UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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Conference: Bucharest University Faculty of Physics 2008 Meeting


Section: Polymer Physics


Title:
Thermally stimulated luminescence studies for polymer materials


Authors:
Margareta CHERESTES, Codrut CHERESTES, Livia Maria CONSTANTINESCU


Affiliation:
Faculty of Physics, University of Bucharest, PO Box MG-11,

Măgurele, Bucharest


E-mail
margareta.cherestes@dozimed.ro


Keywords:
thermoluminescence, polymer


Abstract:
Thermoluminescence of polymer materials has been studied for analyzing phenomena that occur in irradiated polymers. The glow curve can give meaningful information both on the damage of the polymeric structure as induced by scission processes and the growth of new structures owing to the cross-linking of chemically active radicals formed during irradiation. It has been shown that different ionizing radiation at the same dose produce the same kind of effects in polymers. Thermoluminescence of polymethylmethacrylate (PMMA) irradiated with low energy radiation has been studied in the temperature range 100 to 4600K and two glow peaks have been observed. The TL glow curves obey the second order kinetics and it is possible to identify the centers responsible for the two peaks by correlation with electron spin resonance. On the basis of ESR studies, the radiation damage product at room temperature in PMMA the free radicals were identified. Spectral studies of the emission show that the low temperature peak has its maximum at 365 nm while the high temperature peak has its maximum at 480 nm.The thermoluminescence emission from irradiated polyethylene shows three glow peaks whose luminescence intensities are proportional to irradiation doses below 50Gy. The study of kinetics involved shows that all this peaks have the same activation energy at the lowest temperature. By measuring the thermoluminescence emission from polymers, a correlation appears between some of the observed glow peak maxima and the known structural transition temperature of the materials. References: A. Charlesby, R.H. Partridge, Proc .R. Soc., London, A271, 1971 S. Radhakrishna, M. Rama Krishna Murthy, J. Appl. Polym.Sci,15, 1977 Diana-Madleine Ilie, “Radiotermoluminescenta unor polimeri”, Inst. Politehnic Bucuresti, 1988 A.S. Pradhan, Radiation Prot. Dosim. 1, 3, 1981