Intumescent fire-retardant acrylic coatings: Effects of additive loading ratio and scale of testing

Ng, Yan Hao; Dasari, Aravind; Tan, Kang Hai; Qian, Lijun

doi:10.1016/j.porgcoat.2020.105985

Cited by 26 publications

(8 citation statements)

References 28 publications

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“…For the one-directional heating tests, the procedure described in a previous publication was followed using insulation boards. 17 For the three-directional heating tests, the steel plate was placed in an upright position (base being the rectangular uncoated face) at the center of the furnace chamber to allow heating on all sides. For this purpose, a slot was created in a non-combustible refractory board to support the bottom part of the sample.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Some of these include steel member dimensions/section factors, imposed load, edge effects of the sections, presence of reinforcing mesh, adhesion of char to the section, and the imposed fire curve/fire load. [17][18][19] In epoxy-based intumescent coatings, studies have shown that the thermal conductivity of the expanded char measured at ambient temperatures could drop by an order of magnitude to ;0.048-0.099 W/mK from an initial value of 0.41-0.58 W/mK. 18 Even with a classical combination of 40 wt% of intumescent additives (ammonium polyphosphate (APP), pentaerythritol, and melamine with a weight ratio of 5:2:3) in epoxy, peak HRR (pHRR), and THR were reduced by 76% and 41%, respectively, when tested in a cone calorimeter at a heat flux of ;50 kW/m 2 .…”

Section: Introductionmentioning

confidence: 99%

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Material-scale flammability characteristics of epoxy-based coating systems

Siow

Dasari

2022

Journal of Fire Sciences

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Flammability of intumescent coatings at the materials-scale is “expected” to have an impact on their fire resistance offered to the steel member. However, to what extent and at what stage during the exposure to an imposed fire curve in a furnace are not thoroughly established. The role of different functionality of the flame-retardant additives in this process is also not clear despite a thorough understanding of their thermal decomposition mechanisms. In an effort to better understand some of these aspects, in this work, model systems based on different flame-retardant additives in epoxy are chosen to cover various strategies (like intumescent, radical quenching, and endothermic behavior) that are typically employed to reduce the flammability of a coating system. The flame-retardant additives chosen are ammonium polyphosphate, tetrabromobisphenol-A, 9,10-dihydro-9-oxa-10-phosphaphenanthrene oxide, and aluminum trihydroxide. The effects of flame-retardant additives on the curing, thermal decomposition, and flammability of epoxy resin are investigated. Reactive flame-retardant additives, in particular, are found to reduce the enthalpy associated with curing of epoxy by more than 45%. However, as the amount of hardener incorporated in these formulations is not controlled despite the presence of reactive flame-retardant additives, this had a negative effect on the thermal decomposition behavior of the epoxy/flame-retardant formulations, and consequently on the calculated decomposition activation energies. Heating rate seems to be a dominating parameter influencing the flammability of the formulations. Peak heat release rate values, irrespective of the formulation, increased by more than 1382%–1970% by changing the heating rate in a pyrolysis flow combustion calorimeter from 6°C/min to 100°C/min. As the flammable volatiles released per unit time are higher at high heating rates, ignition and subsequent flaming of the coating occurred in the furnace tests, where a cellulosic fire curve was simulated. This has significantly influenced the fire resistance times.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Material-scale flammability characteristics of epoxy-based coating systems

Siow

Dasari

2022

Journal of Fire Sciences

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“…However, the actual char residue obtained in the experiment was 33.4%, indicating that HCS modified by molybdenum compounds facilitated char residue formation and enhanced the thermal resistance of TPU composites under high temperature. 38 Derivative thermogravimetric analysis (DTG)graphs of TPU and its composites were exhibited in Figure 5B, where the peak corresponded to the maximum mass loss rate. Although temperature at which the maximum mass loss rate occurred of all TPU samples was about 420 C (T max ), the maximum mass loss rate of TPU/MOH-4 was only 11.5%/min, which was the lowest among TPU and its composites (27.2%/min for TPU, 18.2%/min for TPU/CAH-4, and 16.2%/ min for TPU/AMH-4 composites).…”

Section: Thermal Stabilitymentioning

confidence: 99%

Fabrication of hollow carbon spheres modified by molybdenum compounds towards toxicity reduction and flame retardancy of thermoplastic polyurethane

Feng

Zhang

Wang

et al. 2021

Polymers for Advanced Techs

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This article mainly studied novel hollow carbon microspheres modified with molybdenum compounds for flame retardancy and toxicity reduction in thermoplastic polyurethane (TPU) elastomer. The structure of hollow carbon spheres (HCS) was investigated by X-ray photoelectron spectroscopy and scanning electron microscopy-energy-dispersive spectrometer, respectively. The specific molybdenum compounds on the surface of HCS were further investigated by X-ray diffraction. The flame retardancy and toxicity reduction of hollow carbon microsphere in TPU composites were studied by cone calorimeter, thermogravimetric analysis, and Fourier transform infrared spectroscopy, and so forth.The result shows that HCS modified by molybdenum compounds (MOH) can reduce fire hazards and toxic release of TPU during combustion. For example, under the same load, the peak heat release rate of TPU/MOH composite decreased by 63.39%, that of TPU composite prepared by modified HCS with ammonium molybdate (TPU/AMH) decreased by 52.89%, and that of TPU composite prepared by introducing acidulated carbonized HCS (TPU/CAH) decreased by 40.73%, compared with that of pure TPU.The peak smoke production rate (pSPR), peak carbon monoxide production (pCOP), and peak carbon dioxide production (pCO 2 P) of TPU/MOH composite decreased by 52.34%, 72.4%, and 68.3%, respectively. Therefore, there is a novel strategy to incorporate modified HCS to TPU, facilitating its widely promising applications in TPU.

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“…In the recent past, many efforts were also diverted towards the further improvement of these compositions. They include the usage of alternate blowing agents like expandable graphite, 4,5 incorporation of nanoparticles (like graphene, clay and carbon nanotubes) to delay the release of volatiles, [6][7][8] and even using filled (with charring agents) natural microtubules to avoid the negative effects of flame retardants on matrix properties. 9 Araby et al 10 have also compared the advantages and disadvantages of the usage of graphene platelets and phosphorous compounds in terms of the resultant mechanical and flame-retardant properties of the matrix.…”

Section: Introductionmentioning

confidence: 99%

Acrylic‐based fire‐retardant coatings for steel protection: Employing the concept of in situ ceramization

Anees

Dasari

2020

J of Applied Polymer Sci

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Traditional intumescent coatings are widely used as passive fire‐protective coatings for steel structures as they are capable of expanding in the range of 20–50 times the original thickness thereby providing excellent insulation. However, the fragile nature of such residue and susceptibility to thermo‐oxidation given their carbonaceous nature are key problematic issues. The concept of in situ ceramization is explored in this work as a means to form inorganic cohesive char with improved rigidity and thermo‐oxidative stability. Coating samples were prepared by incorporating ammonium polyphosphate, talc, Mg(OH)2, and polydimethylsiloxane as additives into acrylic resin at different weight fractions. Thermal analysis and x‐ray diffraction have confirmed the reactions between the additives to form various crystalline magnesium phosphate phases, and to a small extent, silicon phosphate, thereby ensuring the thermo‐oxidative stability of the residue. This is reiterated by the fire performance tests (by exposing the coatings to a temperature profile in a furnace similar to ISO 834 fire curve). Despite the advantages of rigid char and its thermo‐oxidative stability as a result of formation of inorganic phosphates, the lack of swelling has resulted in relatively poor insulation capabilities of the char, and subsequently, compromised the fire protection times (that are in the range of 45–55 min). However, pyrolysis flow combustion calorimeter results of the coatings are promising and have shown a significant drop of up to 70% in the peak of heat release rate values as compared to neat resin.

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Intumescent fire-retardant acrylic coatings: Effects of additive loading ratio and scale of testing

Cited by 26 publications

References 28 publications

Material-scale flammability characteristics of epoxy-based coating systems

Material-scale flammability characteristics of epoxy-based coating systems

Fabrication of hollow carbon spheres modified by molybdenum compounds towards toxicity reduction and flame retardancy of thermoplastic polyurethane

Acrylic‐based fire‐retardant coatings for steel protection: Employing the concept of in situ ceramization

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