Intumescent Fire Retardant Coating Research Articles

Effect of functionalized halloysite nanotubes on fire resistance and water tolerance of intumescent fire-retardant coatings for steel structures

To improve the comprehensive performance of intumescent fire-retardant coatings, the functionalized halloysite nanotubes (HNTs-D, HNTs@Fe3O4, and HNTs-D@Fe3O4) were synthesized as synergistic flame retardants and incorporated into intumescent fire-retardant coatings (IFRC) for steel structures, demonstrating significant flame retardant properties. Among these modified halloysite nanosheets, HNTs-D@Fe3O4 showed the best flame retardancy and water resistance. Adding the optimal addition amount (3 wt%) of HNTs-D@Fe3O4 can increase the residual weight of coating from 28.10 % to 38.40 % and reduce the backside temperature of the coated steel plate from 288 °C to 177 °C, indicating that HNTs-D@Fe3O4 can effectively improve the thermal stability and insulation performances of intumescent fire-retardant coatings. Cone calorimetric analysis showed HNTs-D@Fe3O4 can effectively suppress the heat and smoke release of the intumescent fire-retardant coatings. Compared with the unmodified coating sample, the total heat release (THR) and total smoke release (TSR) of the HNTs-D@Fe3O4-containing coating sample were reduced by 66.04 % and 11.36 %. HNTs-D@Fe3O4 facilitates the formation of dense char layers confirmed by the micro morphology characterization. Further mechanism analysis shows that HNTs-D@Fe3O4 has obvious catalytic carbonization effect and is helpful to construct the dense expanded char layer with higher graphitization degree. The uniformly dispersed HNTs-D@Fe3O4 improved the water resistance of intumescent fire-retardant coatings, which is mainly due to the hydrophobicity and barrier effect, thus effectively preventing the loss of water-soluble components.

Combined kinetic analysis of thermal degradation characteristics and reaction mechanism of thin intumescent fire-retardant coating of steel structure

To determine the thermal kinetic triplets and elucidate the reaction mechanism of thin intumescent fire-retardant coatings (IFR) of steel structures, one efficient combined kinetic approach was implemented in this study. Thermogravimetric experiments were conducted in air atmosphere at four heating rates, and the whole IFR thermal degradation process was divided into two stages. The average activation energy values derived by model-free methods were 78.9 kJ/mol and 175.16 kJ/mol for Stage I (0<α < 0.2) and Stage II (0.2<α < 0.9), respectively. Furthermore, the linear Coats-Redfern (CR) and non-linear Masterplots models were applied to identify the possible reaction mechanism. It was found that the F3/2 mechanistic model was better suited to the main thermal degradation process. Then model reconstruction based on the F3/2 mechanism model was performed. The results showed that the reconstructed model had a strict linear relationship in the independence analysis and KCE analysis, along with a good agreement between the theoretical and experimental results. The current study provided new insights into the systematic thermal degradation mechanism of IFR, and the proposed kinetic model would be helpful for the thermal protection prediction for steel structure during fire.

Waterborne Intumescent Fire-Retardant Polymer Composite Coatings: A Review.

Intumescent fire-retardant coatings, which feature thinner layers and good decorative effects while significantly reducing heat transfer and air dispersion capabilities, are highly attractive for fire safety applications due to their effective prevention of material combustion and protection of materials. Particularly, the worldwide demand for improved environmental protection requirements has given rise to the production of waterborne intumescent fire-retardant polymer composite coatings, which are comparable to or provide more advantages than solvent-based intumescent fire-retardant polymer composite coatings in terms of low cost, reduced odor, and minimal environmental and health hazards. However, there is still a lack of a comprehensive and in-depth overview of waterborne intumescent fire-retardant polymer composite coatings. This review aims to systematically and comprehensively discuss the composition, the flame retardant and heat insulation mechanisms, and the practical applications of waterborne intumescent fire-retardant polymer composite coatings. Finally, some key challenges associated with waterborne intumescent fire-retardant polymer composite coatings are highlighted, following which future perspectives and opportunities are proposed.

Effect of Organic–Inorganic Mixed Intumescent Flame Retardants on Fire-Retardant Coatings

Expandable graphite (EG) was modified with a charring agent and organic–inorganic hybridized intumescent flame retardants (MEG) were synthesized. This study uses a cone calorimeter (CCT) and a DaqPRO 5300 radiation heat flow meter (Fourtec, Tel Aviv, Israel) to evaluate the fire-resistant properties influenced by MEG on intumescent fire-retardant coatings. The impact of MEG on the thermal degradation of these coatings was investigated through the use of thermogravimetric analysis (TGA). The results obtained by CCT demonstrated that the incorporation of MEG markedly diminished the heat release rate and total heat release rate of the coating, in addition to enhancing the char residue compared to coatings with only expandable graphite (EG). Furthermore, TGA results demonstrate that adding MEG increases the weight of the char residue at elevated temperatures, suggesting improved thermal stability. Based on these findings, MEG exhibits a synergistic flame-retardant effect when combined with intumescent fire-retardant (IFR) systems. This synergy not only improves the flame-retardant properties of the coatings but also enhances their overall thermal stability, making MEG a promising additive for developing more efficient fire-retardant materials. Thus, MEG-modified coatings offer superior protection against fire hazards, highlighting their potential for practical applications in fire safety.

Smoke Suppression Properties of Fe2O3 on Intumescent Fire-Retardant Coatings of Styrene–Acrylic Emulsion

The intumescent flame-retardant coatings were prepared using ammonium polyphosphate (APP), pentaerythritol (PER), melamine (MEL), styrene–acrylic emulsion, and iron oxide yellow (FeOOH) as the base material. A cone calorimeter (CCT), smoke density meter (SDA), and scanning electron microscope (SEM) were employed to investigate the smoke suppression and flame retardancy of FeOOH in intumescent fire-retardant coatings. The thermal degradation performance of intumescent fireproofing coatings with varying FeOOH content was investigated through thermogravimetric analysis (TGA). The structure of the carbon slag in the CCT test was analyzed using a scanning electron microscope (SEM). The results of the cone calorimeter (CCT) experiments demonstrated that FeOOH significantly reduced the heat release rate (HRR), total heat release rate (THR), smoke production rate (SPR), and total smoke release rate (TSR) of the coating, while simultaneously increasing the carbon residue rate of the coating. The smoke density analysis (SDA) results demonstrate that adding FeOOH can effectively reduce smoke generation, regardless of whether a pilot flame is used. TGA results demonstrate that FeOOH can enhance the weight of coke residue at elevated temperatures. SEM results indicate that incorporating FeOOH resulted in a more compact coke residue. According to these findings, among all the samples, those containing 2 wt% FeOOH showed low levels of HRR, THR, SPR, and TSR and high levels of SOD, which proves that FeOOH can be used as a smoke inhibitor in flame-retardant coatings.

Synthesis of antioxidant functionalized nano-TiO2 for improving fire resistance and UV-shielding behavior of intumescent fire-retardant coatings for cable

A unique hybridized antioxidant named TiO2-KH550-PA, of which silane modified nano-TiO2 particles were grafted with 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid by acylation reaction, was applied to intumescent fire-retardant coatings for cable. Through fire protection test, contact angle test, thermogravimetric test and UV-ageing test, the effects of TiO2-KH550-PA on hydrophobicity, flame retardancy, smoke suppression, anti-ageing and charring performance for coatings were evaluated. The obtained results indicate that the TiO2-KH550-PA can enhance the hydrophobicity of the coating, thereby reducing the adhesion of dust on the coating surface. Additionally, TiO2-KH550-PA has a greatly promoting role in strengthening the fire protection abilities of the coating, but an appropriate amount is the key. Compared to coatings without composite, the intumescent fire-resistant coating for cable containing 1 wt% TiO2-KH550-PA (IFRCC2) exhibits excellent fire protection performance, including a prolongation by 2.6 times in failure time, an increase by 1.7 times in char layer height, and an increase by 0.4 times in light transmittance for smoke density test. Furthermore, the presence of TiO2-KH550-PA can also strengthen the oxidation resistance, charring ability and char layer stability of the coating, when the remaining mass of IFRCC2 increases to 49.0 % at 800 °C. The anti-ageing performance test demonstrates that the TiO2-KH550-PA can absorb ultraviolet light, eliminate free radicals, and raise the structural stability of the coating, thus reinforcing the durability of the fire resistance for the coating.

Synergistic effect of phytic acid and eggshell bio-fillers on the dual-phase fire-retardancy of intumescent coatings applied on cellulosic substrates

Cellulosic substrates, including wood and thatch, have become icons for sustainable architecture and construction, however, they suffer from high flammability because of their inherent cellulosic composition. Current control measures for such hazards include applying intumescent fire-retardant (IFR) coatings that swell and form a char layer upon ignition, protecting the underlying substrate from burning. Typically, conventional IFR coatings are opaque and are made of halogenated compounds that release toxic fumes when ignited, compromising the roofing's aesthetic value and sustainability. In this work, phytic acid, a naturally occurring phosphorus source extracted from rice bran, was used to synthesize phytic acid-based fire-retardants (PFR) via esterification under reflux, along with powdered chicken eggshells (CES) as calcium carbonate (CaCO3) bio-filler. These components were incorporated into melamine formaldehyde resin to produce the transparent IFR coating. It was revealed that the developed IFR coatings achieved the highest fire protection rating based on UL94 flammability standards compared to the control. The coatings also yielded increased LOI values, indicative of self-extinguishing properties. A 17 °C elevation of the IFR coating's melting temperature and a significant ∼172% increase in enthalpy change from the control were observed, indicating enhanced fire-retardancy. The thermal stability of the coatings was improved, denoted by reduced mass losses, and increased residual masses after thermal degradation. As validated by microscopy and spectroscopy, the abundance of phosphorus and carbon groups in the coatings' condensed phase after combustion indicates enhanced char formation. In the gas phase, TG-FTIR showed the evolution of non-flammable CO2, and fire-retardant PO and P–O–C. Mechanical property testing confirmed no reduction in the adhesion strength of the IFR coating. With these results, the developed IFR coating exhibited enhanced fire-retardancy whilst remaining optically transparent, suggestive of a dual-phase IFR protective mechanism involving the release of gaseous combustion diluents and the formation of a thermally insulating char layer.

Thermo‐mechanical performance of wolframite mineral reinforced siloxane‐modified epoxy‐based intumescent coating for structural steel

AbstractThis study investigated the effects of wolframite on the fire resistance and adhesion strength of intumescent fire‐retardant coating (IFRC) using a siloxane‐modified epoxy binder. The modification of bisphenol A epoxy was confirmed via Hydrogen‐Nuclear Magnetic Resonance Analysis. The IFRC samples were developed with wolframite (0.25–2.0 wt%) and evaluated for Thermogravimetric analysis (TGA), fire resistance test, furnace fire test for char expansion, morphology and chemical composition, adhesion test and water immersion test. This study identified a coating formulation containing 2.0 wt% of wolframite that showed 57.2% improvement in the residual weight, substrate temperature of 176.7°C and produced a compact char. Field Emission Scanning Electron Microscopy showed that the addition of wolframite reduced pore size thereby increasing the char strength. X‐ray diffraction identified iron neodymium compounds in the char layers, which lowered the pore size resulting in lower substrate temperature. X‐ray photoelectron spectroscopy indicated that the antioxidant capability and the carbon content were increased by 6.9% and 50.3% respectively. The adhesion strength was reduced, however, was within the industrial standards of 2.07 MPa. The water immersion test showed a maximum 66.7% reduction (WF2.0) in the water permeation through the coating.

Research and manufacture water-based fire retardant coating mixture using graphene additive for natural wood

Intumescent fire-retardant coatings, especially water-based intumescent fire-retardant coatings, are increasingly attracting attention due to their environmentally friendly properties. In this work, we have successfully manufactured a water-based fire retardant coating mixture using graphene additive for natural wood with three main ingredients (ammonium polyphosphate acidifying agent, pentaerythritol carbonizing agent, melamine blowing agent), and some additives including graphene. We investigated the influence of graphene content on the fire retardant effectiveness of the mixture when coated on natural wood (pine wood) according to UL94-V standard. Test results show that the content of graphene contributes to enhancing the fire retardant effectiveness of the manufactured mixture. SEM imaging method was used to analyze and explain the test results. Some specifications of the manufactured mixture are also analyzed and evaluated. The findings of this research provide a solution to enhance fire resistance for natural wood structures using environmentally friendly materials.

Is titania acting as a synergist in intumescent fire retardant coatings designed for improving reaction to fire of wood?

Intumescent coatings based on ammonium polyphosphate (APP), are widely applied as passive fire protection. For flammable materials like wood, a rapid char expansion is needed to limit fuel gas release to the combustion zone and minimize reaction to fire. It is generally accepted that titanium dioxide (TiO2) improves the fire performance of coatings and acts as a synergist. This study discusses the role of TiO2 in intumescent coatings by investigation of real-time measurement of char expansion during heating, rheology, thermal analysis, cone calorimetry, and chemical composition by X-ray diffraction and IR spectroscopy under different TiO2 loadings. Results show that TiO2 enhance the rate of char expansion despite increased complex viscosity of the molten coating matrix. Further, thermal decomposition and onset of intumescent reactions remained unchanged by increased TiO2 loading which results in a lower final char height. Altogether, TiO2 acts as an incombustible filler reducing char expansion and not fulfilling the definition of a synergist in intumescent coatings for improving reaction to fire of wooden products.

Pyrolysis characteristics and reaction mechanism of intumescent fire-retardant coating with thermogravimetry/Fourier transform infrared analysis

A research of intumescent fire-retardant coating (IFRC) pyrolysis characteristics and reaction mechanism was conducted by thermogravimetric analysis coupled with Fourier transform infrared spectrometry analysis at various heating rates. The results demonstrate that the pyrolysis process of IFRC could be separated into two stages. In stage I, which occurs within the temperature range of 300–800 K, there is a mass loss of 8.5 %. The main gases released during this stage are NH3 and CH4. Moving on to stage II, which takes place within the temperature range of 800–1200 K, there is a significant mass loss of 42.9 %. The main gases released during this stage are CO2 and H2O. Through the use of FTIR spectra, the production amount of main four components ranked as follows: CO2 > H2O > CH4 > NH3. Especially, the reaction expressions were further speculated and proposed. Subsequently, the two aforementioned stages were utilized based on both model-free and model-fitting methods to ascertain the possible reaction mechanism.

Influence of nanoclay on the fire resistance properties of epoxy-based intumescent retardant coatings for steel plate

The intumescent retardant coating was fabricated by a combination of epoxy binder and flame-retardant ingredients for the steel plate. This paper investigates the influence of nanoclay content on improving fire properties of intumescent fire-retardant coatings. The fire performances of the coatings were determined by a fire test at 950oC for one hour. The coating degradation was characterized by Thermal gravimetric analysis (TGA). The morphology, composition of char was studied by Fourier transform infrared spectra (FTIR), scanning electron microscopy (SEM), and energy dispersive X-ray spectra (EDS). The results revealed that the intumescent coating containing 3 wt.% of nanoclay showed the best reduction in substrate temperature compared to the intumescent coating without nanoclay. The results also concluded that nanoclay increased fire protective performances of the intumescent coating.

Influence of Wind Speeds and Heating Exposures on the Thermal Insulation of Intumescent Fire-Retardant Coatings

Influence of Wind Speeds and Heating Exposures on the Thermal Insulation of Intumescent Fire-Retardant Coatings

Fabrication of Intumescent Fire-Retardant Coating for Structural Applications

Applicability of materials limited by the effect of flammability in case of any sudden incident. Worldwide protection of any structure from the fire is covered through intumescent fire resistant coatings since many past years. Purpose of this study is to prepare and to fabricate several intumescent fire retardant coatings (IFRC) using different proportions of materials per unit weight. Also to find most optimistic formulations and analyse the performance of intumescent fire retardant coatings (IFRC). On the basis of background studies 5 different materials were considered to prepare several formulations i-e Titanium dioxide (TiO2), Ammonium polyphosphate (APP), Zinc borate, Epoxy hardener, Kaolinite (Clay), Melamine (MEL) and Expandable Graphite (EG). IFRC formulations were applied on Mild Steel plates after its preparation Each formulation was subjected to a temperature of 700°C for a period of five minutes. The results revealed that the coatings, Out of 5 formulations of IFRC, IFRC-4 exhibited promising performance. It demonstrated excellent stability and adhesion at the elevated temperature, lasting for over five minutes. Additionally, its coating expanded up to four times the initial thickness. Heat Transfer rate was completely reduced.

Dual curing agents for optimized flame-retardancy and physico-mechanical properties of cycloaliphatic epoxy coating

Higher durability with excellent insulation properties is to be considered an important factor for the formulation of intumescent fire-retardant coating (IFR) against the external environment. In this work, two structurally different hardeners such as cycloaliphatic amine and polyamido amine were used for curing hydrogenated bisphenol-A epoxy resin (DGEHBA) to develop intumescent fire-retardant (IFR) coating for exterior applications. Initially, a differential scanning calorimetry study was carried out to estimate the curing kinetics of DGEHBA resin and the hardeners. The IFR coating was prepared by mixing fire-retardant fillers such as ammonium polyphosphate, pentaerythritol and melamine along with TiO2 pigment in DGEHBA resin. The prepared DGEHBA coating was mixed with two different hardeners individually and their combinations in different weight ratios to make a series of epoxy IFR coatings. The impact of curing on the protection ability and integrity of these coatings was evaluated by analyzing their thermal, fire retardance and physico-mechanical virtues. Furthermore, the coatings were also studied for accelerated aging in humidity, weatherometer, seawater immersion and salt spray chamber to deduce the sustainability of the coatings. We have demonstrated enhancement in both, physico-mechanical and fire-retardant properties by using the above prepared coating compositions.

Brand identification of transparent intumescent fire retardant coatings using portable Raman spectroscopy and machine learning

Transparent intumescent fire retardant coatings (IFRC) are widely used to protect ancient buildings and high-end furniture from fire. Currently, IFRC fraud has attracted considerable attention due to the lack of efficient techniques to detect the identity of IFRC products. In this paper, we use Raman spectroscopy and machine learning to identify IFRC brands. A total of 135 transparent IFRC samples of 6 common brands were prepared and scanned using a portable Raman spectrometer. The obtained spectra were pre-processed to remove unwanted variation and classified using partial least squares discriminant analysis (PLS-DA) and kernel extreme learning machine (K-ELM). The accuracies achieved by PLS-DA and K-ELM were 0.978 and 0.993, respectively. In addition, important variables were determined based on the regression coefficients of PLS-DA. The results demonstrate that portable Raman spectroscopy combined with machine learning is a viable approach for rapid, on-situ and low-cost identification of IFRC brands.

Fabrication of Polypyrrole-Decorated Tungsten Tailing Particles for Reinforcing Flame Retardancy and Ageing Resistance of Intumescent Fire-Resistant Coatings.

Polypyrrole-decorated tungsten tailing particles (PPY-TTF) were prepared via the in situ polymerization of pyrrole in the presence of tungsten tailing particles (TTF), and then carefully characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and thermogravimetric analysis (TG) analyses. The effect of PPY-TTF on the flame retardancy, smoke suppression property and ageing resistance of intumescent fire-resistant coatings was investigated by a fire protection test, smoke density test and cone calorimeter test. The results show that PPY-TTF exerts excellent cooperative effect on enhancing the flame retardancy and smoke suppression properties of the intumescent fire-retardant coatings, which is ascribed to the formation of more cross-linking structures in the condense phase that enhance the compactness and thermal stability of intumescent char. The cooperative effect of PPY-TTF in the coatings depends on its content, and the coating containing 3 wt% PPY-TTF exhibits the best cooperative effect among the samples, showing a 10.7% reduction in mass loss and 35.4% reduction in flame-spread rating compared to that with 3% TTF. The accelerated ageing test shows that the presence of PPY-TTF greatly slows down the blistering and powdering phenomenon of the coatings, thus endowing the coating with the super durability of fire resistance and smoke suppression property. This work provides a new strategy for the resource utilization of tungsten tailing in the field of flame-retardant materials.

Synthesis and properties of a fire-retardant coating based on intercalated expandable graphite-modified cellulose for steel structures

In order to improve the performance of intumescent fire-retardant coatings for steel structures and to reduce the defects of the insulating carbon layer (Expanded carbon of fire retardant coatings after thermal degradation.), which usually undergoes cracking and falls off during combustion, we designed a new multifunctional intercalated expandable graphite-hydroxypropyl methylcellulose-uracil ketone (EG-HPMC-UPY) system by ultrasonication. Infrared analysis showed that the 2-ureido-4[1H]-pyrimidinone (UPY) groups were evenly distributed in the coatings to form a large number of reversible covalent and non-covalent bonds; this induced self-healing characteristics in the fire-retardant coatings. Scanning electron microscopy showed that EG expanded into worm-like shapes and intercalated with cellulose in the expanded carbonaceous layer, thus making it more compact and denser. The thermogravimetric analysis and cone calorimetry analysis showed that the weight loss rate and heat release rate of the fire retardant coating added EG-HPMC-UPY decreased by 13% and 65. During fire-resistance tests, it was observed that the temperature of the back and front of the steel plate coated with the fire-retardant coating containing intercalated EG-HPMC-UPY stabilized at 85 and 400 °C, respectively, which values are far lesser than the critical temperature of static equilibrium stability of structural steel (550 °C). Furthermore, the carbon layer formed during combustion did not fall off or crack, thus indicating the excellent flame retardancy potential of the developed coating. Finally, this study describes a new and effective way to improve the fire performance of intumescent fire-retardant coatings for steel structures.

Effect of titania, barite, and kaolinite fillers on char layer formation in water-based intumescent fire-retardant coatings

Effect of titania, barite, and kaolinite fillers on char layer formation in water-based intumescent fire-retardant coatings

Comparative Study of Fire Resistance and Char Formation of Intumescent Fire-Retardant Coatings Reinforced with Three Types of Shell Bio-Fillers.

Three types of shell bio-fillers, including eggshell (CES), conch shell (CHS) and clamshell (CMS), were prepared by cleaning, ultrasonication and pulverizing processes of biowastes, and then applied to intumescent fire-retardant coatings. The effects of shell bio-fillers with different polymorphs on the fire resistance and char-forming of intumescent fire-retardant coatings were investigated by cone calorimeter test, fire protection tests, smoke density test, thermogravimetric analysis (TG), and the fire resistance and char-forming mechanism of bio-fillers in intumescent fire-retardant coatings were proposed. The results show that three kinds of bio-fillers exert an excellent synergistic effect on enhancing the fire resistance and char-forming properties of the intumescent fire-retardant coatings, while clamshell has the best synergistic efficiency among the bio-fillers. Especially, IFRC-CMS coating containing 3 wt% clamshell shows the best fire protection performance and lowest smoke production and heat release, which offers an equilibrium backside temperature of 134.6 °C at 900 s, a flame-spread rating of 14.4, and a smoke density rating value of 22.8%. The synergistic efficiency of bio-fillers in the intumescent coatings depends on the polymorphs of CaCO3 in bio-fillers, and aragonite CaCO3 shows a higher synergistic efficiency compared to calcite CaCO3 and the mixture of aragonite and calcite CaCO3. The CMS composed of aragonite shows the best synergistic effect, CHS composed of aragonite and calcite comes second, and CES composed of calcite has the weakest synergistic effect.