Abstract

ALIEV, Roustam  and  NAVARRO-GONZALEZ, Rafael. Mechanism of radiation-chemical and pyrolytic transformations in lexan ^®. TIP [online]. 2006, vol.9, n.1, pp.5-11. ISSN 1405-888X.

We report here a new approach to study the mechanism of radiation-chemical transformations in polymeric materials based on the combined analysis of radiolytic gases, and pyrolytic products from preirradiated polymers by flash pyrolysis coupled to gas chromatography -Fourier transformed infrared spectroscopy- mass spectrometry with electron impact mode (GC-FTIR-MS). Lexan® (bisphenol-A polycarbonate) was studied in the dose range from 0.125 to 1.0 MGy. Lexan irradiation was accompanied by the preferential release of carbon monoxide followed by minor production of hydrogen, carbon dioxide and methane. Pyrolyzed Lexan releases mainly carbon dioxide, methane, benzene, toluene, phenol and 4-methyl-phenol. On the basis of these results we suggest two main pathways of Lexan radiation-induced scission with equal probabilities: (a) carbonate bond and (b) aliphatic-aromatic bond ruptures.

Keywords : Lexan; radiolysis; flash pyrolysis; GC-FTIR-MS; mechanism of degradation.

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