MASS-SPECTRAL CHARACTERIZATION OF THE THERMAL-DEGRADATION OF POLY(PROPYLENE OXIDE) BY ELECTROSPRAY AND MATRIX-ASSISTED LASER-DESORPTION IONIZATION

The thermal degradation of poly(propylene oxide) (PPO), M(n) = 2000, c an be characterized by electrospray (ESI) and matrix-assisted laser de sorption ionization (MALDI). ESI and MALDI spectra of partially degrad ed PPO provide strong support for the thermal degradation pathway prev iously suggested by Griffiths el al. and Lemaire el al. Although these pathways differ in detail, it is not possible to distinguish between them from the masses of the resultant degradation species. Gel permeat ion chromatography data indicate that both mass spectrometric methods emphasize the presence of low-mass material, particularly in the degra ded samples. This is attributed to the different sensitivities of the two techniques and some in situ fragmentation during mass spectrometri c analysis.