Fire Protection Test Research Articles

Effects of silica aerogel particles on performance of the coatings for new energy vehicle battery packs

In order to reach the fire protection standard for new energy vehicle battery packs, the incorporation of SiO2 aerogel particles as a functional filler in the nitrogen and phosphorus fire-retardant system is necessary due to the inadequate mechanical properties. The effects of SiO2 aerogel on the properties of the coatings for the electric car battery pack were investigated by fire protection test, thermogravimetric analysis, limited oxygen index, UL-94 vertical test, combustion test, mechanical properties test, and weathering resistance test. The backside temperature fireproof coatings containing 1.5% SiO2 aerogel was effectively reduced to 250.2 ± 0.1 °C and the residual weight of the coating reached 32.61 ± 0.01%. The composition and structure of the carbon layer were analyzed further. Especially, the weight loss percentage of the fireproof coating is only 5.87 ± 0.02% in the water resistance test. However, excessive SiO2 aerogel decreased the performances of fireproof 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.

Effect of graphene on properties of acrylic emulsion intumescent fire retardant coating

Nowadays, intumescent paint is one of the most popular fireproof paint products and is widely used in buildings. They can be applied to steel, wood, concrete, etc. This study aimed to enhance the properties of intumescent coating by graphene addition. The effect of graphene (GR) content on fire resistance, thermal and mechanical properties of water-based intumescent coatings were studied. Intumescent coating formulations include acrylic emulsion binder (R4152), flame retardant additives (Ammonium polyphosphate (APP) - acid source, pentaerythritol (PER) - carbon source, melamine (MEL) - foaming source), fire retardant fillers (TiO2, Al(OH)3) were prepared by mixing different graphene content (0.5, 1, 1.5 and 2 wt.% GR). The investigated coating properties were examined by fire protection test, furnace test, static water immersion test, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and mechanical properties (adhesion, pendulum hardness). The results showed that the GR could effectively enhance the fire resistance performance (from 13.6 % to 23.4 %), thermal stability (from 2.9 % to 5.2 %), water resistance (from 5.0 % to 11.9 %), and mechanical properties (from 5 % to 12 %) of the coating.

Effects of biomaterial on the properties of waterborne intumescent fireproof coatings

AbstractSilk fibroin was used to enhance the properties of the fireproof coating, ensuring the safe evacuation of occupants in a fire accident. The effects of biomaterial on the properties of the coatings were investigated by fire protection test, thermogravimetric analysis, limited oxygen index, vertical flame test, water resistance test, and mechanical properties test. The carbon layers were characterized after the fire protection test by scanning electron microscopy, energy dispersive spectroscopy, X‐ray diffraction, and Fourier transform infrared spectroscopy to analyze the microstructure and chemical composition. The results show that the coating with 6% SF demonstrated the best fire protection, thermal stability, and water resistance. The temperature on the backside is only 255.9°C, and the residual weight is 37.52%. However, the coating with 4% SF exhibits good mechanical properties.

Facile strategy of preparing excellently thermal-insulating and fire-safe building materials based on an aromatic Schiff base dicarboxylic acid without additional flame retardants

Developing excellently fire-safe and thermal-insulating building materials is a critical subject in the building sector. In this work, a novel aromatic Schiff base dicarboxylic acid (FN) was synthesized through a facile strategy to prepare high-performance rigid polyurethane foam (RPUF) composites with excellent thermal insulation and fire safety performance. The uniform dispersion of FN in polyether polyol improved the cellular structure of RPUF composites, which was conducive to increasing the thermal insulation of RPUF composites. Therefore, incorporating only 10 wt% FN into RPUF composite (RPUF/10FN) possessed the lowest wall temperature (51.9 °C) and room temperature (38.8 °C) with the lowest temperature growth rate under the continuous thermal radiation of the heat source among all samples in the small chamber test. Moreover, FN remarkably reduced the peak heat release rate, peak smoke production rate, and peak CO production rate of RPUF/10FN by 41.9%, 58.0%, and 59.6% without additional flame retardants, respectively, compared with those of pure RPUF. In addition, FN endowed RPUF/FN composites with better fire resistance and structural integrity compared with pure RPUF in the building facade fire test and fire protection test. The increased fire safety of RPUF/FN composites is due to the barrier effect of the formation of a dense and continuous char layer and the dilution effect of nonflammable gas generated by the thermal degradation of FN. Furthermore, FN enhanced the water contact angle of RPUF/FN composites from 112.2° for pure RPUF to 120.8° for RPUF/10FN, indicating that FN also enhanced the hydrophobicity of RPUF/FN composites. Therefore, the as-designed RPUF composites containing FN possessed a broad application prospect in the building field.

Effects of bagasse fiber as the renewable environmentally friendly material on the properties of the waterborne intumescent fireproof coating

AbstractIn order to recycle the waste, the wasted bagasse was applied as fire‐retardant filler to prepare the waterborne intumescent fireproof coating. The effects of bagasse on the properties of the fireproof coating were investigated by fire protection test, thermogravimetric analysis, smoke suppression test, scanning electron microscope, energy dispersive spectrometer, X‐ray diffraction, Fourier transform infrared spectroscopy, water resistance test and mechanical properties test. The result demonstrated the coating with 1.5% bagasse performed best in the fire protection, thermal stability, and smoke suppression test. Moreover, the char layer of the sample after the fire protection was dense and continuous. However, the fireproof coating contained 2% bagasse had excellent performance in water resistance test and mechanical properties test due to the properties of fiber. Furthermore, the components and chemical structure of char layers were characterized to study the flame retardant mechanism of bagasse in the fireproof coating.

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.

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.

Fire Resistance, Thermal and Anti-Ageing Properties of Transparent Fire-Retardant Coatings Modified with Different Molecular Weights of Polyethylene Glycol Borate.

Four kinds of polyethylene glycol borate (PEG-BA) with different molecular weights were grafted into cyclic phosphate ester (PEA) to obtain flexible phosphate esters (PPBs), and then applied in amino resin to obtain a series of transparent intumescent fire-retardant coatings. The comprehensive properties of the transparent coatings containing different molecular weights of PEG-BA were investigated by various analytical instruments. The transparency and mechanical analyses indicate that the presence of PEG-BA slightly decreases the optical transparency of the coatings but improves the flexibility and adhesion classification of the coatings. The results from fire protection and cone calorimeter tests show that low molecular weight of PEG-BA exerts a positive flame-retarded effect in the coatings, while high molecular weight of PEG800-BA behaves against flame-retarded effect. Thermogravimetric and char residue analyses show that the incorporation of low molecular weight of PEG-BA clearly increases the thermal stability and residual weight of the coatings and generates a more compact and stable intumescent char on the surface of the coatings, thus resulting in superior synergistic flame-retarded effect. In particular, MPPB1 coating containing PEG200-BA exerts the best flame-retarded effect and highest residual weight of 36.3% at 700 °C, which has 57.6% reduction in flame spread rate and 23.9% reduction in total heat release compared to those of MPPB0 without PEG-BA. Accelerated ageing test shows that low molecular weight of PEG-BA promotes to enhance the durability of structural stability and fire resistance of the coatings, while PEG800-BA with high molecular weight weakens the ageing resistance. In summary, the fire-resistant and anti-ageing efficiencies of PEG-BA in the coatings depend on its molecular weight, which present the order of PEG200-BA > PEG400-BA > PEG600-BA > PEG800-BA.

Comparative Study of Fire Resistance and Anti-Ageing Properties of Intumescent Fire-Retardant Coatings Reinforced with Conch Shell Bio-Filler.

Conch shell bio-filler (CSBF) was prepared by washing, ultrasonicating, and pulverizing of conch shells and then was applied in waterborne intumescent fire-retardant coatings. The influence of CSBF on fire resistance and anti-ageing properties of intumescent fire-retardant coatings were studied by using different analytical methods. The fire protection and smoke density tests showed that when the mass fraction of CSBF was 3%, the resulting FRC3 coating had the optimum synergistic flame-retardant and smoke-suppression effects concomitant with a flame-spread rating of 10.7, equilibrium backside temperature of 152.4 °C at 900 s, and smoke-density rating value of 10.4%, which were attributed to the establishment of a more dense and stable intumescent char layer against heat and mass transfer. Thermogravimetric analysis indicated that the presence of CSBF increased the thermal stability and char-forming performance of the coatings, and the char residue of FRC3 rose to 34.6% at 800 °C from 28.6% of FRC0 without CSBF. The accelerated ageing test suggested that the incorporation of CSBF reduced the migration and decomposition of the flame retardants and the yellowing, blistering, and powdering phenomenon, thus improving the structural stability of the coating, resulting in better durability of flame retardancy and smoke-suppression performance.

Influence of carbon nanoparticle geometry on the fire resistance and anti‐aging properties of intumescent fire‐retardant coatings

SummaryThree types of carbon nanoparticles, namely layered graphene (GN), tubular carbon nanotubes (CNTs), and spherical carbon black (CB), were applied in the intumescent fire‐retardant coatings. The influence of carbon nanoparticle geometry on the fire‐resistant and anti‐aging properties of the intumescent coatings was investigated. The fire protection and smoke density tests show that both spherical CB and tubular CNTs can effectively improve the fire resistance and smoke suppression properties of the coatings, which is attributed to the fact that the addition of either CB or CNTs can promote the swelling process of coating and produce a positive effect on improving the compactness and thickness of char residues. Especially, the coating containing 0.1 wt% CB acquires the lowest flame spread rating (FSR) value of 6.5, smoke density rating (SDR) value of 17.6%, and equilibrium backside temperature of 169.2°C at 900 seconds, showing superior fire resistance and smoke suppression performance. However, the layered GN shows a negative effect on the fire resistance and smoke suppression properties of the coating, which is ascribed to the fact that GN platelets inhibit the intumescent process of coating, resulting in the decrease of barrier effect. The results of accelerated aging test show that the incorporation of either CNTs or CB can weaken the blistering and powdering phenomenon, thus imparting superior durability of integrity and fire resistance to the intumescent coatings.

Enhanced residue stability and strength of epoxy-based coating for fire protection via ceramifiable strategy

A combination of talc and ammonium polyphosphate (APP) was used to fabricate the novel epoxy-based fire resistive coatings via ceramifiable strategy designed for steel substrates. The effects of individual and various combinations of fillers on the fire protection, dimensional stability and strength of coating residues fired at high temperatures were evaluated. The optimized formulation (ETA4) exhibited much lower heat release rate, total heat release and smoke production rate, indicating good flame retardance feature. The results of fire protection test indicated that the backside temperature of steel substrate with ETA4 coating decreased significantly (below 200 °C). After firing at 1000 °C, creamic-like foam residue was formed and it showed excellent dimensional stability and good mechanical strength. Furthermore, the possible fire resistive mechanisms of coatings at high temperatures were also proposed by performing different measurements. The decomposition products of APP-cohered talc were obtained at high temperatures, accompanied by the gradual disappearance of talc phase and generation of crystallization reaction. Finally, a ceramic-like residue was formed, leading to enhanced stability of coating residues.

Synergistic effect of clam shell bio-filler on the fire-resistance and char formation of intumescent fire-retardant coatings

Clamshell (CS) bio-filler derived from clam shells was produced and then applied as a synergist in waterborne intumescent fire-retardant coatings. Fire protection and smoke density tests show that the combination of CS bio-filler and intumescent flame retardant (IFR) exhibits excellent synergistic effect on reducing the flame spread index (FSR), char index, weight loss, equilibrium backside temperature and smoke density rating (SDR) of the intumescent coatings. Especially, the FC-3 sample containing 52 wt% IFR and 3 wt% CS bio-filler exhibits the lowest FSR and SDR values, which are 68.3% and 37.3%, respectively, lower than those of FC-0 sample with 55 wt% IFR. The results from the accelerated ageing test show that the combination of IFR and CS imparts super durability of smoke suppression and flame-retardant properties to the intumescent coatings, exhibiting excellent anti-ageing properties. Char residue analysis demonstrates that the FC-3 sample containing 3 wt% CS bio-filler shows higher mass ratios of O/C, N/C and P/C than those of FC-0 without CS bio-filler, indicating more P, N and O-containing cross-linking structures remained in the FC-3 char, thus imparting high char-forming ability and thermal stability to the coatings, as supported by the results of thermogravimetric (TG) analysis and Fourier transform infrared spectroscopy (FTIR) analysis.

Influence of graphene on fire protection of intumescent fire retardant coating for steel structure

Graphene (GR) was used as filler to improve the performance of fire resistance, thermal stability, smoke suppression of waterborne intumescent fire-retardant coating. The influence of graphene (GR) on the properties of the intumescent fire-retardant coating was studied by fire protection test, TGA, SEM and smoke density test. The results showed that the GR can effectively enhanced the performance of fire resistance and thermal stability of the coating. The result of SEM test indicated the coating with GR had excellent intumescent effect and enhanced foam structure. The smoke density test of the coating demonstrated the coating contain GR had excellent performance of smoke suppression.

Effect of Perlite on Fire Protection of Waterborne Coatings for Steel Structure

In this paper, perlite was used as a kind of modifier to prepare waterborne fire resistive coatings for steel structure. The influence of perlite on the properties of the fire resistive coatings was investigated with the help of thermogravimetric analysis (TGA), micro-scale combustion calorimetry (MCC) and fire protection test. The TGA results showed that the char residue weight of the coatings was increased when perlite was loaded and the anti-oxidation performance was enhanced as well and MCC data indicated the addition of perlite reduced the peak heat release rate and total heat release. After the fire protection test, the results confirmed that the fire resistant time of the coating coated with 5 wt% perlite increased up to 114.4 min when the temperature of the sample boards’ backside reached 500?C.

Effects of carbon materials on fire protection and smoke suppression of waterborne intumescent coating

The new carbon materials bring significant progress in fire resistance coating and technology, especially carbon nano materials. Aiming to improve the fire resistance, expanded graphite (EG), carbon nanotubes (CNTs), fullerene (C60), graphene (Gr) were applied as filler in the waterborne intumescent coatings to investigate fire resistance, thermal stability, smoke suppression and water resistance. The effects of carbon materials on fire protection and smoke suppression of waterborne intumescent coating were investigated in detail by fire retardant test, thermogravimetry (TG), differential scanning calorimeter (DSC), smoke density test and water resistance test. The carbon layers were characterized by scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and particle size distribution. The results of fire protection test and SEM indicated that the fire resistance of coatings was enhanced by adding 1% content of carbon materials. TGA analysis showed that carbon materials could increase the residual weight and thermal stability of the coatings. After immersed in water for 360 h, the results of water resistance test, the carbon materials could form barrier to improve the water resistance of the coatings. Especially, the graphene exhibited the best performance among all the carbon materials.

Comparative study of the fire protection performance and thermal stability of intumescent fire‐retardant coatings filled with three types of clay nano‐fillers

SummaryThe fire protection and thermal stability properties of intumescent fire‐retardant coatings filled with three various clay nano‐fillers (layer double hydroxide [LDH], montmorillonite [MMT], and sepiolite) were compared by fire protection tests and thermo‐gravimetric analysis. The fire protection tests show that the incorporation of three fillers improves the fire protection properties of the intumescent fire‐retardant coatings and the addition of 1 wt% sepiolite exhibits the lowest flame spread rating of 9.9 and equilibrium backside temperature of 164.5°C at 900 seconds. TG analysis shows that the incorporation of nano‐fillers imparts a considerable enhancement of thermal stability and char formation to the intumescent coatings. Especially, the coating with 1 wt% sepiolite acquires the highest residual weight of 34.2% among the samples. Char residue analysis presents that the introduction of clay nano‐fillers plays a positive role in enhancing the compactness and anti‐oxidation ability of the char residues, and this positive effect as well as the flame‐retardant efficiency depends on the types of clay nano‐fillers. The three types of layered clay nano‐fillers exhibit synergistic flame‐retardant effectiveness in the order of sepiolite > MMT > LDH.

Study on thermal stability of typical carbon fiber epoxy composites after airworthiness fire protection test

SummaryThe thermal stability of the T700 carbon fiber epoxy composites, which had been tested under different conditions (nonvibration plus nonscrubbing airflow, vibration, scrubbing airflow, and vibration plus scrubbing airflow), were investigated according to the obtained weight loss behavior, integral program decomposition temperature (IPDF), and activation energies (E) by using thermogravietry‐differential thermal analyzer. The results indicate that the weight loss ratio, IPDF, and E of T700 carbon fiber epoxy and its residues in the third and fourth layers are similar under the nonvibration plus nonscrubbing airflow and vibration, and the thermal stability under the vibration condition is slightly stronger. In addition, the weight loss ratio, IPDF, and E of the epoxy and its residues in materials are also similar under scrubbing airflow and vibration plus scrubbing airflow, and the thermal stability under vibration plus scrubbing airflow is better. However, it is significantly less than the thermal stability of materials under nonvibration plus nonscrubbing airflow and vibration. Therefore, it can be found that the vibration exacerbates the flame severity and the scrubbing airflow has a significant cooling effect on the material during the airworthiness fire protection test, which have guiding significance on the airworthiness fire prevention items formulation of carbon fiber composite.

An investigation on thermal performance of wollastonite and bentonite reinforced intumescent fire-retardant coating for steel structures

This research investigates the synthesis of new formulations of intumescent coating with improved thermal performance for steel structures. The coating formulations were based on the expandable graphite reinforced with wollastonite and bentonite. Ten samples of five formulations were synthesized by varying grinding time duration between 1 and 2 min. To analyse the substrate temperature of coated steel, fire test was performed according to ASTM-E119. The char morphology was observed by Field Emission Scanning Electron (FESEM) and Transmission Electron Microscopy (TEM). FTIR and X-ray Diffraction (XRD) test is conducted to analyse the composition of the residual char. The residual char mass was perceived by Thermogravimetric analysis (TGA) of the coating. X-ray Photo Electron Spectroscopy (XPS) was utilized for binding energy and elemental composition of the char. One-hour fire protection test showed 166 °C, the lowest substrate temperature of IFRC5-2 and 40.46% residual mass was obtained by TGA analysis. XRD analysis showed that residual char has aluminum borate and borophosphate and confirmed by functional group analysis using and FTIR. FESEM and TEM illustrated that char relates to hexagonal particles of wollastonite. XPS analysis of IFRC5-2 showed the carbon and oxygen contents were 41.40% and 51.20%. Pyrolysis-Gas Chromatography–Mass Spectrometry (Pyrolysis GC–MS) results showed IFRC-5 produced less concentration of the gaseous products compared to IFRC-C. The formulations developed by grinding solid ingredients for 2 min showed improved thermal performance compared with the formulation produced by grinding solid ingredients for 1 min. Longer grinding time and higher amount of filler improved the thermal properties of the intumescent coating.

Flame retardancy and smoke suppression properties of transparent intumescent fire-retardant coatings reinforced with layered double hydroxides

A series of novel layered double hydroxide (LDH)-modified phosphate esters (LPPBs) flame retardants were synthesized by the reaction of flexible phosphate ester (PPB) and LDHs with different mass ratio and then well characterized by Fourier transform infrared spectroscopy (FTIR) and 1H nuclear magnetic resonance spectroscopy (1H NMR). The obtained LPPBs were mixed with melamine formaldehyde resin to produce transparent fire-retardant coatings applied on wood substrates. The coatings containing LDHs exhibit a high degree of transparency even at high LDH contents due to the well dispersed and completely exfoliated state of LDHs in the amino matrix, as determined from the results of X-ray diffraction (XRD) patterns and scanning electron microscopy (SEM) images. The fire protection tests show that the values of weight loss, char index, and flame spread rating of the coatings are remarkably decreased with the introduction of LDHs concomitant with an increase in the intumescent factor. The cone calorimeter and smoke density tests show that the flame retardancy and smoke suppression properties of the coatings are significantly improved with the introduction of LDHs due to the formation of a more compact, continuous, and intumescent char during combustion. The results of thermogravimetric (TG) analysis show that the thermal stability and residual weight of the coatings are gradually increased with increasing LDH content. Char residue analysis shows that the introduction of LDHs into the coatings contributes to generating more phosphorus-rich crosslinking structures and aromatic structures in the condensed phase that produce a more compact and thermally stable char against the release of heat and smoke, thus exhibiting excellent flame retardancy and smoke suppression properties.