Authors:Y. Nur, D. Colak, I. Cianga, Y. Yagci, and J. Hacaloglu
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.
Authors:Yusuf Nur, Demet Colak, Ioan Cianga, Yusuf Yagci, and Jale Hacaloglu
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.
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.
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.
Authors:Anissa Khelfa, Gisèle Finqueneisel, M. Auber, and J. Weber
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.
Authors:Dursun Ali Köse, Hacali Necefoğlu, Onur Şahin, and Orhan Büyükgüngör
To deduce the thermal decomposition pathway for na and dena complexes mass spectrum were recorded (Figs. 3 and 4 , respectively) using direct insertion probe pyrolysismassspectrometry method. The molecular ion peak was detected at 617 for na and
Khelfa , A , Les Finqueneisel , G , Auber , M , Weber , JV 2008 Influence of some minerals on the cellulose thermal degradation mechanisms thermogravimetic and pyrolysis-massspectrometry studies . J Therm Anal Calorim 92 3 795 – 799 10.1007/s