http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Cf-252 particle desorption mass spectrometry of polymer surfaces
xvii, 158 leaves : illustrations ; 29 cm
Cf-252 particle desorption mass spectrometry was applied to the analysis of synthetic polymers using the low mass region (m/z < 500). For each polymer, a series of characteristic masses were obtained and compared with results from other mass spectrometric techniques. Structures that can stabilize the charge of the fragment ions produce fingerprinting spectra (e.g. poly(ethylene oxide) and polystyrene). Most polymers produced a series of decomposition peaks assigned to unsaturated ring structures. The polymers produced a series of carbons cluster peaks even if the polymer backbone structure was regularly interrupted by oxygen atoms. Thus carbon cluster formation must involve the recombination of atomized carbon as has been suggested with laser vaporization studies of graphite. The low primary ion fluence of PDMS (10² ions/s) mitigates the effects of surface charge-up and damage. We studied the chemical modification of the polystyrene surface caused by photo-oxidation. Peaks from photo-oxidation products were tentatively assigned to hydroperoxides. Physical modifications were studied using polymer-additive systems. Both additive and polymer produced their characteristic fragmentation patterns. PDMS combined with correlated data acquisition permitted the analysis of a heterogeneous surface. To demonstrate heterogeneity: 1) the excitation spot must be a discrete event of small size (less than micrometers), 2) the peak used for the correlation of events must be unique to the compound, 3) the heterogeneity must be of a size larger than the size of the desorption spot (approximately 20 nm for PDMS).