CF-252 PARTICLE DESORPTION MASS-SPECTROMETRY OF PHOTOOXIDIZED POLYSTYRENE

Cf‐252 particle (plasma) desorption mass spectra are presented for polystyrene surfaces before and after exposure in air to UV light. The photo‐oxidation produces changes observed in both positive and negative ion spectra. Oxygen incorporation produces a slight increase in intensity of m/z+ 18 and 19 (H2O+ and H3O+) and m/z− 16 and 17 (O− and OH−). Also, the relative intensity of m/z+ 91 decreases after photo‐oxidation and is interpreted as the formation of a bond alpha to the benzene ring. New peaks are detected at m/z+ 226, 227 and 331, and are tentatively assigned to hydroperoxide‐containing structures. Other changes in the spectrum include the increase in intensity of m/z+ 77 and 105 arising from easily ionized fragments of the oxidation products of polystyrene. Copyright © 1990 John Wiley & Sons Ltd.