RETARDATION OF ANAEROBIC DEGRADATION OF POLY(P-METHOXYACRYLOPHENONE)

The effects of the u.v. absorbers 2,4,-dihydroxybenzophenone (DHB), Ti nuvin 213 and Tinuvin P on the anaerobic photochemistry of poly(4-meth oxyacrylophenone) have been investigated, the additives being incorpor ated into thin films and to solutions of the polymer. All retard the d egradation of the polymer, in particular both rates of coloration and random chain scission are decreased. None of the additives acts simply as a u.v. absorber, although all of their long-wave u.v. absorptions overlap the n --> Pi absorption of the polymer. Rather, experimental evidence supports the proposition that they are acting as quenchers of the CO triplet. The chain scission data conform to Stern-Volmer quenc hing, and the coloration data for the solid state reactions is well re presented by the Perrin equation. DHB is by far the most effective ret arder. (C) 1998 Elsevier Science Limited. All rights reserved.