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1.
Wenxian Wei Bingbing Cui Xiaohong Jiang Ludu Lu 《Journal of Thermal Analysis and Calorimetry》2010,102(3):863-866
The catalytic effect of NiO on thermal decomposition of nitrocellulose (NC) has been investigated via thermogravimetry–mass
spectrometry (TG–MS) coupling technique, and the residue of NC with 20% NiO reacted in tubular furnace was analyzed by X-ray
diffraction (XRD). TG–MS analysis showed that adding 2% NiO to NC accelerated the thermal decomposition process and promoted
the generation of gaseous products. The catalytic mechanism was based on the accelerated generation of NO2, which further reacted with the radical to produce other gaseous products. XRD analysis of catalyst residue showed that Ni
was formed during the catalytic reaction. 相似文献
2.
In order to obtain a better understanding of thermal substituent effects in 1,2,4-triazole-3-one (TO), the thermal behavior
of 1,2,4-triazole, TO, as well as urazole and the decomposition mechanism of TO were investigated. Thermal substituent effects
were considered using thermogravimetry/differential thermal analysis, sealed cell differential scanning calorimetry, and molecular
orbital calculations. The onset temperature of 1,2,4-triazole was higher than that of TO and urazole. Analyses of evolved
decomposition gases were carried out using thermogravimetry–infrared spectroscopy and thermogravimetry–mass spectrometry.
The gases evolved from TO were determined as HNCO, HCN, N2, NH3, CO2, and N2O. 相似文献
3.
A free-base tetraphenyl porphyrin (TPP) and its corresponding metalloporphyrins (MTPP) where M = Co, Fe and Sn were synthesized
and characterized by UV–visible spectroscopy, FTIR and 1Hnmr spectroscopy. Thermal studies of these porphyrins were carried out in synthetic air from room temperature to 800 °C using
thermal analyser. The residues of MTPP after thermal treatment were qualitatively analysed, which showed the presence of corresponding
metal oxides. Further, the above MTPP were subjected to thermogravimetry–evolved gas and mass spectrometry (TG–EGA–MS) analysis
for the detailed information about evolved gases at their corresponding decomposition temperatures. This information may be
used to predict the probable mechanism for ring opening of the macromolecular porphyrins. 相似文献
4.
G. Madhurambal M. Mariappan B. Ravindran S. C. Mojumdar 《Journal of Thermal Analysis and Calorimetry》2011,104(3):885-891
Mixed crystals of various proportions of urea thiourea were grown by slow evaporation of aqueous solution at room temperature.
The bright and transparent crystals obtained were characterized using thermogravimetry–differential thermal analysis (TG–DTA)
and FTIR spectroscopic analyses. A fitting decomposition pattern for the title compound was formulated on the TG curve which
shows a two-stage mass loss between 175 and 750 °C. In this temperature range, DTA curves show exothermic peaks supporting
the formulated decomposition pattern. The FTIR spectra show the characteristic absorption, vibration frequencies due to urea
thiourea. Detailed structural analysis of the compound is under progress. 相似文献
5.
Yu Huimei Qi Lingjun Zhang Qinghong Jiang Danyu Lu Changwei 《Journal of Thermal Analysis and Calorimetry》2011,106(1):47-52
The thermal behavior of the anticancer drug-irinotecan was measured by Thermogravimetry–Differential thermal analysis (TG–DTA)
to explore the application of TG–DTA in nanomedicine firstly. The TG–DTA result showed that the irinotecan was oxidized completely
before 700 °C. When irinotecan was loaded onto nanosized mesoporous silica spheres, the loading capacity for irinotecan measured
by TG–DTA was about 9.11% in the irinotecan/mesoporous SiO2 composite, similar to the typical UV–Vis spectra results (10.5%), which showed that TG–DTA characterization provided an alternative
method to determine the drug loading amount on inorganic carriers. Secondly, Thermogravimetry–Differential scanning calorimetry–Mass
Spectrometry coupling techniques (TG–DSC–MS) were used to characterize the hydrogen adsorption temperature and capacity of
TiCr1.2 (V-Fe)0.6 alloy. The MS result showed that the released region of hydrogen was 250–500 °C, which was consistent with the TG–DSC results.
Lastly, TA–MS combined with pulse thermal analysis (PulseTA) were used for a simultaneous characterizing study in the changes
of mass, determination and quantitative calibration of the evolved nitrogen formed during the thermal decomposition of the
InN powder. The results showed that relative error of this method between measured value and theoretical value was 2.67% for
the quantitative calibration of evolved N2. It shows that TA–MS combined with PulseTA techniques offer a good tool for the quantification of the evolved nitrogen in
the InN powder. 相似文献
6.
Hongqiang Qu Weihong Wu Yunhong Jiao Jixing Xie Jianzhong Xu 《Journal of Thermal Analysis and Calorimetry》2011,105(1):269-277
A flame-retardant wood was prepared using a series of insoluble molybdates through the double bath technique. The flame retardancy
of the wood samples was studied with the limiting oxygen index (LOI) method. The relationships between the flame-retardant
performance and the thermal property of wood were studied by the thermogravimetry (TG), derivative thermogravimetry (DTG),
differential thermal analysis (DTA), scanning electron microscopy (SEM), and the thermogravimetry–mass spectrometry (TG–MS)
analysis methods. The results showed that the insoluble molybdates, which were precipitated into the wood by the double bath
technique, can obviously improve the flame retardancy of wood. Similarly, the transition metal molybdates showed higher flame-retardant
efficiency than the main group metal molybdates do, which probably due to the thermal barrier effect that Fe2(MoO4)3 acts during the combustion of the samples. At the same time, Fe2(MoO4)3 catalyzed the dehydration and carbonization reactions of wood, and caused an increase in the amount of char produced, and
an improvement of the stability of the char residue. Moreover, the mass spectrometry results indicated that the excess transition
metal ions speed up the deep decomposition of the char residue, and resulting in the smoldering of wood. 相似文献
7.
Chun-Hong Jiang Li-Fang Song Cheng-Li Jiao Jian Zhang Li-Xian Sun Fen Xu Yong Du Zhong Cao 《Journal of Thermal Analysis and Calorimetry》2011,103(1):373-380
A three-dimensional lithium-based metal–organic framework Li2(2,6-NDC) (2,6-NDC = 2,6-naphthalene dicarboxylate) has been synthesized solvothermally and characterized by X-ray powder
diffraction, elemental analysis, FT-IR spectroscopy, thermogravimetry and mass spectrometer analysis (TG–MS). The framework
has exceptional stability and is stable to 863 K. The thermal decomposition characteristic of this compound was investigated
through the TG–MS from 293 to 1250 K. The molar heat capacity of the compound was measured by temperature modulated differential
scanning calorimetry (TMDSC) over the temperature range from 195 to 670 K for the first time. The thermodynamic parameters
such as entropy and enthalpy versus 298.15 K based on the above molar heat capacity were calculated. 相似文献
8.
Marieta Muresan-Pop Irina Kacsó Carmen Tripon Z. Moldovan Gh. Borodi S. Simon I. Bratu 《Journal of Thermal Analysis and Calorimetry》2011,104(1):299-306
Ambazone, a well-known antimicrobial compound, presents also oncostatic properties. The solid form, obtained by using solvent-drop
grinding procedure, was characterized by using several physical techniques such as FTIR, X-ray photoelectron spectroscopy,
13C NMR and 15N NMR spectroscopies, thermal analysis, X-ray powder diffraction and mass spectrometry. Based on these data, it was demonstrated
that an ambazone–hydrochloride was obtained: new vibrations corresponding to NH2
+ were identified. DTA–TG–DSC and MS data revealed that a new crystal type has been obtained. X-ray diffraction data allowed
the determination of the lattice parameters and the most probable space group P
21/c
was established also with only one molecule per asymmetric unit. 相似文献
9.
Xinliang Mei Yi Cheng Yanchun Li Xuqiang Zhu Shi Yan Xiangyu Li 《Journal of Thermal Analysis and Calorimetry》2013,114(1):131-135
Characterized with a large gas production and low combustion temperature, the guanidine nitrate (GN) gas-generating agents are studied and applied widely. The determination factors of thermal decomposition properties of guanidine nitrate and basic cupric nitrate (GN/BCN) gas-generating agents for airbag application was investigated by the thermogravimetry–differential scanning calorimetry–mass spectrmetry–Fourier transform infrared spectroscopy (TG-DSC-MS-FTIR) and automatic calorimeter. Five different mass ratios were concerned. Our study showed that the onset reaction temperatures of GN/BCN mixtures were lower than that of individual GN and BCN. The thermal decomposition of GN/BCN mixtures could be divided into three stages, including the dissociation and escape of crystal water, solid (GN)-solid (BCN) phase reaction, and liquid (GN)-solid (BCN) phase reaction. When mass ratio of GN/BCN was 62.24/37.73, the largest value of the reaction heat was measured to 3152.7 J g?1, with N2 and H2O as the major gases during thermal decomposition. 相似文献
10.
Hou-yin Zhao Yan Cao Song P. Sit Quentin Lineberry Wei-ping Pan 《Journal of Thermal Analysis and Calorimetry》2012,107(2):541-547
The pyrolysis behavior of bitumen was investigated using a thermogravimetric analyzer–mass spectrometer system (TG–MS) and
a differential scanning calorimeter (DSC) as well as a pyrolysis-gas chromatograph/mass spectrometer system (Py-GC/MS). TG
results showed that there were three stages of weight loss during pyrolysis—less than 110, 110–380, and 380–600 °C. Using
distributed activation energy model, the average activation energy of the thermal decomposition of bitumen was calculated
at 79 kJ mol−1. The evolved gas from the pyrolysis showed that organic species, such as alkane and alkene fragments had a peak maximum temperature
of 130 and 480 °C, respectively. Benzene, toluene, and styrene released at 100 and 420 °C. Most of the inorganic compounds,
such as H2, H2S, COS, and SO2, released at about 380 °C while the CO2 had the maximum temperature peaks at 400 and 540 °C, respectively. FTIR spectra were taken of the residues of the different
stages, and the results showed that the C–H bond intensity decreased dramatically at 380 °C. Py-GC/MS confirmed the composition
of the evolved gas. The DSC revealed the endothermic nature of the bitumen pyrolysis. 相似文献
11.
K. Muraleedharan M. P. Kannan T. Ganga Devi 《Journal of Thermal Analysis and Calorimetry》2011,103(3):943-955
The thermal decomposition of potassium iodate (KIO3) has been studied by both non-isothermal and isothermal thermogravimetry (TG). The non-isothermal simultaneous TG–differential
thermal analysis (DTA) of the thermal decomposition of KIO3 was carried out in nitrogen atmosphere at different heating rates. The isothermal decomposition of KIO3 was studied using TG at different temperatures in the range 790–805 K in nitrogen atmosphere. The theoretical and experimental
mass loss data are in good agreement for the thermal decomposition of KIO3. The non-isothermal decomposition of KIO3 was subjected to kinetic analyses by model-free approach, which is based on the isoconversional principle. The isothermal
decomposition of KIO3 was subjected to both conventional (model fitting) and model-free (isoconversional) methods. It has been observed that the
activation energy values obtained from all these methods agree well. Isothermal model fitting analysis shows that the thermal
decomposition kinetics of KIO3 can be best described by the contracting cube equation. 相似文献
12.
The thermal decomposition process of mixtures of CoC2O4⋅2H2O (COD) or Co(HCOO)2⋅2H2O (CFD) or [Co(NH3)6]2(C2O4)3⋅4H2O (HACOT) with activated carbon was studied with simultaneous TG–DTG–DTA measurements under non-isothermal conditions in argon
and argon/oxygen admixtures. The results show that the thermal decomposition of the studied mixtures in Ar proceeds in the
same manner. It begins with the salt decomposition to Comet+CoO mixture followed by (T>680 K) the simultaneous reduction of CoO to Cometand carbon degasification. The final product of the thermal decomposition of COD-C and CFD-C mixtures, identified by XRD,
is β-Co. Cobalt contents determined in the final products fall in the range 71–78 mass%. The rest is amorphous residual carbon.
In Ar/O2 admixtures the end product is Co3O4 with ash admixture.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
13.
Hongqiang Qu Weihong Wu Hongjuan Wu Jixing Xie Jianzhong Xu 《Journal of Thermal Analysis and Calorimetry》2011,103(3):935-942
The effect of three flame retardants, K2CO3, Na2SiO3·9H2O, and Na2B4O7·10H2O on the process and composition of volatile products of the thermal degradation of wood has been investigated by the thermogravimetric
(TG), differential thermogravimetry (DTG), differential thermal analysis (DTA), and the synchronous thermogravimetry–mass
spectrometry (TG–MS) analysis methods. The results showed that the ion current intensity and ion peak area of m/z = 18 and 44 MS signals were increased by the flame retardants but the ion peak area of m/z = 28 MS signal was decreased (except K2CO3) at the meantime. What’s more, the ion current intensity and ion peak area of m/z = 60 and 68 MS signals were also decreased (except K2CO3), which mean that Na2B4O7 can significantly enhances the dehydration and inhibits the depolymerization of wood. Although K2CO3 accelerates the dehydration reaction, it cannot inhibit the depolymerization reaction effectively, so the flame retardant
efficiency of K2CO3 is decreased with the higher concentration. The catalysis of dehydration reaction of Na2SiO3 is the worst one. 相似文献
14.
Mohammad?R.?Saraji-Bozorgzad Thorsten?Streibel Markus?Eschner Thomas?M.?Groeger Robert?Geissler Erwin?Kaisersberger Thomas?Denner Ralf?Zimmermann
A newly developed measurement technique for evolved gas analysis in thermogravimetry, viz. a thermo balance coupled to comprehensive
gas chromatography/single photon ionization mass spectrometry (TG–GC × SPIMS), has been applied to investigate the thermal
degradation of two polymers (polycarbonate (PC) blended with ABS and PVC). This detection method provides a two-dimensional
analysis of the evolved gaseous products. TG relevant data is obtained as well as an improved resolution power to separate
isobaric molecular structures without losing any fraction of the samples. In addition, this solution is not associated with
any extension of the measurement time. The assignment of the substance pattern to distinct species is improved compared to
solely using MS without a preceding separation step. Furthermore, hitherto undetected compounds when compared to applying
TG–SPIMS without GC such as benzonitrile and its methylated derivatives have been found in the evolved gases from the thermal
degradation of PC/ABS blend. Finally, a first estimation of the limit of detection has been carried out, yielding 400 ppt
for styrene and 500 ppt for toluene from the thermal decomposition of PC/ABS blend. 相似文献
15.
L’ubomír Ježo Martin Palou Jana Kozánková Tomáš Ifka 《Journal of Thermal Analysis and Calorimetry》2010,101(2):585-593
Isothermal conduction calorimetry, differential thermal analysis (DTA)–thermogravimetric analysis (TG) analysis, and SEM observations
have proved the activation effect of Ca(OH)2 released from the C3S hydration upon blast furnace slag (BFS). Five sample mixtures of BFS and C3S and two samples of pure BFS and C3S were submitted to reaction with water inside the calorimeter at room temperature. The values of hydration heat were recorded
up to 7 days. Samples were stored in humidity during 28 days and then were submitted to DTA–TG and SEM analysis. The effect
of Ca(OH)2 upon heat evolution of sample mixtures has been quantified and its influence upon the formation of new hydrates and microstructure
of pastes was evidenced. 相似文献
16.
Tiit Kaljuvee Merli Keelmann Andres Trikkel Rein Kuusik 《Journal of Thermal Analysis and Calorimetry》2011,105(2):395-403
The thermooxidative decomposition of four oil shale samples from Estonia, Jordan, Israel and Morocco and one sample of Estonian
oil shale derivative, semicoke, was studied with the aim to determine the characteristics of the process and the differences
of it related to the origin of oil shale. The experiments with a Setaram Setsys 1750 thermoanalyzer coupled to a Nicolet 380
FTIR Spectrometer were carried out under non-isothermal conditions up to 1000 °C at the heating rates of 1, 2, 5, 10 and 20 °C min−1 in an oxidizing atmosphere. A model-free kinetic analysis approach based on the differential isoconversional method of Friedman
was used to calculate the kinetic parameters. The results of TG–DTA–FTIR analyses and the variation of activation energy E along the reaction progress α indicated the complex character of thermooxidative decomposition of oil shale and semicoke,
being at that the most complicated for Estonian and Jordanian oil shale characterized by higher content of organic matter
as compared to the other samples studied. 相似文献
17.
Thangamani Rajkumar Chinnaswamy Thangavel Vijayakumar Palanichamy Sivasamy Bojja Sreedhar Charles A. Wilkie 《Journal of Thermal Analysis and Calorimetry》2010,100(2):651-660
Imparting thermal stability to polymethyl methacrylate (PMMA) without affecting its optical clarity is attempted by incorporating
HET acid based oligoesters. Pure PMMA and PMMA containing five and 20 wt% of four different oligoesters are separately prepared
using bulk polymerization. The thermal properties of the materials studied using DSC, TG, TG–FTIR and Pyr–GC–MS are presented.
The main volatile degradation products identified are CO, HCl, CO2, H2O, hexachlorocyclopentadiene, hexachloroendomethylene tetrahydrophthalic acid/anhydride and methyl methacrylate. A detailed
mechanism for the influence of the degradation products of HET acid based oligoesters on the thermal degradation of PMMA is
also presented. 相似文献
18.
Thermal and Spectroscopic Studies on the Decomposition of Some Aminoguanidine Nitrates 总被引:1,自引:0,他引:1
S. R. Naidu K. V. Prabhakaran N. M. Bhide E. M. Kurian 《Journal of Thermal Analysis and Calorimetry》2000,61(3):861-871
Diaminoguanidine nitrate (DAGN) and triaminoguanidine nitrate (TAGN),potential energetic materials in emerging propulsion
technology with high mass impetus at low isochoric flame temperature have been studied as regards kinetics and mechanism of
thermal decomposition using thermogravimetry (TG), differential thermal analysis (DTA),infrared spectroscopy (IR) and hot
stage microscopy. Kinetics of thermolysis has been followed by isothermal TG and IR. For the initial stage of thermolysis
of DAGN the best linearity with a correlation coefficient of 0.9976 was obtained for the Avrami-Erofe'evequation, n=2, by isothermal TG. The activation energy was found to be 130 kJ mol–1 and logA=11.4. The initial stage of thermolysis of TAGN also obeyed the Avrami-Erofe'ev equation, n=2, with a correlation coefficient of 0.9975by isothermal TG and the kinetic parameters are E=160.0 kJ mol–1 and logA=16.0. High temperature IR spectra showed exquisite preferential loss in intensity of the NH2, NH, N–N stretching and CNN bending. Spectroscopic and other results favour deamination reaction involving the rupture of
the N–N bond as the primary step in the thermal decomposition.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
19.
Basile F Zhang S Kandar SK Lu L 《Journal of the American Society for Mass Spectrometry》2011,22(11):1926-1940
We report on the characterization by mass spectrometry (MS) of a rapid, reagentless and site-specific cleavage at the N-terminus
of the amino acid cysteine (C) in peptides and proteins induced by the thermal decomposition at 220–250 °C for 10 s in solid
samples. This thermally induced cleavage at C occurs under the same conditions and simultaneously to our previously reported
thermally induced site-specific cleavage at the C-terminus of aspartic acid (D) (Zhang, S.; Basile, F. J. Proteome Res.
2007, 6, (5), 1700–1704). The C cleavage proceeds through cleavage of the nitrogen and α–carbon bond (N-terminus) of cysteine and
produces modifications at the cleavage site with an amidation (−1 Da) of the N-terminal thermal decomposition product and
a −32 Da mass change of the C-terminal thermal decomposition product, the latter yielding either an alanine or β-alanine residue
at the N-terminus site. These modifications were confirmed by off-line thermal decomposition electrospray ionization (ESI)-MS,
tandem MS (MS/MS) analyses and accurate mass measurements of standard peptides. Molecular oxygen was found to be required
for the thermal decomposition and cleavage at C as it induced an initial cysteine thiol side chain oxidation to sulfinic acid.
Similar to the thermally induced D cleavage, missed cleavages at C were also observed. The combined thermally induced digestion
process at D and C, termed thermal decomposition/digestion (TDD), was observed on several model proteins tested under ambient
conditions and the site-specificity of the method confirmed by MS/MS. 相似文献
20.
Arturo Rodriguez Mohini Sain Robert Jeng 《Journal of Thermal Analysis and Calorimetry》2009,98(1):317-323
The thermal behavior of modified starches (MS) produced by biosynthetic pathway is described based on a comparative analysis
with native starches (NS). MS were produced by fermentation in presence of Ophiostoma spp. cultures. Thermogravimetric analysis (TG) with successive derivatives (DTG) and differential scanning calorimetry (DSC)
were used for this study. NS results showed a single peak dominating both the TG (DTG) and DSC plots. A double thermal transition
event was detected in samples of MS. The procedural decomposition temperature (T
i–T
f; lowest onset temperature of initial and final mass change) was carried out within a narrow interval of temperatures for
NS (610–640 °C). This interval could not be reached within the 1,000 °C range in MS. Residues higher than 10% were recorded
for MS at this temperature. The presence of the double thermal transition in MS is discussed. 相似文献