Fire Retardant Effect Research Articles

Enhancing Fire Safety and Softness: Efficacy of Ethanolamine Polyphosphate as a Fire Retardant for Textiles.

The rising awareness of fire safety among consumers has driven the demand for fire retardants (FRs) that are both cost-effective and efficient across various industries, particularly in textiles. Traditional FRs often compromise fabric softness, resulting in undesirable tactile texture and stiffness changes. While the external addition of softeners can mitigate the stiffness, it may introduce issues such as a greasy texture and increased flammability. This study introduces ethanolamine polyphosphate (EAPP), an innovative organic polyphosphate, as an effective fire retardant that preserves the softness of textiles. Comprehensive evaluations are conducted on EAPP-treated textiles, revealing significant improvements in fire retardancy without compromising fabric quality. EAPP treatment (15wt.% aqueous solutions) increases the limiting oxygen index (LOI) of pure cotton textiles from 17% to 36% and significantly reduces the peak heat release rate (pHRR) and total smoke rate (TSR) as measured by cone calorimetry. Unlike conventional FR products that form FR-salt crystal particles on the fabric surface after drying, EAPP forms a smooth FR protective layer on the fabric, enhancing mechanical fastness and maintaining tactile qualities. These findings highlight EAPP's potential as a non-washing durable, spray-on fire retardant solution for textiles, combining safety with user comfort.

The Recyclability of Fire-Retarded Biobased Polyamide 11 (PA11) Composites Reinforced with Basalt Fibers (BFs): The Influence of Reprocessing on Structure, Properties, and Fire Behavior.

The growing requirements regarding the safety of using polymers and their composites are related to the emergence of more effective, sustainable, and hazardous-limited fire retardants (FRs). Significant amounts of FRs are usually required to effectively affect a polymer's burning behavior, while the knowledge of their recycling potential is still insufficient. At the same time, concerns are related not only to the reduced effectiveness of flame retardancy but also, above all, to the potential deterioration of mechanical properties caused by the degradation of temperature-affected additives under processing conditions. This study describes the impact of the four-time reprocessing of bio-based polyamide 11 (PA11) modified with an intumescent flame-retardant (IFR) system composed of ammonium polyphosphate (APP), melamine cyanurate (MC), and pentaerythritol (PER) and its composites containing additional short basalt fibers (BFs). Composites manufactured via twin-screw extrusion were subjected to four reprocessing cycles using injection molding. A comprehensive analysis of their structural, mechanical, and fire behavior changes in each cycle was conducted. The obtained results confirmed the safety of using the proposed fire-retarded polyamide and its composites while reprocessing under the recommended process parameters without the risk of significant changes in the structure. The partial increase in flammability of reprocessed PA-based materials caused mainly by polymer degradation has been described.

Improving the fire-retardant performance of industrial reactive coatings for steel building structures

The main aim of this study was to determine key factors that regulate fire-retardant effectiveness of intumescent coatings comprising of ammonium polyphosphate, melamine, pentaerythritol, polymer binder. Fulfillment of the research objectives resulted in the development of a coating with R120 fire resistance. The expected service life of the coating is at least 15 years when applied at Z2 type of environmental conditions (indoor use). It was established that in order to provide fire resistance of around R30 it is advisable to use the styrene-acrylic polymers as binders for both water-based and organic-based intumescent systems. The ratio of target components ammonium polyphosphate/melamine/pentaerythritol in such systems should be close to 2/1/1. The coating thickness is to be 0.4–0.5 mm. To achieve higher fire resistance (R60 or more) the coating should include a vinyl acetate derivative as a binder (copolymers with ethylene or vinylversatate). Target components ratio in this case is to be close to 3.5/1/1.5, while the coating thickness should be kept at 1.6–1.8 mm. If the required class of fire resistance is above R120, coating thickness is usually to be kept above 3.5 mm. In order to achieve higher fire resistance, it is advisable to use nano-clay additives and reinforcing fibers in intumescent compositions.The obtained results were used in the development of intumescent coating, which is produced industrially and provides over R120 fire resistance of steel, which was confirmed in standardized full-scale fire tests.

The Effect of Intumescent Coating Containing Expandable Graphite onto Spruce Wood

Wood, one of the materials predominantly employed in construction, possesses various advantageous properties alongside certain drawbacks, such as susceptibility to thermal degradation. To enhance wood fire resistance, one approach involves the application of flame retardants. This study compared the fire-retardant effectiveness of expandable graphite, bonded with water glass, as a coating for spruce wood against commercially available fire-retardant treatments. Spruce wood samples (Picea abies (L.) H. Karst) underwent treatment with three distinct retardants: expandable graphite in combination with water glass, Bochemit Antiflash, and Bochemit Pyro. The fire-technical characteristics of the samples were examined by a non-standard test method—a test with a radiant heat source. The experiment evaluated the fire-retardant properties by recording changes in sample mass, burning rate, and temperature difference. The best results among all flame retardants were achieved by expandable graphite in combination with water glass, in all evaluation criteria. Among all the flame retardants used, expandable graphite in combination with water glass achieved the best results in all evaluation criteria.

The effect of birch (Betula pendula Roth) face veneer thickness on the reaction to fire properties of fire-retardant treated plywood

Birch (Betula pendula Roth) is the primary wood used for plywood manufacturing in the Baltic and Nordic regions. Birch plywood is a valuable material with superior properties to solid wood, but its poor flammability limits its use in building construction and transportation. Several fire-retardant impregnated spruce and birch plywood solutions are available on the market, the majority of which are based on the concept of fire-retardant pressure impregnated veneers or soaked plywood. Hence, the demand for fire-resistant plywood is increasing worldwide. However, for the plywood industry, it is crucial that any fire protection enhancement process does not significantly disrupt the current production setup. This study investigates the effect of face veneer thickness (FVT) and fire retardant (FR) concentration on the fire performance of birch plywood. The FR treatment was applied by roller coating with the main and diluted (70 %) concentrations of a new protic ionic liquid, FR. Three FVTs were evaluated: 1.0 mm, 1.5 mm and 2.6 mm. The cone heater test demonstrated that the 70 % diluted FR did not provide adequate fire protection, while the plywood batches with 2.6 mm FVT provided a better reaction to fire. Conversely, the SBI test revealed that the 1.5 mm plywood meets the EUROCLASS B requirement for building applications, mainly because of the 2.6 mm FVT's 3 % higher total heat release compared to the EUROCLASS requirement. This outcome suggests magnified non-uniformity in large samples, particularly insufficient coverage of FR despite deep penetration with 2.6 mm FVT. Given the current plywood industry practices, roller coating with the main concentration of the protic ionic liquid FR and a 1.5 mm FVT is a feasible method to improve the fire performance of birch plywood for construction applications.

Si-N Matrix as an Effective Fire Retardant Source for Cotton Fabric, Prepared through Sol–Gel Process

In this study, process control factors such as dipping time, heat treatment time and curing conditions were optimized to prepare N-Si network sol–gel-based coatings on a cotton fabric. The dipping time was varied from 14 h to 30 min, the heat treatment time at ~90 °C was varied between no heating conditions to 15 h and the curing was performed at 165 °C. The microstructure of the coating was analyzed using low electron scanning microscopy (LV-SEM), while a compositional study of the coated substrate was carried out using FTIR and EDS techniques. From the thermal and combustion analysis of the coated samples using thermogravimetric and vertical flame test techniques, significant resistance to the degradation process was observed, particularly in the initial stages, in addition to the highest char residue for DI-0.5 h-15~32.93%. Similarly, for DI–5 h–RT, the peak degradation temperature was around ~372 °C, accompanied by a notable char residue of approximately 31.12%. The flame spread and burning rate profile further supported the findings; DI-0.5 h-15 and DI-5 h-RT had the lowest flame spread.

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.

Investigation on the Performance of Fire and Smoke Suppressing Asphalt Materials for Tunnels

The volatilization of asphalt fumes not only affects the health of construction workers, but also damages the environment. It even affects the construction quality of asphalt pavement in tunnels. This article focuses on solving the emission of asphalt fumes to better protect human health and the environment, while satisfying the use of asphalt pavement. A flame retardant and smoke suppressant (compound) with Mg(OH)2 as the main component was developed, and flame retardant asphalt mixture and asphalt mastics were prepared to evaluate the flame retardant and smoke suppressant properties and performance effects. Firstly, its low- and high-temperature performances were investigated with BBR and DSR, respectively. Then, the indoor combustion test and the cone calorimeter test were used to evaluate the fire retardant smoke suppression effect of the asphalt mastic. Thirdly, the flame retardant effect of asphalt mastic mixed with the compound was further analyzed by the TG test and SEM. The pyrolysis temperature, mass loss, and microscopic state of the asphalt surface were used to verify and explain the flame retardant reaction effect and process of the compound. Finally, the asphalt mixture performance was evaluated, as well as the flame retardant smoke suppression effect by asphalt mixture combustion tests. The results showed that the flame retardant smoke suppression time of the flame retardant asphalt mixture was reduced by 66%, and the smoke emission area was reduced by 20%. The flame retardant smoke suppression effect of the asphalt mixture was improved by 44%. It is proven that this kind of fire retardant and smoke suppressing asphalt mastic and mixture met performance needs in use, and the fire retardant and smoke suppressing effect was obvious. This solution addresses the issue of asphalt smoke generated during the construction of asphalt pavement, providing better support for the construction of asphalt pavement in tunnels.

Design of Experiments-Based Fire Performance Optimization of Epoxy and Carbon-Fiber-Reinforced Epoxy Polymer Composites.

The fire performance of epoxy and carbon-fiber-reinforced polymer (CFRP) composites with and without fire retardants (FR) (i.e., ammonium polyphosphate (APP), aluminum trihydroxide (ATH), melamine (MEL), expandable graphite (EG)) was investigated. A design of experiment (DoE) approach was applied to study the single- and multifactorial effects of FR. The fire performance of epoxy and CFRP was evaluated by limiting the oxygen index (LOI) and heat release, which were obtained by limiting the oxygen index test and cone calorimetry. It was found that mixtures of 70 wt.-% epoxy, 24.6 wt.-% of APP, and 5.4 wt.-% MEL resulted in the highest LOI level of 45 within tested groups for epoxy resin and also for CFRP specimens (LOI level of 39). This mixture also resulted in the lowest average heat release rate (HRR180s) of 104 kW·m-2 and a spec. total heat release (THR600s) of 1.14 MJ·m-2·g-1, indicating the importance of balancing spumific and charring agents in intumescent systems and synergy thereof.

The effect of impregnation with fire retardant on the properties of particleboard bonded with PF/pMDI adhesive

ABSTRACT The application of commonly used flame retardants in most cases causes reduction in strength characteristic of particleboard. Therefore, it was decided to carry out research aimed at determining possibility of using pMDI-reinforced PF adhesive to produce board with increased fire resistance. The effect of different shares of particles impregnated with a mixture of potassium carbonate and urea on the particleboard properties such as density, density profile, bending strength, modulus of elasticity, internal bond and internal bond after boiling was investigated. Presented work also determined the effect of fire retardant on the performance of particleboards after ageing test and their reaction to fire. Studies demonstrated that PF adhesive modified with 20% pMDI is suitable for gluing impregnated wood particles. Regardless of their share, resultant panels showed no changes in strength and density. In the case of boards consisting of impregnated particles in the amount of 75% and 100%, lower values of swelling were demonstrated. The boards were classified as load-bearing boards for use in humid conditions. Fire retarding efficiency was confirmed by lowered mass loss, prolonged time needed to reach maximal burning rate, decreased gross calorific value and reduced ignitability when exposed to both radiant heat source and small flame source.

Synergistic fire retardancy of melamine resin modified with pentaerythritol and ammonium polyphosphate in PP

AbstractThe synergistic fire retardancy of modified melamine resin with pentaerythritol (MF‐PER, a novel green and effective triazine charring agent), and ammonium polyphosphate (APP) in polypropylene was investigated by UL‐94 test, LOI measurement, and cone calorimetry test. It is found that the synergism of MF‐PER is obviously better than pentaerythritol (PER). MF‐PER/APP imparts a fire retardancy mainly by the following mode: in burning process, MF‐PER, and APP are first pyrolyzed respectively into polyols and polyphosphoric acid, which is esterified to form phosphoric ester, and the inert gases make the molten residues foaming; When the temperature increases, and polyphosphoric acid is dehydrated to polymetaphosphoric acid, which dehydrates phosphoric ester to form an intumescent char layer, inducing a fire retardant effect by barrier effect. The graphitization degree of the cone calorimetry test residues of the FR‐PP with MF‐PER is higher than that with PER, which leads to a better synergism.Highlights Melamine formaldehyde resins modified with pentaerythritol (MF‐PER) as a novel triazine charring agent was designed and synthesized. MF‐PER is synthesized by solid phase method and using hexahydroxymethyl melamine (HMM) instead of cyanuric chloride as raw material, so the emission of three wastes in its synthesis process is very little, only a small amount of formaldehyde and water are produced. MF‐PER has excellent synergistic fire retardancy with APP in polypropylene. The highly efficient and environmentally benign charring agent show great potential for developing more efficient and eco‐friendly IFR.

The Effect of Flame-Retardant Additives DDM-DOPO and Graphene on Flame Propagation over Glass-Fiber-Reinforced Epoxy Resin under the Influence of External Thermal Radiation.

The flammability of various materials used in industry is an important issue in the modern world. This work is devoted to the study of the effect of flame retardants, graphene and DDM-DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide-4,4'-diamino-diphenyl methane), on the flammability of glass-fiber-reinforced epoxy resin (GFRER). Samples were made without additives and with additives of fire retardants: graphene and DDM-DOPO in various proportions. To study the flammability of the samples, standard flammability tests were carried out, such as thermogravimetric analysis, the limiting oxygen index (LOI) test, and cone calorimetry. In addition, in order to test the effectiveness of fire retardants under real fire conditions, for the first time, the thermal structure of downward flame propagation over GFRER composites was measured using thin thermocouples. For the first time, the measured thermal structure of the flame was compared with the results of numerical simulations of flame propagation over GFRER.

High-yield preparation of coal tar pitch based porous carbon via low melting point fire retardant carbonation strategy for supercapacitor

Currently, the preparation of porous carbon materials with low-cost, high yield and excellent capacitive performance that carbonized carbon precursors in air is suffering from strong technical bottlenecks. In this work, we reported an efficient and simple method for the preparation of high yield porous carbon by carbonizing coal tar pitch (CTP) with the assistance of fire retardants in muffle furnace in air. We investigated in detail the effect of potassium salt fire retardants with different melting points on the yield and morphology of porous carbon, and the fire retarding mechanism in air. Fire retardants could not only prevent CTP from burning completely, but also used as heteroatomic source and morphology regulator to get the heteroatom doped honeycomb structure carbon. It was found that the lower the melting point of the fire retardants, the higher the carbon yield. The yield of N and F doped porous carbon (CKKF700-3) prepared by the optimized K2CO3-KCl-KF molten salt fire retardant was 40.2 wt%, and exhibited excellent supercapacitor performance (379.8F g−1). The energy density of the symmetrical supercapacitor device composed of CKKF700-3 and K2CO3 based deep eutectic solvent electrolyte was 43.7 Wh kg−1, and it could work properly at extreme temperature from −25 to 105 °C

Functionalised biochar in biocomposites: The effect of fire retardants, bioplastics and processing methods

Fire retardants, although can impart fire-safety in polymeric composites, are detrimental to the mechanical properties. Biochar can be used, in conjunction with fire retardants, to create a balance between fire-safety and mechanical performance. It is possible to thermally dope fire retardants into the pores of biochar to make it functionalised. Thus, the current work is intended in identifying a composite having the combination of the most desirable fire retardant, bioplastic, and a suitable processing method. A comparison was made between two fire retardants (lanosol and ammonium polyphosphate), bioplastics (wheat gluten and polyamide 11), and composite processing methods (compression and injection moulding). It was found that wheat gluten containing ammonium polyphosphate-doped biochar made by compression moulding had the best fire-safety properties with the lowest peak heat release rate (186 kW/m2), the highest fire performance index (0.6 m2s/kW), and the lowest fire growth index (1.6 kW/ms) with acceptable mechanical properties compared to the corresponding neat bioplastic. Thus, for gluten-based polymers, the use of ammonium polyphosphate thermally doped into biochar processed by compression moulding is recommended to both simultaneously improve fire-safety and conserve the mechanical strength of the resulting biocomposites.

Robust, Flame-Retardant, and Anti-Corrosive Waterborne Polyurethane Enabled by a PN Synergistic Flame-Retardant Containing Benzimidazole and Phosphinate Groups.

Waterborne polyurethanes (WPUs) have attracted great interest owing to their environmentally friendly properties, and are wildly applied in production and daily life. However, waterborne polyurethanes are flammable. Up to now, the challenge remains to prepare WPUs with excellent flame resistance, high emulsion stability, and outstanding mechanical properties. Herein, a novel flame-retardant additive, 2-hydroxyethan-1-aminium (2-(1H-benzo[d]imidazol-2-yl)ethyl)(phenyl)phosphinate (BIEP-ETA) has been synthesized and applied to improve the flame resistance of WPUs, which has both phosphorus nitrogen synergistic effect and the ability to form hydrogen bonds with WPUs. The WPU blends (WPU/FRs) exhibited a positive fire-retardant effect in both the vapor and condensed phases, with significantly improved self-extinguishing performance and reduced heat release value. Interestingly, thanks to the good compatibility between BIEP-ETA and WPUs, WPU/FRs not only have higher emulsion stability, but also have better mechanical properties with synchronously improved tensile strength and toughness. Moreover, WPU/FRs also exhibit excellent potential as a corrosion-resistant coating.

Combination effects of a bio-based fire retardant and functionalized graphene oxide on a fire retardant and mechanical properties of polylactide

The intrinsic brittleness and flammability of polylactide (PLA) hamper its further application in the industrial and civil fields. Aiming at this point, a bio-derived core-shell flame retardant (CSFR) was applied to improve the flame retardancy of PLA under the condition of maintaining the environmentally friendly profile of this bio-based polymer in this work. However, the enhancing effect of the CSFR on the mechanical properties of PLA was quite limited, and even a deteriorating effect was found on its rigidity. Therefore, functionalized graphene oxide (GO) was utilized through the masterbatch method, which improved not only the flame retardancy but also the mechanical properties such as modulus and impact toughness. The data showed that the combined effect of the CSFR and GO could facilitate to fabricate the flame retardant PLA with better thermal and mechanical properties. PLA/GO-3/4%CSFR got the highest notched impact strength (11.29 kJ/m2), better Young's modulus (4.1 GPa), and improved elongation at break (7.5%). Through the analysis of condensed and gas phase products, it was found that the CSFR and GO performed their function by the condensed-phase flame retardant mechanism.

Kaolin-embedded cellulose hydrogel with tunable properties as a green fire retardant

This study reports the synthesis of methylene bisacrylamide (MBA) crosslinked cellulose-kaolin (CMK) composite hydrogels. The internal structures of hydrogels were deduced using network parameters, viz. elastic modulus, average molecular weight, mesh size, and effective crosslink. Meanwhile, combustion behavior was investigated using the cone calorimeter test (CCT), limiting oxygen index (LOI) test, vertical flammability test (VFT), and open fire test (OFT). Our results revealed that kaolin addition improves the fire retardancy of hydrogels but reduces their swelling ability. Hydrogel having cellulose to MBA ratio of 1:2 and 2 % w/v kaolin (CM2K2) produced 63 % wt. char residue and the hydrogel-coated cotton fabric exhibited the lowest heat release rate (HRR) of 26.60 kJ/m2 and total heat release (THR) of 0.9 MJ/m2. The LOI of the cotton fabric surged from 20 % to 34.37 % after hydrogel coating. Kinetic analysis using the isoconversional model yielded the highest activation energy (216 kJ/mol) for the CM2K2 hydrogel, corroborating the increased LOI after kaolin addition. VFT and OFT validated the delay in the burning process and the formation of a char layer, which protected the underlying layer of cotton from burning. Overall, cellulose-kaolin hydrogels developed in this study are effective green fire retardant coatings for flammable materials.

Effect of metal fire retardants on fire resistance and operational characteristics of intumescent fire-protective coating for wood

Fire-protective properties for wood (according to GOST 16363) and hiding power (according to ISO 6504-3) were tested for eighteen samples of intumescent coatings with various combinations and ratios of metal-containing fire-retardant additives in order to distinguish the optimal metal fire retardant for future use in designing the formulation and technological scheme for production of intumescent fire-protective coating with enhanced operational characteristics.

Fire-retardant properties of wood modified with sorbitol, citric acid and a phosphorous-based system

Abstract Scots pine sapwood (Pinus sylvestris L.) was modified with an aqueous solution of sorbitol and citric acid (SorCA) and a commercial phosphorus-based fire-retardant (FR). The aim of this study was to assess whether the fire behavior can be improved when the SorCA solution is supplemented by an FR and if this effect is resistant to leaching. The fire behavior of modified wood was investigated by a Bunsen burner ignition test, mass loss calorimetry (MLC) and thermogravimetric analysis (TGA). The results demonstrated a significantly improved fire-retardancy based on a decreased burning rate and a reduced mass loss in the Bunsen burner test. Also, the induced formation of a protective char barrier facilitated by the addition of a FR, reduced the heat release rate and delayed the ignition. The fire-retardant effect was still observed, to the less extent, after a cold-water (EN 84 2020) leaching of the specimens.

Mechanisms of the Action of Fire-Retardants on Reducing the Flammability of Certain Classes of Polymers and Glass-Reinforced Plastics Based on the Study of Their Combustion.

In the present review, using an integrated approach based on the experimental and theoretical study of the processes of thermal decomposition and combustion of practically important polymers, such as polymethyl methacrylate, polyethylene, and glass-fiber-reinforced epoxy resin, the features of the mechanism for reducing the combustibility of these materials with phosphorus-containing flame-retardants (FR), as well as graphene, are identified. A set of original experimental methods was developed and applied that make it possible to study the kinetics of thermal decomposition and the thermal and chemical structure of the flames of the studied materials, including those with FR additives, as well as to measure the flame propagation velocity, the mass burning rate, and the heat fluxes from the flame on the surface of a material. Numerical models were developed and tested to describe the key parameters of the flames of the studied polymeric materials. An analysis of the experimental and numerical simulation data presented showed that the main effect of phosphorus-containing fire-retardants on reducing the combustibility of these materials is associated with the inhibition of combustion processes in the gas phase, and the effect of adding graphene manifests itself in both gas and condensed phases.