Intumescent Fire Retardant Research Articles

Effects of the addition mode and amount of organic montmorillonite in soft-core/hard-shell emulsion on fire protection, water resistance and stability of fire retardant coating

Abstract In order to meet the basic demands for everyday use and construction requirements, the organic montmorillonite/poly-(Methyl methacrylate-butyl acrylate)/poly-(Methyl methacrylate-butyl acrylate −methacrylic acid) soft-core/hard-shell emulsion was synthesized and used as the film former of the waterborne intumescent fire retardant coating. The effects of addition mode and amount of organic montmorillonite in emulsion on coating properties were studied. Emulsion stability analysis, water resistance tests of films and fire resistance tests all showed the optimum addition mode of OMMT was in the core layer of soft-core/hard-shell emulsion. The reason could be that the addition of OMMT in core layer could not destroy core-shell structure and cross-linked structure, and parallel-arranged OMMT was distributed well. The result of differential scanning calorimetry (DSC) showed that soft-core/hard-shell emulsion containing OMMT in core layer had lower glass transition temperature (Tg) of core layer and higher glass transition temperature (Tg) of shell layer, which play an important role in lowering film-forming temperature and enhancing resistance to water. The results of fire protection test indicated the fire resistance of coatings were significantly improved by adding OMMT in the range of 1.0 wt.% to 1.5 wt.% in core layer and scanning electron microscopy (SEM) demonstrated that the well-dispersed OMMT could improve the foam structure of char layer by limiting the escape of inert gases and filling carbon layer’s tiny cracks generated at high temperature.

Effects of nano-sized boron nitride (BN) reinforcement in expandable graphite based in-tumescent fire retardant coating

The purpose of in-tumescent fire retardant coating (IFRC) is to protect substrate from fire attack by limiting heat transfer. A range of coating formulations have been prepared using Bisphenol A epoxy resin BE-188 and polyamide solidifier H-2310 as two-part binder, ammonium polyphosphate (APP) as acid source, melamine (MEL) as the blowing agent, expandable graphite (EG) as carbon source and nano-boron nitride (BN) as inorganic nano filler. The filler was used to improve the performances of the APP-EG-MEL coating. The effects of nano-BN on the char morphology and thermal degradation were investigated by fire test, thermo gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X- ray photoelectron spectroscopy (XPS) and field emission scanning electron microscopy (FESEM). The results showed that by substituting or reinforcing of 4% weight percentage of nano-BN, residual weight of the char increases by 23.82% compared to APP-EG-MEL coating without filler. Higher carbon content was obtained in the char and a more compact char was produced. The results indicated that nano-BN could be used as a filler to improve thermal stability of the APP-EG-MEL coating.

Thermal properties of polyethylene flame retarded with expandable graphite and intumescent fire retardant additives

SummaryLow‐density polyethylene was flame retarded by combinations of expandable graphite with either ethylenediamine phosphate or 3,5‐diaminobenzoic acid phosphate. Cone calorimeter, laser pyrolysis, and open flame exposure tests (supported by video and infrared camera data capture and analysis) were conducted to assess ignition and burn behavior. Cone calorimeter results indicated substantial reductions in the peak heat release rates for all flame‐retarded samples but with reduced ignition times and increased flame out times. Smoke generation was suppressed in the presence of expandable graphite. Infrared and video data from open flame fire tests indicated cohesive bonding of expanded strings and thermal shielding properties in all binary systems. All binary systems delivered fire retardation exceeding any of the single fire retardant compounds. They were also able to withstand higher temperatures before ignition, burn through, or sag occurred. All ethylenediamine phosphate‐containing binary systems prevented sample burn through, maintaining structural integrity of samples until eventual melting of the polymer media occurred. Thermogravimetric analysis laser pyrolysis results confirmed the good thermal shielding imparted by the intumescent additives. Copyright © 2016 John Wiley & Sons, Ltd.

Thermal Degradation and Char Morphology of HNTs Reinforced Epoxy Based Intumescent Fire Retardant Coatings

This study investigates the effectiveness of halloysite nanotube as filler on improvement in thermal performance of epoxy based intumescent fire retardant coating. Several intumescent fire retardant formulations were developed with and without halloysite nanotube. The thermal performance and char morphology of Intumescent fire retardant formulations was studied. Bunsen burner (ASTM E-119) test revealed that incorporation of HNTs (1.5 wt. %) improved flame retardancy by reducing the temperature of steel substrate up to 99 °C when exposed to fire for 1 hour. This study also revealed the physical and chemical mechanisms of action of HNTs in the intumescent systems. Results showed that halloysite improved the growth of the intumescent shield and give better quality of char. HNT formed aluminosilicate network for the phosphocarbonaceous structure by chemical contacts with ammonium polyphosphate. These new chemical species enhanced thermal stabilization of the char at high temperature and offered good structural properties on micro and macro scale. This increased the mechanical strength of the shielding layer during burning and also enhanced the residual weight percentage after thermal degradation as shown in thermal gravimetrical curves.

Smoke suppression properties of epoxy crosslinked structure and intumescent fire retardant in epoxy‐based intumescent fire‐retardant coating

ABSTRACTIn this article, the smoke production behaviors of crosslinked epoxy/polyamide resin (EP/PA) and intumescent fire retardant (IFR) in epoxy‐based intumescent fire‐retardant coating (IFR‐EP) have been investigated using cone calorimeter, smoke density instrument, and thermogravimetric analysis and Fourier transform infrared spectroscopic measurement. The static and dynamic smoke production behaviors of EP/PA and IFR‐EP indicate that the IFR has an excellent smoke suppression effect on EP/PA by forming protective char layer in the late combustion stage, while the epoxy crosslinked structure in IFR‐EP can enhance the thermal stability and reduce smoke production in the early combustion stage. In addition, according to the discussion of pyrolysis gas products, the IFR can effectively suppress the production of toxic and inflammable gases during the combustion process. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43912.

Preparation and performances of novel waterborne intumescent fire retardant coatings

Abstract The core–shell organic-modified montmorillonite (OMMT)/epoxy resin/styrene-acrylic emulsion was prepared using semi-continuous seeded emulsion polymerization and used as the binder of the waterborne intumescent fire retardant coating to improve the fire resistance performance and other basic performance such as water resistance performance, anti-yellowing and adhesion to substrates. Observation with transmission electron microscopy showed that core–shell emulsion had been synthesized successfully. The small angle X-ray diffraction results showed that OMMT was exfoliated and dispersed well in the emulsion within the appropriate content. Fire resistance test, thermal analysis, scanning electron microscopy (SEM), water resistance and yellowing resistance test respectively demonstrated that OMMT greatly improve fire resistance, thermal stability, water resistance and yellowing resistance performance with the addition of in the range of 1.5–2.5 wt.%. Moreover, the core–shell styrene-acrylic emulsion with 5 wt.% epoxy resin (E-44) improve the adhesion of the film to plywood (from 2 grade to 0 grade).

Research of Effectiveness of „Plamostop“ Fire Retardand and Suitability of Testing Methods for Wood Flame Retardants Evaluating

Abstract The paper deals with testing of a water-miscible intumescent fire retardant. Experiments are conducted by thermal analysis (TG/DTG, DSC), cone calorimeter and non-standardized methods for monitoring weight loss when exposed to flame burning. Based on the experiment results and other information the most appropriate methods for testing fire retardants are reviewed. All methods by which experiments have been carried out are described. Our own method for testing fire retardants was created. It is also evaluated the effectiveness of a representative fire retardant of wood by all mentioned methods. The result of the experiment is to evaluate the suitability of each method for testing of fire retardants and evaluation fire retardant “Plamostop”.

Effect of Dolomite Clay on Thermal Performance and Char Morphology of Expandable Graphite Based Intumescent Fire Retardant Coatings

Dolomite Clay was introduced in a traditional intumescent flame retardant system which contains ammonium polyphosphate/expandable graphite/melamine (APP–EG–MEL) to evaluate its effects on char morphology and fire performance. The effect of dolomite clay on the fire-resistance and thermal properties of expandable graphite based Intumescent fire retardant coatings has been investigated by using Bunsen burner fire test and thermal gravimetric (TG) techniques. The current study describes the effects of Dolomite Clay on the heat shielding performance of intumescent passive fireproofing coatings during fire testing. The fire performance of dolomite clay reinforced intumescent coating formulations were evaluated by Bunsen burner fire test according to ASTM E-119. Results showed that the dolomite reinforcement in IFRC formulation significantly reduced the steel substrate temperature up to 180°C after 1 hour of fire exposure. The coating degradation was studied using thermogravimetric analysis (TGA). The physical morphology and alignment of intumescent char residue were studied by field emission scanning electron microscopy (FESEM). TGA analysis revealed that IFD (8) containing 8wt. % of dolomite clay enhanced residual weight by 37.30%. It is suggested that Dolomite clay can enhance the fire performance and can significantly affect the formation of dense and continuous char if incorporated as a filler in conventional intumescent fire resistive systems.

Effect of cenospheres on the char formation and fire protective performance of water-based intumescent coatings on structural steel

Abstract Intumescent coatings are passive fireproofing materials, used to prevent fire induced structural collapse of tall buildings by decreasing the heat transfer to the substrate. Present research describes the results of various formulations developed to study the effects of fly ash cenospheres on the heat shielding performance of intumescent passive fire proofing coatings during fire testing. The intumescent fire retardant coating formulations (IFR) were tested at nearly 950 °C for 1 h. The results showed that the coatings form a stable char having good adhesion to the substrates. The coating degradation was studied using Thermo gravimetric analysis (TGA). The morphology of chars was studied by Environmental scanning electron microscopy (ESEM). The coating char after fire test was examined by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The presence of titanium phosphate and boron phosphate in the residual char was observed and XRD also confirmed the interaction of cenospheres with the coating ingredients at high temperatures. TGA showed that IFR CN 4 containing 10 phr of cenospheres enhanced residual weight by 39.30%. It is also concluded from the results that cenospheres increased the anti oxidation ability of the intumescent char.

Smoke suppression and synergistic flame retardancy properties of zinc borate and diantimony trioxide in epoxy-based intumescent fire-retardant coating

In this article, smoke suppression and synergistic flame retardancy properties of zinc borate (ZB) and diantimony trioxide (Sb2O3) in epoxy-based intumescent fire-retardant (IFR) coating were investigated based on cone calorimeter test, smoke density test, scanning electron microscopy, thermogravimetric and Fourier transform infrared spectroscopic analyses. The measurement results of the dynamic combustion and smoke production behaviors and static smoke production behaviors of these IFR coatings showed that the values of heat release rate, smoke production rate, smoke factor and fire growth index all decreased significantly with the addition of ZB and Sb2O3. At the same time, the specific optical densities were remarkably reduced due to the existence of ZB and Sb2O3. These attractive data clearly demonstrated that the ZB and Sb2O3 had a good effect on smoke suppression and synergistic flame retardancy of the IFR coating. Besides, the scanning electron microscopy and the infrared spectroscopic analyses during coating thermal degradation were also carried out to explore the outstanding synergistic smoke suppression and flame retardancy mechanism of ZB and Sb2O3. With the melt of ZB and Sb2O3, a lot of heat was absorbed, and then, the glassy protective layer associated with the graphite char would effectively retard heat and suppress smoke.

Study of Fire Retardancy and Thermal and Mechanical Properties of HDPE-Wood Composites

This article reports a study of flame retardancy and thermal and mechanical properties of wood-plastic composites (WPCs) based on high-density polyethylene and pine flour. The study shows that sample composition plays an important role in WPCs' properties. The influence of additives like fillers (SiO2 or CaCO3) and flame retardants ammonium polyphosphate (APP) and pentaerythritol (PER) on WPCs' properties has been considered. The best properties are shown in samples using SiO2 as filler and treated with the intumescent fire retardant APP/PER. Such samples have excellent fire retardancy with V-0 rating (UL-94 test) and imply that APP/PER fire retardant ensures effective fire retardancy for WPCs.

Influence of hybrid functionalized graphite nanoplatelets-tripolyphosphate on improvement in fire protection of intumescent fire resistive coating for steel structures

Functionalized graphite nanoplatelets (FGNP) were modified with tripolyphosphate (TPP) as a thermal oxidation inhibitor. The hybride nano-particles (FGNP-TPP) effects on improvement of fire retardant properties of a traditional intumescent fire retardant (IFR) formulation were investigated. FT-IR results showed that TPP was linked to FGNP nano-particle by hydrogen bondings. TEM image showed homogenous dispersion of FGNP-TPP nano-particles in epoxy. Thermogravimetric analysis (TGA) in air showed the oxidation onset temperature of FGNP was increased by approximately 125 °C in the presence of TPP. Incorporation of 2 wt.% of FGNP-TPP into the traditional IFR coating increased the LOI value from 27.1 to 32. Also, a crack free char with high adhesion to the metal substrate was observed in bunsen burner test which increased the time of failure from 43 to 94 min. The results showed the hybrid nano-particles can improve the thermal oxidation stability of the IFR coating at higher temperatures (900–1000 °C) leading to improved char strength, char adhesion, char morphology, residual weight and fire protection properties.

Retraction of “Synergistic Effect of Expandable Graphite and Lanthanum Cerium Oxide on Intumescent Fire Retardant Coating for Structural Applications”

Intumescent fire retardant coatings (IFRC), as a passive form of fire protection, are extensively used by the oil and gas industries to protect steel against corrosion and fire. In this study, an epoxy based IFRC was prepared with different flame retardants. IFRC was reinforced with lanthanum cerium oxide (LCO) to study its effect on thermal insulation before and after immersion in salt water for a period of one month. Characterization techniques include FESEM with EDS, TGA, XPS, XRD,and Pyrolysis GC-MS. Results demonstrated that coating with 4 wt % LCO and 3 wt % EG provided better thermal insulation both before and after salt water immersion and exhibited less weight loss as per TGA analysis.

Influence of the pentaerythritol phosphate melamine salt content on the combustion and thermal decomposition process of intumescent flame‐retardant ethylene–vinyl acetate copolymer composites

ABSTRACTPentaerythritol phosphate melamine salt (PPMS) as a single‐molecule intumescent fire retardant was synthesized and characterized. The influence of the PPMS content on the combustion and thermal decomposition processes of intumescent‐flame‐retardant (IFR) ethylene–vinyl acetate copolymer (EVA) composites was studied by limiting oxygen index (LOI) measurement, UL 94 rating testing, cone calorimetry, thermogravimetric analysis, and scanning electron microscopy. The LOI and UL 94 rating results illustrate that PPMS used in EVA improved the flame retardancy of the EVA composites. The cone calorimetry test results show that the addition of PPMS significantly decreased the heat‐release rate, total heat release, and smoke‐production rate and enhanced the residual char fire performance of the EVA composites. The IFR–EVA3 composite showed the lowest heat‐release and smoke‐production rates and the highest char residue; this means that the IFR–EVA3 composite had the best flame retardancy. The thermogravimetry results show that the IFR–EVA composites had more residual char than pure EVA; the char residue yield increased with increasing PPMS content. The analysis results for the char residue structures also illustrated that the addition of PPMS into the EVA resin helped to enhance the fire properties of the char layer and improve the flame retardancy of the EVA composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42148.

Experimental Study on Heat Transfer of Intumescent Fire Retardant Polypropylene Materials

Intumescent fire retardant polypropylene (IFR-PP) materials, primarily comprising polypropylene, ammonium polyphosphate (APP), pentaerythritol (PER), and polyamide-6, were prepared. The burning behavior of IFR-PP materials was measured using a cone calorimeter. The heat transfer processes for IFR-PP materials were studied using a cone calorimeter and a multi-channel data acquisition instrument. The temperature distribution results inside IFR-PP materials indicated that the temperature measured near the top surface of the sample was much higher than the temperature at far from the top surface. The external temperature field measurement results for IFR-PP samples showed that the temperature rose gradually with time before the intumescent char was formed. Then the temperature values of the sample decreased sharply due to the formation of char cap and accumulating gases. The heat transfer processes of IFR-PP materials were also affected by the difference in formulations such as changes in the contents of APP and PER.

Evaluation of intumescent fire retardants and synergistic agents for use in wood flour/recycled polypropylene composites

The effects of fire retardant synergistic agents zinc borate (ZB), montmorillonite (MMT), manganese dioxide (MnO2) and stannic oxide (SnO2) on the mechanical properties, thermal degradation and flame retardant performance of wood flour–recycled polypropylene composites (WPC) comprised of intumescent flame retardants (IFR) were studied. The species were characterized by thermogravimetric analysis (TGA), limiting oxygen index (LOI), UL-94 tests, and cone calorimeter measurements. The results showed that the synergistic effect between IFR and ZB or MnO2 was greater than that of MMT or SnO2. The addition of 5wt% of ZB or MnO2, MMT and SnO2 created fire retardant WPC with a V0 rating, exhibiting excellent fire retardancy.

Development and Testing of Intumescent Fire Retardant Coating on Various Structural Geometries

Materials are prone to fire and in modern construction their protection from fire is required. In any structure, various joints such as T-joint, I-beam and elbows are used. The geometry of the component has significant role in protection of structure. A weak joint may lead to failure of main structure. In order to meet these challenges, Intumescent fire retardant coating (IFRC) were developed and tested on various structural geometries such as T-joints, elbows, I-beams and pipe. The control coating formulation (IFC-C) was developed from main ingredients; Ammonium Polyphosphate (APP), expandable Graphite (EG), Melamine (Mel), Boric Acid (BA) mixed with bisphenol A epoxy resin and polyamide hardener. Another set of formulations containing various percentage of aluminium Tri-Hydrate (ATH). Fire test results of ATH based formulation showed that I-beam geometry showed the high expansion of 19 mm. T-joint showed the average surface temperature of 55°C after one hour of Bunsen burner test. The X-ray Diffraction (XRD) showed the presence of boron oxide, boron phosphate, sassolite and aluminium oxide in IFC-ATH5 residual char. The 5wt% ATH filler in IFC-C enhanced the fire protection performance of intumescent fire retardant coating formulation.

Thermal characterization of intumescent fire retardant paints

Intumescent coatings are now the dominant passive fire protection materials used in industrial and commercial buildings. The coatings, which usually are composed of inorganic components contained in a polymer matrix, are inert at low temperatures and at higher temperatures, they expand and degrade to provide a charred layer of low conductivity materials. The charred layer, which acts as thermal barrier, will prevent heat transfer to underlying substrate. The thermal properties of intumescent paints are often unknown and difficult to be estimated since they vary significantly during the expansion process; for this reason the fire resistance validation of a commercial coatings is based on expensive, large-scale methods where each commercial coating-beam configuration has to be tested one by one. Adopting, instead, approaches based on a thermal modelling of the intumescent paint coating could provide an helpful tool to make easier the test procedure and to support the design of fire resistant structures as well. The present investigation is focused on the assessment of a methodology intended to the restoration of the equivalent thermal conductivity of the intumescent layer produced under the action of a cone calorimetric apparatus. The estimation procedure is based on the inverse heat conduction problem approach, where the temperature values measured at some locations inside the layer during the expansion process are used as input known data. The results point out that the equivalent thermal conductivity reached by the intumescent material at the end of the expansion process significantly depends on the temperature while the initial thickness of the paint does not seem to have much effect.

Synergistic effects of kaolin clay on intumescent fire retardant coating composition for fire protection of structural steel substrate

Intumescent coating is an insulating material designed to decrease heat transfer to a substrate structure. This research presents the results of different formulations developed to study the effects of kaolin clay on expansion of coating and heat shielding during the fire test. The intumescent coating formulations (ICFs) were tested at 950 °C for 1 h. The results showed that the coatings were stable and well bound with substrate. The coatings were characterized by using Field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The morphology of char was studied by FESEM on the coating after fire test. XRD and FTIR showed the presence of carbon (graphite), boron phosphate, boron oxide, sassolite and kaolinite in the residual char. TGA showed that kaolin clay reinforced formulation; IF5-KC enhanced 49% residual weight than that of IF-Control formulation. XPS analysis showed that elemental composition of IF5-KC char residue gave 41.80% carbon content in the residual char. An accelerated weathering test ASTM D 6695-03 showed that IF5-KC coating sustained its integrity up to 90 days under accelerated weathering chamber.

Special Spherical Shell-shaped Foam deriving from Guanidine Phosphate – Pentaerythritol system and its Intumescent Fire Retardant effects on Polypropylene

An intumescent fire retardant (IFR) system based on guanidine phosphate (GP) and pentaerythritol (PER) was proposed. Decomposition products of GP were studied by thermogravimetric analysis (TGA) combined with pyrolysis gas chromatography-mass spectrometry (Pyrolysis GC–MS) at first. The pure intumescent fire retardant (IFR) GP-PER was studied then. When the IFR was combusted, the special spherical shell-shaped foam was generated. The foam was made up of soluble phosphorus degradation products (PDPs) and insoluble nitrogenous - carbonaceous char consisting of fused ring and heterocyclic ring structures derived from the degradation products of pentaerythritol phosphate esters and condensed cyanamide derivatives. Scanning electron microscopy (SEM) and Raman spectroscopy as well as Ion chromatography (IC) and elemental analysis were used to study the morphology and the moieties of the foam. The mechanism of the special foam formation was proposed with the help of TGA results in the paper. Eventually, mixtures of this IFR blended in polypropylene (PP) matrix were prepared and the fire retardancy was studied. Fourier transform infrared spectroscopy (FTIR) indicated the variation of the foam moieties from 270 °C to 500 °C. Experiments proved the optimal mass ratio of GP and PER is 2:1 to get fire retardancy in PP matrix. With an addition of 25 wt%, the limited oxygen index (LOI) could reach 31% and vertical burning ratings (UL-94 tests) reach a V-0 rating.