STATIC SECONDARY ION MASS SPECTROSCOPIC INVESTIGATIONS OF DEUTERATED POLY(ETHYLENE-TEREPHTHALATE)

The positive and negative ion static SIMS spectra of poly(ethylene terephthalate) (PET) deuterium labeled on either the ethylene glycol units or the terephthalate units were obtained and compared to those of unlabeled PET. These data confirm the ion structure assignments previously reported and allow the assignment of the origins and structures of most of the remaining peaks. The majority of the ions derive logically from the PET structure. A major mode of fragmentation of the PET chains is shown to be the break-up of ester linkages to produce a carboxylic acid and a vinyl ester. This involves predominate transfer of a hydrogen atom from the glycol unit to the newly formed acid group. Minor, but interesting, ions have been detected which result from the recombination of fragments. These ions have structures not directly derived from the original polymer backbone and may add to the difficulties involved in analyzing the static SIMS spectra of 'unknown' surfaces as they suggest atomic connectivities which are not present on the original surface.