用锥形量热仪研究聚氨酯泡沫的阻燃性能

在50 kW/m2辐射功率下,利用锥形量热仪研究了氢氧化铝、卤系阻燃剂、氮系阻燃剂和磷系阻燃剂阻燃聚氨酯泡沫(PUF)的阻燃特性,获得了点燃时间、最大热释放速率、总热释放、比消光面积及质量损失速度等参数。结果表明,将热释放速率、燃烧总释放热和烟气释放量作为材料阻燃性能好坏的评价指标,阻燃剂聚磷酸铵（APP）和三聚氰胺磷酸盐（MP）是PUF的理想阻燃剂。     

Flammability testing of pure and flame retardant-treated cotton fabrics

A Controlled-atomosphere cone calorimeter was used to investigate the burning of pure and flame retardant-treated cotton fabrics. The condensed-phase flame retardants used were Morguard (containing ammonium dihydrogen phosphate and diammonium hydrogen phoisphate) and Nochar (containing ammonium sulfate and a sodium salt). The fabrics were tested at 25 kW m^?2 incident heat flux in environments containing 15–30% oxygen. The flame retardants increased the time to ignition, residue yield, and CO and CO₂ yields. The flame retardants decreased the peak and average mass loss rates, the peak and average heat release rates, the effective heat of combustion at peak heat release rate, and the propensity to flashover. The effect of oxygen concentration on the burning of pure and flame retardant-treated cotton fabrics has also been investigated. The flame retardants had better performance when the treated fabrics burned in the lower oxyge concentrations. The result of this study indicate that the controlled-atmosphere cone calorimeter is a good tool for studying the effect of flame retardant and oxygen concentration on the burning of materials.     

Synergistic flame retardancy of tris(1-methoxy-2,2,6,6-tetramethyl-piperidin-4-yl)phosphite and tris(2,4,6-tribromophenoxy)-1,3,5-triazine/Sb2O3 in high-impact polystyrene

Synergistic flame retardancy of tris(1-methoxy-2,2,6,6-tetramethyl-piperidin-4-yl) phosphite (NORPM) and tris(2,4,6-tribromophenoxy)-1,3,5-triazine (TTBPC)/Sb₂O₃ in high-impact polystyrene (HIPS) was studied by limiting oxygen index (LOI) determination, UL-94 test, and cone calorimetry test (CCT). NORPM has an exceptional synergistic effect in HIPS. When the dosage of TTBPC, Sb₂O₃, and NORPM was 12.8, 3.2, and 0.5 wt% respectively, flame retardant effectivity and synergistic effectivity were 0.424 and 1.15 respectively. Compared with the Flame retardant (FR)-HIPS containing 16.0 wt% of TTBPC/Sb₂O₃, the LOI of FR-HIPS increases from 23.8% to 25.4%, the flame-retardant rating of FR-HIPS can be improved from UL 94 V-2 to V-0, and the peak heat release rate and total heat release are significantly reduced by combining NORPM in 0.5 wt% concentration. NORPM induces the synergistic effect mainly through the following mechanisms: the active radicals produced by the pyrolysis of NORPM promote the release of bromine radicals from TTBPC and the formation of HBr, which improves the flame retardancy of TTBPC; the above active radicals, together with HBr, quench active free radicals, such as the hydroxyl radical (·OH) and decompose the free radical source, which interrupts the chain reaction during combustion and results in a more efficient flame retardant effect in gaseous phase.     

Methods of calculating the physical acation of flame retardants

The chemical mechanisms for the action of flame retardants are often mentioned in the literature but the physical modes of action are seldom. Discussed. This article presents one way to quantify their efficiency. The technique is based on literature data for the physical and thermal properties of flams retardants for temperatures from 25°C up to 1000°C. The prolongation of the time to ignition by heat absorption by the retardant and the amount of inert gas evolved by the retardant are calculated at a given radiation for a material flame-proofed with a given amount of the flame retardant. The ability to form an insulating surface layer is considered but not quantified. It is assumed that a medium density wood fibre building boards is treated with 2 kg of flame retardant per m². The flame retardants included are borates, boric acid, phosphates and silicates. The board is assumed to be irradiated with an intensity of 15 k W m^?2. Under these conditions an untreated board ignites after 6–7 min. The time to ignition is prolonged by 1–5 min through heat absorption by the different retardants, and the amount of inert gases evolved may be as high as 2.6 m³ per m² board. The formation of an insulating surface layer is more difficult to quantify. The results confirm the importance of the physical modes of action of flame retardants and the technique could form the basis for evaluating materials in simulated fire situations.     

The flame retardant and smoke suppression effect of fullerene by trapping radicals in decabromodiphenyl oxide/Sb2O3 flame‐retarded high density polyethylene

To improve the large release of smoke and heat for brominated flame retardants (BFRs) in fire hazard, fullerene (C₆₀) had been introduced in high density polyethylene (HDPE)/bromine flame retardant (Deca/Sb₂O₃, BFR in short) system in this study. The effects of C₆₀ on the thermal properties, flame retardant properties, rheological behaviors, and smoke release behaviors in HDPE/BFR blends were researched. During polymer thermal degradation, C₆₀ and BFR exhibited the trapping radical ability in condensed phase and gaseous phase, respectively. The intergrated effects of C₆₀ and BFR on the thermal stability and flammability of HDPE were studied by thermo‐gravimetry and cone calorimeter. It was indicated that the introduction of C₆₀ improved the thermal and thermo‐oxidative stability of HDPE/BFR blends. A remarkable advantage of adding C₆₀ was to reduce the peak heat release rate and the average specific extinction area, especially at higher concentration of C₆₀. The analysis of rheological behaviors and pyrolysis products revealed that C₆₀ can capture alkyl radicals, chain radicals, and bromine radicals in the condensed phase, which was in favor of terminating the thermo‐oxidative decomposition and inhibiting the heat and smoke release of HDPE/BFR blends during combustion.     

Grafting multi-elements hybrid polymer brushes on graphene oxide for epoxy composite with excellent flame retardancy

In this paper, a silicon-oxygen coupling agent (MPS) with a double bond is hydrolyzed with graphene oxide (GO) to obtain MPS-GO. The polymerization of MPS-GO with the phosphorus-containing monomer (HEPO) is initiated with 2,2′-Azobis(2-methylpropionitrile) (AIBN) to obtain multi-elements hybrid polymer brushes grafting graphene oxide (HM-GO). As a flame retardant, different amounts of HM-GO are added to obtain EP composites. In this system, the properties of composite flame retardant obviously increase with the increasing of HM-GO. The limiting oxygen index (LOI) value of composites with 4 wt% addition of HM-GO is 31.0%, while the LOI value of EP-0 is only 23.9%. And the peak heat release rate (PHRR) value is reduced from 515.8 W g⁻¹ of pure epoxy resin to 376.9 W g⁻¹. In addition, with the increase of HM-GO addition, the T_g value, flexural strength and flexural modulus of EP composites are improved. Through calculation, it is proved that the rising of T_g was due to the increase of crosslink density of the system. The flame retardant performance and mechanical properties of the composite materials are steadily improved, indicating that such flame retardants are dispersed well in the epoxy resin. HM-GO is an efficient macromolecular modified graphene oxide halogen-free flame retardant, which can improve both flame retardant properties and mechanical properties.     

Flame resistance and foaming properties of NBR compounds with halogen‐free flame retardants

Acrylonitrile butadiene rubber (NBR) foams compounded with various halogen‐free flame retardants were prepared. The influence of nonhalogen flame retardants on the flame resistance and foaming properties of the NBR compounds were investigated. The foaming properties (expandability 980%–1050%, closed‐cell structure) of NBR compounds with expandable graphite (EG) and ammonium polyphosphate (APP) flame retardants were similar to the NBR base compounds which contained primarily aluminum hydroxide (ATH). The heat release capacity (HRC) ranged from 10 to 74 J/g‐K, the average heat release rate (A‐HRR) ranged from 8 to 60 kW/m², and the total heat release (THR) ranged from 2.6 to 7.3 MJ/m² for the nonhalogenated NBR foams with closed‐cell structure and were significantly decreased upon increasing the amounts of flame retardants. This reduction is attributed to the hard char formation and production of water from the interaction with ATH. The limiting oxygen index (LOI) and time to ignition (TTI) show opposite results. The smoke density (0.050–0.037) of the NBR foams with EG flame retardant was decreased when compared to the NBR foam (0.107). The EG flame retardant was more effective than the phosphorus/nitrogen flame retardants in reducing the HRR and smoke density. The use of both ATH and EG is very effective in improving flame resistance. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers     

Heat resistant properties of PP/Al(OH)<Subscript>3</Subscript>/Mg(OH)<Subscript>2</Subscript> flame retardant composites

Vicat softening point temperature (T _V) and heat deflection temperature (T _d) are important parameters for characterization of heat resistant properties of polymeric materials. PP/Al(OH)₃/Mg(OH)₂ flame retardant composites were prepared using a twin-screw extruder, and the T _V and T _d of the composites were measured. The results showed that the T _V and T _d increased nonlinearly with an addition of the weight percentage of the flame retardant additives except for individual data points, while the T _V and T _d decreased with increasing the filler particle size when the content of flame retardant additives was constant. Under the same conditions, filling small amount of zinc borate into the composites might improve the heat resistant properties of the composite systems. Moreover, the morphology of the impact fracture surface of the specimens was observed by means of scanning electron microscope to understand the dispersion and distribution of the filler particles in the PP matrix.     

Synthesis and flammability testing of epoxy functionalized phosphorous‐based flame retardants

Several potential new phosphorus‐containing flame retardant molecules were evaluated for heat release reduction potential by incorporation of the molecules into a polyurethane, generated from methylene diphenyl diisocyanate and 1,3‐propane diol. The heat release reduction potential of these substances was evaluated using the pyrolysis combustion flow calorimeter (PCFC). The polyurethanes were prepared in the presence of the potential flame retardants via solvent mixing and copolymerization methods to qualitatively evaluate their potential reactivity into the polyurethane prior to heat release testing. The functionality of the flame retardants was epoxide based that would potentially react with the diol during polyurethane synthesis. Flammability testing via PCFC showed that the heat release reduction potential of each of the flame retardants was structure dependent, with phosphates tending to show more effectiveness than phosphonates in this study, and alkyl functionalized phosphorus groups (phosphate or phosphonate) being more effective at heat release reduction than cyclic functionalized groups. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42296.     

Melt shear viscosity of PP/Al(OH)3/Mg(OH)2 flame retardant composites at high extrusion rates

The melt apparent shear viscosity (η_a) of polypropylene (PP) composites filled with aluminum hydroxide [Al(OH)₃] and magnesium hydroxide [Mg(OH)₂] was measured by means of a capillary rheometer under experimental conditions of temperature ranging from 180 to 200°C and apparent shear rate varying from 10 to 2 × 10³ s⁻¹, to identify the effects of the filler particle content and size on the melt viscosity. The results showed that the melt shear flow of the composites obeyed the power law and presented pseudoplastic behavior. The dependence of η_a on temperature was consistent with the Arrhenius equation. The sensitivity of η_a for the composite melts to temperature was greater than that of the unfilled PP, and weakened with increasing apparent shear rate. The η_a increased linearly with an increase of the weigh fraction of the flame retardant, especially in the low apparent shear rate region. The η_a of the composites decreased slightly with an increase of particle size of flame retardant. Moreover, the variation for the η_a with particle size of flame retardant was much less than with apparent shear rate under these test conditions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Flame retardant,mechanical, and hot air aging properties of ethylene-propylene-diene monomer/ammonium polyphosphate/nano-silic composite rubber

In this work, effect of the ratio of nonhalogenated flame retardants (ammonium polyphosphate [APP] and nano-silica [nano-SiO₂]) on the mechanical, thermal, and flame retardant properties of ethylene-propylene-diene monomer (EPDM) composite rubber were investigated. Vulcanization characteristics, high temperature compression permanent deformation, thermal oxygen aging, dynamic thermodynamic analysis, thermal stability, cone calorimetry, limiting oxygen index (LOI), horizontal vertical combustion (UL-94), and scanning electron microscopy were carried out. The experimental results showed that the mechanical properties of the composite rubber decreased with the addition of APP. However, the addition of nano-SiO₂ was found to significantly improve the mechanical properties of the composite rubber when it was incorporated. In terms of flame retardant properties of EPDM composite rubber, the combination of APP and nano-SiO₂ has a synergistic flame retardant effect in comparison to the use of single APP flame retardant. The heat release rate of EPDM composite rubber decreased by 34%, the total heat release decreased by 19%, the LOI increased by 76%, and the flame retardant grade of EPDM composite rubber reached V-0. The EPDM composite rubber fabricated in the present study showed excellent fire resistance and desirable mechanical properties, which are of practical significance for further expanding the application ranges of EPDM rubbers.     

Influence of thermal behavior of phosphorus compounds on their flame retardant effect in PU rigid foam

Phosphorus‐containing compounds have been widely used as flame retardants for polyurethane rigid foam (PURF). In this work, a number of phosphorus compounds were utilized and studied as flame retardants for PURF, including ammonium polyphosphate, pentaerythritol phosphate, triethyl phosphate, and dimethyl methyl phosphonate. The thermal behavior of flame retardants was thoroughly investigated, such as degradation, vaporization, and the properties of degraded products. The influence of thermal behavior of phosphorus flame retardants on PURF was examined and analyzed. The results indicated that the effect of flame retardant was highly related to their thermal behavior. Phosphorus compounds for gas phase flame retardants were very effective in decreasing the heat release rate and increase limited oxygen index of PURF, while condensed phase flame retardants showed better comprehensive flame retardant effect, such as reducing the toxicity of combustion product. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis of FePP@MoS2@Ni-MOF composites for improving thermal and flame retardant safety properties of polyurea

Polyurea (PUA) is widely used as a coating in construction, tunnels, bridges, and other fields because of its excellent performance. However, its combustion emits toxic gases and smoke, hindering escape and posing potential fatality risks. Enhancing the flame retardancy of PUA is crucial for safety and expanding its applications. The synthesis of two-dimensional FePP nanosheets was reported in this paper, employing the solvothermal method, followed by the sequential growth of MoS₂ and Ni-MOF to establish a multilayer composite structure. The elemental composition and morphology of the synthesized FePP@MoS₂@Ni-MOF flame retardants were characterized and analyzed. The flame retardant properties of polyurea composites with varying amounts of FePP@MoS₂@Ni-MOF were investigated using Cone calorimeter tests. The results showed that the prepared flame retardant had good thermal stability and significantly improved fire safety properties. The PUA/FePP@MoS₂@Ni-MOF 3.0 composite exhibited notable improvements compared to pure PUA. Specifically, the peak heat release rate, total heat release rate and peak smoke production rate were reduced by 39.76%, 29.33% and 17.86%, respectively, while total smoke production and total CO production (COP) were reduced by 21.30% and 54.47%. This study provides new insights and experimental basis for the technological development of novel flame retardant coating materials.     

Effect of zinc oxide on properties of phenolic foams/halogen‐free flame retardant system

A halogen‐free flame retardant system consisting of ammonium polyphosphate (APP) as an acid source, blowing agent, pentaerythritol (PER) as a carbonific agent and zinc oxide (ZnO) as a synergistic agent, was used in this work to enhance flame retardancy of phenolic foams. ZnO was incorporated into flame retardant formulation at different concentrations to investigate the flammability of flame retardant composite phenolic foams (FRCPFs). The synergistic effects of ZnO on FRCPFs were evaluated by limited oxygen index (LOI), thermogravimetric analysis (TGA), cone calorimeter tests, and images of residues. Results showed that the flame retardant significantly increased the LOI of FRCPFs. Compared with PF, heat release rate (HRR), total heat release (THR), effective heat of combustion (EHC), production or yield of carbon monoxide (COP or COY) and Oxygen consumption (O₂C) of FRCPFs all remarkably decreased. However specific extinction area (SEA) and total smoke release (TSR) significantly increased, which agreed with the gas‐phase flame retardancy mechanism of the flame retardant system. The results indicated that FRCPFs have excellent fire‐retardant performance and less smoke release. And the bending and compression strength were decreased gradually with the increase of ZnO. The comprehensive properties of FRCPFs were better when the amount of ZnO was 1～1.5%. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42730.     

Epoxy resin/phosphorus‐based microcapsules: Their synergistic effect on flame retardation properties of high‐density polyethylene/graphene nanoplatelets composites

Two types of microcapsule flame retardants are prepared by coating ammonium polyphosphate (APP) and aluminum diethylphosphinate (ADP) with epoxy resin (EP) as the shell via in situ polymerization, and blended with high density polyethylene (HDPE)/graphene nanoplatelets (GNPs) composites to obtain flame‐retardant HDPE materials. Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), and water contact angle results confirm the formation of core–shell structures of EP@APP and EP@ADP. The limiting oxygen index (LOI), vertical burning test (UL‐94), cone calorimetry, and Raman spectroscopy are employed to characterize the HDPE/GNPs composites filled with EP@APP and EP@ADP core–shell materials. A UL94 V‐0 level and LOI of 34% is achieved, and the two flame retardants incorporated in the HDPE/GNPs composite at 20 wt % in total play a synergistic effect in the flame retardancy of the composite at a mass ratio of EP@ADP:EP@APP = 2:1. According to the cone‐calorimetric data, the compounding composites present much lower peak heat release rate (300 kW/m²) and total heat release (99.4 MJ/m²) than those of pure HDPE. Raman spectroscopic analysis of the composites after combustion reveals that the degree of graphitization of the residual char can reach 2.31, indicating the remarkable flame retarding property of the composites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46662.     

A new flame-retardant medium density fiberboard with no formaldehyde release: Wood fiber cell walls template zeolite via in situ thermocompression

Fiberboard which is not flame retardant and releases formaldehyde is widely used in residents' life, which brings serious problems. Now, we use water glass and Al₂(SO₄)₃ to form zeolite precursor, and use UP as adhesive to prepare zeolite-based flame retardant formaldehyde-free medium density fiberboard in situ within a few minutes. The molecular sieve structure was characterized by SEM, TEM, BET, and XRD. At the same time, we put forward the possible mechanism of zeolite formation according to the internal temperature and pressure test during fiberboard production. Wood fiber is coated with zeolite, which separates pyrolysis gas from air and avoids further combustion, resulting in low heat release, low smoke and toxic carbon monoxide emission, high residue, and good flame retardant performance. Furthermore, the formaldehyde emission of the formaldehyde-free flame retardant board is 0.047 mg/L, which proves that it does not contain formaldehyde.     

Improving the flame‐retardant efficiency of aluminum hydroxide with fullerene for high‐density polyethylene

The influence of fullerene (C₆₀) on the flame retardancy and thermal stability of high‐density polyethylene (HDPE)/aluminum hydroxide (ATH) composites was studied. After the addition of three portions of C₆₀ to an HDPE–ATH (mass ratio = 100:120) composite, a V‐0 rating in the UL‐94 vertical combustion test was achieved, and the limiting oxygen index increased by about 2%. The results of cone testing also showed that the addition of C₆₀ effectively extended the time to ignition and the time to maximum heat‐release rate while cutting down the peak heat‐release rate. Thus, fewer flame retardants were needed to achieve a satisfactory flame retardance. Consequently, the adverse effects on the mechanical properties because of the high level of flame‐retardant loading was reduced, as evidenced by the obvious enhancements in the tensile strength, elongation at break, and flexural strength. Electron spin resonance spectroscopy proved that C₆₀ was an efficient free‐radical scavenger toward HO· radicals. Thermogravimetric analysis coupled to Fourier transform infrared spectroscopy demonstrated that in both N₂ and air atmospheres, C₆₀ increased the onset temperature of the matrix by about 10 °C because of its enormous capacity to absorb free radicals evolved from the degradation of the matrix to form crosslinked network, which was covered by aluminum oxide. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44551.     

Pyrolysis gas chromatographic analyses of untreated and flameproofed wools

The thermal degradation of untreated and wool treated by various flame retardants, using pyrolysis gas chromatography, has been studied. The concentration of CO, CO₂ and benzene produced does not appear to be affected by the flame retardants studied. The latter slightly decreases the concentration of toluene produced while the HCN production depends on the chemical composition of the retardant and on the temperature of exposure.     

Improving the Flame Retardancy and Smoke Suppression of Poly(Lactic Acid) with a SiO2@ammonium Molybdate Core-Shell Nanotubes

Design and fabrication of SiO₂@ammonium molybdate(AM) core-shell nanotubes are important for polylactic acid (PLA), these two components form a well-defined core-shell configuration that is distinct from simple core-shell or hybrid structures. The PLA was investigated by limiting oxygen index, vertical burning test and smoke density, cone calorimeter test, SEM and TGA. The results showed that SiO₂@AM nanotube can effectively increase the flame retardancy and smoke suppression properties, and that it can apparently reduce heat release rate, total heat release and total smoke release. Furthermore, the addition of SiO₂@AM nanotube brings better mechanical properties than the sample contain SiO₂ nanotube. Here, SiO₂@AM nanotube was considered to be an effective flame retardant in PLA.