Thermal luminescence spectroscopy of γ-irradiated elastomers using a multichannel Fourier-transform chemiluminescence spectrometer

Chemiluminescence spectra of natural rubber, chloroprene rubber and ethylene propylene diene rubber were measured in N2 and in air with a multichannel Fourier-transform chemiluminescence spectrometer. Samples were measured after γ-ray irradiation in air and in the absence of O2. No strong emission was observed for natural rubber heated in N2 after the sample was γ-irradiated in the absence of O2, but a strong emission from the sample was observed at 631 nm in air. An emission from chloroprene rubber was observed around 659 nm even when the sample was not γ-irradiated. A similar band was observed after the sample was γ-irradiated in air and in the absence of O2. A strong emission from ethylene propylene diene rubber was observed in air only when the sample was γ-irradiated in air. The observed spectrum was separated into two bands at 678 and 523 nm, where the former and the latter were tentatively assigned to peroxidic compounds and excited carbonyl groups, respectively. The relative intensity of the two bands changed during the measurement. It is concluded that luminescence spectroscopy using a multichannel spectrometer is a powerful technique to examine the oxidative degradation of elastomers