Effects of oxygen in gamma irradiated aromatic polyesters in film |
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Authors: | Ugo Ravasio Antonio Faucitano Fiorenza Quasso |
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Affiliation: | a Dipartimento di Ingegneria Nucleare, Politecnico di Milano, Piazza Leonardo da Vinci, 32-20133 Milano, Italy b Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci, 32-20133 Milano, Italy c Dipartimento di Chimica Generale, Università degli Studi, via Taramelli 12, 27100 Pavia, Italy |
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Abstract: | The effect of gamma irradiation in air is investigated on four thermoplastic polyesters (PET, PBT, PEN, PCT-co-ET) in films containing aromatic rings, in order to evaluate the influence of aromatic density and the role of oxygen on radiation resistance. Physical-chemical-nuclear analyses were used to this purpose. EPR measurements were carried out to detect radical stability against oxygen permeation. Viscometric investigations reported a very similar trend for all the investigated polyesters: a chain break effect that decreases at the highest doses. FT-IR analyses focused on the formation of oxidized species. Positron annihilation spectra pointed out a decrease of the intensity of ortho-positronium formation, while its lifetime remains unchanged with radiation dose. |
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Keywords: | Free volume Oxygen Polyesters Positron annihilation lifetime spectroscopy Radiation |
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