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Abstract  

Thermal degradation characteristics of a new macromonomer polystyrene with central 4,4′-dicarbaldehyde terphenyl moieties and poly(phenylene vinylene) with well-defined polystyrene (PPV/PSt) as lateral substituents were investigated via direct pyrolysis mass spectrometry. A slight increase in thermal stability of PSt was detected for (PPV/PSt) and attributed to higher thermal stability of PPV backbone. It was almost impossible to differentiate products due to the decomposition of PPV backbone from those produced by degradation of PSt.

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Abstract  

High temperature pyrolysis studies of poly(phenylene vinylene)s PPVs with lateral substituents poly(ε-caprolactone) (PPV–PCL) or poly(ε-caprolactone) and alternating Br (PPV–PCL–Br) or polystyrene (PPV–PSt) clearly showed that thermal stability of both the substituent and PPV were affected by the thermal stability of the other. In all the polymers under investigation, decomposition started by the degradation of the substituent. The thermal stability of the PPV backbone increased in the order PPV–PCL–Br < PPV–PCL < PPV–PSt. When the thermal stability of the substituent was significantly lower than that of the PPV backbone, as in the case of PPV–PCL and PPV–PCL–Br, then the radicals generated at early stages of pyrolysis coupled before the temperature reached to the values necessary for complete decomposition. This inturn yielded a thermally more stable crosslinked structure. The increase in thermal stability was greater upon coupling of the radicals generated on the PPV backbone.

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Abstract  

Thermal characteristics of a new thiophene derivative, 2-(thiophen-3-yl-)ethyl octanoate (OTE), its homopolymer (POTE), and copolymer with thiophene P(OTE-co-Th) were investigated via pyrolysis mass spectrometry. Thermal degradation of the copolymer started by lose of side chains and thiophene involving products evolved almost in the same temperature range where PTh degradation was detected, at slightly higher temperatures than PTh backbone decomposed during the pyrolysis of POTE. The extent of doping and network structure decreased in the order POTE<P(OTE-co-Th)<PTh.

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Journal of Thermal Analysis and Calorimetry
Authors: Chinnaswamy Vijayakumar, Nagarajan Mathan, Vijayakumar Sarasvathy, Thangamani Rajkumar, Arunachalam Thamaraichelvan, and Durairaj Ponraju

Abstract  

Intumescent materials, 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro-[5,5]-undecane-3,9-dioxide and 3,9-dichloro-2,4,8,10-tetraoxa-3,9-diphosphaspiro-[5,5]-undecane having the capacity to produce dehydrating agent, blowing agent, and undergo carbonization during burning have been synthesized. The thermal behavior of the synthesized materials was investigated using differential thermal analysis, thermal volatilization analysis, programmed vacuum pyrolysis–mass spectrometry, flash pyrolysis–mass spectrometry and off-line pyrolysis–gas chromatography–mass spectrometry. The materials show exothermic degradation after 250 °C. Monitoring the release of hydrogen chloride and water, the blowing agents for the production of carbon foam, clearly indicated the superior performance of the pentavalent phosphorus compound over the trivalent phosphorus compound. The major gaseous degradation products released during pyrolysis showed the presence of sufficient quantities of several alkyl-substituted benzenes and fused aromatics. Suitable degradation mechanism has been proposed and discussed to explain the formation of various organics during thermal degradation.

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Influence of some minerals on the cellulose thermal degradation mechanisms

Thermogravimetic and pyrolysis-mass spectrometry studies

Journal of Thermal Analysis and Calorimetry
Authors: Anissa Khelfa, Gisèle Finqueneisel, M. Auber, and J. Weber

Abstract  

The influence of different inorganic salts (MgCl2, ZnCl2, NiCl2 and H2PtCl6) on the primary mechanisms of cellulose thermal degradation has been conducted by using thermogravimetric (TG-DTG) and pyrolysis-mass spectrometry (Py-MS) analysis at low heating rate (10°C min-1) from ambient temperature to 500°C. The results clearly demonstrate that the used salts influence the primary degradation mechanisms. Furthermore, we can assume that some inorganic salts could be considered as specific catalysts and some others as inhibitors. MgCl2 promotes selectively initial low temperature dehydration as observed both by TG and Py-MS. ZnCl2 strongly changes the thermal behaviour of impregnated sample. The maximum mass loss rate temperature is shifted to lower temperature and on the basis of our results we can conclude that ZnCl2 acts as catalyst in all primary degradation mechanisms. NiCl2 and H2PtCl6 do not modify significantly the cellulose thermal behaviour but change the composition of both produced gases and liquids suggesting that these minerals catalyse some secondary reactions.

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. Bilke A. Mosandl 2002 Measurements by gas chromatography/pyrolysis/mass spectrometry: Fundamental conditions in 2H/1H isotope ratio analysis

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491 500 Goodacre, R. (1997): Use of pyrolysis mass spectrometry with supervised learning for the assessment of the adulteration of milk of different species. Appl

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To deduce the thermal decomposition pathway for na and dena complexes mass spectrum were recorded (Figs. 3 and 4 , respectively) using direct insertion probe pyrolysis mass spectrometry method. The molecular ion peak was detected at 617 for na and

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Investigation of polymers by a novel analytical approach for evolved gas analysis in thermogravimetry

Gas chromatography comprehensively coupled to single photon ionization mass spectrometry

Journal of Thermal Analysis and Calorimetry
Authors: Mohammad R. Saraji-Bozorgzad, Thorsten Streibel, Markus Eschner, Thomas M. Groeger, Robert Geissler, Erwin Kaisersberger, Thomas Denner, and Ralf Zimmermann

. Yun , Y , Meuzelaar , HLC , Simmleit , N , Schulten , HR . Vacuum pyrolysis mass spectrometry of Pittsburgh No. 8 coal: comparison of three different, time resolved techniques . Energy Fuels . 1991 ; 5 : 22 – 29 . 10.1021/ef00025a002

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. Khelfa , A , Les Finqueneisel , G , Auber , M , Weber , JV 2008 Influence of some minerals on the cellulose thermal degradation mechanisms thermogravimetic and pyrolysis-mass spectrometry studies . J Therm Anal Calorim 92 3 795 – 799 10.1007/s

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