Direct mass spectrometry of polymers. XI. Primary thermal fragmentation processes in aromatic–aliphatic polyesters

The thermal decomposition of two series of isomeric aromatic–aliphatic polyesters was studied by direct pyrolysis-mass spectrometry. The results indicate that intramolecular exchange reactions predominate in the primary thermal fragmentation processes to cause the formation of cyclic oligomers. Several secondary thermal processes may occur after the primary step: hydrolytic cleavage of the ester bond, decarboxylation, and β-hydrogen transfer.