Sherif Khairy - Academia.edu (original) (raw)

Papers by Sherif Khairy

Research paper thumbnail of High -k Green Polymer Nano composites Based on Polyvinyl Alcohol for Electrostatic Dissipation Applications

Egyptian Journal of Chemistry

Research paper thumbnail of Preparation and Characterization of Novel Polyvinyl Alcohol Hybrid Composites Based On Barium Titanate and Magnetite Nanoparticles

Egyptian Journal of Chemistry

Novel nanocomposites comprised polyvinyl alcohol (PVA) as a host matrix and different concentrati... more Novel nanocomposites comprised polyvinyl alcohol (PVA) as a host matrix and different concentration of magnetite (Fe3O4) nanoparticles and barium titanate (BaTiO3) nanoparticles before and after treatment with ionic liquid (IL) as dopant were synthesized by casting method. Transmission Electron Microscope (TEM) was used to determine the particle size of the particles under investigation. The morphology of the samples was done by Scan Electron Microscope (SEM) shows an improvement of the distribution of BaTiO3 inside PVA matrix after ionic liquid treatment. X-ray Diffraction Spectra (XRD) has been hired for the characterization of the composites under investigation. XRD revealed a decrease in degree of crystallinity by increasing BaTiO3 concentrations (5-20) % in PVA / 10 wt% Fe3O4 before the treatment whereas a notable increase is found by increasing IL treated BaTiO3. Fourier Transformation Infrared Spectroscopy (FTIR) of PVA through its respective functional groups is noticed by addition of Fe3O4 nanoparticles and BaTiO3 nanoparticles before and after modification as well. A considerable change in characteristic peaks in the FTIR spectra was detected. The mechanical parameters; tensile strength (σR), elongation (εR) and hardness (Hv) were also investigated. Mechanical properties investigations refer that 10 (Fe3O4 / IL treated BaTiO3) wt% is the optimum concentration. Moreover, linear hardness increases with the increase of the Fe3O4 content, as well as after modification BaTiO3 with the ionic liquid.

Research paper thumbnail of FTIR spectroscopic analysis of zinc cobalt phosphate glass matrix

Research paper thumbnail of Optical spectroscopic study of glass containing zinc cobalt-doped phosphate as a promising material for various photonic applications

Research paper thumbnail of Effect of rapid thermal annealing on sprayed Cu2SnS3 thin films for solar-cell application

Japanese Journal of Applied Physics, 2020

Ternary compound Cu2SnS3 (CTS) thin films were synthesized using two simple and non-vacuum proces... more Ternary compound Cu2SnS3 (CTS) thin films were synthesized using two simple and non-vacuum processes: chemical spray pyrolysis and rapid thermal annealing (RTA). The crystal quality of CTS films improved and the band tailing, shown in Tauc's plot, tended to vanish after annealing in a nitrogen atmosphere using RTA. Although ethanol was used as a solvent in the spray pyrolysis, the CTS film was not contaminated by carbon and oxygen. The bandgap of CTS was changed via sulfurization. The optimization of the RTA process affected the composition of the CTS thin films, modifying material defects and improving the crystal quality. These results represent the initial step toward the practical application of CTS solar cells using an inexpensive fabrication process.

Research paper thumbnail of Dielectric investigations and charge transport in PS-PAni composites with ionic and nonionic surfactants

Journal of Physics and Chemistry of Solids, 2019

We present the preparation of polystyrene-polyaniline composites by an emulsion polymerization te... more We present the preparation of polystyrene-polyaniline composites by an emulsion polymerization technique. Polyethylene glycol and dodecylbenzenesulfonic acid were used as nonionic and anionic surfactants, respectively, for emulsion preparation. Fourier transform IR spectroscopy, UV-vis spectroscopy, and thermogravimetric analysis were used to characterize the composites obtained. Surface morphological investigations by scanning electron microscopy showed that the emulsion technique using polyethylene glycol produces the most homogeneously distributed composites. Thermal analysis in conjugation with broadband dielectric spectroscopy revealed that as the composite conductivity increased, the temperature at which the maximum degradation rate was achieved gradually decreased. The dielectric investigation showed the α-relaxation process in pure polystyrene has an activation energy of 10.8 kJ/mol and is accompanied by a dielectrically determined glass transition temperature of about 366 K. After addition of polyaniline, this α-relaxation process was masked by the conductivity contribution. Moreover, polyaniline prepared with the anionic surfactant had higher electrical conductivity than that prepared with the nonionic surfactant because of its ordering effect on the structure. Surprisingly, the dependence of the conductivity of the composites on temperature, regardless of the preparation method, has two different trends, and each can be attributed to a different mechanism of charge transport.

Research paper thumbnail of Relaxation dynamic and electrical mobility for poly(methyl methacrylate)‐polyaniline composites

Journal of Applied Polymer Science, 2017

ABSTRACTComposites of emeraldine form of polyaniline (PAni) and poly(methyl methacrylate) (PMMA) ... more ABSTRACTComposites of emeraldine form of polyaniline (PAni) and poly(methyl methacrylate) (PMMA) are prepared by emulsion polymerization method in definite ratios. The chemical structure of the samples and their morphologies have been investigated by different techniques including FTIR, UV–vis, XRD, SEM, and TGA. Enhancement in thermal stability of the obtained composites by PAni additions has been confirmed. Alpha analyzer, in frequency range 0.1 Hz to 20 MHz, was employed to investigate the molecular dynamics of the prepared samples and the accompanied electrical conductivity at temperatures ranging from 223 to 423 K. Conductivity investigations showed that mobility has the more dominant effect on the charge transportation. The dynamic peak at lower temperatures of the PMMA has high activation energy (83.8 kJ/mol). While, Maxwill‐Wagner‐Siller process due to the interfacial polarization in the composites has only 7.5 kJ/mol activation energy. This is a clear indication of the ease...

Research paper thumbnail of Influence of static and cyclic compression on the electrical conductivity of FEF black‐loaded rubbers

Journal of Applied Polymer Science, 1992

It was found that the electrical conductivity of fast extrusion furnace black-loaded rubber vulca... more It was found that the electrical conductivity of fast extrusion furnace black-loaded rubber vulcanizates (SBR, NR, BR, NBR, IIR) is most pressure sensitive for the SBR and NR composites and exhibits a slight dependence upon the number of compression cycles. In addition, the temperature coefficient of conductivity for SBR shows a weak dependence upon the stress amplitude and the number of compression cycles

Research paper thumbnail of Physical properties of PVDF-GO/black-TiO2 nanofibers and its photocatalytic degradation of methylene blue and malachite green dyes

Environmental Science and Pollution Research, 2021

Background: Black TiO2 and Graphene Oxide (GO) have attracted intensive attention as an effective... more Background: Black TiO2 and Graphene Oxide (GO) have attracted intensive attention as an effective catalyst on visible light driven for photodegrading of dyes. In this study, nano-black TiO2 was prepared by a simple hydrogenation of the anatase titanium oxide and the graphene oxide was prepared by applying the modified Hummers method. The prepared powders and nanofiber membranes are carefully examined to ensure their single phase and compound structure formation as well as to measure the equivalent crystallite size and particle distributions. Results: The optimum degradation efficiency of malachite green and methylene blue dyes occurred at pH values of 8 and 10, respectively. Afterwards, at the optimum pH value of 8, for malachite green, the degradation efficiency is peaked at 20 mg of the nano-black TiO2 concentration. Then, a comparison of the degradation efficiency of the two mentioned dyes are performed as the fore-mentioned nanofibers are loaded with 20 mg nano-black TiO2 at the corresponding optimum pH vales. Conclusions: The diffuse reflectance spectroscopy has been investigated to find out the optical energy gaps of the treated and nano-black samples. Finally, a schematic of the redox reaction mechanism has been proposed.

Research paper thumbnail of Impact of Na and/or Sb on the CTS thin films and solar cell performance

Japanese Journal of Applied Physics, 2021

Cu2SnS3 (CTS) thin films were synthesized onto a soda lime glass substrate coated molybdenum by s... more Cu2SnS3 (CTS) thin films were synthesized onto a soda lime glass substrate coated molybdenum by sulfurization the Cu–Sn stacks were prepared using RF sputtering. The influence of Na-doped CTS, Sb-doped CTS, and Sb+Na co-doped CTS films on their physical properties has been investigated. The undoped and doped films have been illustrated in a monoclinic structure with no shifts in peak position. Larger grain size has been obtained with Sb doping compared to undoped CTS. Enhancement in photoluminescence sharpening and yield spectra were indicated in the existence of Na and/or Sb. The power conversion efficiency was enhanced by the addition of Na and/or Sb to the CTS absorber layer, from 0.32% for undoped CTS to 1.54, 1.89 and 0.76% for Na, Sb, and co-doping CTS, respectively. As a result, the influence of doping has improved all cell efficiency with an increasing ratio of 381, 490, 137% with Na, Sb, and co-doping, respectively.

Research paper thumbnail of High -k Green Polymer Nano composites Based on Polyvinyl Alcohol for Electrostatic Dissipation Applications

Egyptian Journal of Chemistry

Research paper thumbnail of Preparation and Characterization of Novel Polyvinyl Alcohol Hybrid Composites Based On Barium Titanate and Magnetite Nanoparticles

Egyptian Journal of Chemistry

Novel nanocomposites comprised polyvinyl alcohol (PVA) as a host matrix and different concentrati... more Novel nanocomposites comprised polyvinyl alcohol (PVA) as a host matrix and different concentration of magnetite (Fe3O4) nanoparticles and barium titanate (BaTiO3) nanoparticles before and after treatment with ionic liquid (IL) as dopant were synthesized by casting method. Transmission Electron Microscope (TEM) was used to determine the particle size of the particles under investigation. The morphology of the samples was done by Scan Electron Microscope (SEM) shows an improvement of the distribution of BaTiO3 inside PVA matrix after ionic liquid treatment. X-ray Diffraction Spectra (XRD) has been hired for the characterization of the composites under investigation. XRD revealed a decrease in degree of crystallinity by increasing BaTiO3 concentrations (5-20) % in PVA / 10 wt% Fe3O4 before the treatment whereas a notable increase is found by increasing IL treated BaTiO3. Fourier Transformation Infrared Spectroscopy (FTIR) of PVA through its respective functional groups is noticed by addition of Fe3O4 nanoparticles and BaTiO3 nanoparticles before and after modification as well. A considerable change in characteristic peaks in the FTIR spectra was detected. The mechanical parameters; tensile strength (σR), elongation (εR) and hardness (Hv) were also investigated. Mechanical properties investigations refer that 10 (Fe3O4 / IL treated BaTiO3) wt% is the optimum concentration. Moreover, linear hardness increases with the increase of the Fe3O4 content, as well as after modification BaTiO3 with the ionic liquid.

Research paper thumbnail of FTIR spectroscopic analysis of zinc cobalt phosphate glass matrix

Research paper thumbnail of Optical spectroscopic study of glass containing zinc cobalt-doped phosphate as a promising material for various photonic applications

Research paper thumbnail of Effect of rapid thermal annealing on sprayed Cu2SnS3 thin films for solar-cell application

Japanese Journal of Applied Physics, 2020

Ternary compound Cu2SnS3 (CTS) thin films were synthesized using two simple and non-vacuum proces... more Ternary compound Cu2SnS3 (CTS) thin films were synthesized using two simple and non-vacuum processes: chemical spray pyrolysis and rapid thermal annealing (RTA). The crystal quality of CTS films improved and the band tailing, shown in Tauc's plot, tended to vanish after annealing in a nitrogen atmosphere using RTA. Although ethanol was used as a solvent in the spray pyrolysis, the CTS film was not contaminated by carbon and oxygen. The bandgap of CTS was changed via sulfurization. The optimization of the RTA process affected the composition of the CTS thin films, modifying material defects and improving the crystal quality. These results represent the initial step toward the practical application of CTS solar cells using an inexpensive fabrication process.

Research paper thumbnail of Dielectric investigations and charge transport in PS-PAni composites with ionic and nonionic surfactants

Journal of Physics and Chemistry of Solids, 2019

We present the preparation of polystyrene-polyaniline composites by an emulsion polymerization te... more We present the preparation of polystyrene-polyaniline composites by an emulsion polymerization technique. Polyethylene glycol and dodecylbenzenesulfonic acid were used as nonionic and anionic surfactants, respectively, for emulsion preparation. Fourier transform IR spectroscopy, UV-vis spectroscopy, and thermogravimetric analysis were used to characterize the composites obtained. Surface morphological investigations by scanning electron microscopy showed that the emulsion technique using polyethylene glycol produces the most homogeneously distributed composites. Thermal analysis in conjugation with broadband dielectric spectroscopy revealed that as the composite conductivity increased, the temperature at which the maximum degradation rate was achieved gradually decreased. The dielectric investigation showed the α-relaxation process in pure polystyrene has an activation energy of 10.8 kJ/mol and is accompanied by a dielectrically determined glass transition temperature of about 366 K. After addition of polyaniline, this α-relaxation process was masked by the conductivity contribution. Moreover, polyaniline prepared with the anionic surfactant had higher electrical conductivity than that prepared with the nonionic surfactant because of its ordering effect on the structure. Surprisingly, the dependence of the conductivity of the composites on temperature, regardless of the preparation method, has two different trends, and each can be attributed to a different mechanism of charge transport.

Research paper thumbnail of Relaxation dynamic and electrical mobility for poly(methyl methacrylate)‐polyaniline composites

Journal of Applied Polymer Science, 2017

ABSTRACTComposites of emeraldine form of polyaniline (PAni) and poly(methyl methacrylate) (PMMA) ... more ABSTRACTComposites of emeraldine form of polyaniline (PAni) and poly(methyl methacrylate) (PMMA) are prepared by emulsion polymerization method in definite ratios. The chemical structure of the samples and their morphologies have been investigated by different techniques including FTIR, UV–vis, XRD, SEM, and TGA. Enhancement in thermal stability of the obtained composites by PAni additions has been confirmed. Alpha analyzer, in frequency range 0.1 Hz to 20 MHz, was employed to investigate the molecular dynamics of the prepared samples and the accompanied electrical conductivity at temperatures ranging from 223 to 423 K. Conductivity investigations showed that mobility has the more dominant effect on the charge transportation. The dynamic peak at lower temperatures of the PMMA has high activation energy (83.8 kJ/mol). While, Maxwill‐Wagner‐Siller process due to the interfacial polarization in the composites has only 7.5 kJ/mol activation energy. This is a clear indication of the ease...

Research paper thumbnail of Influence of static and cyclic compression on the electrical conductivity of FEF black‐loaded rubbers

Journal of Applied Polymer Science, 1992

It was found that the electrical conductivity of fast extrusion furnace black-loaded rubber vulca... more It was found that the electrical conductivity of fast extrusion furnace black-loaded rubber vulcanizates (SBR, NR, BR, NBR, IIR) is most pressure sensitive for the SBR and NR composites and exhibits a slight dependence upon the number of compression cycles. In addition, the temperature coefficient of conductivity for SBR shows a weak dependence upon the stress amplitude and the number of compression cycles

Research paper thumbnail of Physical properties of PVDF-GO/black-TiO2 nanofibers and its photocatalytic degradation of methylene blue and malachite green dyes

Environmental Science and Pollution Research, 2021

Background: Black TiO2 and Graphene Oxide (GO) have attracted intensive attention as an effective... more Background: Black TiO2 and Graphene Oxide (GO) have attracted intensive attention as an effective catalyst on visible light driven for photodegrading of dyes. In this study, nano-black TiO2 was prepared by a simple hydrogenation of the anatase titanium oxide and the graphene oxide was prepared by applying the modified Hummers method. The prepared powders and nanofiber membranes are carefully examined to ensure their single phase and compound structure formation as well as to measure the equivalent crystallite size and particle distributions. Results: The optimum degradation efficiency of malachite green and methylene blue dyes occurred at pH values of 8 and 10, respectively. Afterwards, at the optimum pH value of 8, for malachite green, the degradation efficiency is peaked at 20 mg of the nano-black TiO2 concentration. Then, a comparison of the degradation efficiency of the two mentioned dyes are performed as the fore-mentioned nanofibers are loaded with 20 mg nano-black TiO2 at the corresponding optimum pH vales. Conclusions: The diffuse reflectance spectroscopy has been investigated to find out the optical energy gaps of the treated and nano-black samples. Finally, a schematic of the redox reaction mechanism has been proposed.

Research paper thumbnail of Impact of Na and/or Sb on the CTS thin films and solar cell performance

Japanese Journal of Applied Physics, 2021

Cu2SnS3 (CTS) thin films were synthesized onto a soda lime glass substrate coated molybdenum by s... more Cu2SnS3 (CTS) thin films were synthesized onto a soda lime glass substrate coated molybdenum by sulfurization the Cu–Sn stacks were prepared using RF sputtering. The influence of Na-doped CTS, Sb-doped CTS, and Sb+Na co-doped CTS films on their physical properties has been investigated. The undoped and doped films have been illustrated in a monoclinic structure with no shifts in peak position. Larger grain size has been obtained with Sb doping compared to undoped CTS. Enhancement in photoluminescence sharpening and yield spectra were indicated in the existence of Na and/or Sb. The power conversion efficiency was enhanced by the addition of Na and/or Sb to the CTS absorber layer, from 0.32% for undoped CTS to 1.54, 1.89 and 0.76% for Na, Sb, and co-doping CTS, respectively. As a result, the influence of doping has improved all cell efficiency with an increasing ratio of 381, 490, 137% with Na, Sb, and co-doping, respectively.