Py-GC/MS analyses of poly(ethylene terephthalate) film without and with the presence of tetramethylammonium acetate reagent. Comparative study

The pyrolytic products obtained from a poly(ethylene terephthalate) (PET) film at the same temperature of 770 °C without or with the use of tetramethylammonium acetate (TMAAc) were identified. The analyses were carried out using the Curie-point pyrolyzer - gas chromatography - mass spectrometry (Py-GC/MS) instrument. In both cases, it was found a significant difference between the chemical composition of their pyrolytic products. Only in the pyrolyzate obtained in the presence of TMAAc, the terephthalic acid which was identified as dimethyl terephthalate (DMT) and other products having carboxyl groups detected as their methyl or vinyl esters were present. In this pyrolyzate, the palmitic acid as methyl palmitate has also been identified. Most likely, it is the organic impurity of the inorganic salt of fatty acid used as the PET additive. The common feature of both Py-GC/MS analyses of PET film was the presence of diesters of 1,2-monoethylene glycol and some benzoic acid derivatives in their pyrolyzates.