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111.
El Watik L. Claire Y. Zineddine H. Rossi C. Kaloustian J. Sergent M. Périchaud A. 《Journal of Thermal Analysis and Calorimetry》1999,58(1):19-28
The study of the thermal degradation of the fireproof polystyrene—butadiene copolymer by an intumescent system: ammonium polyphosphate (APP)—pentaerythritol (PER)—talc (TAL), was done through an experimental process. Thermogravimetry under air sweeping was used. We observed for the degradation rate of the mixture with fireproofing agents, in the field of 20 to 50% mass loss, a better linear increasing when this mixture contains more TAL and the ratio APP/PER is smaller.
This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
112.
Mineral oil type lubricating oils have an important role in reducing engine wear. But after some period, depending on the
oil quality, oil replacement is needed since the oil loses its properties. In this paper, an engine oil was tested in a 1300
cc engine car and the change of the thermal stability of the collected portions of oil at different usage periods were experimented
by TG/DTG and DSC techniques. Results show that, as usage period increases lubricating oil contains more of the light components
that distill at low temperatures. The increase in the peak maximum temperature, Tmax, of the DTG, as usage period increases, proposes that the molecular mass of the oil increase, which presumably changes the
viscosity characteristics. Moreover as the usage period increases some residue type components, which only can be destroyed
at very high temperatures, are produced in oil phase.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
113.
The thermal decomposition of sodium ethyl xanthate (SEX) was used to compare the techniques of pyrolysis-gas chromatography-mass
spectrometry (py-GC-MS), thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR), and TG-MS.
In the py-GC-MS analysis, SEX was pyrolysed at 400°C in an inert atmosphere. Major gases evolved were carbon disulfide, diethyl
sulfide, ethanol, and carbonyl sulfide. The TG of SEX exhibited a sharp mass loss at 201°C (42.3%) and a gradual mass loss
at 217-325°C (20.8 %). The MS spectra of the evolved gases were complex due to overlapping of molecular, isotope, and fragment
ion signals. Using the MS in selected ion monitoring mode, the major gases evolved were found to be carbon disulfide and carbonyl
sulfide. The FTIR spectra of the evolved gases displayed vibrational frequencies due to alkanes, carbonyls, carbonyl sulfide,
and carbon disulfide.
From the analyses it was concluded that py-GC-MS provided unambiguous gas identification. Interpretation of the MS results
was reliant on the py-GC-MS results, and the FTIR data was limited to identifying gases with very characteristic vibration
frequencies.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
114.
Jozef Rychlý Aysegul Kocer Fathy Tanis Lyda Matisová-Rychlá Ivica Janigová Katarína Csomorová 《Chemical Papers》2009,63(4):471-478
Difference in the kinetics of chemiluminescence (CL) and differential scanning calorimetry records for decomposition of originally
solid benzoyl peroxide continuing as a melt reaction was outlined. While the main portion of heat measured by DSC is released
in the spontaneous decomposition of benzoyl peroxide starting as a homolytic scission of peroxidic bonds, the CL light emission
in oxygen comes presumably from the subsequent disproportionation reaction of polyphenyl peroxyl radicals and monitors the
induced decomposition of peroxide. Thermogravimetry revealed that oxygen remains partially bound to the products of benzoyl
peroxide decomposition. 相似文献
115.
Jnos Madarsz Petra Bombicz Czugler Mtys Ferenc Rti Gbor Kiss Gyrgy Pokol 《Thermochimica Acta》2009,490(1-2):51-59
Detailed study on identification and thermal decomposition of solid title compounds 1 and 2 crystallized from the used aqueous ammonia solutions of Pd(NH3)2(NO2)2 and Pt(NH3)2(NO2)2, has been carried out. Beyond the composition of complexes 1 and 2, their trans square planar configuration have already been recognized by reference IR spectra and powder XRD patterns, nevertheless their exact molecular and crystal structure as of trans-Pd(NH3)2(NO2)2 (1, Pd-NN) and trans-Pt(NH3)2(NO2)2 (2, Pt-NN) has been determined by single crystal X-ray diffraction (R = 0.0515 and 0.0341), respectively. Despite their compositional and configuration analogy, they crystallize in different crystal systems and space groups. The crystals of 1 (Pd-NN) are triclinic (space group No. 2, P-1, a = 5.003(1) Å, b = 5.419(1) Å, c = 6.317(1) Å, α = 91.34(2)°, β = 111.890(10)°, γ = 100.380(10)°), while those of 2 (Pt-NN) are monoclinic (space group No. 5, C2, a = 7.4235(16) Å, b = 9.130(2) Å, c = 4.4847(10) Å, β = 99.405(7)°).The pyrolytic processes of 1 and 2 (which might be sensitive to shock and heat) have been followed by simultaneous thermogravimetric and differential thermal analysis (TG/DTA), while the evolved gaseous species have been traced in situ by online coupled TG/DTA–EGA–MS and TG–EGA–FTIR instruments in He and air. Pd and Pt powders, forming as final solid products in single step, are captured and checked by TG and XRD. Whilst the unified evolved gas analyses report evolution of N2, H2O, NH3, N2O, NO, and NO2 gases as gaseous product components in the exothermic decomposition of both trans-Pd(NH3)2(NO2)2 (1) and trans-Pt(NH3)2(NO2)2 (2) starting from ca. 230 and 220 °C, in sealed crucibles with a pinhole on the top, respectively. 相似文献
116.
The combustion kinetics of Göynük oil shale, polystyrene and several polystyrene-oil shale blends were investigated by thermogravimetric analysis in the present study. Experiments were conducted at non-isothermal conditions with a heating rate of 5, 10 and 20 K min?1 in the 298–1173 K temperature interval under an air atmosphere. Differential thermogravimetric data were analyzed by two different models. Effects of blending ratio of oil shale and polystyrene and heating rate on the combustion kinetics were investigated. Kinetic parameters were determined and the results were discussed. 相似文献
117.
Recently, Órfão obtained two simple equations for the estimation of the relative error in the activation energy calculated by the integral methods [2]. In this short communication, the validity of the equations has been evaluated by comparing the results calculated by the equations with the results calculated by the equation from theoretical derivation without introducing any assumption. 相似文献
118.
H. Polli L. A. M. Pontes A. S. Araujo Joana M. F. Barros V. J. FernandesJr. 《Journal of Thermal Analysis and Calorimetry》2009,95(1):131-134
The degradation kinetics of the ABS terpolymer (acrylonitrile-butadiene-styrene) was investigated by means of thermogravimetric
analysis. The samples were heated from 30 to 900°C in nitrogen atmosphere applying three different heating rates: 5, 10 and
20°C min−1. The Vyazovkin model-free kinetic method was used to calculate the activation energy (E) of the degradation process as a function of conversion and temperature. Between 20 and 80% of conversion, E was calculated
and the figures were: for ABS GP, E is 204.5±11.5 kJ mol−1 (medium value); for ABS HI, E is 239.0±9.8 kJ mol−1; for ABS HH, E is 242.4±5.4 kJ mol−1. 相似文献
119.
Summary: An amorphous grade Poly (lactic acid) (PLA) was selected for an accelerated burial in soil test during 450 days. Thermogravimetric analyses were carried out to study the effects of degradation in soil on the thermal stability and the thermal decomposition kinetics. A single stage decomposition process is observed for all degradation times. It is shown that the thermal stability of PLA is slightly affected by degradation in soil. Concerning the study of the thermal decomposition kinetics, Criado master curves were plotted from experimental data to focus the study of the thermodegradation kinetic model.The kinetic methods proposed by Broido and Chang were used to calculate the apparent activation energies (Ea) of the degradation mechanism. These results were compared to the Ea values obtained by the method developed by Coats and Redfern in order to prove the applicability of the former methods to the kinetic study. As expected, non-linear tendency is found out for Ea variation along the degradation times, which can be explained as an evolution by stages. 相似文献
120.
Lower order three-dimensional Burgers equation having non-Maxwellian ions in dusty plasmas
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Apul N Dev 《中国物理 B》2017,26(2):25203-025203
The dust acoustic(DA) shock wave with dust charge fluctuations, non-Maxwellian ions, and non-isothermal electrons is studied theoretically. The perturbation technique is employed to derive the lower order three-dimensional(3D) Burgers equation, and shock wave solution is explored by the tan-hyperbolic method. The effects of flat trapped and trapped electron distributions in the presence of Maxwellian and non-Maxwellian ions on characteristics shock waves are observed. The temperature ratio of non-Maxwellian ion temperature and non-isothermal electron temperature is found to play an important role in forming the shock-like structure. 相似文献