Thermal degradation of g-irradiated PVC: I-dynamical experiments

Polymers used in nuclear industry are important constituents of nuclear wastes. In case of fire during waste transportation, package temperature could rise markedly. Within this context, the objective of this work is to analyze the thermal degradation of irradiated polymers. The dynamical degradation of radio oxidized poly(vinyl chloride) was investigated by thermogravimetry coupled with mass spectrometry and by thermodesorption coupled with gas chromatography-mass spectrometry. Additive-free and plasticised PVC was pre-aged using g-irradiation under air at room temperature. Pre-irradiation induces a decrease of the initial degradation temperature and leads to an early formation of HCl and benzene. Although dehydro chlorination remains the predominant degradation process within the temperature range used in this study, others processes contribute to the mass loss such as dehydration and desorption of degradation molecules resulting from radio-oxidation. (authors)