Dimethyl Methylphosphonate Addition Research Articles

Experimental Investigation of the Effect of Flame-Retardant Additive Dimethyl Methylphosphonate on Combustion Behaviors of Electrolytes

Abstract Adding flame-retardant additives to electrolytes can significantly enhance the safety of lithium-ion batteries. To clarify the effects of flame-retardant additive dimethyl methylphosphonate (DMMP) on electrolyte flammability under practical battery fire conditions, experimental studies are conducted on an electrolyte pool fire setup. It is observed that the flame of carbonate solvent is blue, while the flames of electrolyte and electrolyte with DMMP addition are yellow, due to the formation of phosphorus-containing particles in the flame. With 30 wt% DMMP addition, the combustion duration, combustion mass ratio, and flame height decrease significantly by 40%. The electrolyte achieves non-flammability when the additive fraction increases to 40%. It is observed that with DMMP addition the charred layer forms on the surface of electrolyte liquid, and slows down the heat and mass transfer between the gas and electrolyte liquid. This is the flame-retardant mechanism of DMMP in the condensed phase. The flame spectrum results show that with LiPF6 and DMMP addition the OH emission intensities are weakened dramatically. This is because LiPF6 and DMMP decompose to the radicals containing phosphorus, which can scavenge the vital radicals (H and OH), and then suppress the combustion chain branching reactions. This is the flame-retardant mechanism of LiPF6 and DMMP in the gas phase.

Fabrication of flame retardant poly(methyl methacrylate) with excellent comprehensive properties based on a new phosphorus-silicon-nitrogen-synergistic system

In general, the addition of phosphate ester flame retardants can improve the flame retardancy of polymethyl methacrylate (PMMA), but the flame retardant efficiency is low when phosphate ester is used alone and the tensile strength and hardness of the material are reduced. It is a challenge to improve the flame retardancy of PMMA while maintaining its inherent mechanical properties. In this study, a polyphosphate-coated silica (SZP) was prepared, which was compounded with dimethyl methylphosphonate (DMMP). At the same time, methacrylamide (MAM), which can be copolymerized with PMMA, was introduced to construct a synergistic phosphorus-nitrogen-silicon flame retardant system. The three components can work together in the gas phase and condensed phase. The results showed that when 12.5% DMMP, 5% MAM and 2.5% SZP were added, the composite material had the best comprehensive performance, its limiting oxygen index (LOI) reached 25.1%, and its total heat release was only 70% of the pure sample. More importantly, the addition of DMMP would significantly reduce the mechanical properties of PMMA. The introduction of SZP and MAM alleviated this problem. Compared with the pure sample, the mechanical properties of PMMA7 did not decrease but increased slightly. The flame retardant mechanism was also analyzed. This study provides a new idea for the industrialization of flame retardant PMMA.

Combining inherent and additive phosphorus-containing flame retardants for enhancing flame retardancy and smoke suppression effects on polyisocyanurate-polyurethane foam

This study focuses on further improving flame retardancy and reducing the amount of toxic-smoke released of phosphorous-containing flame-retardant polyisocyanurate-polyurethane foams (FPIRs) through the additive effect between reactive flame-retardant diol (BEOPMS) and dimethyl methylphosphonate (DMMP). The surface morphologies, combustion behavior and flame-retardant mechanism of FPIRs were evaluated by scanning electron microscope (SEM), limiting oxygen index (LOI), cone calorimeter (CC) and thermogravimetry-Fourier transform infrared (TG-FTIR) analysis. It was found that the addition of DMMP decreased the thermal-degradation temperature and reduced the compressive strength gradually of FPIRs. More importantly, the PHRR, THR, and TSR of FPIR were observed to be depressed by 72%, 82% and 38%, respectively, in the case of adding only 15 phr DMMP in the FPIR system. The LOI of FPIR could significantly improve from 22.0 vol% to 29.5 vol% after the introduction of BEOPMS and 25 phr DMMP together. Based on CC, TG-FTIR, and SEM/EDS analysis, an additive effect mainly in the gas phase between BEOPMS and DMMP was included to explain the beneficial effect in suppressing heat and smoke release.

Experimental and theoretical study on the suppression effect of water mist containing dimethyl methylphosphonate (DMMP) on hydrogen jet flame

This work investigates the suppression effect of water mist containing dimethyl methylphosphonate (DMMP) on H2 jet flame. The flame appearances are analyzed and the flame temperature is recorded by a high-speed infrared camera. Results show that the suppression effect of water mist containing DMMP is better than that of pure water mist. To better understand the suppression effect of water mist containing DMMP, the burning velocity, heat production and free radicals are analyzed. Results indicate that suppressant could scavenge lots of free radicals to reduce the burning velocity in a wide range of equivalence ratios. Moreover, the influence of DMMP on lean CH4 and H2 flames is compared. Different with that of lean CH4 flame, the combustion parameters of lean H2 flame decline with DMMP addition. There is no combustion enhancement effect of DMMP on lean H2 flame. Because of the higher combustion intensity of lean H2 flame, the hydrocarbon in DMMP has little impact on the combustion. Furthermore, the reaction path of DMMP decomposition is analyzed. Results demonstrate that the rates of most phosphorus reactions in H2 flame are larger than that in CH4 flame. This work could provide foundation for improving the safety of hydrogen energy application.

Dimethyl Methylphosphonate for the Suppression of Coal Spontaneous Combustion

ABSTRACT The inhibitory effect of dimethyl methylphosphonate (DMMP) on coal spontaneous combustion was investigated. The influence of DMMP on the thermal mass loss and thermal properties in the coal oxidation process was analyzed by synchronous thermal analysis. A DMMP inhibitor concentration of 10% provided the best inhibitory effect on coal oxidation. Addition of DMMP increased the coal ignition temperature by approximately 33°C, the burnout temperature by approximately 63°C, and the initial exothermal temperature by approximately 12°C. It also reduced the total heat release of the coal oxidation process by approximately 1200 J/g. Kinetic analysis of raw coal and DMMP-treated coal showed that DMMP exerted physical inhibition by blocking contact between coal and oxygen in the low-temperature oxidation stage. In the high-temperature oxidation stage, the chemical inhibition effect of DMMP was enhanced and the activation energy increased significantly (approximately 54.79 kJ/mol). Gas phase analysis indicated that DMMP could reduce oxygen consumption and CO emission during the coal oxidation process. On the basis of the above results and quantum chemical analysis, a mechanism for DMMP suppression of coal spontaneous combustion was proposed. This study provides reference data for prevention of coal spontaneous combustion and development of new inhibitors.

Inhibition of turbulent methane/air premixed bunsen flames by dimethyl methylphosphonate

There is little knowledge about the inhibition efficiency of dimethyl methylphosphonate (DMMP) against turbulent flames, in which vortices of different sizes corrugate and stretch the flame front. This study is to investigate the performance and the mechanism of DMMP in inhibiting turbulent methane/air premixed Bunsen flames. Several important parameters are chosen to characterize the combustion of the flames, including flame brush height, flame brush thickness and turbulent burning velocity. It is found that the flame brush expands both horizontally and vertically with the increase of turbulent intensity. For all the flames, the centerline mean flame brush thickness increases linearly with flame height. Turbulent burning velocity decreases monotonically with the increasing of DMMP addition. However, the normalized turbulent burning velocity increases with the normalized turbulent intensity. Compared with the performance in laminar premixed flames, the inhibition efficiency depends on the turbulent intensity. For low-intensity turbulent flames, the inhibition efficiency is higher than that in laminar premixed flames, but the relative inhibition efficiency decreases with DMMP addition. This can be attributed to the relative size of the vortices and the flame front thickness: when the Kolmogorov length scale is less than the preheat zone thickness but greater than the reaction zone thickness, vortices reduce the burning velocity; when the Kolmogorov length scale is less than the reaction zone thickness, vortices facilitate the combustion. The trend is opposite in high-intensity turbulent flames, which is mainly attributed to the generating of the flame pockets in the flame tips.

Investigation of the effect of dimethyl methylphosphonate (DMMP) on flame extinction limit of lithium-ion battery electrolyte solvents

An experimental and numerical study was conducted to quantify the flame retardant effects of different DMMP addition loadings on the flame extinction limits of four lithium-ion battery electrolyte solvents. The minimum extinguishing concentration (MEC) of CO2, which was measured using the cup-burner method, was applied to characterize the flame retardant effects of different DMMP loadings. Then, a model based on the perfectly stirred reactor concept was constructed to calculate the MEC and interpret the measurements established in the cup-burner test. A comparison was conducted between the measured and calculated MECs of N2 and a satisfactory agreement was obtained. Further investigation found that DMMP could significantly improve the extinction temperature by clearing the H radical, suppressing the reaction temperature and increasing the sensitivity of temperature to reaction rate constants, which caused the decrease in the flame extinction limit of solvents. The experimental results showed that DMMP has a certain saturation effect on reducing the flame extinction limits of solvents. For the four solvents, the sensibilities of the flame extinction limits to the DMMP additions were different, which were ranked in the order of diethyl carbonate > ethyl methyl carbonate > dimethyl carbonate > ethyl acetate.

Bi‐phase flame‐retardant effect of dimethyl methylphosphonate and modified ammonium polyphosphate on rigid polyurethane foam

The flame‐retardant rigid polyurethane foams (RPUFs) with dimethyl methylphosphonate (DMMP) and modified ammonium polyphosphate (MAPP) were prepared. The results showed that the limiting oxygen index (LOI) value was improved by adding DMMP into RPUF/MAPP composite; 10 wt% of DMMP addition can increase the LOI value from 24.3% to 26.0%, where the commercial application standard of RPUF is achieved. Further benefits of using DMMP/MAPP system included restraining of total heat and smoke release, improvement of thermal stability, and char yield of RPUF. The thermogravimetric analysis (TGA)‐gas chromatography‐mass spectrometer (GC‐MS) results indicated that DMMP/MAPP could continuously release PO2 and PO·free radicals in the gas phase. In addition, DMMP/MAPP exhibited the charring effect and barrier effect in the condensed phase, such bi‐flame retardant effect exerted by DMMP/MAPP resulted in the enhanced flame retardant property of RPUF.

Novel Biobased Polyol Using Corn Oil for Highly Flame-Retardant Polyurethane Foams

A novel bio-based polyol was synthesized using corn oil and 2-mercaptoethanol via thiol-ene reaction as an alternative to petroleum-based polyol for the synthesis of polyurethane foams. The polyol was analyzed using wet chemical techniques to obtain hydroxyl number and viscosity. Infrared spectroscopy and gel permeation chromatography were used to confirm the structural properties of the foams. Flame-retardant polyurethane foams were prepared by the addition of different concentrations of dimethyl methyl phosphonate (DMMP) in final foam composition. The effect of DMMP on the thermo-mechanical properties of the polyurethane foams was analyzed. The TGA analysis showed improved stability of the final char with addition of DMMP in the foams. All the foams maintained a well-defined cellular structure and over 95% of closed cell content. The horizontal burning test showed reduced burning time and weight loss from 115 s and 38 wt.% for the neat foams, to 3.5 s and 5.5 wt.% for DMMP-containing foams (1.94 wt.% P). The combustion test using cone calorimeter showed a considerable reduction in heat release rate and total heat release. Thus, our study shows that corn-oil based polyol can be used to produce renewable polyol for industrially producible rigid polyurethane foams. The addition of a small amount of DMMP could result in a significant reduction in the flame-retardant properties of the polyurethane foams.

Investigation of the influence of DMMP on the laminar burning velocity of methane/air premixed flames

This paper conducted experimental and numerical studies to evaluate the performance of dimethyl methylphosphonate (DMMP) in suppressing methane/air premixed flames. Laminar burning velocities were measured using the Bunsen flame method at an elevated temperature (373 K). As the concentration of DMMP increased, the laminar burning velocity initially decreased quickly and then gradually, which indicated the appearance of the saturation effect of the inhibition efficiency. The saturation effect was especially obvious for flames at an equivalence ratio of 1.2. Numerical calculations coupling with detailed chemical reaction mechanism were conducted to interpret the measurements. The newly constructed mechanism predicted well the laminar burning velocities. Sensitivity analyses revealed that as the equivalence ratio increased, reactions involving high-valence phosphorus had diminishing influence on the laminar burning velocity but the reactions involving low-valence phosphorus became more influential. By comparing the thermal and chemical effects of the main phosphorus-containing reactions in the rich flames (φ = 1.2), it was found that the thermal effect increased while the chemical effect decreased with the increase of DMMP addition. Therefore, the saturation effect of the inhibition efficiency of DMMP at high loadings was partially attributed to the heat release of the recombination reactions involving small P-bearing species.

Experimental study of the influence of dimethyl methylphosphonate on methane/air coflow diffusion flames using OH-PLIF

Experiments were conducted to evaluate the inhibition efficiency of dimethyl methylphosphonate (DMMP) on methane/air coflow diffusion flames. An optical diagnostic system (hydroxyl planar laser-induced fluorescence) was used to measure the OH radical distribution in the flames. The minimum extinguishing concentration (MEC) of CO2, as a function of DMMP addition, was measured to characterize the inhibition efficiency of DMMP. Results show that, when the concentration of DMMP is higher than 0.6%, DMMP’s marginal inhibition efficiency reduces to almost zero. It is found that the normalized peak OH concentrations keep unchanged with a value of 0.9 for flames at conditions near extinction limit. This is firstly observed based on experimental measurements. Furthermore, using DMMP alone cannot extinguish the flame even with 4.59% DMMP addition. When the inhibition efficiency of DMMP gets saturated, a large amount of phosphorus-containing molecules agglomerate around the flame. These particles act as sinks for the active phosphorus-containing species with a high inertial force, which are hard to diffuse horizontally into the flame. Therefore, it is concluded that the generation of the particles is a reason for the saturation phenomenon of DMMP in extinguishing the coflow diffusion flames.

Experimental and modeling study on the effects of dimethyl methylphosphonate (DMMP) addition on H2, CH4, and C2H4 ignition

Dimethyl methylphosphonate (C3H9O3P, DMMP) is considered both a surrogate of Sarin, a chemical weapon of mass destruction, and a fire suppressant. In this study, new ignition delay time measurements were taken in a heated shock tube for a mixture of DMMP/O2 in 99% Ar and for diluted mixtures of H2, CH4, and C2H4 doped with DMMP. These data can be used to validate and refine a detailed kinetics model for DMMP. Results showed that the DMMP addition did not modify the ignition delay times obtained with the C2H4 mixture, while a strong promoting effect was observed with CH4. Results were compared to detailed kinetics models from the literature, and it was shown that these models need to be significantly improved. A tentative model was assembled based on a modern hydrocarbon mechanism from the group of Curran and on updated phosphorus chemistry and thermochemistry recently proposed. Computations using this tentative model exhibited the need to revise several aspects of the DMMP oxidation chemistry, such as the rate coefficients of the reactions describing the rapid thermal fragmentation of DMMP and potentially the interactions between the phosphorus chemistry and radicals and molecules in the C2 chemistry.

Highly flame retardant and bio‐based rigid polyurethane foams derived from orange peel oil

Limonene dimercaptan (LDM), an orange peel oil‐based derivative, and glycerol‐1‐allyl ether (GAE) were used to synthesize bio‐based polyol (LDM‐GAE) using one step photochemical thiol‐ene reaction. The synthesized polyol was used to prepare flame retardant polyurethane foams using dimethyl methyl phosphonate (DMMP) as an additive flame retardant (AFR) and a new bromine containing reactive flame retardant (RFR) derived from 2,4,6‐tribromophenol. Both flame retardants lead to rigid polyurethane foams with excellent physical‐mechanical properties with a short self‐extinguishing time (7.5 and 12.8 sec for DMMP and bromine‐based foams, respectively) and with low weight loss after burning. The reactive bromine polyol lead to rigid polyurethanes with better physical‐mechanical properties than those of foams based on AFR with phosphorous, but the flame retardant properties of foams prepared using AFR are superior to the foams prepared using bromine polyol (RFR). Low addition of DMMP is sufficient to reduce the flammability of polyurethane foam without compromising its physical‐mechanical properties. These flame retardant rigid polyurethane foams based on limonene dimercaptan can be used in all applications of rigid polyurethane foams especially where flammability is an issue such as for insulation of buildings. POLYM. ENG. SCI., 58:2078–2087, 2018. © 2018 Society of Plastics Engineers

Effects of Dimethyl Methylphosphonate (DMMP) Flame Retardant on Rigid Polyurethane Foam

In this work, dimethyl methylphosphonate (DMMP) was used as a flame retardant to prepare flame-retardant rigid polyurethane foam (RPUF). The LOI value of RPUF is increased from 18.2 (for RPUF without DMMP) to 26.5. TGA results indicate that the first and the third maximum weight loss temperature (Tmax1 and Tmax3) increase. Cone calorimeter (CC) results show that the peak of heat release rate (HRR) and smoke production rate (SPR) are respectively decreased by 43.1% and 22.4%, indicating that DMMP endows RPUF with excellent flame retardant properties. Particularly, the addition of DMMP hardly affects the physical-mechanical properties and morphology of RPUF.

Synergistic effect of combined dimethyl methylphosphonate with aluminum hydroxide or ammonium polyphosphate retardant systems on the flame retardancy and thermal properties of unsaturated polyester resin

ABSTRACTA series of flame-retardant unsaturated polyester resin (UPR) were prepared by the addition of dimethyl methylphosphonate (DMMP) with various amounts of aluminum hydroxide (ATH) or ammonium polyphosphate (APP) as the flame retardants. The combustion resistance effects of ATH/DMMP and APP/DMMP systems were evaluated by limiting oxygen index test and vertical burning test (UL-94). The thermal properties of UPR were investigated by thermogravimetric analysis. The structure of char was observed by scanning electron microscopy. DMMP incorporated with ATH or APP improved the flame retardancy and thermal properties of UPR. However, the fire-retardant mechanism of these two systems were different: The ATH/DMMP system provided synergistic effect in charring property of the UPR, produced great amount of residual char, and thus revealed the excellent flame retardancy. The APP/DMMP system further improved the flame retardancy of the UPR due to the change in the residual char structure rather than the increase in the production of char.

Chemically modulated graphene quantum dot for tuning the photoluminescence as novel sensory probe.

A band gap tuning of environmental-friendly graphene quantum dot (GQD) becomes a keen interest for novel applications such as photoluminescence (PL) sensor. Here, for tuning the band gap of GQD, a hexafluorohydroxypropanyl benzene (HFHPB) group acted as a receptor of a chemical warfare agent was chemically attached on the GQD via the diazonium coupling reaction of HFHPB diazonium salt, providing new HFHPB-GQD material. With a help of the electron withdrawing HFHPB group, the energy band gap of the HFHPB-GQD was widened and its PL decay life time decreased. As designed, after addition of dimethyl methyl phosphonate (DMMP), the PL intensity of HFHPB-GQD sensor sharply increased up to approximately 200% through a hydrogen bond with DMMP. The fast response and short recovery time was proven by quartz crystal microbalance (QCM) analysis. This HFHPB-GQD sensor shows highly sensitive to DMMP in comparison with GQD sensor without HFHPB and graphene. In addition, the HFHPB-GQD sensor showed high selectivity only to the phosphonate functional group among many other analytes and also stable enough for real device applications. Thus, the tuning of the band gap of the photoluminescent GQDs may open up new promising strategies for the molecular detection of target substrates.

Influence of hydrocarbon moiety of DMMP on flame propagation in lean mixtures

Phosphorus-containing compounds (PCCs) have been found to be significantly more effective than CF3Br for reducing burning velocity when added to stoichiometric hydrocarbon-air flames. However, when added to lean flames, DMMP (dimethylmethylphosphonate) is predicted to increase the burning velocity. The addition of DMMP to lean mixtures apparently increases the equivalence ratio (fuel/oxidizer) and the combustion temperature, as a result of hydrocarbon content of DMMP molecule. Premixed flames studies with added DMMP, OP(OH)3, and CF3Br are used to understand the different behavior with varying equivalence ratio and agent loading. Decrease of the equivalence ratio leads to the decrease of inhibition effectiveness of PCCs relative to bromine-containing compounds. For very lean mixtures CF3Br becomes more effective inhibitor than PCCs. Calculations of laminar burning velocities for pure DMMP/air mixtures predict the maximum burning velocity of 10.5cm/s at 4.04% of DMMP in air and at an initial temperature of 400K. Adiabatic combustion temperature is 2155K at these conditions.

A comparison of the gas-phase fire retardant action of DMMP and Br2 in co-flow diffusion flame extinguishment,

Phosphorus-containing compounds are added to polymers as fire retardants and they are believed to act in both the gas and solid phases. In gaseous flame studies, they have been shown to be very effective gas-phase flame inhibitors; however, their performance varies with flame type. In particular, their effectiveness in co-flow diffusion flames is much lower than in other flames. To understand this behavior, co-flow diffusion flame experiments have been performed using dimethyl methylphosphonate (DMMP) added to the fuel stream. CO2 flame extinguishing tests show that phosphorus (via DMMP addition) is much more effective (∼4 times) than bromine (Br2) at low concentrations. At higher concentrations (above ∼5000µL/L), the efficiency ranking is reversed due to saturation of the DMMP inhibition effect, which is not observed in the case of Br2 addition. The role of particle formation (via condensation of active phosphorus-containing species) in the loss of effectiveness of DMMP is investigated using Rayleigh scattering measurements. In order to understand the behavior of the flame stabilization region that is disrupted during flame extinguishment, premixed burning velocity simulations with detailed kinetics are performed for DMMP or Br2 addition to the flames.

Experimental and numerical investigation of the gas‐phase effectiveness of phosphorus compounds

SummaryThe effectiveness of phosphorus‐containing compounds as gas‐phase combustion inhibitors varies widely with flame type. To understand this behavior, experiments are performed with dimethyl methylphosphonate (DMMP) added to the oxidizer stream of methane–air co‐flow diffusion flames (cup‐burner configuration). At low volume fraction, phosphorus (via DMMP addition) is shown to be about four times as effective as bromine (via Br2 addition) at reducing the amount of CO2 required for extinguishment; however, above about 3000 μL/L to 6000 μL/L, the marginal effectiveness of DMMP is approximately zero. In contrast, the diminished effectiveness does not occur for Br2 addition. To explore the role of condensation of active phosphorus‐containing compounds to the particles, laser‐scattering measurements are performed. Finally, to examine the behavior of the flame stabilization region (which is responsible for extinguishment), premixed burning velocity simulations with detailed kinetics are performed for DMMP addition to methane–air flames. Analyses of the numerical results are performed to understand the variation in the inhibition mechanism with temperature, agent loading, and stoichiometry, to interpret the loss of effectiveness for DMMP in the present experiments. Copyright © 2015 John Wiley & Sons, Ltd.

Effects of added dibutyl phosphate on the luminescent properties of europium tetrakis dibenzoylmethide triethylammonium

Since 2003, the authors have been pushing the boundaries on a special type of functional material, i.e., a material that gives off light when it is stressed, strained, and/or fractured. This unique class of materials has been proposed for the active element of impact sensors, earthquake detectors, and stress sensors. However, in order for this concept to go from the lab to real world applications, the light emission from these functional materials must be bright such that inexpensive light detectors can be used. One of the brightest materials found thus far is europium tetrakis dibenzoylmethide triethylammonium (EuD4TEA). This material has an emission so bright that it can be observed in daylight. In 2013, the authors discovered that the addition of dimethyl methylphosphonate (DMMP) increased the light emission two fold. As a result, a search for similar compounds was conducted to determine if the emission can be increased further. This paper explores the effects of dibutyl phosphate (DBP) on EuD4TEA. The effects of DBP on the triboluminescence, photoluminescence, and crystal structure of EuD4TEA will be determined. This paper will show that DBP has an even greater effect on the properties of EuD4TEA than DMMP.