Chemical tuning of the thermal decomposition temperature of inorganic hydrides: Computational aspects

2005 ◽  
Vol 404-406 ◽  
pp. 31-34 ◽  
Author(s):  
W. Grochala ◽  
P.P. Edwards
2010 ◽  
Vol 654-656 ◽  
pp. 2022-2024
Author(s):  
Nan Wang ◽  
Yue Yuan Li ◽  
Hong Wei Ni

Magnesium carbonate whisker was prepared by thermal decomposition of Mg(HCO3)2 solution that was prepared through hydration and carbonation of light burnt magnesia derived from magnesite tailings. The effects of thermal decomposition conditions on the morphology of magnesium carbonate crystal were investigated. Magnesium carbonate whiskers were successfully prepared when a kind of soluble magnesium salt was added, and magnesium carbonate whiskers with the length of 20 to 60μm and aspect ratio of 10~20 were obtained under the condition of 50 °C thermal decomposition temperature and 200 rpm stirring intensity.


Author(s):  
Munemichi Kawaguchi

Abstract In decommissioning sodium-cooled fast reactors, the operators can be exposed to radiation during dismantling of cold trap equipment (C/T). The C/T is higher dose equipment because the C/T trapped tritium of fission products during the operation to purify the sodium coolant. In this study, thermal decomposition temperature and rate of sodium hydride (NaH) were measured as a fundamental research for development of “thermolysis” process prior to the dismantling. We measured the thermal decomposition temperature and rate using NaH powder (95.3%, Sigma-Aldrich) in alumina pan with ThermoGravimetry-Differential Thermal Analysis (TG-DTA) instrument (STA2500 Regulus, NETZSCH Japan). The heating rates of TG-DTA were set to β = 2.0, 5.0, 10.0 and 20.0 K/min. The DTA showed endothermic reaction and the TG showed two-steps mass-loss over 580K. This first-step mass-loss was consistent with change of chemical composition of the NaH with heating (NaH → Na+1/2H2). The thermal decomposition temperature and rate were obtained from the onset temperature of the mass-loss and the simplified Kissinger plots, respectively. Furthermore, we set to the thermal decomposition temperature of around 590K, and the mass-loss rates were measured. As a result, over 590K, the thermal decomposition occurred actively, and showed good agreement with the estimation curves obtained by the simplified Kissinger plots. The thermal decomposition rate strongly depended on the heating temperature.


2019 ◽  
Vol 49 (3) ◽  
pp. 251-259 ◽  
Author(s):  
Mohammed Ameen Ahmed Qasem ◽  
Abuzar Khan ◽  
Sagheer A. Onaizi ◽  
Hatim Dafalla Mohamed ◽  
Aasif Helal ◽  
...  

2015 ◽  
Vol 33 (3) ◽  
pp. 560-565 ◽  
Author(s):  
Yifu Zhang ◽  
Xianfang Tan ◽  
Changgong Meng

Abstract The influence of vanadium dioxide VO2(B) on thermal decomposition of ammonium perchlorate (AP) has not been reported before. In this contribution, the effect of VO2(B) nanobelts on the thermal decomposition of AP was investigated by the Thermo- Gravimetric Analysis and Differential Thermal Analysis (TG/DTA). VO2(B) nanobelts were hydrothermally prepared using peroxovanadium (V) complexes, ethanol and water as starting materials. The thermal decomposition temperatures of AP in the presence of I wt.%, 3 wt.% and 6 wt.% of as-obtained VO2<B) nanobelts were reduced by 39 °C. 62 °C and 74 °C, respectively. The results indicated that VO2(B) nanobelts had a great influence on the thermal decomposition temperature of AP Furthermore, the influence of the corresponding V2Os, which was obtained by thermal treatment of VO2(B) nanobelts, on the thermal decomposition of AP was also investigated. The resufs showed that VO2(B) nanobelts had a greater influence on the thermal decomposition temperature of AP than that of V2Os.


2016 ◽  
Vol 66 (2) ◽  
pp. 100 ◽  
Author(s):  
Dhirendra Kshirsagar ◽  
Ramesh Kurva ◽  
Kashinath Dhabbe ◽  
Lalita Jawale ◽  
Sudhir Singh ◽  
...  

<p>Different compositions have been prepared by incorporating nano sized chromium oxide from 0.25 % to 1 % in HTPB/AP/Al based composite propellant formulation having 86% of solid loading and studied its effect on viscosity build-up, thermal, mechanical and ballistic properties. The findings reveal that on increasing the percentage of nano Cr2O3 in the composition, there is an increase in end of mix viscosity, elastic modulus and tensile strength while elongation decreases accordingly. The data on thermal properties envisage the reduction in thermal decomposition temperature of ammonium perchlorate as well as formulations based on HTPB/AP/Al. The data on ballistic properties reveal that there is an enhancement in burning rate from 6.11 mm/s to 7.88 mm/s at 6.86 MPa, however, marginal increase in  pressure exponent (‘n’ values) from 0.35 to 0.53 with 1 wt % of nano Cr2O3 was observed  in comparison to reference composition without chromium oxide. </p><p> </p>


2011 ◽  
Vol 311-313 ◽  
pp. 1065-1070
Author(s):  
Guo Lan Huan ◽  
Jian Li Liu ◽  
Qi Yun Du ◽  
Xiao Yu Hu

In this article, the thermal stability of PU/PVDF blend was investigated by thermogravimetry (TG), and their rheological property was studied through testing and analyzing the rheological curves. The results showed that, with the increase in PVDF content, the thermal decomposition temperature of PU/PVDF blend increased, and by fitting relevant data to thermal decomposition dynamic equations, it was found that thermal decomposition activation energy of the blend increased gradually, i.e. the thermal stability of the blend increased gradually. Meantime, based on the curves of shear stress vs. shear rate of the blend at 180°C and 200°C, it was shown that for PU/PVDF blend, with the decrease of temperature and the increase in PVDF content, the non-Newtonian index decreased, while the viscosity of the blend increased.


2014 ◽  
Vol 608-609 ◽  
pp. 996-1000
Author(s):  
Yan Bing Luo

Organic/inorganic nanocomposites have been widely focused because of their special properties. By modifying nanoTiO2and polylactic acid (PLA) with lactic acid, PLA/TiO2nanocomposites was prepared, and the test on the dynamic mechanical property, thermal property, and thermal deformation temperature showed that adding nanoTiO2helped improve PLA's mechanics property, thermal decomposition temperature, and thermal deformation temperature to certain extent.


2011 ◽  
Vol 239-242 ◽  
pp. 1317-1321 ◽  
Author(s):  
Xiao Yan Li ◽  
Xia Wang

By using Bisphenol A bis (diphenyl) phosphate ester (BDP) and a kind of Intumescent Flame Retardant (IFR) as Halogen-free Flame Retarding (HFFR), flame retarded oil-extended hydrogenated styrene-butylenes-styrene (SEBS) were prepared. The samples were systemically characterized by TGA, LOI and FESEM; influence of BDP and IFR for oil-extended SEBS was compared. The results showed that BDP can improve thermal decomposition temperature of SEBS; while the IFR retardant can produce remarkable residual chars to improve SEBS’s decomposition temperature; meanwhile BDP and the IFR retardant can bring synergistic effects in the flame retardancy for the oil-extended SEBS.


2021 ◽  
Author(s):  
pragnesh N Dave ◽  
Ruksana Sirach ◽  
Riddhi Thakkar ◽  
M P Deshpande

Abstract Less sensitive high energetic materials (HEMs) are explored as a potential replacement of highly sensitive HEMs in propellants, and explosive applications. More research have been devoted to improve the thermal decomposition of such a less sensitive HEMs. Nanosize Cobalt ferrite (CoF) has been successfully synthesized using the co-precipitation method. Synthesis of less sensitive HEM 3-nitro-2,4-dihydro-3H-1,2,4-triazol-5-one(NTO) and its size reduction using solvent-antisolvent method is successfully achieved. Effect of 5 % by weight CoF on the thermolysis of NTO and NTO with reduced size (r-NTO) has been studied using the simultaneous thermal analysis. Three isoconversional methods namely Flynn Ozawa Wall, Kissinger-Akahira-Sunose (KAS), and Starink are employed to evaluate the kinetic parameter of NTO, and r-NTO in the presence of CoF additive. It was found that both the addition of CoF as well as reducing size of NTO can decrease the thermal decomposition temperature of NTO, the later decreasing the thermal decomposition temperature to a good extent compared to former. However, the kinetic study using isoconversional methods suggested that in the presence of CoF additive, the activation energy of both NTO as well as n-NTO is increased.


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