Ageing of EPDM-I: Photo and thermal stability of EPDM hydroperoxides

EPDM hydroperoxides photogenerated by singlet oxygen were decomposed both by UV (lambda greater than or equal to 300 nm) and thermal (85 degrees C) irradiation under vacuum. The peroxy radical formation was followed by performing photolysis at -60 degrees C directly in the cavity of an ESR spectrometer. Photolysis and thermolysis decomposition products were identified by FTIR spectroscopy coupled with gaseous derivatization reactions by NO, SF4 and NH3. High levels of alcohol groups (approximate to 60%) and small amounts of carbonyl products (approximate to 10%) such as carboxylic acids, ketones and esters were detected. No significant stoichiometric differences were revealed between photo- and thermolysis; however, saturation reactions of the double bond in the alpha position largely prevailed in the case of thermolysis. (C) 1996 Elsevier Science Limited