We report a combination of the evaporation-grinding MALDI sample preparation method, MALDI-TOF/TOF CID, and Py-GC/MS to examine the fragmentation mechanisms of polysulfone (PSF). MALDI-TOF/TOF CID Studies yield a wealth of information about the mass, structure (linear or cyclic), and end-groups of species generated in the synthesis and fragmentation of these polymers. Additionally, Py-GC/MS experimental data are presented, for comparison of the multimolecular free radical reactions in pyrolysis with the unimolecular fragmentation reactions of MS/MS. TOF/TOF CID results indicate that linear PSF undergoes main chain fragmentation at characteristic locations. However, cyclic species produce "unexpected" fragment ions, presumably due to their different gas-phase configuration and the multiple main-chain breaks required to generate CID spectra. These results are supported by Py-GC/MS data and are consistent with Our proposed degradation mechanisms.