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Irina A. Uspenskaya - One of the best experts on this subject based on the ideXlab platform.
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Thermodynamic properties of Ammonium Sulfamate
The Journal of Chemical Thermodynamics, 2019Co-Authors: Daria A. Kosova, Anna I. Druzhinina, L. A. Tiflova, A.s. Monayenkova, Elizaveta V. Belyaeva, Irina A. UspenskayaAbstract:Abstract Molar heat capacity of Ammonium Sulfamate (NH4SO3NH2) was measured in the temperature range from 8 K to 335 K by low-temperature vacuum adiabatic calorimetry. Obtained data were approximated by linear combination of Einstein functions. Heat content and entropy of NH4SO3NH2 were calculated from these data. Enthalpy of NH4SO3NH2 dissolution in water was determined at 298.15 K by means of solution calorimetry. On the basis of experimental data the standard entropy, enthalpy and Gibbs energy NH4SO3NH2 formation at 298.15 K were calculated. The phase transition of NH4SO3NH2 was observed by adiabatic calorimetry.
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a water urea Ammonium Sulfamate system experimental investigation and thermodynamic modelling
Fluid Phase Equilibria, 2016Co-Authors: Daria A. Kosova, A. L. Voskov, N. A. Kovalenko, Irina A. UspenskayaAbstract:Abstract The Water–Urea–Ammonium Sulfamate ternary system was investigated by means of experimental methods and thermodynamic modelling. Experimental part of the work includes (i) DSC measurements of liquidus and solidus of the Urea–Ammonium Sulfamate, the Water–Ammonium Sulfamate subsystems with the estimation of eutectic point position and a set of experiments on the phase boundaries in the ternary system; (ii) vapor pressure measurements in the binary Water–Ammonium Sulfamate and ternary Water–Ammonium Sulfamate–Urea systems at 298.15 K in a wide concentration range. Excess Gibbs energies of the Water–Ammonium Sulfamate–Urea system and its binary subsystems were described by the Pitzer-Simonson-Clegg model which is reduced to polynomial formalism in case of nonelectrolyte systems. Results of the Water–Urea subsystem reassessment are given.
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Volumetric Properties of Binary and Ternary Solutions in the Water–Urea–Ammonium Sulfamate System
Journal of Solution Chemistry, 2016Co-Authors: Daria A. Kosova, A. L. Voskov, Irina A. UspenskayaAbstract:Densities of liquid phases in the water–urea–Ammonium Sulfamate ternary system and in the binary water–Ammonium Sulfamate subsystem were investigated in a wide concentration range at 288.15, 298.15 and 323.15 K. A volumetric model of the aqueous ternary solutions was proposed.
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volumetric properties of binary and ternary solutions in the water urea Ammonium Sulfamate system
Journal of Solution Chemistry, 2016Co-Authors: Daria A. Kosova, A. L. Voskov, Irina A. UspenskayaAbstract:Densities of liquid phases in the water–urea–Ammonium Sulfamate ternary system and in the binary water–Ammonium Sulfamate subsystem were investigated in a wide concentration range at 288.15, 298.15 and 323.15 K. A volumetric model of the aqueous ternary solutions was proposed.
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A Water–Urea–Ammonium Sulfamate system: Experimental investigation and thermodynamic modelling
Fluid Phase Equilibria, 2016Co-Authors: Daria A. Kosova, A. L. Voskov, N. A. Kovalenko, Irina A. UspenskayaAbstract:Abstract The Water–Urea–Ammonium Sulfamate ternary system was investigated by means of experimental methods and thermodynamic modelling. Experimental part of the work includes (i) DSC measurements of liquidus and solidus of the Urea–Ammonium Sulfamate, the Water–Ammonium Sulfamate subsystems with the estimation of eutectic point position and a set of experiments on the phase boundaries in the ternary system; (ii) vapor pressure measurements in the binary Water–Ammonium Sulfamate and ternary Water–Ammonium Sulfamate–Urea systems at 298.15 K in a wide concentration range. Excess Gibbs energies of the Water–Ammonium Sulfamate–Urea system and its binary subsystems were described by the Pitzer-Simonson-Clegg model which is reduced to polynomial formalism in case of nonelectrolyte systems. Results of the Water–Urea subsystem reassessment are given.
Daria A. Kosova - One of the best experts on this subject based on the ideXlab platform.
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Thermodynamic properties of Ammonium Sulfamate
The Journal of Chemical Thermodynamics, 2019Co-Authors: Daria A. Kosova, Anna I. Druzhinina, L. A. Tiflova, A.s. Monayenkova, Elizaveta V. Belyaeva, Irina A. UspenskayaAbstract:Abstract Molar heat capacity of Ammonium Sulfamate (NH4SO3NH2) was measured in the temperature range from 8 K to 335 K by low-temperature vacuum adiabatic calorimetry. Obtained data were approximated by linear combination of Einstein functions. Heat content and entropy of NH4SO3NH2 were calculated from these data. Enthalpy of NH4SO3NH2 dissolution in water was determined at 298.15 K by means of solution calorimetry. On the basis of experimental data the standard entropy, enthalpy and Gibbs energy NH4SO3NH2 formation at 298.15 K were calculated. The phase transition of NH4SO3NH2 was observed by adiabatic calorimetry.
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a water urea Ammonium Sulfamate system experimental investigation and thermodynamic modelling
Fluid Phase Equilibria, 2016Co-Authors: Daria A. Kosova, A. L. Voskov, N. A. Kovalenko, Irina A. UspenskayaAbstract:Abstract The Water–Urea–Ammonium Sulfamate ternary system was investigated by means of experimental methods and thermodynamic modelling. Experimental part of the work includes (i) DSC measurements of liquidus and solidus of the Urea–Ammonium Sulfamate, the Water–Ammonium Sulfamate subsystems with the estimation of eutectic point position and a set of experiments on the phase boundaries in the ternary system; (ii) vapor pressure measurements in the binary Water–Ammonium Sulfamate and ternary Water–Ammonium Sulfamate–Urea systems at 298.15 K in a wide concentration range. Excess Gibbs energies of the Water–Ammonium Sulfamate–Urea system and its binary subsystems were described by the Pitzer-Simonson-Clegg model which is reduced to polynomial formalism in case of nonelectrolyte systems. Results of the Water–Urea subsystem reassessment are given.
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Volumetric Properties of Binary and Ternary Solutions in the Water–Urea–Ammonium Sulfamate System
Journal of Solution Chemistry, 2016Co-Authors: Daria A. Kosova, A. L. Voskov, Irina A. UspenskayaAbstract:Densities of liquid phases in the water–urea–Ammonium Sulfamate ternary system and in the binary water–Ammonium Sulfamate subsystem were investigated in a wide concentration range at 288.15, 298.15 and 323.15 K. A volumetric model of the aqueous ternary solutions was proposed.
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volumetric properties of binary and ternary solutions in the water urea Ammonium Sulfamate system
Journal of Solution Chemistry, 2016Co-Authors: Daria A. Kosova, A. L. Voskov, Irina A. UspenskayaAbstract:Densities of liquid phases in the water–urea–Ammonium Sulfamate ternary system and in the binary water–Ammonium Sulfamate subsystem were investigated in a wide concentration range at 288.15, 298.15 and 323.15 K. A volumetric model of the aqueous ternary solutions was proposed.
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A Water–Urea–Ammonium Sulfamate system: Experimental investigation and thermodynamic modelling
Fluid Phase Equilibria, 2016Co-Authors: Daria A. Kosova, A. L. Voskov, N. A. Kovalenko, Irina A. UspenskayaAbstract:Abstract The Water–Urea–Ammonium Sulfamate ternary system was investigated by means of experimental methods and thermodynamic modelling. Experimental part of the work includes (i) DSC measurements of liquidus and solidus of the Urea–Ammonium Sulfamate, the Water–Ammonium Sulfamate subsystems with the estimation of eutectic point position and a set of experiments on the phase boundaries in the ternary system; (ii) vapor pressure measurements in the binary Water–Ammonium Sulfamate and ternary Water–Ammonium Sulfamate–Urea systems at 298.15 K in a wide concentration range. Excess Gibbs energies of the Water–Ammonium Sulfamate–Urea system and its binary subsystems were described by the Pitzer-Simonson-Clegg model which is reduced to polynomial formalism in case of nonelectrolyte systems. Results of the Water–Urea subsystem reassessment are given.
Serge Bourbigot - One of the best experts on this subject based on the ideXlab platform.
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Flame Retardancy of PA6 Using a Guanidine Sulfamate/Melamine Polyphosphate Mixture
Polymers, 2015Co-Authors: Mathieu Coquelle, Sophie Duquesne, Mathilde Casetta, Jun Sun, Sheng Zhang, Serge BourbigotAbstract:Polyamide 6 (PA6) is a widely-used polymer that could find applications in various sectors, including home textiles, transportation or construction. However, due to its organic nature, PA6 is flammable, and flame-retardant formulations have to be developed to comply with fire safety standards. Recently, it was proposed to use Ammonium Sulfamate as an effective flame retardant for PA6, even at low loading content. However, processing issues could occur with this additive considering large-scale production. This paper thus studies the use of another Sulfamate salt—guanidine Sulfamate (GAS)—and evidences its high efficiency when combined with melamine polyphosphate (MPP) as a flame retardant for PA6. A decrease of the peak of the heat release rate by 30% compared to pure PA6 was obtained using only 5 wt% of a GAS/MPP mixture in a microscale calorimeter. Moreover, PA6 containing the mixture GAS/MPP exhibits a Limiting Oxygen Index (LOI) of 37 vol% and is rated V0 for the UL 94 test (Vertical Burning Test; ASTM D 3801). The mechanisms of degradation were investigated analyzing the gas phase and solid phase when the material degrades. It was proposed that MPP and GAS modify the degradation pathway of PA6, leading to the formation of nitrile end-group-containing molecules. Moreover, the formation of a polyaromatic structure by the reaction of MPP and PA6 was also shown.
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flame retardancy of pa6 using a guanidine Sulfamate melamine polyphosphate mixture
Polymers, 2015Co-Authors: Mathieu Coquelle, Sophie Duquesne, Mathilde Casetta, Jun Sun, Sheng Zhang, Serge BourbigotAbstract:Polyamide 6 (PA6) is a widely-used polymer that could find applications in various sectors, including home textiles, transportation or construction. However, due to its organic nature, PA6 is flammable, and flame-retardant formulations have to be developed to comply with fire safety standards. Recently, it was proposed to use Ammonium Sulfamate as an effective flame retardant for PA6, even at low loading content. However, processing issues could occur with this additive considering large-scale production. This paper thus studies the use of another Sulfamate salt—guanidine Sulfamate (GAS)—and evidences its high efficiency when combined with melamine polyphosphate (MPP) as a flame retardant for PA6. A decrease of the peak of the heat release rate by 30% compared to pure PA6 was obtained using only 5 wt% of a GAS/MPP mixture in a microscale calorimeter. Moreover, PA6 containing the mixture GAS/MPP exhibits a Limiting Oxygen Index (LOI) of 37 vol% and is rated V0 for the UL 94 test (Vertical Burning Test; ASTM D 3801). The mechanisms of degradation were investigated analyzing the gas phase and solid phase when the material degrades. It was proposed that MPP and GAS modify the degradation pathway of PA6, leading to the formation of nitrile end-group-containing molecules. Moreover, the formation of a polyaromatic structure by the reaction of MPP and PA6 was also shown.
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investigation of the decomposition pathway of polyamide 6 Ammonium Sulfamate fibers
Polymer Degradation and Stability, 2014Co-Authors: Mathieu Coquelle, Sophie Duquesne, Mathilde Casetta, Jun Sun, Sheng Zhang, Serge BourbigotAbstract:Abstract Polyamide 6 (PA6) is one of the most used polymers for synthetic textiles. PA6 fibers must be flame retarded to be used in building, home textiles or in transportation and must meet strict legislation. At this time, no acceptable flame-retardant solutions exist for PA6 fibers mainly because of processing issues (melt spinning of the fibers containing flame retardant additives). It was demonstrated in the literature that Ammonium Sulfamate (AS) is a flame retardant for polyamide 6. This paper investigates the effect of such additive in PA6 fibers. It was shown that fibers containing less than 7 wt.% of AS are spinnable while preserving the mechanical properties. Moreover, the peak of heat release rate measured in microcalorimeter decreases as a function of AS content in the formulation. It is reduced by 30% at 7 wt.% loading. The decomposition pathway of such material was investigated and the results suggest an action in the gas phase. Thermogravimetric analyses also reveal that a condensed phase mechanism is involved in the mechanism of action of AS in PA6. Solid state nuclear magnetic resonance (NMR) of the charred residues confirms this result and shows that AS promotes the formation of aromatic char.
A. L. Voskov - One of the best experts on this subject based on the ideXlab platform.
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a water urea Ammonium Sulfamate system experimental investigation and thermodynamic modelling
Fluid Phase Equilibria, 2016Co-Authors: Daria A. Kosova, A. L. Voskov, N. A. Kovalenko, Irina A. UspenskayaAbstract:Abstract The Water–Urea–Ammonium Sulfamate ternary system was investigated by means of experimental methods and thermodynamic modelling. Experimental part of the work includes (i) DSC measurements of liquidus and solidus of the Urea–Ammonium Sulfamate, the Water–Ammonium Sulfamate subsystems with the estimation of eutectic point position and a set of experiments on the phase boundaries in the ternary system; (ii) vapor pressure measurements in the binary Water–Ammonium Sulfamate and ternary Water–Ammonium Sulfamate–Urea systems at 298.15 K in a wide concentration range. Excess Gibbs energies of the Water–Ammonium Sulfamate–Urea system and its binary subsystems were described by the Pitzer-Simonson-Clegg model which is reduced to polynomial formalism in case of nonelectrolyte systems. Results of the Water–Urea subsystem reassessment are given.
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Volumetric Properties of Binary and Ternary Solutions in the Water–Urea–Ammonium Sulfamate System
Journal of Solution Chemistry, 2016Co-Authors: Daria A. Kosova, A. L. Voskov, Irina A. UspenskayaAbstract:Densities of liquid phases in the water–urea–Ammonium Sulfamate ternary system and in the binary water–Ammonium Sulfamate subsystem were investigated in a wide concentration range at 288.15, 298.15 and 323.15 K. A volumetric model of the aqueous ternary solutions was proposed.
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volumetric properties of binary and ternary solutions in the water urea Ammonium Sulfamate system
Journal of Solution Chemistry, 2016Co-Authors: Daria A. Kosova, A. L. Voskov, Irina A. UspenskayaAbstract:Densities of liquid phases in the water–urea–Ammonium Sulfamate ternary system and in the binary water–Ammonium Sulfamate subsystem were investigated in a wide concentration range at 288.15, 298.15 and 323.15 K. A volumetric model of the aqueous ternary solutions was proposed.
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A Water–Urea–Ammonium Sulfamate system: Experimental investigation and thermodynamic modelling
Fluid Phase Equilibria, 2016Co-Authors: Daria A. Kosova, A. L. Voskov, N. A. Kovalenko, Irina A. UspenskayaAbstract:Abstract The Water–Urea–Ammonium Sulfamate ternary system was investigated by means of experimental methods and thermodynamic modelling. Experimental part of the work includes (i) DSC measurements of liquidus and solidus of the Urea–Ammonium Sulfamate, the Water–Ammonium Sulfamate subsystems with the estimation of eutectic point position and a set of experiments on the phase boundaries in the ternary system; (ii) vapor pressure measurements in the binary Water–Ammonium Sulfamate and ternary Water–Ammonium Sulfamate–Urea systems at 298.15 K in a wide concentration range. Excess Gibbs energies of the Water–Ammonium Sulfamate–Urea system and its binary subsystems were described by the Pitzer-Simonson-Clegg model which is reduced to polynomial formalism in case of nonelectrolyte systems. Results of the Water–Urea subsystem reassessment are given.
Menachem Lewin - One of the best experts on this subject based on the ideXlab platform.
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Flame retarding polymer nanocomposites: Synergism, cooperation, antagonism
Polymer Degradation and Stability, 2011Co-Authors: Menachem LewinAbstract:Abstract Three systems of FR treatments of polyamide 6 with conventional flame retarding additives in the absence and in the presence of nanoparticles are discussed: I. Ammonium Sulfamate (AS) and dipentaerythritol (Di) II. melamine cyanurate (MC) III. pentabromobenzyl acrylate in the monomeric (PMA) and the polymeric (PPA) form. Depending on the concentration of the nanoparticles; synergism, antagonism, and cooperation in flame retardancy as well as in mechanical properties are observed. Cooperation between the OMMT in the concentration range of 0.5–1.0 wt% and the FR in all three systems is observed. The decrease in PHRR (ΔPHRR) is different for the three systems. In system III the brominated FR behaves similarly to OMMT with respect to ΔPHRR. The interaction between the molten polymeric matrix and the nanoparticles increases the viscosity in all three systems, which slows down the supply of the flame retarding moieties to the flame and lowers the FR rating, as measured by the UL-94 and OI tests. A new approach for assessing the viscosity of the pyrolyzing nanocomposite is presented by determining the size and mass of the drops formed during the UL-94 test. Dispersion of the nanoparticles in the polymer decreases the HRR and MRR and decreases the UL-94, OI ratings, and the mechanical properties, as evidenced by the different behavior of OMMT and Na + MMT. The time of ignition decreases markedly by the addition of the nanoparticles, due to the low thermal conductivity and heat transfer of the protective barrier on the surface of the pyrolyzing nanocomposite in the pre-ignition phase. A possibility of restoring the high FR rating in the presence of higher concentrations of nanoparticles is indicated. The significance of the results obtained for the future of the use of nanoparticles in FR is discussed.
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flammability of polyamide 6 using the Sulfamate system and organo layered silicate
Polymers for Advanced Technologies, 2007Co-Authors: Menachem Lewin, Jin Zhang, Eli M Pearce, Jeffrey W GilmanAbstract:A high degree of flame retardancy (FR) of polyamide 6 (PA6) is obtained by adding low weight per cent NH2SO3NH4 (Ammonium Sulfamate, AS) and dipentaerythritol (Di). This result is preserved when 1 wt% of organo-layered montmorillonite (OMMT) is dispersed in the AS + Di formulation. Increasing OMMT decreases these FR ratings. The surfaces of the gallery or exfoliated layers of OMMT adsorb and immobilize a part of AS + Di preventing its contribution to the FR reactions. The addition of the hydrophilic poly(vinylpyrrolidone) (PVP) partly restores the original FR ratings so a greater amount of AS + Di remains effective. The decrease in the high heat release rate (HRR) of the AS + Di containing PA6 by OMMT imparts to the PA6 lowered peak HRR (PHRR) and slower burning. Addition of pristine montmorillonite (MMT) up to 5 wt% does not decrease the UL-94 V-0 rating. The smaller surface area of the relatively large particles of the non-colloidal pristine MMT adsorbs less AS + Di than OMMT. A straight line relationship was found between oxygen index (OI) values and ignition times in the cone calorimeter. The char resulting from combustion is composed mainly of MMT and some graphitic carbon. XRD found that the d(100) spacing for the clay in the final chars from burning was found to be 1.27 nm, corresponding to a 2θ peak of 7.0. No correlation between the size of the floccular structures on the char surface and the decrease in PHRR is found. Mechanistic considerations are presented. Copyright © 2007 John Wiley & Sons, Ltd.
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Flammability of polyamide 6 using the Sulfamate system and organo‐layered silicate
Polymers for Advanced Technologies, 2007Co-Authors: Menachem Lewin, Jin Zhang, Eli M Pearce, Jeffrey W GilmanAbstract:A high degree of flame retardancy (FR) of polyamide 6 (PA6) is obtained by adding low weight per cent NH2SO3NH4 (Ammonium Sulfamate, AS) and dipentaerythritol (Di). This result is preserved when 1 wt% of organo-layered montmorillonite (OMMT) is dispersed in the AS + Di formulation. Increasing OMMT decreases these FR ratings. The surfaces of the gallery or exfoliated layers of OMMT adsorb and immobilize a part of AS + Di preventing its contribution to the FR reactions. The addition of the hydrophilic poly(vinylpyrrolidone) (PVP) partly restores the original FR ratings so a greater amount of AS + Di remains effective. The decrease in the high heat release rate (HRR) of the AS + Di containing PA6 by OMMT imparts to the PA6 lowered peak HRR (PHRR) and slower burning. Addition of pristine montmorillonite (MMT) up to 5 wt% does not decrease the UL-94 V-0 rating. The smaller surface area of the relatively large particles of the non-colloidal pristine MMT adsorbs less AS + Di than OMMT. A straight line relationship was found between oxygen index (OI) values and ignition times in the cone calorimeter. The char resulting from combustion is composed mainly of MMT and some graphitic carbon. XRD found that the d(100) spacing for the clay in the final chars from burning was found to be 1.27 nm, corresponding to a 2θ peak of 7.0. No correlation between the size of the floccular structures on the char surface and the decrease in PHRR is found. Mechanistic considerations are presented. Copyright © 2007 John Wiley & Sons, Ltd.
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the system polyamide Sulfamate dipentaerythritol flame retardancy and chemical reactions
Polymers for Advanced Technologies, 2002Co-Authors: Menachem Lewin, Jiri Brozek, Marvin M MartensAbstract:The use of sulfur compounds and particularly Sulfamates for flame-retarding cellulose and other polymers is reviewed. Recent results on flame-retarding polyamides in this laboratory are presented. The system developed requires the use of 1.5–2.5 wt% of Ammonium Sulfamate (AS) or diAmmonium imidobisulfonate (DIBS) together with 0.4–0.85 wt% of pentaerythritol (petol) or dipentaerythritol (dipenta) to obtain fully flame-retardant polyamide 6 and 66. The properties of the flame-retarded products, obtained both by Brabender mixing and by twin-screw extrusion are: UL-94 rating of V-0 on bars of 1/16″ and 1/32″; no flaming drips; very low burn time; tensile strength of 11 KPSI; 10–20% elongation and CTI values of ca. 600 V. Thermoanalytical and FTIR data are presented that indicate the thermal stability of the system and the chemical reactions occurring. Mechanisms are discussed. Copyright © 2003 John Wiley & Sons, Ltd.
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The system polyamide/Sulfamate/dipentaerythritol: flame retardancy and chemical reactions†
Polymers for Advanced Technologies, 2002Co-Authors: Menachem Lewin, Jiri Brozek, Marvin M MartensAbstract:The use of sulfur compounds and particularly Sulfamates for flame-retarding cellulose and other polymers is reviewed. Recent results on flame-retarding polyamides in this laboratory are presented. The system developed requires the use of 1.5–2.5 wt% of Ammonium Sulfamate (AS) or diAmmonium imidobisulfonate (DIBS) together with 0.4–0.85 wt% of pentaerythritol (petol) or dipentaerythritol (dipenta) to obtain fully flame-retardant polyamide 6 and 66. The properties of the flame-retarded products, obtained both by Brabender mixing and by twin-screw extrusion are: UL-94 rating of V-0 on bars of 1/16″ and 1/32″; no flaming drips; very low burn time; tensile strength of 11 KPSI; 10–20% elongation and CTI values of ca. 600 V. Thermoanalytical and FTIR data are presented that indicate the thermal stability of the system and the chemical reactions occurring. Mechanisms are discussed. Copyright © 2003 John Wiley & Sons, Ltd.