Effects of oxygen in gamma irradiated aromatic polyesters in film

• DOI: 10.1016/j.eurpolymj.2007.03.024
• Publication Date: 2007-03-21T10:52:47Z
• Authors: Ugo Ravasio; Giovanni Consolati; Antonio Faucitano; Mario Mariani; Fiorenza Quasso
• Keywords: Oxygen; Positron annihilation lifetime spectroscopy; Radiation; Polyester; 610; Free volume; 02 engineering and technology; 0210 nano-technology

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.