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In order to explore flame retardant systems with higher efficiency in rigid polyurethane foams (RPUFs), aluminum hydroxide (ATH), [bis(2-hydroxyethyl)amino]-methyl-phosphonic acid dimethyl ester (BH) and expandable graphite (EG) were employed in RPUF for constructing ternary synergistic flame retardant systems. Compared with binary BH/EG systems an...
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... ATH/BH/EG ternary flame retardant systems, the condensed-phase synergistic flame retardant mechanism of ATH with BH/EG was systematically investigated. The ATH/BH/EG ternary synergistic flame retardant mechanism is illustrated in Figure 6. When the RPUFs containing ATH/BH/EG were ignited, EG expanded rapidly and formed a worm-like thermal-insulating layer. ...
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Citations
... Metal hydroxide, Aluminum Tri-hydroxide (Al2O3) (ATH) decomposes its molecule endothermically and also releases water vapor at the lowest pyrolysis temperature [12]. Metal hydroxide, Aluminum Tri-hydroxide (Al2O3) (ATH) decomposes its molecule endothermically and also releases water vapor at the lowest pyrolysis temperature [13]. FRA Tri-hydroxide (Al2O3) 15-20 wt % in the polyamide 11 have better performance of mechanical properties than other nano-clay FRA [14]. ...
Digital light processing (DLP) technology has been developed based on stereolithography (SLA) 3D-printing principle. The biodegradable and low-cost polylactic-acid (PLA) has so far been used as polymeric material for photopolymer resin in SLA and DLP. To achieve functional SLA-processed product, the properties of such PLA has been improved, with the aim to make it flame retardant, less viscous, and having light transmittance characteristics. In this study, the liquid raw PLA photopolymer was changed by adding different contents of Ammonium Phosphate (APP), melamine cyanurate (MCA), Aluminum Tri-hydroxide (Al 2 O 3 ) and Nano-silicon dioxide (SiO 2 ) additives. The solid PLA nanocomposite specimens were printed by using DLP device according to the standard geometry for burning test UL-94 to evaluate its flame-retardant property. In addition, the printing product and residue after burning test was analyzed for their morphological characteristic by using SEM. The results showed that the low weight fraction of MCA showed excellent performance. PLA/MCA successfully kept green body form until the sintering temperature of stainless steel was achieved. It can become a reference for application DLP 3D printing products in the casting and sintering process.
... [10][11][12][13] As one of the most effective methods, the flame-retardant coating method has attracted the attention from researchers in recent years. 14,15 At present, surface flame-retardant coatings are mainly used for steel structures, wood, and fabric, [16][17][18] but research on engineering flame-retardant RPUFs has been limited. [19][20][21] Wang et al. 22 synthesized a silicone resin (poly-DDPM) and coated it with expandable graphite on the surface of RPUF by brush coating to improve the flame retardancy, minimize the damage to the inherent mechanical properties, and increase the limiting oxygen index (LOI) from 18% to 32.3%. ...
The design of environment‐friendly fireproof rigid polyurethane foams (RPUFs) that completely prevent ignition or the spread of fires is important for energy conservation and emission reductions. In this paper, an intumescent flame‐retardant coating was prepared and coated onto the surface of a RPUF to improve its flame retardancy. Vertical combustion experiments (UL‐94) showed that, compared with the pure RPUF, a RPUF coated with the expansion coating successfully self‐extinguished without a droplet formed after ignitor removal. Thermogravimetric analyses showed that the expanded coating effectively increased the rate of carbon residue formation. Cone calorimetry showed that when the pigment‐to‐binder ratio was 3.5:1, with 5% modified montmorillonite, 6% aluminum hydroxide, and 4% titanium dioxide, the intumescent coating effectively reduced the heat release rate and total heat release of the RPUF. Remarkably, the smoke release rate and total exhaust gas volume showed that the expanded coating provided obviously enhanced smoke suppression. Therefore, the flame retardancy and toxic smoke suppression provided by the RPUF thermal insulation material is essential and very useful for healthy development of human society and the environment.
... Foam is a lightweight material. Therefore, it is widely used, replacing other, heavier materials, e.g., in the packaging industry, aviation, transport, construction, military applications, airplanes, furniture, in insulation, toys and the automotive industry [3][4][5][6][7][8][9][10][11][12][13][14]. They are used for products that come into contact with food. ...
... The a*, b* and L* values describe a path (a color trajectory) in the CIELAB color space [55]. Equation (10) was used to calculate the difference between two colors in space: ...
... Apparent density is a very important factor in the usability of RPUFs [10]. The apparent density of the obtained foams containing coffee (KR) is about 37-41 Kg/m 3 and does not change significantly in relation to the density of the foam W. On the other hand, the apparent density of foams with cocoa (K) slightly decreases compared to the density of the foam W and varies in the range of about 36-30 Kg/m 3 . ...
Two series of rigid polyurethane–polyisocyanurate (PU/PIR) foams were obtained. They were modified using powder fillers, such as industrial food cocoa (K5–K15 foam) and instant freeze-dried coffee (KR-KR15) added in amounts of 5, 10 and 15 wt.%. W foam (reference) was obtained without filler. The foams were degraded in a climate chamber for 1 week, 2 weeks or 3 weeks. Appropriate temperature, humidity and UV radiation were set in the chamber, which did not change throughout the degradation process. The foams were also degraded in an oven for two days at 120 °C. The foam tests carried out indicated, among others, on the decrease in compressive strength along with the increase in the residence time of the samples in the chamber. Degraded foams also changed color. Foams containing 5% and 10% of industrial cocoa or freeze-dried coffee were more susceptible to degradation. The addition of 15% coffee or cocoa slows down the degradation process. In the present study, industrial food cocoa and instant freeze-dried coffee were used as modifiers of rigid PU/PIR foam. These fillers have two functions: they accelerate the biodegradation of foams and have antioxidant properties.
... Recently, various nonhalogen flame retardants have been used as a replacement, including aluminum trihydrate (ATH) and phosphorous compounds. Aluminum trihydrate (ATH) is widely used in industry because of its low cost and non-toxic gas emissions [18][19][20][21][22]. It undergoes endothermic dehydration upon heating above 180 • C, suppressing the flame spread and smoke emission. ...
Epoxy resin was mixed with benzoxazine resin and an aluminum trihydrate (ATH) additive to provide flame retardancy and good mechanical properties. The ATH was modified using three different silane coupling agents and then incorporated into a 60/40 epoxy/benzoxazine mixture. The effect of blending compositions and surface modification on the flame-retardant and mechanical properties of the composites was investigated by performing UL94, tensile, and single-lap shear tests. Additional measurements were conducted including thermal stability, storage modulus, and coefficient of thermal expansion (CTE) assessments. The mixtures containing more than 40 wt% benzoxazine revealed a UL94 V-1 rating with high thermal stability and low CTE. Mechanical properties including storage modulus, and tensile and shear strength, also increased in proportion to the benzoxazine content. Upon the addition of ATH to the 60/40 epoxy/benzoxazine mixture, a V-0 rating was achieved at 20 wt% ATH. The pure epoxy passed a V-0 rating by the addition of 50 wt% ATH. The lower mechanical properties at high ATH loading could have been improved by introducing a silane coupling agent to the ATH surface. The composites containing surface-modified ATH with epoxy silane revealed about three times higher tensile strength and one and a half times higher shear strength compared to the untreated ATH. The enhanced compatibility between the surface-modified ATH and the resin was confirmed by observing the fracture surface of the composites.
... In the European Union (EU), halogenated flame retardants were prohibited in electronic display from March 2021. Recently, aluminum trihydrate (ATH) is widely used as a replacement because of its low cost and non-toxic gas emissions [17][18][19][20][21][22]. It undergoes endothermic 2 of 9 dehydration upon heating above 180 o C, suppressing the flame spread and smoke emission]. ...
Epoxy was blended with benzoxazine resin and aluminum trihydrate (ATH) additive to render flame retardancy while maintaining mechanical properties. The ATH was modified using three different silane coupling agents and then added to 60/40 epoxy/benzoxazine mixtures. The effect of blend compositions and surface modification on flame retardant and mechanical properties of the composites was investigated by UL94, tensile, and shear tests. Resin mixtures containing more than 40 wt% benzoxazine revealed a UL94 V-1 rating with enhanced tensile and shear strength. Upon addition of 20 wt% ATH to 60/40 epoxy/benzoxazine, a V-0 rating was achieved. The lowered tensile and adhesive properties of the composites in the presence of ATH were improved by modifying the ATH surface using silane coupling agents.
... WPC products have been produced from different types of natural fiber resources and virgin thermoplastics including polyethylene [4], polypropylene [5], polyvinyl chloride [6], poly (lactic acid) [7]. Among them, polyurethane (PU) foam has been widely used in many fields due to its excellent properties [8,9]. In combination with wood processing residues (wood flour, wood fiber) and other wastes as blends, porous foamed polyurethane-based WPC can be prepared [10]. ...
To improve the flammability of foamed polyurethane/wood-flour composites (FWPC), ammonium polyphosphate (APP) was used as a flame retardant to modified FWPC. The effects of different flame treatment processes on flame performance, smoke suppression, thermal property, and surface micrographs of flame retardant FWPC were investigated. The results showed that FWPC with the addition or impregnation process both improved the combustion behaviors. Compared with the addition process, FWPC-impregnation (FWPC–I) had a lower total heat release (THR), lower peak heat release rate (PHRR), prolonged time to ignition (TTI), more residues, and better combustion safety. FWPC-I had the highest residual carbon rate reaching 39.98%. A flame-retardant layer containing the P–O group was formed in the residual carbon of FWPC-I. Although APP had negative effects on the physical properties of FWPC, it was an effective flame-retardant ability for foamed polyurethane/wood-flour composites.
... The initial HRR waveforms are similar for both PUFs. HRR of obtained PUFs falls within typical range of flame retarded PUFs (which is 38-133 kW/m 2 ) as was obtained by us previously and in other laboratories [56][57][58][59][60][61]. Small difference in elemental compositions of polyols (see Table 1) and PUFs obtained from them as well as similarity of structural fragments of both products (Table 4) may lead to little differences in HRR. ...
New oligoetherols with based on cyclotriphosphazene ring were synthesized by functionalization of hexachlorocyclotriphosphazene with glycidol followed by reaction with ethylene glycol and glycerol. Oligoetherols were characterized by IR, ¹ H-NMR, and MALDI-ToF and hydroxyl number as well as physical properties like density, viscosity and surface tension. The oligoetherols were further converted into polyurethane foams. The rigid foams of enhanced thermal stability and considerably diminished flammability were obtained and their apparent density, water uptake and polymerization shrinkage, thermal conductivity coefficient and thermal stability were determined. The flammability of foams was studied by microcalorimetric methods, horizontal flaming test and oxygen index. The obtained polyurethane foams with incorporated cyclotriphosphazene ring are self-extinguishing.
Graphical abstract
... In order to examine the flame retardancy of RPUFs, Xi et al. [115] used aluminum hydroxide (ATH), [bis(2-hydroxyethyl)amino]-methyl-phosphonic acid dimethyl ester (BH), aluminum oxide (AO), and EG for modification of RPUF. As shown in Fig. 6a, after ignition, the HRR value of RPUF dramatically increased to maximum burning intensity (322 kW/m 2 ), whereas due to the synergetic effects of FRs including ATH/BH/EG, AO/BH/EG, and BH/EG, PHRR dramatically decreased. ...
... As Fig. 7b shows, the modified WPU obtained the efficient fire retardancy through the covalent functionalization of graphene oxide-silica nanocomposite (0.2%) and the synergistic effects with fire retardants. Reproduced with permission from reference [115]. Copyright (2019) MDPI Ma et al. [119] synthesized silicone-modified graphene using 3-aminopropyltriethoxysilane (AMEO). ...
Polyurethane foams (PUFs) are widely used in several applications including fire-alarm sensors, electromagnetic interference shielding, insulation material, and anti-corrosion coating. On the other hand, PUFs are highly flammable and their further development is dependent on their fire retardancy property. Therefore, development of PUFs with fire-retardant properties has been at the core of attention in recent years. Graphene-based nanomaterials (GNs) such as graphene and graphene oxide improve the thermal stability of PUFs and delay their ignition. In addition, GNS can suppress fire from spreading during PUFs burning. Despite the outstanding properties of GNs, their sheets may stack, shrink, and lose their large surface area. This directly affects their dispersion and compatibility with the parent polymer. To address these challenges, GNs can be modified with namely intumescent including an acid source, a gas source, and a carbon source and non-intumescent with zero, one, and 2D assembly materials. Incorporating modified GNs FRs into PUFs is performed using both surface coating, reactive, or additive methods. In the present review, the state-of-the-art reports on the use of modified GNs into PUFs have been highlighted. Moreover, the challenges of GNs flame-retardant PUFs as well as various strategies to tackle these challenges and improve the flame retardancy of PUFs are stated.
... Due to increased climate and environmental concerns, there was a need to design a new effective fire-retardant system from halogen-free fire retardants [4][5][6][7], with aluminum hydroxide (ATH), magnesium hydroxide (MDH), carbon nanotube (CNT), expandable graphite, halloysite nanotubes with POSS, etc. Furthermore, in the construction industry, a lot of effort has been put to fulfil ever stricter reactions to fire requirements, and therefore over the years a lot of knowledge has been accumulated about the influence of various environmentally acceptable additives and retardants to fire resistance of the PURs, with a synergistic effect on improving the thermal insulating properties [8,9]. However, there is less known about the influences of those fire-retardant additives on the mechanical properties of the PURs. ...
In the presented work, the influence of two flame retardants—ammonium polyphosphates and 2,4,6-triamino-1,3,5-triazine on the polyurethane foam (PUR) systems were studied. In this paper, these interactive properties are studied by using the thermal analytical techniques, TGA and DTA, which enable the various thermal transitions and associated volatilization to be studied and enable the connection of the results with thermal and mechanical analysis, as are thermal conductivities, compression and bending behavior, hardness, flammability, and surface morphology. In this way, a greater understanding of what the addition of fire retardants to polyurethane foams means for system flammability itself and, on the other hand, how this addition affects the mechanical properties of PUR may be investigated. It was obtained that retardants significantly increase the fire resistance of the PURs systems while they do not affect the thermal conductivity and only slightly decrease the mechanical properties of the systems. Therefore, the presented systems seem to be applicable as thermal insulation where low heat conductivity coupled with high flame resistance is required.
... The formation of water promotes the dilution of combustible gas, thereby avoiding the effect of oxygen and inhibiting the propagation rate of the flame. Xi et al. prepared a new fire retardant (polyurethane foams) and analyzed its flame retardant effect [15]. As shown in Figure 3, the added ATH showed a better flame retardant as compared to other additives such as AO. ...
Flame retardants have become an integral part of the construction industry, not only to bring safety to residents in the event of fire, but also to reduce property damage. As excellent flame retardant materials, common flame retardant polymer composites mainly include two types, that is, traditional flame retardant and nano flame retardant. This research introduces the different flame retardants under the two categories and their corresponding flame retardant mechanisms in detail. And some other flame retardant polymer composites. In terms of mechanism, two important flame retardant mechanisms include dehydration and charring. In this research, the advantages and disadvantages of different flame retardant mechanisms in different polymers and their causes are introduced in detail. In addition, this research will compare the advantages and disadvantages of existing flame retardant materials and look forward to their future development trends, hoping to provide a new idea for the development of new flame retardant materials.
