Browsing by Author "Zaki, M. F."

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Modifications induced by gamma irradiation to Makrofol polymer nuclear track detector
(ELSEVIER SCIENCE BV, 2015) Tayel, A.; Zaki, M. F.; El Basaty, A. B.; Hegazy, Tarek M.
The aim of the present study was extended from obtaining information about the interaction of gamma rays with Makrofol DE 7-2 track detector to introduce the basis that can be used in concerning simple sensor for gamma irradiation and bio-engineering applications. Makrofol polymer samples were irradiated with 1.25 MeV Co-60 gamma radiations at doses ranging from 20 to 1000 kG y. The modifications of irradiated samples so induced were analyzed using UV-vis spectrometry, photoluminescence spectroscopy, and the measurements of Vickers' hardness. Moreover, the change in wettability of irradiated Makrofol was investigated by the contact angle determination of the distilled water. UV-vis spectroscopy shows a noticeable decrease in the energy band gap due to gamma irradiation. This decrease could be attributed to the appearance of a shift to UV spectra toward higher wavelength region after irradiation. Photoluminescence spectra reveal a remarkable change in the integrated photoluminescence intensity with increasing gamma doses, which may be resulted from some matrix disorder through the creation of some defected states in the irradiated polymer. The hardness was found to increase from 4.78 MPa for the unirradiated sample to 23.67 MPa for the highest gamma dose. The contact angle investigations show that the wettability of the modified samples increases with increasing the gamma doses. The result obtained from present investigation furnishes evidence that the gamma irradiations are a successful technique to modify the Makrofol DE 7-2 polymer properties to use it in suitable applications. (C) 2014 Production and hosting by Elsevier B.V. on behalf of Cairo University
Opto-structural characterization of gamma irradiated Bayfol polymer track detector
(ELSEVIER, 2013) Tayel, A.; Zaki, M. F.; El Basaty, A. B.; Hegazy, Tarek M.
Bayfol CR 1-4 is one of polymeric solid state nuclear track detector which has numerous applications due to its outstanding optical, mechanical, thermal and electrical properties. In the present study, Bayfol polymer is irradiated with different doses of gamma rays ranging from 0 to 1000 KGy. The effects of gamma irradiations on the optical, structural and chemical properties of Bayfol were studied using Ultraviolet and visible (UV/Vis) spectroscopy, X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The UV-Vis spectra of irradiated samples show that the absorption edge is shifted towards longer wavelength comparing to pristine sample spectrum. This behavior indicates that there is a decrease in the band gap after irradiation. The maximum decrease in the band gap is about 0.8 eV. The XRD patterns of amorphous halo of pristine and irradiated samples show a fluctuation of integrated intensity of amorphous halo. This indicates a change in the structure due to gamma irradiation. In order to understand that structure change mechanism, we used the FTIR spectroscopy. (C) 2013 Elsevier B.V. All rights reserved.
Structural alterations of polycarbonate/PBT by gamma irradiation for high technology applications
(TAYLOR & FRANCIS LTD, 2016) Zaki, M. F.; Elmaghraby, Elsayed K.; Elbasaty, A. B.
In this work, polycarbonate/polybutylene terephthalate (PC/PBT) was irradiated with different gamma doses ranging from 200kGy to 1950kGy. Structural alterations of irradiated PC/PBT polymer blend have been studied using UV-vis spectroscopy, X-ray diffraction, and Fourier transform infrared (FTIR), as well as surface wettability. The results of UV-vis spectra showed that gamma irradiation induced an increase in the optical absorption with an increase in the gamma doses with shift in the optical absorption edge in the irradiated samples toward the higher wavelength. This shift is correlated with the decrease in optical band gap energy. Optical band gap decreases up to 12 and 20% with respect to pristine sample for direct and indirect transition, respectively. The number of carbon atoms per conjugated length has been estimated. The phase and phase of the crystalline PBT structure were observed. The phase reflections are slightly increased due to the irradiation but the accompanying to transformation alters the results. FTIR investigation showed slight variation in the absorption spectrum specially in the range from 1300 to 1001cm(-1) which are related to the O-C-O arrangements that is found to be the most affected part of the molecule by irradiation. A remarkable increase was observed in the wettability, surface free energy, and adhesion work of irradiated samples with an increase in the gamma doses.