THE PHOTODEGRADATION OF POLY(2,6-DIMETHYL-1,4-PHENYLENE OXIDE) - A FLASH-PHOTOLYSIS STUDY OF POLYMER AND MODEL COMPOUNDS

Laser flash photolysis and time-resolved resonance Raman spectroscopy were applied to elucidate the mechanism of photodegradation of poly(2, 6-dimethyl-1,4-phenylene oxide). Based also on the results obtained fo r several model compounds it is concluded that dissociation of the ter minal phenolic unit yielding phenoxy radicals is the dominant primary photoreaction. In model compounds lacking the hydroxyl groups at the e nd, a transient T-T absorption is observed. Ether bond breakage should occur with very low yield, either as a one step process or as the res ult of 1,5-hydrogen transfer followed by hydrogen abstraction. No evid ence was found for photoinduced electron transfer producing the radica l ions of the monomeric units. (C) 1998 Elsevier Science Limited. All rights reserved.