Evaluation of condensed phase: Char/residue analysis

Bourbigot, Serge

doi:10.1016/b978-0-12-824045-8.00006-x

Cited by 6 publications

(5 citation statements)

References 78 publications

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“…This denotes variation in the structural configuration of the char and that in some samples, the char becomes more amorphous, possibly through cross-linking of the system by boron ester bonds creating a more turbostratic architecture. It has been shown that this structure is preferred for effective condensed phase action, as increased organization may lead to cracks that lead to volatile leakage …”

Section: Resultsmentioning

confidence: 99%

“…Raman spectroscopy was used to analyze changes in the degree of graphitization of char samples with the addition of APB by comparing the ratio of peak intensity of the defect carbon band (∼1360 cm –1 ) and graphitic carbon band (∼1590 cm –1 ), − otherwise known as the I D / I G ratio. Representative spectra and ratios are shown in Figure S4 and Table .…”

Section: Resultsmentioning

confidence: 99%

“…It has been shown that this structure is preferred for effective condensed phase action, as increased organization may lead to cracks that lead to volatile leakage. 55 Gas phase action was analyzed during pyrolysis using TGA-MS under nitrogen (Figure 7). At 325 °C, CH 4 (16, 17 amu), H 2 O (17, 18 amu), and CO 2 (44 amu) begin to be released as neat cotton begins to depolymerize.…”

Section: Flame Retardant Mechanismmentioning

confidence: 99%

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Boron Improved High Limiting Oxygen Index Polyelectrolyte Treatment for Cotton

Vest,

Convento,

Rodriguez-Melendez

et al. 2023

ACS Appl. Eng. Mater.

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The flammability of cotton fabric poses a risk of injury and death, specifically in aerospace applications, where oxygen concentrations are higher than typical atmospheric conditions. In an effort to reduce its flammability in high-oxygen environments, cotton was treated with a 12bilayer coating consisting of poly(allylamine hydrochloride) (PAH), poly(sodium phosphate) (PSP), and ammonium pentaborate tetrahydrate (APB). With a formulation of 6.5% PAH/8% PSP+5% APB, cotton is rendered self-extinguishing, exhibiting a reduction in peak heat release and fire growth capacity of 72 and 88%, respectively. Moreover, cotton remains self-extinguishing in highly oxygenated environments, having a limiting oxygen index of 35.5%. This layer-by-layer assembled coating operates via an intumescent mechanism that is aided by the formation of borate esters cross-linking the char structure, resulting in reduced gas diffusion and increased thermal stability. This unique, scalable treatment is especially promising for space exploration and could potentially be used in other polymeric materials.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Flame Retardant Mechanismmentioning

confidence: 99%

See 1 more Smart Citation

Boron Improved High Limiting Oxygen Index Polyelectrolyte Treatment for Cotton

Vest,

Convento,

Rodriguez-Melendez

et al. 2023

ACS Appl. Eng. Mater.

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“…Three possible variants of FRI are defined as per Equations ( 2)- (4). Although the parameters in Equation (2) are not nominally the same as of those in Equation ( 1), both equations are conceptually identical. Correspondingly, possible correlations between the FRI values are visualized as a function of FRs weight percent (wt.%) for a number of flame retardant polymer materials based on the availability and authenticity of data collected from the literature (Table 1…”

Section: Conceptualizationmentioning

confidence: 99%

“…Cone calorimetry is a well-known bench-scale testing method for the quantification of flame retardancy performance of polymers, which offers useful information about FRs' action, particularly when it comes with barrier mechanism of the condensed phase. Since highly flame-retardant polymers generally benefit from the synergistic effects of two or more types of FRs, additional morphological and/or elemental composition analyses on char residue are required to explain the action of FRs [2]. Cone calorimetry analysis makes it possible to explore fire behavior/scenarios in terms of the heat release rate (HRR) as a function of time [3].…”

Section: Introductionmentioning

confidence: 99%

Flame Retardancy Index (FRI) for Polymer Materials Ranking

et al. 2023

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In 2019, we introduced Flame Retardancy Index (FRI) as a universal dimensionless index for the classification of flame-retardant polymer materials (Polymers, 2019, 11(3), 407). FRI simply takes the peak of Heat Release Rate (pHRR), Total Heat Release (THR), and Time-To-Ignition (ti) from cone calorimetry data and quantifies the flame retardancy performance of polymer composites with respect to the blank polymer (the reference sample) on a logarithmic scale, as of Poor (FRI ˂ 100), Good (100 ≤ FRI ˂ 101), or Excellent (FRI ≥ 101). Although initially applied to categorize thermoplastic composites, the versatility of FRI was later verified upon analyzing several sets of data collected from investigations/reports on thermoset composites. Over four years from the time FRI was introduced, we have adequate proof of FRI reliability for polymer materials ranking in terms of flame retardancy performance. Since the mission of FRI was to roughly classify flame-retardant polymer materials, its simplicity of usage and fast performance quantification were highly valued. Herein, we answered the question “does inclusion of additional cone calorimetry parameters, e.g., the time to pHRR (tp), affect the predictability of FRI?”. In this regard, we defined new variants to evaluate classification capability and variation interval of FRI. We also defined the Flammability Index (FI) based on Pyrolysis Combustion Flow Calorimetry (PCFC) data to invite specialists for analysis of the relationship between the FRI and FI, which may deepen our understanding of the flame retardancy mechanisms of the condensed and gas phases.

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