Yasser K. Abdel-Monem

Effect of Electron Beam Irradiation and Reactive Compatibilizers on Some Properties of Polypropylene and Epoxidized Natural Rubber Polymer Blends

Effect of reactive compatibilizers on the mechanical, thermal and morphological properties of polymer blends based essentially on polypropylene (PP) and different ratios of epoxidized natural rubber (ENR) was investigated. The same properties were also, studied before and after electron beam irradiation to various doses. The results showed that the mechanical and thermal properties of unirradiated PP/ENR blends were improved after using the reactive compatibilizers: PP graft copolymer with maleic anhydride (PP-g-MAH) or 1,6-hexandiol-diacrylate (HDDA). This improvement was attributed to the formation of interfacial bonding between PP and ENR phases during the melt processing. Further improvement in these properties was observed under effect of electron beam irradiation and the reactive compatibilizer. However, this effect was clear in the case of the monomer HDDA than PP-g-MAH. Scanning electron microscopy (SEM) micrographs indicated that the morphology was improved by the addition of the reactive compatibilizers and electron beam irradiation. The wide angle X-ray diffraction (WAXD) results indicated that the crystallinity of the blend was increased by the addition of the compatiblizing agents due to the plasticizing effect and/or the nucleatating properties of the compatibilizer. However, the crystallinity of the PP/ENR blend was decreased after electron beam irradiation.

Structural, spectral, magnetic and thermal studies of 5-(thiophene-2-ylmethine azo) uracil metal complexes

Abstract Mono- and bimetallic 5-(thiophene-2-ylmethine azo) uracil complexes were prepared in a pure ethanol or ammoniacal solution. The complexes were characterized by elemental analyses, thermal analyses, magnetic moment and spectroscopic measurements. The infrared and 1H-NMR studies revealed that the ligand reacts with all metal ions in a neutral keto form. Also, the ligand behaves as a tridentate or bidentate and coordinated with metal ions by ONS, NS and ON donors atoms, where azomethane nitrogen atom, and/or sulfur atom of thiophene ring and oxygen atom of uracil ring are participated to construct mononuclear Co(II), Ni(II), Zn(II), bimetallic Cd(II); mononuclear Cu(II) and Mn(II) complexes, respectively. However, in case of bimetallic Co(II) 7 and Ni(II) 8 ammine complexes, the ligand bridge is considered to indicate the ligand has tetra- and pentadentate character toward two metal ions, respectively. The magnetic moment values and the Nujol mull electronic spectra showed that all complexes have an octahedral geometry, except Cu(II) complex, 4 has a square planar structure. All the thermal decomposition processes led to formation of metal oxides. The hydrated complexes displayed a higher thermal stability than that of ammine complexes. Theoretical investigations have also been carried out at CAM-B3LYP/LANL2DZ to study the structure of the ligand and its Mn(II) complex. The results confirmed the experimental discussion.

Influence of Mo or Cu doping in Fe/MgO catalyst for synthesis of single-walled carbon nanotubes by catalytic chemical vapor deposition of methane

ABSTRACT A series of mono-, bi- or tri-metallic Fe–Mo-Cu/MgO catalysts with the same metal loading of 6 wt% were prepared by impregnation method and used as catalysts for synthesis single-walled carbon nanotubes (SWCNTs) via methane decomposition. XRD, H2-TPR, and nitrogen physisorption techniques were used to characterize the freshly calcined catalysts, while HRTEM, Raman spectroscopy and TGA were employed to investigate the morphology and microstructure of the SWCNTs product. The obtained results indicated that the introduction of Mo or Cu in the Fe/MgO catalyst enhanced the catalytic growth activity. TEM images showed that both bundles and isolated SWCNTs were obtained over Mo containing catalysts, whereas only SWCNTs bundles were grown over the Fe-Cu/MgO catalyst. The obtained SWCNTs having a diameter of around 0.9–2.4 nm. Raman analysis illustrated that all promoted catalysts produced high quality of SWCNTs compared to the unpromoted Fe/MgO catalyst.

The effect of surface charge on photocatalytic degradation of methylene blue dye using chargeable titania nanoparticles

Herein, a simple approach based on tailoring the surface charge of nanoparticles, NPs, during the preparation to boost the electrostatic attraction between NPs and the organic pollutant was investigated. In this study, chargeable titania nanoparticles (TiΟ2 NPs) were synthesized via a hydrothermal route under different pH conditions (pH = 1.6, 7.0 and 10). The prepared TiΟ2 NPs were fully characterized via various techniques including; transmission electron microscopy (TEM), X-ray diffraction (XRD), N2 adsorption/desorption, X-ray photoelectron spectroscopy (XPS), Ultraviolet–visible spectroscopy (UV-Vis) and dynamic light scattering (DLS). The influence of the preparation pH on the particle size, surface area and band gap was investigated and showed pH-dependent behavior. The results revealed that upon increasing the pH value, the particle size decreases and lead to larger surface area with less particles agglomeration. Additionally, the effect of pH on the surface charge was monitored by XPS to determine the amount of hydroxyl groups on the TiO2 NPs surface. Furthermore, the photocatalytic activity of the prepared TiΟ2 NPs towards methylene blue (MB) photodegradation was manifested. The variation in the preparation pH affected the point of zero charge (pHPZC) of TiO2 NPs, subsequently, different photocatalytic activities based on electrostatic interactions were observed. The optimum efficiency obtained was 97% at a degradation rate of 0.018 min−1 using TiO2 NPs prepared at pH 10.

Organic nanoparticles of acetohydrazides as novel inhibitors for mild steel corrosion

Novel organic nanoparticles (ONPs) of (E)-2-(4-(hydrazonomethyl)phenoxyl) acetohydrazide (H2) and N′((E)-benzylidene)-2-(4-((E)hydrazonomethyl)phenoxyl)acetohydrazide (H3) were prepared by the re-precipitation method. The ONPs were characterized using MS, 1H-NMR, 13C-NMR, FT-IR, DLS, TEM and XRD. Both nanoparticles revealed a hemispherical shape with a particle size of 3.0 nm and 2.0 nm for H2 and H3 nanoparticles, respectively. The protective effect of the ONPs on mild steel in 1.0 M HCl was monitored by polarization, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The obtained results revealed that the inhibition efficiency increased with an increase in inhibitor concentration. The maximum inhibition efficiencies at a constant concentration of 1 × 10−3 M were 88.2% and 96.7% for H2 and H3, respectively. The inhibition mechanism depended on the physical adsorption of the nanoparticles on the steel surface, which was confirmed by SEM, AFM and impedance results. These novel nanomaterials showed great anti-corrosion behavior and thus can be potentially used in industrial applications such as cooling water systems, pipes, and oil production units.