Person: GÜLLÜOĞLU, ARİF NİHAT
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GÜLLÜOĞLU
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ARİF NİHAT
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Publication Metadata only Effect of irradiation by 140 Mev Ag11+ ions on the optical and electrical properties of polypropylene/TiO2 composite(ELSEVIER, 2009) GÜLLÜOĞLU, ARİF NİHAT; Qureshi, Anjum; Singh, Dolly; Singh, N. L.; Ataoglu, S.; Gulluoglu, Arif N.; Tripathi, Ambuj; Avasthi, D. K.Changes in the optical, structural, dielectric properties and surface morphology of a polypropylene/TiO2 composite due to swift heavy ion irradiation were studied by means of UV-visible spectroscopy, X-ray diffraction, impedance gain phase analyzer and atomic force microscopy. Samples were irradiated with 140 MeV Ag11+ ions at fluences of 1 x 10(11) and 5 x 10(12) ions/cm(2). UV-visible absorption analysis reveals a decrease in optical direct band gap from 2.62 to 2.42 eV after a fluence of 5 x 10(12) ions/cm(2). X-ray diffractograms show an increase in crystallinity of the composite due to irradiation. The dielectric constants obey the Universal law given by epsilon proportional to integral(n-1), where n varies from 0.38 to 0.91. The dielectric constant and loss are observed to change significantly due to irradiation. Cole-cole diagrams have shown the frequency dependence of the complex impedance at different fluences. The average surface roughness of the composite decreases upon irradiation. (C) 2009 Elsevier B.V. All rights reserved.Publication Metadata only Dielectric properties of polymer composites filled with different metals(TAYLOR & FRANCIS INC, 2008) GÜLLÜOĞLU, ARİF NİHAT; Qureshi, Anjum; Mergen, Ayhan; Eroglu, Mehmet S.; Singh, N. L.; Gulluoglu, ArifElectrically conductive composite systems based on polyvinyl chloride (PVC) and polymethyl methacrylate (PMMA) filled with metal powders of Al and Cu have been studied. The composite preparation conditions allow the formation of a random distribution of metallic particles in the polymer matrix. Dependence of the dielectric and conductivity properties of the PVC and PMMA/fillers was studied over a broad range of frequency and volume fraction of metal fillers. The experimental results could be explained by means of the conductivity of fillers and the interface polarization between polymers and fillers. Percolation was also seen in this study when the volume fraction of conducting fillers was close to critical value, in which the composites undergo an insulator-conductor transition. The relation among the dielectric property and the fillers with different conductivity was proposed.Publication Metadata only Electrical and Thermal Studies on the Polyvinylchloride/Carbon Black Composites Induced by High Energy Ion Beam(TAYLOR & FRANCIS LTD, 2010) GÜLLÜOĞLU, ARİF NİHAT; Singh, Dolly; Singh, N. L.; Qureshi, Anjum; Gavade, Chaitali; Avasthi, D. K.; Gulluoglu, Arif N.; Phase, D. M.Modification induced by energetic ion in polyvinylchloride (PVC)/carbon black (CB) composites was studied using impedance gain-phase analyzer, differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Different concentrations of CB were dispersed in PVC films. These films were irradiated with 140 MeV Ag11+ ions at the fluences of 1 x 10(11) and 1 x 10(12)ions/cm(2). The ac electrical conductivity and dielectric response were studied as a function of filler, frequency and ion fluence. It was found that ac electrical conductivity increases with increasing the percentage of CB, frequency and ion fluence. The observed enhancement in ac electrical conductivity is attributed to the increase in the number of conduction paths created by the carbon black contents in the composites to give a higher electrical conductivity. An increase in dielectric constant was observed with the ion fluence and also with the carbon black content, which is attributed to the interfacial polarization of heterogeneous systems. Differential scanning calorimetry (DSC) analysis showed that the glass transition temperature (Tg) shifted towards lower temperature with increasing the ion fluence. It may be attributed to the scissioning of polymer chains and as a result increase of free radicals, unsaturation etc., which lead to the transformation of polymer into amorphous phase. Atomic force microscopy (AFM) studies revealed that the surface average roughness of the composites increases as filler concentration increases and decreases upon irradiation. SEM micrographs showed that carbon black particles organized into aggregates of micro spherical voids and decreased its size upon irradiation.