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1 – 10 of over 1000Abd El Hakeem Abd El Naby and M.F. Abd El Kareem
The peristaltic motion for Carreau fluid by means of an infinite train of sinusoidal waves traveling along the walls of a circular cylindrical flexible tube is investigated. The…
Abstract
The peristaltic motion for Carreau fluid by means of an infinite train of sinusoidal waves traveling along the walls of a circular cylindrical flexible tube is investigated. The fluid is subjected to a constant transverse magnetic field. A perturbation solution is obtained for the case in which Weissenberg number is small. The effects of Hartmann number, Weissenberg number, power‐law index and amplitude ratio on the pressure rise and the friction force are discussed. The trapping limit and the trapping occurrence region at the centerline decrease by increasing Hartmann number but they are independent approximately of Weissenberg number and power‐law index.
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S. Abd El Wanees, E.E. Abd El Aal and A. Abd El Aal
The potentiodynamic anodic polarization curves for the lead electrode were obtained in 0.1 mol L‐1 KOH solution in the absence and presence of C103‐ or C104‐ as aggressive ions at…
Abstract
The potentiodynamic anodic polarization curves for the lead electrode were obtained in 0.1 mol L‐1 KOH solution in the absence and presence of C103‐ or C104‐ as aggressive ions at different concentrations. Lower concentrations of these ions have no significant influence on the passive film, while higher concentrations raise the active dissolution current density, and cause destruction of passivity and initiation of pitting corrosion. The critical pitting corrosion potential varies with the concentration of the aggressive ions according to sigmoidal curves. These curves were explained on the basis of the formation of passivitable, active and continuously propagagting pits depending on the range of the aggressive ion concentration. Additions of increasing concentrations of chromate, phosphate, sulphate and carbonate ions cause a shift of the critical pitting potential in the noble direction accounting for increase resistance to pitting attack (inhibition). The pitting corrosion potential varies with the concentration of the inhibitive ions, in the presence of a constant concentration of the aggressive ions, according to curves of sigmoidal shape. From these curves one can determine the minimum concentration of the inhibitive ions necessary for inhibition of pitting corrosion to occur.
Abd El-Wahab H., Farouk Abd El-Monem, Naser M.A., Hussain A.I., Elshhat H.A. Nashy and Lin L.
The purpose of this paper is devoted to application of the emulsion polymer of poly(methyl methacrylate-co-butyl acrylate) prepared with in situ nano-silica as a novel tanning…
Abstract
Purpose
The purpose of this paper is devoted to application of the emulsion polymer of poly(methyl methacrylate-co-butyl acrylate) prepared with in situ nano-silica as a novel tanning agent of hide to partly or totally replace chrome salt and to improve physical, thermal and mechanical properties of the tanned leather and to reduce the environmental impact of chrome tanning effluent.
Design/methodology/approach
Polymer/nano-silica hybrid emulsions were prepared via in situ seed emulsion polymerisation. The prepared polymers were characterised for solid content, molecular weight, viscosity, drying time, minimum film-forming temperature (MFFT) and microstructures (via transmission electron microscopy). The mechanical, thermal and surface morphological (by scanning electron microscope) properties of the treated samples were also investigated. The influences of the increase in the content of organic nano-silica on the properties of the tanned leather are discussed.
Findings
It was found that the viscosity, the particle size and the solid content of the prepared polymers increased as the content of the nano-silica increased while gloss and drying time of the resulting polymer film decreased. Tanning buffalo hide by Polymer F (containing a high content of nano-silica) gave desirable properties in terms of tensile strength, thermal stability and shrinkage temperature.
Research limitations/implications
This paper discusses the preparation and the characterisation of emulsion polymers with in situ nano-silica and their application in tanning process to enhance and improve the leather quality, as well as reduce the use of chrome tanning materials and consequently chrome tanning waste.
Practical implications
The tanned leather showed an improvement of physico-mechanical properties and enhancement of thermal stability. Furthermore, the tanned leather has uniform colour, softness and firmness of grain. All these promising results provide evidence to support the applicability of the prepared co-polymer/nano-silica emulsions as an efficient tanning agent that also provides lubricating properties for leather.
Originality/value
Since May 2015, REACH Annex XVII restricts Cr(VI) in leather articles or leather parts of articles that come into contact with skin to a concentration of less than 3 mg/kg. Cases of discovery of Cr(VI) in leather papers have been reported by the European rapid alert system on dangerous consumer products (RAPEX). The emulsion poly (methyl methacrylate-co-butyl acrylate) with in situ nano-silica that has been developed via the study reported in this paper is one of the better technologies for the reduction of chromium ratio used in tanning industry.
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The electrochemical behaviour of zinc in different concentrations of Na2SO4 (pH = 6.0) was investigated using the potentiodynamic anodic polarization single sweep and cyclic…
Abstract
The electrochemical behaviour of zinc in different concentrations of Na2SO4 (pH = 6.0) was investigated using the potentiodynamic anodic polarization single sweep and cyclic voltammogram techniques. The anodic portion is characterized by one distinct peak corresponding to Zn(OH)2 or ZnO. This is followed by a passive region up to a certain potential; the passive current suddenly rises steeply without any sign of oxygen evolution. This denotes the breakdown of the passive film and initiation of pitting corrosion. It was found that the breakdown potential depends on the sulphate concentration, type of aeration, scan rate, solution temperature and pH. The pitting initiation may be explained through the adsorption of SO42– anion on the oxide film formed. This decreases the repair efficiency and causes further metal dissolution. From the cyclic voltammogram of zinc in different concentrations of Na2SO4, it was found that the change in the integrated anodic charge, Δqa, which is taken as a measure of the extent of pitting, varies linearly with concentration of SO42– anion.
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F.F. Abd El Mohsen, R.M. Mohsen and Y.M. Abu Ayana
Modern glues are manufactured with high moisture and water resistance; urea‐formaldehyde resins for gluing purposes are based on the fact that excellent control of the…
Abstract
Modern glues are manufactured with high moisture and water resistance; urea‐formaldehyde resins for gluing purposes are based on the fact that excellent control of the condensation reaction is possible by variation of pH, which can be applied easily at the production process. Among conclusions is that the shear stress of these resins is twice that of the unmodified type.
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M. Moustafa, I.A. Sabbah, S.I. Darwish and F. Abd El‐Hai
Rosin‐modified polyesteramide resins are prepared covering a wide range of oil lengths by partial replacement of hydroxy ethyl fatty acid amides employed in resin formulations by…
Abstract
Rosin‐modified polyesteramide resins are prepared covering a wide range of oil lengths by partial replacement of hydroxy ethyl fatty acid amides employed in resin formulations by rosin‐diethanolamine derivative without affecting the resin constants. This is followed by a study of the optimum amount of modifier which improve the resins performance and durability without affecting the other properties. Optimum modifier concentration and durability characteristics are then determined.
Ahmed Mohamed, Abdelhalim Mustafa, M.S.A. Elgaby, H. Abd El-Wahab, Said Ahmed Abed and A. Kazlauciunas
This paper aims to prepare a new modified poly(ester amide) (PEA) resins and use it as a binder for anticorrosive and antimicrobial coatings.
Abstract
Purpose
This paper aims to prepare a new modified poly(ester amide) (PEA) resins and use it as a binder for anticorrosive and antimicrobial coatings.
Design/methodology/approach
New modified PEA compositions were prepared based on 4-amino-N, N-bis(2-hydroxyethyl) benzamide (AHEB) as the ingredient source of the polyol used and evaluated as vehicles for surface coating. The structure of the modifier and PEA resin was confirmed by FT-IR, H¹-NMR, MW, thermogravimetric analysis and scanning electron microscope studies. Coatings of 50±5 µm thickness were applied to the surface of glass panels and mild steel strips by means of a brush. The coating performance of the resins was evaluated using international standard test methods and involved the measurement of phyisco-mechanical properties and chemical resistance.
Findings
The tests carried out revealed that the modified PEA based on AHEB enhanced both phyisco-mechanical and chemical properties. Also, the resins were incorporated within primer formulations and evaluated as anti-corrosive and antimicrobial single coatings. The results illustrate that the introduction of AHEB, within the resin structure, improved the film performance and enhances the corrosion resistance and antimicrobial activity performance of PEA resins.
Practical implications
The modified PEA compounds can be used as binders in paint formulations to improve the chemical, physical, corrosion resistance and antimicrobial activity properties.
Originality/value
Modified PEA resins are cheaper and can be used to replace other more expensive binders. These modified PEA resins can compensate successfully for the presence of many the anticorrosive and antimicrobial paint formulations, and thus, lower the costs. The main advantage of these binders is that they combine the properties of both polyester and polyamide resins based on nitrogenous compound, are of lower cost and they also overcome the disadvantages of both its counterparts. Also, they can be applied in other industrial applications.
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H. Abd El‐Wahab, F. Abd El‐Hai, M. Abd El‐Fattah and L. Lin
Demands for coatings with superior technical characteristics have induced the use of composite coatings, which usually represent an extremely strong product. The resin blend…
Abstract
Purpose
Demands for coatings with superior technical characteristics have induced the use of composite coatings, which usually represent an extremely strong product. The resin blend technique is a simple and useful method for improving paint properties. Coal tar resins are the most economical coating extensively used in the industry; short oil‐length alkyd resins are usually used for air and force‐dry industrial coatings for metal surfaces. The purpose of this paper is to evaluate coating blends composed of these resins, in particular, the effects of short oil‐length alkyd additive on the properties of coal tar binder.
Design/methodology/approach
One way to achieve new types of binders is to make combinations of the existing ones, in an ideal case retaining the desirable properties of both. The alkyd has important properties over the original drying oil. To achieve the goal of improving coal tar resin properties, short oil‐length alkyd was blended with it. The prepared short oil‐length alkyd was characterised using IR and 1HNMR spectroscopy. The mixing ratio of short oil‐length alkyd with coal tar was up to 25 per cent. The compatibility of coating blend was characterised by scanning electron microscope. The physical, mechanical and chemical properties of the coating blend in addition to the corrosion resistance were determined according to ASTM methods.
Findings
In spite of a large number of synthetic resins being available for use in paint formulations, the alkyd resins surpassed all of them in versatility and low cost. The blend of short oil‐length alkyd resin with coal tar has yielded better coating blend properties. The coating blend showed significant enhancement of physical, mechanical and chemical properties such as gloss, drying time, adhesion, scratch hardness, acid and solvent resistance because the coating blend combines the properties of thermosetting and thermoplastic resins.
Research limitations/implications
Alkyd resins are the most extensively used synthetic polymers in the coating industry. Modification of coal tar blend based on other type of polyester resins could also be studied in order to assess the applicability of the coal tar blend system found for other applications.
Practical implications
These types of alkyd resins can be applied in other bitumen composites as additives and reinforce agent.
Originality/value
The paper shows how the low‐cost modified coal tar binder can be used for air and force‐dry industrial coatings for metal surfaces.
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H. Abd El‐Wahab, F. Abd El‐Hai, A.M. Naser, Z.I. El‐Bialy, M. Mostafa and L. Lin
Polymeric systems based on polyesteramides (PEA) are high performance materials, which combine the useful properties of polyester and polyamide resins, and find many applications…
Abstract
Purpose
Polymeric systems based on polyesteramides (PEA) are high performance materials, which combine the useful properties of polyester and polyamide resins, and find many applications, most importantly as protective surface coatings. The purpose of this paper is to characterise and evaluate new modified anti‐corrosive PEA resins for use in protective coating formulations.
Design/methodology/approach
In the study report here, new modified PEA compositions were prepared and evaluated as vehicles for surface coating. The PEA resins were obtained by means of a condensation polymerisation reaction between phthalic anhydride (PA) and N,N‐bis‐(2‐hydroxyethyl) linseed oil fatty acid amide (HELA) as the ingredient source of the polyol used. The phthalic anhydride was partially replaced with N‐phthaloylglutamic acid NPGA as the ingredient source of the dibasic acid. The structure of the resin was confirmed by FT‐IR spectral studies. Coatings of 50±5 μm thickness were applied to the surface of glass panels and mild steel strips by means of a brush. The coating performance of the resins was evaluated using international standard test methods and involved the measurement of phyisco‐mechanical properties and chemical resistance.
Findings
The tests carried out revealed that the modified PEA based on N‐phthaloylglutamic acid (NPGA) enhanced both phyisco‐mechanical and chemical properties. Also, the resins were incorporated within primer formulations and evaluated as anti‐corrosive single coatings. The results illustrate that the introduction of N‐phthaloylglutamic acid, within the resin structure, improved the film performance and enhances the corrosion resistance performance of PEA resins.
Practical implications
The modified PEA compounds can be used as binder in paint formulations to improve chemical, physical and corrosion resistance properties.
Originality/value
Modified PEA resins are cheaper and can be used to replace other more expensive binders. These modified PEA resins can compensate successfully for the presence of many the anticorrosive paint formulations and thus lower the costs. The main advantage of these binders is that they combine the properties of both polyester and polyamide resins based on nitrogenous compound, are of lower cost, and they also overcome the disadvantages of both its counterparts. Also, they can be applied in other industrial applications.
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Nashwa Mostafa Saleh, Maha Mohammed Elsawy, Hamada Abd El-Wahab, Salem Salah Salem and Nour El-Din Abd El-Sattar
The purpose of this study is to develop a new protective coating formulation for industrial use, using benzodiazepine derivatives as double function additives.
Abstract
Purpose
The purpose of this study is to develop a new protective coating formulation for industrial use, using benzodiazepine derivatives as double function additives.
Design/methodology/approach
Benzodiazepine’s derivatives of types (3–5) were prepared and confirmed by infrared, Mass, 1H-Proton nuclear magnetic resonance (NMR) and 13C NMR spectra. The synthesized compound was physically incorporated in the alkyd paint formulation by pebble mill grinding until all particulates are smaller than 20 ums. The prepared coatings were applied by air spray on steel panels. The physical, mechanical characteristics, corrosion resistance and antimicrobial test of the prepared coatings were studied to evaluate the prepared compounds drawbacks.
Findings
The results of the mechanical and physical properties of the paint formulation revealed that the paint formulation incorporating benzodiazepines derivatives 3–5 performed best and improved corrosion-resistance and antibacterial activity tests.
Research limitations/implications
In alkyd paint, heterocyclic compounds are the most used antibacterial additives. Other functionalities of these compounds, such as corrosion inhibitors, might be studied to see if they are suited for these applications.
Practical implications
Because of the activity of various benzodiazepine derivatives, which may be attributable to the presence of some function groups such as sulfonamide aromatic amino NH2 group, and elements such as Sulphur, Nitrogen, Chlorine, in its chemical structure. As a result, paint compositions including these compounds as additives can be used as dual-purpose paint and for a variety of industrial applications.
Originality/value
The research demonstrates how a low-cost paint composition based on synthesized benzodiazepine derivatives 3–5 may be used as a dual-function paint for industrial use.
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