Commercial Fire Retardants Research Articles

A Comparative Analysis of Tannin and Commercial Fire Retardants in Wood Fire Protection

In civil construction, one of the primary challenges associated with wood application is its high flammability and low durability during fires. Although chemical treatment with fire-retardant properties exists, they are expensive and of non-renewable origin. Tannin, a wood extractive, being a phenolic compound, holds promise for enhancing the thermal properties of wood. This study aimed to assess the efficacy of tannin as a fire retardant and compare it with a commercial product, as well as comparing different application techniques for these products. Wood samples from the Simarouba amara Aubl. species were utilized. Tannin and a commercial flame retardant were applied via immersion, vacuum impregnation, brushing, and a treatment of tannin incorporated into water-based wood varnish. Alongside the burning test performance, assessments of the wood’s physical properties, such as colorimetry, thermal stability, and mass retention, were conducted. The application of tannin altered the wood’s color and reduced the spread of fire; its presence significantly reduced the flame duration and maintained the wood’s structural integrity. However, tannin retention was lower compared to commercial flame retardant, leading to reduced fire retardancy. Among the methods tested, immersion proved to be the most effective in enhancing the wood’s resistance to flame contact.

Synthesis and thermal characterization of composites based on Epidian 601 with flame retardants compounds

Abstract This study presents the preparation and flammability characteristics of polymeric composites based on the epoxy resin Epidian® 601. The triethylenetetramine (TETA) and commercial curing agents based on polyamines (IDA and PAC) were used as crosslinking compounds. Moreover, two flame retardant compounds were added to this composition, the commercial Fire Retardant (FR) and triphenyl phosphate (TP). The chemical structure of the composites and the course of curing processes were confirmed by the ATR/FT-IR (Attenuated Total Reflection–Fourier Transform Infrared) analysis. The influence of different amounts of FR or TP on the flammability and thermal resistance was discussed in detail. After the flammability test the samples were also studied to assess their thermal destruction. In addition, the composites were subjected to the swelling tests, solvent resistance, and microscopic observations. The DSC curves revealed that all materials were characterized by good thermal properties. All materials were temperature resistant up to 300 °C. Furthermore, the measurements of the hardness of the composite demonstrated that the material EP601 + TETA + 10 %FR is the hardest. The addition of FR and RP influenced the flammability of the composites increasing the thermal resistance. The ageing tests in methanol, acetone, hydrochloric acid, and potassium hydroxide were also carried out.

Burning Behaviour of Rigid Polyurethane Foams with Histidine and Modified Graphene Oxide.

Since rigid polyurethane (PU) foams are one of the most effective thermal insulation materials with widespread application, it is an urgent requirement to improve its fire retardancy and reduce the smoke emission. The current work assessed the fire behavior of PU foam with non-halogen fire retardants system, containing histidine (H) and modified graphene oxide (GOA). For investigated system, three loadings (10, 20, and 30 wt.%) were used. The Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analysis, cone calorimetry (CC) and smoke density chamber tests as well as pre- and post-burning morphological evaluation using scanning electron microscope (SEM) were performed. Moreover, TGA combined with FT-IR was conducted to determine the substances, which could be evolved during the thermal decomposition of the PU with fire retardant system. The results indicated a reduction in heat release rate (HRR), maximum average rate of heat emission (MAHRE), the total heat release (THR) as well as the total smoke release (TSR), and maximum specific optical density (Dsmax) compared to the polyurethane with commercial fire retardant, namely ammonium polyphosphate (APP). A significantly improvement, especially in smoke suppression, suggested that HGOA system may be a candidate as a fire retardant to reduce the flammability of PU foams.

Fire Characteristics of Selected Tropical Woods without and with Fire Retardant

The flammability of tropical woods and the effect of a selected fire protection coating were evaluated using a cone calorimeter at a cone radiancy of 35 kW/m2. Three samples were from the South American continent (Cumaru, Garapa, Ipe), and two were from the Asian continent (Kempas and Merbau). Samples were treated with commercial fire retardant (FR) containing ferrous phosphate as an essential component. The untreated samples were used as reference materials that were of particular interest concerning their flammability. It was shown that there is unambiguous correlation between the effective heat of combustion (EHC) and total oxygen consumed (TOC) related to mass lost during burning for both the untreated and treated samples. In the case of Cumaru and Garapa, there exists an inverse relation between the amount of smoke and carbon residue. The decisive effect on the time of ignition was performed by the initial mass of the sample. This is valid for the spruce and the Cumaru, Ipe, and Kempas, both treated and untreated with retardant, while Garapa and Merbau were found to decline. According to the lower maximum average rate of heat emission (MARHE) parameter, a lower flammability was observed for the treated samples of wood, except for Garapa wood. Fire-retardant treated Garapa and Merbau also have a significantly lower time to ignition than untreated ones.

The synergistic effect of intumescent coating containing titanium dioxide and antimony trioxide onto spruce and alder wood species

This paper investigates the effect of coating of antimony trioxide and titanium dioxide combined commercial fire retardant paint onto alder and spruce solid wood surface. The purpose of this study was to determine the relationship between fire behavior of these chemicals and wood surface in order to obtain an eco-friendly product from alder and spruce wood with preferable properties that capable to compete in the market. The fire retardant intumescent coating for wood surfaces are frequently used in working and living areas where the safety is required. The antimony trioxide and titanium dioxide were separately added to the fire retardant paint as 1% and 2%, and then applied by brush on wood surfaces. The alder wood surface for 2% antimony trioxide loadings provided 10% improvement on LOI value compared to the alder wood surface with only coated the fire retardant paint. Compared to the spruce wood surface with only coated fire retardant paint, the coated spruce wood surface with 2% both of antimony trioxide and titanium dioxide also showed 8% increasing on LOI value. The results showed that these wood surfaces coated by different percentage of ammonium trioxide and titanium dioxide added to fire retardant paint had an affirmative effect on the physical properties as well as a good fire retardant property.

Lignosulfonates as Fire Retardants in Wood Flour-Based Particleboards

Wood flour particleboards (WFP), like other wood-based items, require the addition of fire retardants (FRs) to reduce their high flammability. In this work, a waste lignosulfonate (CaLS) from paper mill is used as a low-cost FR to reduce WFP flammability. CaLS is purified by dialysis and the dialysed lignosulfonate (LD) is used, alone or combined with ammonium polyphosphate (APP), as a FR additive in the preparation of urea-formaldehyde WFP. The fire behaviour of the modified WFPs is studied by cone calorimetry. The use of 15 wt.% LD reduces the peak of heat release rate (HRR) and total smoke production by 25%, also increasing char formation. HRR peak is further reduced up to 40%, if APP is introduced in the formulation. This work discloses a viable and cost-effective strategy for improving the fire retardancy performance of WFP by partial replacement of a commercial FR with a fully renewable additive, isolated through a green and cost-effective process.

Investigation of Factory Fire Retardant Treatment of Eucalyptus Plywood

Abstract Eucalyptus has become an important substitute material for the burgeoning plywood industry in China, whereas the corresponding fire retardant–treated products remain to be developed. This study preliminarily evaluated the feasibility of manufacturing fire retardant–treated eucalyptus plywood in the traditional industrial plant by veneer impregnation. Eucalyptus saligna and Eucalyptus dunnii veneers were impregnated by a commercial fire retardant at room temperature and atmospheric pressure. After redrying, the veneers were hot pressed into fire retardant–treated plywood in a conventional way. Fire performance was evaluated by cone calorimeter test. Basic properties (i.e., moisture content, bonding strength, and formaldehyde emission), mechanical properties (including modulus of rupture and modulus of elasticity), and hygroscopicity were also investigated. The fire retardancy of plywood was significantly improved by the fire retardant treatment, in terms of decreased heat release rate and increased residual mass fraction. The flame spread index values for plywood, which were calculated from the results from cone calorimeter tests, indicate that the fire performance of plywood improves from Class III to Class II after the treatment. The basic properties of fire retardant–treated plywood meet the requirements of GB/T 9846 (Standardization Administration of the People's Republic of China 2004). The mechanical and hygroscopic properties of fire retardant–treated plywood satisfy demands of general interior applications. The veneer treatment could be a suitable approach for Eucalyptus plywood factories to manufacture fire retardant–treated products.

Layer double hydroxide and sodium montmorillonite multilayer coatings for the flammability reduction of flexible polyurethane foams

ABSTRACTFlexible polyurethane foam (PUF) is coated by layer‐by‐layer (LbL) assembly using branched polyethyleneimine (BPEI), poly(acrylic acid) (PAA), and two different charged nanoparticles, such as sodium montmorillonite (Na‐MMT) and layered double hydroxide (LDH). Three different deposition strategies, that is, bilayer, trilayer, and quadlayer, exhibit different coating growth, morphology, and flammability properties. Changing the nanosheet from LDH to MMT dramatically alter the coating mass for the same number of layers. A five bilayer PAA/BPEI+LDH coating reduced the peak heat release rate by 40% and the average heat release rate by 70%, which is two times more effective than commercial fire retardants (FRs) and other LbL‐FR coatings for PUF. MMT and LDH mixed multilayers resulted in effective flame‐retardant coatings with less coating mass by manipulating the deposition strategy. This study manifests the flexibility of LbL to fine‐tune flammability reduction by switching the coating weight gains, which is significant to accelerate the development of other LbL coating regardless of the intended applications. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41767.

Effects of novel brominated flame retardants on steroidogenesis in primary porcine testicular cells

Brominated flame retardants are chemicals with fire quenching properties which are extensively used in manufacturing. Historically, less regulated use of legacy brominated flame retardants (BFRs) for a number of years has resulted in ubiquitous contamination of the environment. As a result, some of the more persistent BFRs have been phased out and are being replaced by a next generation of brominated compounds for which there is little toxicological data. The study investigated effects of 2-ethylhexyl tetrabromobenzoate (TBB), 1,2,5,6-tetrabromocyclooctane (TBCO), and bis-(2-ethylhexyl) tetrabromophthalate (TBPH) on steroidogenesis in a porcine primary testicular cell model. TBB did not affect sex-steroid production in this cell model; rather the data suggest a flux towards synthesis of aldosterone and cortisol via up-regulation of CYP21A2. At the greatest concentrations of TBCO and TBPH tested greater production of sex hormones testosterone (T) and estradiol (E2) was observed. Effects were mediated by regulation of multiple molecular targets in the steroidogenesis pathway; CYP11A in the case of TBPH and CYP17A1 in the case of TBCO. This investigation is the first of its kind to use a testicular mixed population cell model to investigate mechanism(s) of action of three chemically diverse compounds currently used in commercial fire retardants.

Treated and untreated foam core particleboards with intumescent veneer

The effectiveness of treatments for the surface layer of novel foam core particleboards was evaluated by means of Cone calorimeter tests. Foam core particleboards with variations of surface layer treatment, adhesives, and surface layer thicknesses under similar processing conditions were used to produce the test specimen for the Cone calorimeter tests. Ignitability, heat release rate profile, peak of heat release rate, total heat released, effective heat of combustion, mass loss rate, gaseous emissions, and specific extinction area were measured using the cone irradiance of 50 kW m−2. Additional analysis of this data provided fuel composition information that could reveal the pyrolysis events of the composite boards. Thermocouples at various depths were used to provide further verification of pyrolysis events. The unprotected foam core panels generally had much higher heat release rates, somewhat higher heat of combustion and much higher smoke production due to the polymeric foam component of tested panels, whereas time to ignition and total heat release were not pronounced from the veneer treated boards. Adding the commercial fire retardant veneer to the face particleboard provided a dramatic improvement to the measured flammability properties. It worked sufficiently well with a 3 mm thick surface layer to improve the predicted flame spread rating of the foam core particleboards.

Flame Retardant Low Density Polyethylene with Aluminium Hydroxide/ Commercial Fire Retardants FR01 Synergistic System

Low density polyethylene (LDPE) was modified by the addition of commercial fire retardants FR01 and aluminium hydroxide (ATH). ATH/FR01/LDPE composites were prepared by melt blending and extrusion in a twin-screw extruder. ATH was first modified by a silane coupling agent KH550 then added to LDPE. The flame retardancy, electrical property and thermal behavior of the LDPE composites were investigated by limiting oxygen index (LOI), volume resistivity and thermogravimetric analysis (TGA), respectively. The results indicated that the surface modification of ATH (M-ATH) could greatly improve the dispersibility and compatibility with LDPE matrix. The mechanical property tests showed good mechanical properties of composite, compared with unmodified one, tensile strength and elongation of M-ATH/LDPE were all improved, and the addition of FR01 improved the flame retardancy of ATH/LDPE remarkably. TGA results demonstrate that char yield of M-ATH/FR01/LDPE (30/15/70) reaches 27 wt% at 600 °C in Ar atmosphere.

Controlling polyurethane foam flammability and mechanical behaviour by tailoring the composition of clay-based multilayer nanocoatings

This study is a thorough evaluation of clay-based Layer-by-Layer (LbL) coatings intended to reduce the flammability of polymeric materials. Through a systematic variation of a baseline coating recipe, an ideal combination of the coating attributes that provides a rapidly developing coating with an optimum balance of flammability, mechanical, and physical attributes on a complex 3D porous substrate, polyurethane foam (PUF) was identified. Using a unique trilayer (TL) assembly approach, the coating growth was significantly accelerated by the polymer (poly(acrylic acid) (PAA)/branched polyethylenimine (BPEI)) concentration in the formulation. However, to significantly reduce flammability without compromising other performance attributes, the concentration of the nanoparticle fire retardant (nanoFR, clay) suspension was critical. This study has resulted in the most significant reduction in PUF flammability using LbL technology without compromising any of the mechanical or physical attributes of the PUF. More specifically, a reduction in the peak heat release rate (pHRR) and average heat release rate (aHRR) of 33% and 78%, respectively, has been achieved. This reduction in flammability is at least two times more effective than commercial fire retardants and other LbL FR coatings for PUF. The insights gained through this research are expected to accelerate the development of other LbL coatings regardless of the intended application.

Innovative Approach to Rapid Growth of Highly Clay-Filled Coatings on Porous Polyurethane Foam.

An innovative twist to fabricating layer-by-layer coatings resulted in transparent, high-content clay coatings on porous polyurethane foam. The addition of an anionic poly(acrylic acid) (PAA) monolayer between anionic clay and cationic branched-polyethylenimine (PEI) monolayers resulted in a trilayer nanocomposite structure with an order of magnitude thicker coating using 40% less monolayers than the conventional bilayer approach. The eight trilayer system thoroughly coated all internal and external surfaces of the porous polyurethane foam, creating a clay brick wall barrier that reduced the foam flammability by as much as 17% of the peak heat release rate and 21% of the total burn time. Though the flammability reduction is comparable to common commercial fire retardant polyurethane foam, the clay is used at a 50% lower amount and may be a greener solution as many of the commercial fire retardants (e.g., halogen bases) have potential environmental and health concerns.

Methoxyethoxyethoxyphosphazenes as ionic conductive fire retardant additives for lithium battery systems

The current highly flammable configurations for rechargeable lithium batteries generate safety concerns. Although commercial fire retardant additives have been investigated, they tend to decrease the overall efficiency of the battery. We report here ionically conductive, non-halogenated lithium battery additives based on a methoxyethoxyethoxyphosphazene oligomer and the corresponding high polymer, which can increase the fire resistance of a battery while retaining a high energy efficiency. Conductivities in the range of 10 −4 S cm −1 have been obtained for self-extinguishing, ion-conductive methoxyethoxyethoxyphosphazene oligomers. The addition of 25 wt% high polymeric poly[bis(methoxyethoxyethoxy)phosphazene] to propylene carbonate electrolytes lowers the flammability by 90% while maintaining a good ionic conductivity of 2.5 × 10 −3 S cm −1.

Comparative study on the flammability of polyethylene modified with commercial fire retardants and a zinc aluminum oleate layered double hydroxide

Polyethylene (PE) was modified by the addition of a layered double hydroxide of zinc aluminum oleate (ZnAl) and/or commercial fire retardants. Commercial additives included: melamine polyphosphate (MPP), ammonium polyphosphate (APP), triphenol phosphate (TPP), resorcinol diphosphate (RDP), decabromophenyl oxide (DECA) and antimony oxide (AO). The thermal stability and the combustion behaviors of the new composite polymeric materials are evaluated in TGA experiments and cone calorimetry. At 20% total additive loading, APP and LDH enhance the thermal stability of the PE composites and favor char formation. ZnAl leads to the best reduction in the peak of heat release rate (PHRR), 72%, while the combinations of PE with other additives give reductions in the range 20–40%. The combination of DECA and AO effectively increases the time to ignition and time to PHRR while LDH lowers these two parameters. APP and MPP on the other hand, do not affect the time to ignition, but they effectively increase the time to PHRR relative to the pristine polymer.

Commercial fire-retarded PET formulations – Relationship between thermal degradation behaviour and fire-retardant action

Many types of fire retardants are used in poly(ethylene terephthalate), PET, formulations, and two commercial fire retardants, Ukanol ® and Phosgard ®, have been shown to improve significantly PET flame-retardancy when used as comonomers. Phosgard incorporates a phosphorus atom within the main chain whereas Ukanol incorporates a phosphorus atom as a pendent substituent. Despite their acknowledged effectiveness, the mode of action of these fire retardants remains unclear, and in this paper we present a comparison of the overall thermal degradation behaviour of PET and Ukanol and Phosgard fire-retarded formulations. DSC and particularly TGA data show that both Ukanol and Phosgard have some stabilising influence on PET degradation, especially under oxidative conditions. TGA and pyrolysis experiments both clearly indicate that neither of the additives acts as a char promoter. Only the Phosgard formulation shows any release of volatile phosphorus species which could act in the gas phase. On the other hand, the most striking feature of the pyrolysis experiments is the macroscopic structure of the chars produced by the fire-retarded formulations, which hints at their fire-retardancy action – an open-cell charred foam was obtained upon charring at 400 °C or 600 °C. This foaming layer between the degrading melt and the flame would lower the amount of fuel available for combustion, and would also limit the feedback of heat to the condensed phase.

Structural and thermal interpretation of the synergy and interactions between the fire retardants magnesium hydroxide and zinc borate

The mechanism of cooperative action of commercial fire retardants is interpreted as resulting from specific chemical reaction and phase changes. This investigation focuses on the thermally initiated interactions between two forms of commercially available fire retardant compounds. The fire performance of a polyolefin with a metal hydroxide fire retardant, magnesium hydroxide, can significantly reduce the heat release rate through absorption of heat during conversion to its metal oxide. Formation of water, followed by vaporisation, decreases heat and dilutes volatiles from polymer degradation. The second form of fire retardant compounds are zinc borates (2ZnO·3B 2O 3·3H 2O and 4ZnO·B 2O 3·H 2O), that undergo dehydration with increasing temperature. Differential thermal analysis and wide-angle X-ray spectroscopy indicated that various structural changes occurred during heating. Endothermic transitions were observed for all components, while zinc borate (2ZnO·3B 2O 3·3H 2O) showed an exothermic crystallisation transition at relatively high temperature. The exotherm was modified by the development of a new crystalline phase, magnesium orthoborate (3MgO·B 2O 3) that formed on reaction with magnesium oxide (MgO) at temperatures greater than 500 °C. Formation of crystalline zinc oxide (ZnO) was also detected. From zinc borate (4ZnO·B 2O 3·H 2O), ZnO was primarily formed. No new crystalline phases were observed in the presence of MgO over the temperature range investigated.

Daphnia emergence: a sensitive indicator of fire-retardant stress in temporary wetlands

Fire-retardant formulations are increasingly used by fire managers to control wildland fires. Their extensive use requires an assessment of their impacts in those ecosystems that could be affected by them. Recent studies indicate the potential for environmental impacts when accidentally delivered to surface waters. Yet the response of temporary wetlands, such as vernal pools, typical in Mediterranean areas, is unknown. This study reports on the emergence response of a wetland population of Daphnia curvirostris Eylmann (Cladocera, Crustacea) from sediments that were treated with a commercial fire retardant (Fire-Trol® 934). Three application levels were used: 1, 3 and 5 L m −2. The low and medium levels are in the range of manufacturer's recommendations of use in the field based on the fuel characteristics. The high level simulates local elevated concentrations that may result from inhomogeneous retardant delivery. Results indicate that emergence success decreases with increasing application rate, leading to a complete failure with application levels of 5 L m −2. This suggests that benthic–pelagic interactions in temporary wetlands—often the primary way by which recolonization of isolated wetlands occurs—can be significantly impacted by fire retardants once they fill with fall/winter rains, thereby serving as a sensitive indicator of fire-retardant contamination. Results highlight a research need for establishing of criteria for effective, but environmentally safe use of fire retardants in the environment.

A study of fire-retardant mechanisms in the gas phase by FTIR spectroscopy

This paper presents initial results of vapour-phase chemistry of volatile fire retardants, which may contain phosphorus, bromine or iron, in the presence of fuel from the burning material. Two studies have been carried out using an isothermal tubular-flow reactor. In the first study the influence of a flame-retardant ignition limits of fuel/fire-retardant additive at different temperatures has been determined. These results indicate that a commercial fire retardant (Reofos 95), a phosphorus-containing additive, and ferrocene, are effective gas-phase additives with isooctane, but that bromobenzene is not. With toluene, all additives have a negative effect on the ignition temperature of the fuel. In the second study, the gas-phase mechanisms of fire-retardant action have been studied using Fourier-transform infrared spectroscopy (FTIR). The FTIR study combined with target factor analysis chemometric software indicates that product and intermediate gas-phase species (H 3 PO 4 , (CH 3 O) 2 P(OH)O and CH 3 OP(OH) 2 O) can be detected over a wide range of temperatures (400-900°C).

A Model of Heat Transfer Across an Epoxy Based Fire Retardant Layer Undergoing Sublimation, Intumescence and Degradation

AbstractA model has been developed to predict the rate of heat flux through fire retardant coatings subjected to a surface flame at 1080°C. The model includes the effect of the material subliming, intumescing and degrading, and of temperature effects on the material properties. Temperature profiles were compared with experimental data obtained on commercial fire retardants using a small‐scale fire testing apparatus developed for the study of passive fire protection materials. Temperature predictions of the model agreed within 10% of experimental results except when erosion and cracking of the retardant was observed.