PHOTODEGRADATION OF ALPHA-OLEFIN CARBON-MONOXIDE ALTERNATING COPOLYMER

The anaerobic photodegradation behaviors of bulk alternating copolymers of propylene/carbon monoxide (CO) and ethylene/CO have been studied by irradiation with 2537-A light. Photolysis of the former resulted in weight loss, molecular weight depression, cross-linking, and the formation of hydroxyl and terminal vinyl groups. The room temperature quantum yields of chain scission and Norrish type II reactions were found to be 0.015 +/- 0.002 and 0.011 +/- 0.002, respectively. Ethylene/CO alternating copolymer does not undergo Norrish type II photolysis because of the absence of gamma-hydrogens. Even the Norrish type I processes occur with low probability probably because of the strong ''cage effect'' and reactivity of the primary radicals produced.