| Abstract: | The ESR study of the radicals formed in mechanochemical polymerization of acrylamide (AAM) was undertaken. The nature of the radical formation was compared with the mechano-radical formation produced by mechanical fracture of polyacrylamide (PAAM). The structure of radicals formed were all identified to be an end-chain radical, equivalent to a polymer-chain propagating radical. The computer simulation disclosed that the observed spectra of the propagating radical can be approximated essentially by two kinds of component spectra, a large amount of triplet, and a small amount of quarter (a triplet of doublets). Thus, the existence of two major conformers in a single end-chain radical has been proposed. The ESR kinetics of the radical formation were further studied and its correlation with the nature of polymerization (the changes in molecular weight and polymer conversion) was discussed. |
