A MALDI, TGA, TG/MS, and DEA study of the irradiation effects on PMMA

Poly(methyl methacrylate) (PMMA) (Mw=6.4×103, PD=1.06) was irradiated under vacuum. The constant dose rate was 1.66×104 rad/min at doses between 10 and 100 Mrad using a cobalt-60 source. The samples were then analyzed by matrix assisted laser desorption/ionization (MALDI), hyphenated thermogravimetric/mass spectrometry (TG/MS), and dielectric analysis (DEA), all novel methods for the analysis of polymers damaged by radiation. Gel permeation chromatography (GPC), nuclear magnetic resonance (NMR), and differential scanning calorimetry (DSC) were also used for analysis. This study evidenced main chain scission, the removal of ester side groups, and the production of monomer as a result of ionizing radiation.