Preparation of Nano-titanium Dioxide in Propane/Air Diffusion Flame

Titanium dioxide (TiO2) nanoparticles were synthesized by the oxidation of titanium tetrachloride (TiCl4), in propane/air diffusion flame. The propane/air diffusion flame is generated using a multi-port diffusion type burner composed of 4 concentric tubes. Flow rates of TiCl4 and combustion gases such as air, industrial propane and carrier gas were chosen as key experimental variables for the control of the particle size and morphology. Effects of propane/air mole ratio and precursor flow rate on particle size, morphology, structure and carbon dots of titanium dioxide particles were studied.     

Some Features of Gas‐Flame Propagation in Narrow Tubes

The dependence of the flamefront curvature on the composition of the mixture in tubes of various diameters is considered. The combustionwave velocities are measured for different fractions of fuel in the mixture. It is shown that the dependence of the burning velocity on the composition of the mixture has two maximums, one of them being related to the transition of the laminar combustion mode to turbulent combustion. Combustion turbulization is caused by flame instability to acoustic oscillations. Variations of the combustionwave shape due to acoustic oscillations are observed.     

Flame Propagation in a Variable–Section Channel with Gas Filtration

A one–dimensional unsteady model is proposed, which describes gas–flame propagation in a narrow variable–section channel with a gas counterflow and takes into account heat propagation over the channel walls. The case of the channel cross section changing slowly at a distance of the order of the thermal thickness of the combustion wave is considered. It is shown that various regimes of flame propagation are possible in such a system: a regime of flame propagation with a high velocity (of the order of the burning velocity of the flame), a regime of flame propagation with a low velocity as in the case of filtrational gas combustion in a porous medium, and an intermittent regime of combustion, where the flame has a high velocity in the wide section of the channel and a low velocity in the narrow section. A simple analytical model of flame oscillations in such a system is constructed. The possibility of these oscillations was predicted by numerical simulation results. The simple model considered is an attempt to take into account the large–scale inhomogeneity of the porous medium in simulation of filtrational combustion of gases.     

Experimental Study of a Cellular Ethanol Flame Evaporating “On the Ceiling”

This paper describes the study of evaporation and combustion of ethanol under a horizontal wall in a stratified shear gas layer in the case of the Rayleigh–Taylor instability. Data on the nature of flow are obtained with the use of particle image velocimetry (PIV), and temperature profiles are recorded by a thermocouple. It is shown that cells are formed in a narrow range of air velocity of 0.6 ± 0.05 m/s and does not depend on the height of the obstacle (backward ledge or an edge is 0–7 mm in height). The flow between the wall and flame front is an alternation of mushroom-shaped structures moving from one wall to another. In the cellular flame, the flow of substance (with respect to the air flow) exceeds its level in a standard laminar boundary layer three times. The averaged transverse velocity is directed away from the wall in the boundary layer with combustion without cells, and it is reduced and directed toward the wall in the cellular flame between the wall and flame front.     

Flame retardant UV-curable acrylated epoxidized soybean oil based organic–inorganic hybrid coating

Organic–inorganic hybrid coating based on methacrylated/phosphorylated epoxidized soybean oil were obtained by combining photopolymerization and sol–gel process. A series of novel methacrylated and phosphorylated epoxidized soybean oil/silica coating materials were prepared from tetraethoxysilane (TEOS), and acrylated soybean oil via sol–gel technique. Acrylated epoxidized soybean oil (AESO) is obtained by reacting epoxidized soybean oil (ESO) with methacrylic acid and vinyl phosphonic acid. The characterization of AESO was performed by NMR and IR spectroscopy.     

Temperature and OH Concentration Measurements in Alcohol–Air Flame Using Laser-Induced Fluorescence

Temperatures and OH concentrations in ethanol flames were measured using laser-induced fluorescence and probe methods. The maximum temperatures recorded by different methods agree with each other. During combustion of ethanol evaporating from the surface of a sphere 15 mm in diameter, the radical concentration was 7 · 10¹⁶ cm^-3 taking into account fluorescence extinction. In concentration measurements, the equipment was calibrated in experiments with a hydrogen flame, for which these data are known. It has been established that in both cases, the maximum of the OH concentration is displaced with respect to the temperature maximum. The data obtained can be useful in studying the combustion of liquid fuel drops.     

Some Phenomena During Flame Propagation in a Half‐Open Channel with an Obstacle

A laminar flame front propagating in a closedend channel with an obstacle is simulated. Ignition is initiated at the closed end of the channel. The simulations revealed the entrainment of the flame in the vortex behind the obstacle, the expulsion of the vortex from the channel by the flame, and flame fragmentation.     

Gas‐Dynamic Method of Combustion Control and Flame Stabilization in a Pseudoliquid Fuel Flow

A gasdynamic method for controlling combustion and flame stabilization in a pseudoliquid fuel flow is proposed. The method is based on injection of additional air jets with varied frequency into a chamber with abrupt expansion. It is shown that the characteristics of combustion of the pseudoliquid fuel can be controlled by varying the frequency of injection of periodic air jets.     

Model of an Ideal Solid‐Flame Combustion Wave with a Variable Chemical‐Reaction Surface

A model for a combustion wave in condensed mixtures with autoinhibition by a highmelting reaction product is constructed with allowance for a reduction in the particle surface of the highmelting reactant during chemical interaction with the lowmelting reactant. An approximate analytical solution is derived using the method of a semiinfinite reaction zone. The method is validated by qualitative and numerical studies of differential equations. The literature model of the process considered ignores the variation in the particle surface of the highmelting reactant, which leads to neglect of the key characteristics of all chemical reactions — a continuous decrease in the reaction rate during combustion of the reactants.     

Preparation and Performance of a P–N Containing Intumescent Flame Retardant Based on Hydrolyzed Starch

Halogen-free flame retardant is receiving an increased attention recently due to its hypotoxicity and high efficiency. Intumescent flame retardant is a hot spot in research of the halogen-free flame retardant. In this work, a P–N containing intumescent flame retardant named hydrolyzed starch phosphamide from melamine was synthesized via hydrolysis of starch, phosphorylation of the starch with phosphorus oxychloride, and the reaction between the phosphorylated starch and melamine. PU/hydrolyzed starch phosphamide from melamine composites was prepared using different additive amounts of hydrolyzed starch phosphamide from melamine. Fourier transform infrared, scanning electron microscopy, and thermogravimetric analysis were used to characterize the structures and thermal stabilities of related compounds. Flame retardation performance of hydrolyzed starch phosphamide from melamine was investigated by UL94, limit oxygen index test, and cone calorimetry. Result shows that the PU/hydrolyzed starch phosphamide from melamine composites with 30.0 php of hydrolyzed starch phosphamide from melamine got a limit oxygen index of 29.0 and UL94-V0 ranking. Heat release rate, rate of smoke release, and total smoke release were decreased distinctly.     

Flame retardancy of water-based intumescent coatings with etherified melamine–formaldehyde and polyvinyl acetate copolymer hybrid resin

This study investigated etherified melamine–formaldehyde (MF) and polyvinyl acetate copolymer hybrid resins with different intumescent formulations to improve the flame retardancy of plywood. The CO and CO₂ emissions of intumescent coatings were also investigated. The miscibility of two resins is indicated by a single cure peak. Intumescence with a hybrid resin demonstrated better flame retardancy relative to that with a pure etherified MF resin. The results of scanning electron microscopy and a cone calorimeter test indicated that a lower binder resin (BR) content enhances fire retardancy and forms an ideal char. Furthermore, an evaluation of total heat release in addition to CO and CO₂ emissions (for 300 s) revealed that the intumescent coating had the same flame retardancy when the BR content was increased by 40%. The survival duration of the chemical structures of the phosphocarbonaceous chars was verified using Fourier-transform infrared spectroscopy and solid-state phosphorus-31 nuclear magnetic resonance analyses.     

Metal–Organic Frameworks Derived from Zn and p-Hydroxybenzoic Acid for Smoke Suppression and Flame Retardation in Vinyl Resin

A metal–organic framework (MOF) formed between Zn and p-hydroxybenzoic acid (PHBA) is synthesized using a solvothermal method. These Zn-PHBA nanorods, which are inexpensive and suitable for mass production, are added as a flame-retardant into vinyl resin (430 LV, a material used in marine composites). Data from cone calorimetric test demonstrates that adding the Zn-PHBA nanorods to 430 LV significantly improves flame retardation and smoke suppression. At a high Zn-PHBA content of 10.0 wt%, the limiting oxygen index of 430 LV increases from 19.5% to 28.5%, and the material reaches the V-0 rating in vertical burning tests (UL-94). Moreover, the tensile and impact strengths of 430 LV containing 10 wt% Zn-PHBA as flame-retardant do not deteriorate and are even slightly improved. This work demonstrates that this MOF synthesized by a simple and efficient method may be used to produce nanocomposites with excellent flame retardation and mechanical properties, while keeping the material cost sufficiently low for marine applications.     

Chemical Analysis of Magnesia and Magnesia-Alumina Refractory Materials ——Flame atomic absorption spectrometric method for determination of calcium oxide content

GB/T 5069.10-2001 1 Scope This standard specifies the determination of calcium oxide content by flame atomic absorption spectrometric method. This standard applies to the determination of calcium oxide content in magnesia and magnesia-alumina refrac…     

The Effect of a Polymeric Flame Retardant Containing Phosphorus–Sulfur–Silicon and a Caged Group on Unsaturated Polyester Resin

Journal of Inorganic and Organometallic Polymers and Materials - Currently, the issue of natural flammability of unsaturated polyester resin (UPR) severely restrains its application. In this study,...     

Properties of Colloidal Silica‐Fixed and Propionylated Wood Composite (II): Flame Resistance and Other Properties of the Composites

Abstract

The flame resistance, color change, strength, and decay resistance of colloidal silica‐fixed (CSW), propionylated only, and propionylated dual‐treated wood (CSPW) composites were evaluated. The oxygen indexes of the CSPW composites were similar to the CSW composites but much higher than those of untreated woods and the propionylated woods. The oxygen indexes increased with an increase in the weight percent gain of the colloidal silica (WPG_csi) in the composites, showing an effective reduction in the flammability by the fixation of colloidal silica. The CSPW composites showed little or no difference in the modulus of elasticity and modulus of rupture compared with the untreated woods, indicating little or no significant reduction in strength properties of the wood specimens. The color difference of the wood specimens before and after treatment changed slightly. Minimal weight losses of the CSPW composites occurred upon fungal attack by T. versicolor and F. palustris, showing good decay resistance by propionylation of the composites.     

Development of Siloxane Based Tetraglycidyl Epoxy Nanocomposites for High Performance Applications—Study of the Mechanical,Thermal, Water Absorption and Flame Retardant Behaviour

A study was made in the present investigation on siloxane containing tetraglycidyl epoxy nanocomposites in order to determine their suitability for use in high performance applications. The synthesis of the siloxane tetraglycidyl epoxy resin denoted as ‘E’ was done and it was characterized by Fourier Transform Infrared (FT-IR) spectra and ¹H, ¹³C Nuclear Magnetic Resonance (NMR) spectra. Nanoclay and polyhedral oligomeric silsesquioxanes (POSS)-amine nanoreinforcements denoted as N1 and N2 were incorporated into the synthesized epoxy resin. Curing was done with diaminodiphenylmethane (DDM) and bis (3-aminophenyl) phenylphosphine oxide (BAPPO) curing agents denoted as X and Y respectively. The mechanical, thermal, flame retardant and water absorption behaviour of the epoxy nanocomposites were studied and the results are discussed.     

One-Step Flame Synthesis of an Active Pt/TiO2 Catalyst for SO2 Oxidation—A Possible Alternative to Traditional Methods for Parallel Screening

Flame synthesis as a route for production of composite metal oxides has been employed for the one-step synthesis of a supported noble metal catalyst, i.e., a Pt/TiO₂ catalyst, by simultaneous combustion of Ti-isopropoxide and platinum acetylacetonate in a quench-cooled flame reactor. The average size of the platinum particles supported on aggregated nanoparticles of TiO₂ is approximately 2 nm. The high SO₂ oxidation activity of the catalyst proves that platinum is not “hidden” in the titania matrix. The flame-produced catalyst showed catalytic activity similar to that of samples prepared by wet platinum impregnation of pure titania.     

Macromolecular Chelator‐Amberlite XAD‐16 Anchored with 2,3‐Dihydroxypyridine (DHP) for Enrichment of Metal Ions before their Determination by Flame Atomic Absorption Spectrometry

Abstract

2,3‐Dihydroxypyridine (DHP) was loaded onto Amberlite XAD‐16 via azo linker and the resulting resin AXAD‐16‐DHP explored for enrichment of Zn(II), Mn(II), Ni(II), Pb(II), Cd(II), Cu(II), Fe(III), and Co(II) in the pH range 4.0–6.5. The sorption capacity was found in the range 120–512 µmol g^?1 and the preconcentration factor from 200 to 300. Tolerance limits for foreign species are reported. The kinetics of sorption is fast, as t_1/2 is generally ≤2 min. The chelating resin can be reused for fifty cycles of sorption‐desorption without any significant change (≤2.0%) in its sorption capacity. The limit of detection values (blank + 3s) are 2.90, 3.80, 5.17, 7.02, 1.91, 1.63, 4.59, and 5.02 µg L^?1 for Zn, Mn, Ni, Pb, Cd, Cu, Fe, and Co respectively. The corresponding limit of quantification (blank + 10 s) values are 5.30, 6.20, 8.38, 9.54, 4.22, 4.17, 8.62, and 9.86 µg L^?1, respectively. The enrichment on AXAD‐16‐DHP coupled with monitoring by flame atomic absorption spectrometry (FAAS) is used to determine these metal ions in river and synthetic water samples, Co in vitamin tablets, and Zn in milk samples. AXAD‐16‐DHP has been found to perform better than DHP loaded cellulose and Amberlite XAD‐2.     

β-cyclodextrin as a Partial Replacement of Phosphorus Flame Retardant for Poly(Lactic Acid)/Poly(Methyl Methacrylate): A More Environmental Friendly Flame-Retarded Blends

β-Cyclodextrin was used together with isopropylated triaryl phosphate ester flame retardant to improve the flame resistance of poly(lactic acid)/poly(methyl methacrylate). Poly(lactic acid)/poly(methyl methacrylate)/flame-retardant blend (with and without β-cyclodextrin) was evaluated using limiting oxygen index, Underwriters Laboratories-94 vertical burning test, scanning electron microscopy, and thermogravimetric analysis (in O₂ and N₂). The addition of β-cyclodextrin was able to reduce the amount of flame retardant required for poly(lactic acid)/poly(methyl methacrylate) blends to achieve self-extinguishing properties. The poly(lactic acid)/poly(methyl methacrylate)20/flame-retardant/β-cyclodextrin blends achieved Underwriters Laboratories-94, V-0, and limiting oxygen index value of 29.3%. A compact and wide coverage of char layer was formed on the burning surface of poly(lactic acid)/poly(methyl methacrylate)20/flame-retardant/β-cyclodextrin blends.