AGING OF EPDM-I - PHOTO AND THERMAL-STABILITY OF EPDM HYDROPEROXIDES

EPDM hydroperoxides photogenerated by singlet oxygen were decomposed b oth by UV (lambda greater than or equal to 300 nm) and thermal (85 deg rees C) irradiation under vacuum. The peroxy radical formation was fol lowed by performing photolysis at -60 degrees C directly in the cavity of an ESR spectrometer. Photolysis and thermolysis decomposition prod ucts were identified by FTIR spectroscopy coupled with gaseous derivat ization reactions by NO, SF4 and NH3. High levels of alcohol groups (a pproximate to 60%) and small amounts of carbonyl products (approximate to 10%) such as carboxylic acids, ketones and esters were detected. N o significant stoichiometric differences were revealed between photo- and thermolysis; however, saturation reactions of the double bond in t he alpha position largely prevailed in the case of thermolysis. (C) 19 96 Elsevier Science Limited