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Journal of Thermal Analysis and Calorimetry
Authors: F. Paulik, J. Paulik, M. Arnold, J. Inczédy, J. Kristóf, and A. Langier-Kuzniarowa
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Derivatograph-C-a microcomputer-controlled simultaneous TG, DTG, DTA, TD and EGA apparatus

Part II. A simple method of estimating kinetic parameters

Journal of Thermal Analysis and Calorimetry
Authors: M. Arnold, P. Somogyvári, J. Paulik, and F. Paulik
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Journal of Thermal Analysis and Calorimetry
Authors: A. Langier-Kuzniarowa, J. Inczédy, J. Kristóf, F. Paulik, J. Paulik, and M. Arnold
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Abstract  

Thermogravimetry (TG/DTG) coupled with evolved gas analysis (MS detection) of volatiles was used to characterize the thermal behavior of commercial PVC cable insulation material during heating in the range 20-800C in air and nitrogen, respectively. In addition, simultaneous TG/FTIR was used to elucidate chemical processes that caused the thermal degradation of the sample. A good agreement between results of the methods was found. The thermal degradation of the sample took place in three temperature ranges, namely 200-340, 360-530 and 530-770C. The degradation of PVC backbone started in the range 200-340C accompanied by the release of HCl, H2O, CO2 and benzene. The non-isothermal kinetics of thermal degradation of the PVC cable insulation in the temperature range 200-340C was determined from TG results measured at heating rates of 1.5, 5, 10, 15 and 20 K min-1 in nitrogen and air, respectively. The activation energy values of the thermal degradation process in the range 200-340C of the PVC cable insulation sample were determined from TG results by ASTM method.

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Abstract  

Coupled TG-FTIR technique was used for identification of gaseous compounds evolved at thermal treatment of six coal samples from different deposits (Bulgaria, Russia, Ukraine). The experiments were carried out under dynamic heating conditions up to 900C at heating rates of 5, 10 or 50 K min–1 in a stream of dry air. The emission of CO2, H2O, CO, SO2, COS, methane, methanol, formic acid, formaldehyde, acetaldehyde, chlorobenzene was clearly identified in FTIR spectra of the samples studied. The formation of ethanol, ethane, ethylene and p-xylene, at least on the level of traces, was also identified. At the heating rate of 5C min–1 the temperature of maximum intensities of the characteristic peaks of COS was 270C, of formaldehyde, formic acid, ethane and methanol 330C, of SO2, CO, acetic acid, ethylene and p-xylene 400C and of chlorobenzene 500C. At 10C min–1 and 50C min–1 these temperatures were shifted, respectively, by 70–300C and 150–450C towards higher temperatures and the respective absorption bands in FTIR spectra were, as a rule, more intensive.

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Journal of Thermal Analysis and Calorimetry
Authors: J. Mullens, G. Reggers, M. Ruysen, R. Carleer, J. Yperman, D. Franco, and L. Van Poucke

Abstract  

The oxidative degradation of HET-acid (1,4,5,6,7,7-hexachlorobicyclo [2.2.1] hept-5-en-2, 3-dicarboxylic acid) is studied by the combination of TG, FTIR, MS and GC-MS. The gases evolved during the decomposition of this flame retardant are investigated on-line by FTIR and by MS. Simultaneously the evolved gases are collected by an adsorbent and, after the thermal experiment, desorbed to release the volatile products for identification using GC-MS. The combination of these techniques offers the unambiguous identification of the evolved products as a function of temperature. The main identified products are CO2, H2O, Cl2, HCl, C2Cl4, maleic acid anhydride, HET-acid anhydride, chlorinated cyclic hydrocarbons and chlorinated unsaturated linear hydrocarbons.

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Abstract  

FTIR spectrometry combined with TG provides information regarding mass changes in a sample and permits qualitative identification of the gases evolved during thermal degradation. Various fuels were studied: coal, peat, wood chips, bark, reed canary grass and municipal solid waste. The gases evolved in a TG analyser were transferred to the FTIR via a heated teflon line. The spectra and thermoanalytical curves indicated that the major gases evolved were carbon dioxide and water, while there were many minor gases, e.g. carbon monoxide, methane, ethane, methanol, ethanol, formic acid, acetic acid and formaldehyde. Separate evolved gas spectra also revealed the release of ammonia from biomasses and peat. Sulphur dioxide and nitric oxide were found in some cases. The evolution of the minor gases and water parallelled the first step in the TG curve. Solid fuels dried at 100C mainly lost water and a little ammonia.

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Abstract  

The potential of hyphenating thermogravimetry (TG) and soft photo ionisation mass spectrometry (EBEL-SPI-MS) for fundamental and applied research and material analysis has been demonstrated by a newly developed TG-SPI quadrupole MS coupling (TG-SPI-QMS). Thermal decomposition of three common plastics, polyethylene (PE), polystyrene (PS) and polyvinylchloride (PVC) has been studied. While the decomposition of PE and PS in inert atmosphere takes place in a one step process (main mass loss at about 490 and 420 °C, respectively), PVC decomposes in a two step mechanism. The organic signature of the PE decomposition shows homologous series of alkenes and polyenes, while PS is forming mainly styrene mono- and oligomers. In the PVC decomposition, firstly hydrogen chloride (HCl) is eliminated in a hydro-dechlorination reaction (1st mass loss step: 285–305 °C), this is accompanied by the emission of the carbon skeletons of small aromatics (predominately benzene and naphthalene). In the second step (2nd mass loss step: 490–510 °C), the residual cross-linked polyolefin moieties decompose under release of heavily alkylated aromatics, including larger PAH. Chlorinated aromatics are formed only in trace levels.

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Summary A thermal study was performed on the RuSr2GdCu2O8 (Ru-1212) magnetic superconductor phase to investigate the effect of the annealing treatments in flowing O2 on the stability limit of the phase and on its structural, magnetic and transport properties. DTA-TG measurements were utilized to determine the decomposition process and the dependence of the decomposition temperature on the annealing atmosphere. The decomposition of the Ru-1212 phase was found sensitive to the oxygen partial pressure and increases with PO2 and the annealing time. The annealing treatments exert a depressing effect on the strength of the magnetic interaction, an enhancement on the superconductive properties and the vanishing of the magnetostriction. A decomposition reaction of Ru-1212 phase was proposed and discussed.

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