Thermal degradation and mass-spectrometric fragmentation processes of polyesters studied by time/temperature-resolved pyrolysis-field ionization mass spectrometry

Linear polyesters of the lactone and the diol-dicarboxylic acid types have been pyrolyzed in the ion source of a mass spectrometer. The gaseous degradation products were softly ionized by means of field ionization. Oligomers were the dominant products observed as protonated species. In contrast to the general experience with soft ionization mass spectrometry, with polyesters distinct mass spectometric fragmentation occurs forming singly charged and doubly charged carboxonium and hydroxonium ions, respectively. A fundamental interpretation of the processes of polyesters in pyrolysis-field ionization mass spectrometry is given Les polyesters sont du type de poly(lactone-acide dioldicarboxylique). Les oligomeres sont des produits dominants parmi les especes protones. La fragmentation distincte de spectrometrie de masse a lieu, formant des ions de carboxonium et d'hydroxonium avec une ou deux charges. Les fragments simples sont formes avec une intensite elevee, quand la formation simultanee de plusieurs doubles liaisons est possible avec les sous unites presentes. Une interpretation fondamentale du processus de fragmentation est donnee