REACTIVITY OF RADICALS DERIVED FROM DIMETHYLANILINES IN ACRYLIC PHOTOPOLYMERIZATION

Relative reactivities of radicals derived from several p-dimethylanili nes toward the polymerization of butyl acrylate have been calculated. It was observed that the reactivity of the radicals increases as the e lectron-withdrawing character of the groups attached in the para posit ion increases. The experimental efficiency factor (f) has been found t o be proportional to the sigma(p) value defined in the Hammett equatio n. The dependence of the reactivities on the nature of the radicals ha s also been explained through their frontier orbital characteristics. The high similarity of the behavior of f versus sigma(p) and f versus E(SOMO) led us to conclude that the simple perturbative molecular orbi tal calculations can be used to predict the relative reactivity of ini tiating radicals with similar structure toward the polymerization of a crylic monomers.