Evolved Gas Analysis Using Photoionization Mass Spectrometry, EGA-PIMS: Characterization of Pyrolysis Products from Polymers

Abstract

Evolved gas analysis using photoionization mass spectrometry (PIMS) in conjunction with a vacuum ultraviolet (VUV) light source provides an e$cient and a fragment-free method for the soft ionization of gaseous compounds. This permits a better understanding of the pyrolysis behavior and chemical composition of polymeric materials. A capillary interface type TG-DTA(EGA)-MS and a skimmer interface type EGA-MS which was modified to combine the PI source was successfully developed. The pyrolysis of a blend of polymers and various Nylon samples in an inert gas atmosphere were examined by EGA-PIMS. The capability and utility of the EGA-PIMS method was evaluated by comparing it with the conventional EGA-EIMS. The results showed that the resulting PI mass spectrum can be satisfactorily characterized pyrolysis using only the parent ions with no contribution as a result of fragmentation during the ionization process. The applicability of the EGA-PIMS to unknown polymeric materials was evaluated by comparison with the unique PI mass spectra obtained from the pyrolysis of some standard reagent polymers.