the ambient pressure, dominates the increased dripping frequency.

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A method to assess downward flame spread and dripping characteristics of fire‐retardant polymer composites

Cited by 5 publications

References 51 publications

Apparatus for investigating the burning and dripping of vertically oriented polyurethane foams

Apparatus for investigating the burning and dripping of vertically oriented polyurethane foams

Research on the Fire Behaviors of Polymeric Separator Materials PI, PPESK, and PVDF

Melt dripping behavior in the process of flame spread over energized electrical wire at different pressures

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