Degradation kinetics of poly(ether-urethane) Estane® induced by electron irradiation

Radiation effects on a segmented aromatic poly(ether-urethane) induced by electron beam irradiation under oxygen atmosphere were investigated using Fourier transform infrared spectroscopy (FTIR) and electron paramagnetic resonance (EPR) in order to determine the degradation mechanisms. Thin films have been irradiated under a dose rate of 1 MGy/h with absorbed doses varying from 25 to 1000 kGy under O2. FTIR spectra have shown the formation of hydroperoxides, carboxylic acids, primary amines, alcohols, esters and formates. Moreover, the decrease of urethane and ether absorbances revealed the degradation of both soft and hard segments. Spin-trapping technique was used to monitor the evolution of short-lived peroxy and alkyl radicals at room temperature. Finally, a mechanism of degradation for electron irradiated polyurethane is proposed.