Investigation of Hydrogen Atom Addition to Vinyl Monomers by Time Resolved ESR Spectroscopy

By means of time resolved ESR spectroscopy in the microsecond time scale the H atom addition to different vinyl monomers was investigated. The H atoms produced by pulse radiolysis of aqueous solutions show a strong recombination CIDEP effect which also allows the recombination rate constant of H atoms to be determined. By analysis of ESR time profiles with the modified Bloch equations the relaxation times T1, T2, the polarization factors and the chemical rate constants with scavengers were obtained. Besides the H atom addition rate constants to different vinyl monomers the structure of the monomer radical was determined for acrylic acid.