PULSE-RADIOLYSIS OF METHACRYLOYL-L-PROLINE METHYL-ESTER IN DILUTE AQUEOUS-SOLUTION

The reactions of hydroxyl radical, hydrogen atom and hydrated electron intermediates of water radiolysis with a hydrogel-forming monomer, me thacryloyl-L-proline methyl ester (MA-ProOMe), were studied by pulse r adiolysis in dilute aqueous solutions and compared with the reactions of the acrylic derivative (A-ProOMe). The spectral and kinetic charact eristics of the first step of OH, H and e(aq)(-) reactions with the tw o monomers an very similar. There are considerable differences in the next steps. In neutral solutions, the electron adduct of A-ProOMe deca ys in slow radical-radical reactions. The adduct of MA-ProOMe, however undergoes a fast irreversible protonation resulting in alpha-carboxya lkyl radical. The oligomerization reactions occurring in MA-ProOMe sol utions are slow, and under adopted pulse radiolytic conditions, they a re observable only at high monomer concentrations. In A-ProOMe solutio ns the reaction is significantly faster.