Thermal behavior study and degradation mechanism by TG/MS/FTIR technique of some poly(aryl ether ether ketone)s

This study assesses the thermal and thermo-oxidative stability of some aromatic poly(aryl ether ether ketone)s as well as the degradation mechanism by the TG/MS/FTIR technique (simultaneous mass spectrometry and Fourier transform infrared spectroscopy of off-gases from thermogravimetric analyzer), in two working atmospheres, air and helium. This type of polymers is used in many applications in the electronic, automotive and aerospatial fields. The polymers were synthesized by polycondensation reaction of 4,4'-difluorobenzophenone with several bisphenols, such as 9,9-bis(4-hydroxyphenyl)fluorene, 4,4'-cyclohexylidenebisphenol, 2-(bis[4-hydroxyphenyl] methyl)benzoic acid (phenolphthalin) and 2,5-bis(4-hydroxyphenyl)-1,3,4-oxadiazole. They were characterized by FTIR and H-1 NMR spectroscopy, solubility, inherent viscosity and thermogravimetric analysis. Moreover, the main products of polymer thermal decomposition were determined in air and in inert atmosphere (helium). The degradation mechanism of the analyzed samples is influenced by their structure and working atmosphere. Molecular dynamics simulation was also used to evaluate thermal stability of the polymers.