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Etude de la dégradation thermique de deux copolymères réalisés entre l'acrylonitrile ou le méthacrylonitrile et l'α‐acétoxyacrylate de méthyle. Analyse thermogravimétrique et chromatographique en phase gazeuse couplée à la spectrométrie de masse
Author(s) -
Ouillon Isabelle,
Raihane Mustapha,
Zerroukhi Amar,
Bio Bernard
Publication year - 1997
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1997.021981108
Subject(s) - chemistry , acrylonitrile , activation energy , polymer chemistry , copolymer , thermogravimetry , isothermal process , methacrylonitrile , thermal stability , atmospheric temperature range , order of reaction , kinetics , reaction rate constant , polymer , thermodynamics , organic chemistry , inorganic chemistry , physics , quantum mechanics
The thermal degradation behaviour of two copolymers poly(acrylonitrile‐ co ‐methyl α‐acetoxyacrylate) and poly(methacrylonitrile‐ co ‐methyl α‐acetoxyacrylate) was studied by means of dynamic and isothermal thermogravimetry in the range 246–302°C and gas chromatography/mass spectrometry analysis. The main volatil products are acetic acid and methyl acetate and methanol in minor amounts. There is no monomer from the first copolymer. The global reaction order is zero over a wide range of conversion (α = 0,1 – 0,6), then it is one for α > 0,7, with activation energies of 160,5 and 142,9 kJ ˙ mol −1 , respectively. Some amount of comonomers was found in addition in the case of the second copolymer. The kinetic law may be written as:\documentclass{article}\pagestyle{empty}\begin{document}$$ \frac{{{\rm d}a}}{{{\rm d}t}} = k(C + \alpha )(A - \alpha ) $$\end{document} where A and C are constants for every temperature. The global activation energy was found to be 127,0 kJ ˙ mol −1 . A kinetic model of a one order reaction with a partial auto catalytic character allows a very good fit of the experimental data with the theoretical curves over a wide range of conversion (α = 0,1–0,8).