Flame Retardant Coatings Research Articles

Flame-retardant cotton fabrics modified with phosphoramidate derivative via electron beam irradiation process

In this study, a novel flame-retardant diethyl methacryloylphosphoramidate containing phosphorus and nitrogen was synthesized and characterized by Fourier transform infrared and nuclear magnetic resonance. The synthesized compound was grafted onto cotton fabrics using electron beam irradiation and pad dry cure processes. Scanning electron microscope and X-ray photoelectron spectroscopy were used to characterize the surfaces of the modified cotton fabrics to confirm that diethyl methacryloylphosphoramidate was grafted on cotton fabrics successfully. Both electron beam–cotton and pad dry cure–cotton exhibited efficient flame retardancy which was proved by limiting oxygen index and vertical flammability test. Thermogravimetric analysis results showed that both electron beam-cotton and pad dry cure–cotton degraded at lower temperature and produced higher yields at 600℃. The tensile loss of electron beam–cotton was lower than that of pad dry cure–cotton, and within the acceptable range in flame retardant finishing.

Research progress of bio-based polymer flame retardant coating

Bio-based polymers have been applied to packaging, automobiles, electronic appliances and other fields because of their green, environmental-friendly, renewable and biodegradable properties. Some bio-based polymers (such as chitosan, starch, etc.) are gradually used in the flame retardant field due to their good char-forming abilities. These bio-based polymers are mainly introduced into the material by adding and coating methods to give the material good flame retardant properties. In this paper, the research progress of flame retardant coatings made of bio-based polymer materials such as chitosan, starch, DNA and phytic acid, including the composition, coating mode and flame retardant effect of each coating, is reviewed. Moreover, several bio-based functional flame retardant coatings are briefly introduced. Finally, the development trend of bio-based flame retardant coating is prospected.

A Green Water-Soluble Cyclophosphazene as a Flame Retardant Finish for Textiles.

Poly- and cyclophosphazenes are excellent flame retardants but currently, are not used as textile finishing agents because water-soluble and permanent washing systems are missing. Here, we demonstrate for the first time, the successful usage of a water-soluble cyclotriphosphazene derivative for textile finishing for cotton, different cotton/polyester, and cotton/polyamide blend fabrics. A durable finish was achieved using a photoinduced grafting reaction. The flame retardant properties of the various fabrics were improved with a higher limiting oxygen index, a reduced heat release rate, and an exhibition of intumescent. Furthermore, the finished textiles passed several standardized flammability tests.

Enhanced Thermal Properties of Zirconia Nanoparticles and Chitosan-Based Intumescent Flame Retardant Coatings

Zirconia (ZrO2)-based flame retardant coatings were synthesized through the process of grinding, mixing, and curing. The flame retardant coatings reinforced with zirconia nanoparticles (ZrO2 NPs) were prepared at four different formulation levels marked by F0 (without adding ZrO2 NPs), F1 (1% w/w ZrO2 NPs), F2 (2% w/w ZrO2 NPs), and F3 (3% w/w ZrO2 NPs) in combination with epoxy resin, ammonium polyphosphate, boric acid, chitosan, and melamine. The prepared formulated coatings were characterized by flammability tests, combustion tests, and thermogravimetric analysis. Finally, char residues were examined with scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The peak heat release rate (PHRR) of the controlled sample filled with functionalized ZrO2 NPs was observed to decrease dramatically with increasing functionalized ZrO2 NPs loadings. There was an increase in the limit of oxygen index (LOI) value with the increase in the weight percentage of ZrO2 NPs. The UL-94V data clearly revealed a V-1 rating for the F0 sample; however, with the addition of ZrO2 NPs, the samples showed enhanced properties with a V-0 rating. Thermal gravimetric analysis (TGA) results revealed that addition of ZrO2 NPs Improved composite coating thermal stability at 800 °C by forming high residual char. The results obtained here reveal that the addition of ZrO2 NPs in the formulated coatings has shown the excellent impact as flame retardant coatings.

Layer-by-layer-assembled flame-retardant coatings from polydopamine-induced in situ functionalized and reduced graphene oxide

An environmentally friendly chemical method was used to reduce the graphene oxide (GO) and subsequently, noncovalent functionalization of the GO with dopamine hydrochloride was carried out via self-polymerization reaction under a weak alkaline condition. The as-prepared nanocomposite was donated as PDA-rGO and later on, flame-retardant coatings were developed into the flexible polyurethane foams (FPUFs) surfaces using polyacrylic acid, and polyethyleneimine along with PDA-rGO via layer-by-layer assembly. The growth process of the deposited coatings was tailored by altering the pH and concentration of the PDA-rGO suspension. Cone calorimeter test results indicated that PDA-rGO-based coating with three tri-layer deposition effectively reduced the peak heat release rate by 49.3%, the total smoke release by 33.1%, and the peak of release for the production of CO by 46.2% compared to the neat FPUF, which could be attributed to the physical barrier effect of rGO sheets and the free-radical scavenging property of polydopamine.

Effect of a flame­retardant coating on the burning parameters of wood samples

The studies of influence of wood fire protection on ignition have established parameters of flame propagation and combustion suppression which makes it possible to influence this process. It was proved that fire protection consists in creation of a layer on the material surface which prevents the material from warming up to its critical temperature. Experimental studies confirmed that the untreated wood specimen ignited under thermal action resulting in its combustion with a burnout rate of 18 g/(m2∙s). With an increase in intensity of combustion of the ignition gas mixture by 25 % and 50 %, rate of the specimen weight loss increased by 1.4 times and 1.8 times, respectively. In the case of wood impregnation, the rate of weight loss was reduced to 4.8 g/(m2∙s) due to decomposition of flame retardants under thermal action with release of non-combustible gases which inhibited material oxidation and formed a coke layer. When treating wood with an inorganic coating, a heat-resistant ceramic film is formed on the wood surface which reduces the burnout rate 3.8 times. But with an increase in intensity of combustion of the igniting gas mixture by 50 %, the wood specimen has ignited which was reflected by increase in the weight loss rate. Application of organic-mineral coatings under thermal action has resulted in formation of a layer of foamed coke, inhibition of heat transfer from high-temperature flame and reduction of burnout rate to 3 g/(m2∙s). This has made it possible to determine conditions of change and inhibition of the combustion parameters for fire protection of wood by creation of a barrier for thermal conductivity. The results of comparison of experimental data on the wood burning rate with the derived analytical equations have shown conformity between them. Thus, there are grounds to assert about the possibility of directed regulation of processes of wood fire protection by using flame retardant coatings capable of forming a protective layer on the material surface that reduces the wood burnout rate

An emerging mineral-based composite flame retardant coating: Preparation and enhanced fireproof performance

An emerging composite flame retardant has been prepared by sodium modification of natural mineral rectorite (REC), and waterborne intumescent fire retardant coating (IFR-Na-REC) containing sodium-modified rectorite (Na-REC) was successfully fabricated. The flame retardancy, morphology, structure, chemical composition and mechanical property of the intumescent coating were in detail investigated. The results showed that Na-REC could greatly promote the heat insulation effect of waterborne intumescent coatings. The temperature of the backside of steel plate for the IFR-Na-REC coating with 10% Na-REC was recorded to be 202 °C after 60 min of fire test, 24 °C lower than that of the control coating, and the flame retardant time reached up to 119 min. The enhanced fireproof performance could be attributed to the increased adhesion of the coating to the substrate and the formation of ceramic-like protective layer between rectorite and components in intumescent coating, which acted as a fire barrier to protect the internal matrix. Our work could offer a more benign approach to the general production of composite flame retardant coatings for fire protection.

Facile flame retardant finishing of cotton fabric with hydrated sodium metaborate

Flame retardant (FR) cotton fabric was facilely prepared using hydrated sodium metaborate (SMB) crystalized in situ in the interstices and on the surface of cotton fabric via one-pot impregnation approach, and the thermal, FR and mechanical properties were investigated. TGA results showed that SMB treatment improved the thermal stability of cotton fabric and enhanced the char yield. The treated cotton also had an LOI value of 28.5% with an afterglow time of less than 1 s in the UL-94 test (V-0). Considerable reductions in peak heat release rate (PHRR ~ 91.8%), total heat release (THR ~ 47.2%), peak carbon monoxide and carbon dioxide produced (PCOP ~ 28.6, PCO2P ~ 85.5%) were obtained. The postburn residues examined by SEM and Raman spectroscopy revealed a preserved fabric structure with high graphite content. SMB treated cotton fabrics demonstrated negligible changes in the tensile strength and the elongation at break. The result demonstrates SMB as an effective flame-retardant for cotton fabrics.

NanoTiO2@DNA complex: a novel eco, durable, fire retardant design strategy for cotton textiles

A strategy for the design of cotton flame retardant coatings is described, exploiting the natural intumescent formulation of nucleic acids, the intrinsic thermal inertia of TiO2 ceramic phase and the strong affinity that TiO2 nanoparticles shows for amphiphilic biomolecules (e.g. proteins, nucleic acids) and hydrophilic substrates. Two different self-assembled TiO2@DNA systems are obtained by mixing two opposite charged TiO2 nanoparticles suspensions with DNA solution. The colloidal behavior of separate and mixed phases was investigated, as well as the morphological, chemical structure and thermal properties of resulting coatings, in order to make some hypothesis on the observed synergic effects. Scanning electron microscopy (SEM) and Attenuated Total Reflectance (ATR) spectroscopy demonstrated the homogeneous distribution of nano-TiO2@DNA based coatings on the treated fabrics. The washing fastness tests evidenced the highly improved performance of hybrid coatings if compared with DNA alone. The flammability and cone calorimetry test results confirmed this positive synergy that resulted quite effective in slowing down (or even blocking) the propagation of a flame within the treated substrates and in improving the resistance of the fabrics to the applied heat flux, these latter leaving increased residues at the end of the test.

Mechanochemical Phosphorylation of Polymers and Synthesis of Flame-Retardant Cellulose Nanocrystals

Phosphorylated polymers are versatile materials for a broad range of applications from flame-retardant coatings to bioactive scaffolds. Traditionally, they are synthesized in solution using corrosi...

Flame retardant finishing of the polyester/cotton blend fabric using a cross‐linkable hydroxy‐functional organophosphorus oligomer

SummaryBlend fabrics of cotton and polyester are widely used in apparel, but high flammability becomes a major obstacle for applications of those fabrics in fire protective clothing. The objective of this research was to investigate the flame retardant finishing of a 50/50 polyester/cotton blend fabric. It was discovered previously thatN,N′‐dimethyloldihydroxyethyleneurea (DMDHEU) was able to bond a hydroxy‐functional organophosphorus oligomer (HFPO) onto 50/50 nylon/cotton blend fabrics. In this research, the HFPO/DMDHEU system was applied to a 50/50 polyester/cotton twill fabric. The polyester/cotton fabric treated with 36% HFPO and 10% DMDHEU achieved char length of 165 mm after 20 laundering cycles. The laundering durability of the treated fabric was attributed to the formation of polymeric cross‐linked networks. The HFPO/DMDHEU system significantly reduced peak heat release rate (PHRR) of cotton on the treated polyester/cotton blend fabric, but its effects on polyester were marginal. HFPO/DMDHEU reduced PHRR of both nylon and cotton on the treated nylon/cotton fabric. It was also discovered that the nitrogen of DMDHEU was synergistic to enhance the flame retardant performance of HFPO on the polyester/cotton fabric.

Effect of Graphene on Flame Retardancy of Graphite Doped Intumescent Flame Retardant (IFR) Coatings: Synergy or Antagonism

A comparative study between graphene and modified graphene oxide (mGO) on the flame retardancy of graphite doped intumescent flame retardant (IFR) coatings is preliminarily investigated by cone calorimeter (CC), XRD, and SEM, with the final aim of clarifying the interactions between different graphenes and graphite doped coatings (polyester resin-ammonium polyphosphate-urea-pentaerythritol). The CC results determine that graphene exerts an obviously antagonistic effect on flame resistance, evidenced by the increased peak heat release rate (p-HRR) of 56.9 kW·m−2 for SD8+graphene (sample coating contains graphite with a particle size of 8 μm and 0.5 wt.% graphene as dopant), which increased by 80.6% compared with SD8 (coating contains graphite with a particle size of 8 μm); substitution with graphene or mGO imparts an acceleration of fire growth, because graphene inertness improves the viscosity of melting system, evidenced by the cracked appearance and porous structure of SD8+graphene. However, the higher reactivity of mGO favors the combustion; the barrier effect inhibits the transfer of mass and heat simultaneously, leading to a slight influence on flame retarding efficiency.

СПОСОБЫ И СРЕДСТВА ОБЕСПЕЧЕНИЯ ТРЕБУЕМЫХ ПОКАЗАТЕЛЕЙ ПОЖАРОБЕЗОПАСНОСТИ КОНСТРУКЦИЙ ИЗ ПОЛИМЕРНЫХ КОМПОЗИТОВ (ОБЗОР)

Introduction. Publications reflecting the peculiarities of creating structures made of polymer composite materials (PCM) on determining the required fire-safety level are studied. It was noted that insufficient attention to ensuring the required level of fire resistance of PCM structures, which prevents their use in various fields and, in particular, in engineering is paid. Analytical part. The analysis of publications on research flame retardant efficiency of intumescent flameretardant coatings (FRC) indicators as one of the polymer types and fire protection means of structures made of PCM is carried out. The necessity of solving the urgent task of ensuring the required adhesion between the FRC and PCM, as well as ensuring durability and durability of coatings during the operation period is noted. The results, indicating the possibility of a significant improvement in the PCM fire risk indicators at a relatively low coating thickness are presented. The analysis of publications showed the important role and possibilities of heat engineering calculations for modeling temperature fields in structures and determining the required thicknesses of intumescent FRC and other fire protection equipment. This role is partly associated with the fact of impossibility of testing such PCM structures as well. It is shown that there is a technique that is currently being successfully used to calculate the heating of polymer composite structures and can be considered as a basis for further improvement. As can be seen from the presented simulation results, bearing composite structures have to be designed in an optimal shape, which, in combination with fire-retardant coatings, will ensure their fire resistance. Conclusion. The results, demonstrating possible ways to ensure the required fire safety indicators of the PCM structures are presented. On this important and promising topic, tasks that need to be carried out are also noted.

INVESTIGATION OF THE EFFICIENCY OF THE STEEL TUBE CONFINEMENT CONCRETE PILLARS PROTECTION BY FIRE-RETARDANT MATERIALS

Currently, in Ukraine and abroad for the construction of high-rise buildings and structures using pipe-like structures. Wide application of pipe concrete columns is due to their high carrying capacity at relatively smaller overall dimensions due to the blocking of cracking in concrete by a steel clasp. The advantages of concrete columns should include more simplified conditions of technology of manufacturing and installation on their basis of bearing structures of floor covering.
 Piping constructions consist of steel shells and concrete core. Since the steel pipe mainly provides the bearing capacity of the concrete column, its failure or reduction of stiffness, which is characteristic of the fire under the influence of its thermal factors, leads to destruction. Investigation of fire resistance of concrete structures, which are not protected by flame retardant coatings, showed that a steel clasp during a fire after 15 minutes is heated to a critical temperature of 500 ° C.The use of flame retardant coatings is an effective method of fire protection of concrete constructions, which prevents the rapid heating of steel welds and provides a normalized fire resistance limit for such structures. In this work, studies were carried out on the effectiveness of fire protection of concrete columns with different types of fire-retardant materials - mineral wool slabs, special flame retardants and flame-retardant coatings. For fire protection mineral wool materials were used ROCKWOOL plates of the series "Conlit SL150". Mineral wool plates "Conlit SL 150" consist of fibers of rocks of a basalt group, they can withstand, without melting, temperature more than 1000 ° С. The silica-based adhesive "Conlit Glue" can withstand temperatures above 900 ° C, has good adhesion when bonding Conlit SL 150 mineral wool slabs with protective structures. From the second type of fire-retardant materials, the fire-proof composition "Naktresk" was chosen on the basis of gypsum. The coating is formed in the process due to hardening of the mixture on protected surfaces. The third type of flame retardant materials is the flame-retardant intumessent coating "Pyro-Safe Flammoplast SP-A2".It has been established that with the use of fire protection systems on the basis of mineral wool plates "Conlit SL150" and fire retardant "Nutresc", the fire resistance class of reinforced concrete columns increases from R 15 to R 180. The fire protection system on the basis of the painted paint "Pyro-Safe Flammoplast SP-A2" »Increases fire resistance from R 15 to R 75

High synergistic effects of natural-based tea saponin in intumescent flame-retardant coatings for enhancement of flame retardancy and pyrolysis performance

Tea saponin intumescent flame-retardant coatings (TS-IFRCs) is a green and high-efficiency flame-retardant coating based on natural-based tea saponin (TS), and has been confirmed with superior flame retardancy. The present study determined and assessed the effects of TS on the flame-retardant mechanism in composite tea saponin intumescent flame-retardant coatings (CTS-IFRCs) through the analysis of TG-DSC, FT-IR, SEM-EDS and pyrolysis kinetics. It has been demonstrated from the results that TS, synergized with other components in CTS-IFRCs, has direct and significant impacts on the char layer microstructure, flame retardancy and pyrolysis performance, these influences contributed to the double effects of TS as a blowing agent in gas phase flame-retardant mechanism, and as a carbon agent in condensed phase flame-retardant mechanism. High synergistic effects of natural-based TS revealed in this study have provided effective theoretical basis for emerging environmentally friendly bio-based flame-retardant materials and explored a new way for the utilization of TS.

Use of DMDHEU with novel FR chemical for CO/PET blends

In present study, DMDHEU (dimethylol dihydroxyethyleneurea), which has been used for wrinkle-resistant finishing in textile, was used in FR finishing of CO/PET blends as a crosslinker with novel FR chemical (Fire-off). Flame retardancy performance of CO/PET fabrics treated with Fire-off and Fire-off/DMDHEU were investigated and compared. In addition, wrinkle resistant test was performed for untreated and Fire-off/DMDHEU treated fabrics to investigate the effect of the treatment on wrinkle recovery performance of fabrics. Results showed that Fire-off/DMDHEU system is a more effective nitrogen provider than Fire-off alone to enhance the flame retarding performance of the treated CO/PET fabrics through phosphorus-nitrogen synergism, therefore the presence of DMDHEU in the flame retardant finishing system increases the flame resistance of the treated CO/PET fabric. In addition, DMDHEU does not significantly change the wrinkle recovery of fabrics when used with Fire-off.

UV-curable flame-retardant coatings based on phosphorous and silicon containing oligomers

Current research on flame-retardant coatings explores alternatives to halogen-based products. Reactive compounds based on phosphorous and silicon were synthesized and cooperated in epoxy acrylate oligomers to form UV-curable flame-retardant wood coatings. FTIR, 1H NMR, hydroxyl and iodine values confirmed successful synthesis of these products. The effect of the varying proportion of the synthesized compounds on the mechanical, chemical and thermal properties of photopolymerized coatings was investigated. Further, the efficacy of flame retardants was estimated by limiting oxygen index and UL-94 vertical burning test. The synergistic behavior between silicon and phosphorous resulted in an optimum formulation giving an LOI of 24 and VTM-0.

Waterborne polyurethanes: A three step synthetic approach towards environmental friendly flame retardant coatings

Flame retardant waterborne polyurethanes (WBPU) were synthesized by reacting a phosphorous based polyester polyol with isophorone diisocyanate (IPDI) in different mole ratios of NCO:OH in three steps. In first step, the polyester polyol was synthesized by reacting tris(bisphenol-A)mono phosphate (TBAMP), sebacic acid, polyethylene glycol which was characterised by measuring acid value and hydroxyl value. Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy and gel-permeation chromatographic techniques were used for the characterization of polyester polyol. In second step, the polyurethanes were synthesized by reacting polyester polyol with diisocyanate in different proportions. In third step, the polyurethane was neutralised using tertiaryamine. A calculated amount of water was then added at this stage followed by addition of a chain extender at controlled pH. This resulted into waterborne polyurethanes. By varying the proportion of NCO/OH, four WBPUs have been prepared. These WBPUs were subjected for coating and casting purposes. Physico-chemical properties such as particle size, dispersion stability, viscosity were measured. The flame retardency of casted films were studied by LOI (limiting oxygen index) and UL-94 test methods. Thermal properties were determined using thermogravimatric analysis (TGA) technique of casted film. Chemical resistance and Mechanical properties of the coated samples have been found out.

Boron-containing UV-curable oligomer-based linseed oil as flame-retardant coatings: synthesis and characterization

A boron-containing UV-curable oligomer was derived from linseed oil, phenylboronic acid and glycidyl methacrylate to use in flame-retardant coating applications. The synthesized UV-curable oligomer was characterized for its structural and physicochemical properties by means of Fourier transform infrared (FTIR), 1H and 11B-nuclear magnetic resonance (NMR) spectroscopy techniques. The boron-containing UV-curable oligomer (BELO) was added to a conventional polyurethane acrylate (PUA) at varying concentrations ranging from 10 to 40 wt% in the presence of a photoinitiator and a reactive diluent. LOI and UL-94 tests were performed to understand the flame-retardancy behavior of the synthesized BELO oligomer, and the results revealed that the flame retardancy of UV-curable coatings enhanced as the percentage of BELO oligomer in the coating formulations increased. The glass transition temperature (Tg) and thermal stability of cured coatings were analyzed by differential scanning calorimetry and thermogravimetric analysis, respectively. The TGA analysis showed that char yield at 600 °C increased by increasing the BELO oligomer content. The mechanical properties, and stain, solvent, and chemical resistance and thermal behavior of the coatings were investigated. Incorporation of BELO into the PUA coating formulations and the comparison of the properties of BELO-incorporated PUA coatings with those of the conventional PUA coating exhibited interesting results.

One-pot fabrication of superhydrophobic and flame-retardant coatings on cotton fabrics via sol-gel reaction

Waterproof and flame-retardant fabrics are widely utilized in many fields, such as automotive interiors, indoor decorations, outdoor clothing and tents. Herein, a facile one-pot sol-gel approach was developed to construct superhydrophobic and flame-retardant (SFR) coatings on cotton fabrics. The cotton fabric was activated by O2 plasma and then immersed into the ethanol suspension containing tetraethoxysilane (TEOS), hydroxyl-terminated polydimethylsiloxane (HPDMS) and ammonium polyphosphate (APP). The hydrogen bonding interaction between APP and cellulose motivated the APP to attach to the cotton fibers during the initial stirring process. After the addition of ammonia, the in situ sol-gel reaction of TEOS and HPDMS was initiated to generate polydimethylsiloxane-silica hybrid (PDMS-silica). The micro-nano structured composite coating on cotton fabric was successfully fabricated by the PDMS-silica and APP. The SFR cotton fabric showed outstanding durability and self-cleaning ability with a water contact angle (WCA) above 160°. When exposed to fire, the SFR cotton fabric quickly charred to extinguish the fire by generating a dense intumescent char layer under the physical barrier effect of PDMS-silica and the intumescent flame-retardant effect of APP. This one-pot approach for fabricating SFR cotton fabric is simple, cost-effective and timesaving, demonstrating significant advantages in practical production.