TY - JOUR A1 - Asanova, T.I. A1 - Asanov, Igor A1 - Yusenko, Kirill A1 - Le Fontane, Camille A1 - Gerasimov, E.Y. A1 - Zadesenetz, A.V. A1 - Korenev, S.V. T1 - Time-resolved study of Pd-Os and Pt-Os nanoalloys formation through thermal decomposition of Pd(NH3)(4) OsCl6 and Pt(NH3)(4) OsCl6 complex salts JF - Materials Research Bulletin N2 - The formation mechanisms of Pd-Os and Pt-Os alloys in the course of thermal decomposition of iso-formular and isostructural complex salts [Pd(NH3)4][OsCl6] and [Pt(NH3)4][OsCl6] in an inert atmosphere have been studied by in-situ QXAFS, XPS and PXRD. The mechanisms of thermal decomposition of the precursors are found to differ from each other, but the detected intermediate products show no significant effect on the local atomic structure around Os, Pt/Pd in their final products. A crystalline beta-trans-[Pd(NH3)2Cl2] intermediate of the first step of thermal decomposition of [Pd(NH3)4][OsCl6] makes the anion [OsCl6]2− transform differently than that of [Pt(NH3)4][OsCl6]. It transforms into a short-lived [Os(NH3)xCl6-x] (2≤x≤4), and then to a distorted octahedron [OsCl6]2−, similar to the high-temperature modification of OsCl4. In case of [Pt(NH3)4][OsCl6], the intermediate [Os(NH3)2Cl4] modifies into four chlorine coordinated Os,{OsCl4}0/1−. Consecutive reduction of Pd(II)/Pt(II) and Os(IV) to the metals defines the homophilic atomic order with the fcc-Pd covered by a random Pd-Os alloy layer and Os on the surface, that is supported by High-Resolution Transmission Electron Mictroscopy (HRTEM) and Scanning TEM (STEM) energy dispersive X-ray (EDX) data, and the diffusion direction going from the surface (hcp-Os) to bulk (fcc-Pd/Pt). As a result, the heterogeneous alloys are formed with a very similar electronic and local atomic structure of Os and Pd/Pt. Upon alloying, the Os 5d5/2,3/2 and Pt 5d5/2,3/2 levels are depleted in the Pt-Os alloys compared to dispersed hcp-Os, fcc-Pt, and Pt foil. This is an unusual behaviour for Os and Pt, calling into question the versatility of d-band theory in bimetallic Os-alloys. The spin-orbit effect at the Os site has been found for both the Pd-Os and Pt-Os alloys, but it is about 4 times less compared to the complex salts. The obtained values for the complex compounds are comparable with those for the iridates, proposed as materials with spin-orbit-induced properties. KW - Thermal decomposition KW - Quick-EXAFS PY - 2021 DO - https://doi.org/10.1016/j.materresbull.2021.111511 VL - 144 SP - 111511 PB - Elsevier Ltd. AN - OPUS4-54010 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Berger, Anka A1 - Wehrstedt, Klaus-Dieter T1 - Azodicarboxylates: Explosive properties and DSC measurements JF - Journal of loss prevention in the process industries N2 - A large number of azodicarboxylates and their derivatives are produced and used in the chemical industries. The versatile applications of these azodicarboxylates in research institutes and in the chemical industries for chemical synthesis arouse additional hazards. The intent of this paper is to obtain first knowledge about the structure–response relationship regarding the explosive properties and the thermal hazards of different versatile used azodicarboxylates. The substances are examined with the differential scanning calorimetry (DSC). Furthermore, different laboratory test methods, based on the UN Recommendations on the Transport of Dangerous Goods, are applied to determine the explosive properties of the mentioned substances. On the basis of the obtained results, the known influence of the nitrogen content within the molecule regarding their thermal behaviour could be confirmed. The measured heat of decomposition appeared to be proportional to the nitrogen content within the group of the aliphatic and the aromatic azodicarboxylates. To emphasize this dependency, further investigations should be done. The long term objective of this research is to develop structure–response relationships of the explosive properties and the thermal hazards originating from azodicarboxylates. KW - Azodicarboxylates KW - Thermal decomposition KW - Differential scanning calorimetry (DSC) KW - Explosive properties PY - 2010 DO - https://doi.org/10.1016/j.jlp.2010.06.019 SN - 0950-4230 SN - 1873-3352 VL - 23 IS - 6 SP - 734 EP - 739 PB - Butterworth CY - Guildford, Surrey AN - OPUS4-22652 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lörchner, Dominique A1 - Dittmann, Daniel A1 - Braun, Ulrike A1 - Kroh, L. W. A1 - Köppen, Robert T1 - Investigation of two triazine-based heterocyclic brominated flame retardants by coupled thermogravimetry-Fourier transform infrared spectroscopy JF - Journal of Analytical and Applied Pyrolysis N2 - In this study, the thermal decomposition of 1,3,5-tris-(2,3-dibromopropyl)-1,3,5-triazine-2,4,6-trione (TDBPTAZTO) and 2,4,6-tris-(2,4,6-tribromo-phenoxy)-1,3,5-triazine (TTBP-TAZ) were investigated for the first time by thermogravimetric analysis. Both compounds were thermal degraded between 225 and 350 °C (TDBP-TAZTO) as well as 300 and 400 °C (TTBP-TAZ). As a result, mass loss (%) of 98.5% for TTBP-TAZ and 95.4% for TDBP-TAZTO at 600 °C under N2 were observed. The major pyrolytic degradation products of TTBP-TAZ were formed in a single step and identified by FTIR analysis as 2,4,6-tribromophenol and further bromine-substituted aromatic compounds. In comparison, TDBP-TAZTO was pyrolytic degraded in two steps, whereby on the first step the release of hydrogen Bromide and 1,3,5-triallyl-1,3,5-triazine-2,4,6-trione could be detected. In the second minor step, isocyanic acid could be additionally identified. Subsequently, the obtained products of the TGA-FTIR measurements were used for a targeted search for mass fragments in mass spectrometry measurements. For TTBP-TAZ, only the degradation product 1,3,5-tribromobenzene could be detected by MS/MS analyzes. No comparable thermal degradation products, except hydrogen bromide, were observed in the MS/MS spectra of TDBP-TAZTO. Therefore, the search of further mass fragments was not possible compared to the findings of the TGA-FTIR measurements. KW - Pyrolysis KW - Thermal decomposition KW - TGA-FTIR KW - Mass spectrometry PY - 2019 DO - https://doi.org/10.1016/j.jaap.2019.104635 VL - 141 SP - 104635-1 EP - 104635-5 PB - Elsevier B.V. AN - OPUS4-48506 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Malow, Marcus A1 - Michael-Schulz, Heike A1 - Duerrstein, St. A1 - Kappler, C A1 - Neuhaus, I. A1 - Gödde, M. T1 - Model-Based Prediction of the Adiabatic Induction Period and SADT of Dicumyl Peroxide Solution and Comparison to Large-Scale Experiments Performed Using 216.5-Liter Steel Drums in the UN-Test H.1 JF - 15th International Symposium of Loss Prevention and Safety Promotion in the Process Industries N2 - The thermal decomposition of dicumyl peroxide dissolved in ethylbenzene has been studied in our laboratories using differential scanning calorimetry (DSC), calvet calorimetry (C80), adiabatic calorimetry, reaction calorimetry and micro calorimetry. Based on the DSC and C80 experiments a formal kinetics model has been derived, which was compared to the other applied techniques. Finally we used our model to predict the thermal response of 216.5 L steel drums to exposure to constant elevated temperatures, both using the stationary Semenov approach as well as time-resolved CFD simulations. The prediction was compared to one-to-one testing using the UN-Test H.1. The observed level of consistency between model and experiments is remarkably good. The comparison with the 216.5 L testing clearly demonstrates that reliable and conservative predictions for technically relevant scales are possible as long as a validated model is used. T2 - 15th International Symposium of Loss Prevention and Safety Promotion in the Process Industries CY - Freiburg, Germany DA - 05.06.2016 KW - Thermal decomposition KW - Self-accelerating decomposition temperature KW - Dicumyl peroxide KW - CFD simulations KW - Real scale FST PY - 2016 SN - 978-88-95608-39-6 DO - https://doi.org/10.3303/CET1648080 SN - 2283-9216 VL - 48 SP - 475 EP - 480 PB - AIDIC CY - Freiburg AN - OPUS4-37875 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sypaseuth, Fanni D. A1 - Gallo, Emanuela A1 - Çiftci, Serhat A1 - Schartel, Bernhard T1 - Polylactic acid biocomposites: approaches to a completely green flame retarded polymer JF - e-Polymers N2 - Basic paths towards fully green flame retarded kenaf fiber reinforced polylactic acid (K-PLA) biocomposites are compared. Multicomponent flame retardant Systems are investigated using an amount of 20 wt% such as Mg(OH)2 (MH), ammonium polyphosphate (APP) and expandable graphite (EG), and combinations with Silicon dioxide or layered silicate (LS) nanofillers. Adding Kenaf fibers and flame retardants increases the E modulus up to a factor 2, although no compatibilizer was used at all. Thus, in particular adding EG and MH decreases the strength at maximum elongation, and kenaf fibers, MH, and EG are crucial for reducing the elongation to break. The Oxygen index is improved by up to 33 vol% compared to 17 vol% for K-PLA. The HB classification of K-PLA in the UL 94 test is outperformed. All flame retarded biocomposites show somewhat lower thermal stability and increased amounts of residue. MH decreases the fire load significantly, and the greatest reduction in peak heat release rate is obtained for K-PLA/15MH/5LS. Synergistic effects are observed between EG and APP (ratio 2:1) in flammability and fire properties. Synergistic multicomponent systems containing EG and APP, or MH with adjuvants offer a promising route to green flame retarded natural fiber reinforced PLA biocomposites. KW - Biopolymers KW - Composites KW - Flame retardance KW - Natural fibres KW - Thermal decomposition PY - 2017 DO - https://doi.org/10.1515/epoly-2017-0024 SN - 2197-4586 SN - 1618-7229 VL - 17 IS - 6 SP - 449 EP - 462 PB - De Gruyter AN - OPUS4-42872 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Witke, Klaus A1 - Kunze, Ralf A1 - Neubert, Dietmar A1 - Mehner, Hartmut A1 - Feist, M. A1 - Kemnitz, E. T1 - Two oxidation states and four different coordinations of iron in an unusual chloro complex: TG-MS, Raman and Mössbauer spectroscopic investigations of the thermal behaviour JF - Thermochimica Acta N2 - Conventional simultaneous thermal analysis, capillary-coupled TG–MS, in situ and ex situ Raman and Mössbauer spectroscopy, as well as chemical analysis have been used for the investigation of the first decomposition step of the mixed valence chloroferrate (dmpipzH2)6[Fe(II)Cl4]2[Fe(III)Cl4]2[Fe(II)Cl5][Fe(III)Cl6]. Under argon at ca. 200°C, an almost complete reduction proceeds in a solid state reaction forming Fe(II). It is accompanied by the release of HCl and, to a minor degree, carbon containing species. A multi-phase product with at least two chloroferrate species, coke, and C,H,N-containing polymers is formed. Binuclear iron complexes, such as (dmpipzH)2[Fe(II)2Cl6], and small amounts of (dmpipzH)[Fe(III)Cl4] have been proposed to be the major and minor component of the product mixture, respectively. KW - Mixed valence chloroferrate KW - Thermal decomposition KW - Intramolecular reduction PY - 2000 DO - https://doi.org/10.1016/S0040-6031(00)00546-3 SN - 0040-6031 SN - 1872-762X VL - 361 IS - 1-2 SP - 53 EP - 60 PB - Elsevier CY - Amsterdam AN - OPUS4-988 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yusenko, Kirill A1 - Domonov, D. A1 - Pechenyuk, S. A1 - Belyevskii, A. T1 - Formation of Nanostructured Carbon from [Ni(NH3)6]3[Fe(CN)6]2 JF - Nanomaterials N2 - The products of thermal decomposition in an argon atmosphere of [Ni(NH3)6]3[Fe(CN)6]2 as a precursor has been studied. Decomposition products were studied up to 800◦C. Above 600◦C, all coordination bonds in the residues are broken with a formation of Ni3Fe, Fe, and free carbon with a small admixture of nitrogen. Elementary carbon can be easily separated from metals by treatment with a water solution of hydrochloric acid. Only carbon is responsible for the specific surface of the composite products. The released carbon has a high degree of graphitization and begins to oxidize in air above 500°C and is completely oxidized above 700°C. KW - Carbon materials KW - Double complex compound KW - Thermal decomposition PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508188 DO - https://doi.org/10.3390/nano10020389 VL - 10 IS - 2 SP - 389 PB - MDPI CY - Basel AN - OPUS4-50818 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yusenko, Kirill A1 - Zvereva, V. A1 - Martynova, S. A1 - Asanov, I. A1 - La Fontaine, C. A1 - Roudenko, O. A1 - Gubanov, A. A1 - Plyusnin, P. A1 - Korenev, S. A1 - Asanova, T. T1 - Insight of the thermal decomposition of ammonium hexahalogenoiridates(IV) and hexachloroiridate(III) JF - PCCP N2 - Thermal decomposition of (NH4)3[IrCl6]·H2O, (NH4)2[IrCl6] and (NH4)2[IrBr6] in reductive and inert atmospheres has been investigated in situ using quick-EXAFS and temperature-resolved powder X-ray diffraction. For the first time, (NH4)2[Ir(NH3)Cl5] and (NH4)2[Ir(NH3)Br5] have been proven as intermediates of thermal decomposition of (NH4)3[IrCl6]·H2O, (NH4)2[IrCl6] and (NH4)2[IrBr6]. Thermal degradation of (NH4)2[IrCl6] and (NH4)2[IrBr6] is a more complex process as suggested previously and includes simultaneous formation of (NH4)2[Ir(NH3)Cl5] and (NH4)2[Ir(NH3)Br5] intermediates mixed with metallic iridium. In the inert atmosphere, complexes (NH4)[Ir(NH3)2Cl4] and (NH4)[Ir(NH3)2Br4] as well as [Ir(NH3)3Br3] were proposed as possible intermediates before formation of metallic iridium particles KW - Thermal decomposition KW - Iridium compounds KW - EXAFS KW - In situ PXRD PY - 2020 DO - https://doi.org/10.1039/D0CP02743J VL - 22 IS - 40 SP - 22923 EP - 22934 AN - OPUS4-51224 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -