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Article
Publication date: 1 April 1994

E.E. Abd El Aal, A. Abd El Aal and S.M. Abd El Haleem

The effect of the addition of aggressive salts such as LiCl, NaCl, KCl, RbCl and MgCl2 on the steady‐state potential of a Zn electrode previously equilibrated in a

Abstract

The effect of the addition of aggressive salts such as LiCl, NaCl, KCl, RbCl and MgCl2 on the steady‐state potential of a Zn electrode previously equilibrated in a passivating chromate solution is established. S‐shaped curves are obtained for the variation of the steady‐state potential with the quantity of aggressive salt added. For each inhibitor concentration, Cinh, the addition of aggressive ions up to a certain concentration has no effect on the passivity of Zn. However, higher Cl ion concentration causes destruction of the passive film and initiation of pitting corrosion. Destruction of passivity occurs after an induction period which decreases with the increase in the concentration of the attacking ion and/or the decrease in that of the inhibiting ions. The concentration of aggressive ion, Cagg, that can be tolerated by a certain concentration of the inhibiting ions, Cinh, is given by the relation : log Cinh =K + n log CCl−, where K and n are constants. The efficiency of these salts in initiating pitting corrosion increases in the order RbCl ≤ MgCl2, ≤ KCl < NaCl < LiCl. The change in the degree of aggressivity of these salts could be attributed either to the incorporation of the cations in the passive film or to their effect on pH.

Details

Anti-Corrosion Methods and Materials, vol. 41 no. 4
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 October 1999

E.E. Abd El Aal

The electrochemical behaviour of zinc in different concentrations of Na2SO4 (pH = 6.0) was investigated using the potentiodynamic anodic polarization single sweep and…

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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Anti-Corrosion Methods and Materials, vol. 46 no. 5
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 February 1990

A.A. Abd El‐Hakim, M.A. Abd El‐Ghaffar, M.M. Abd El‐Malek and E.A.M. Youssef

Results and discussion Adsorption isotherms of stearic acid on the surface of manganese ore samples:

Abstract

Results and discussion Adsorption isotherms of stearic acid on the surface of manganese ore samples:

Details

Anti-Corrosion Methods and Materials, vol. 37 no. 2
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 June 1996

M.A. Abd El‐Ghaffar, E.A.M. Youssef, M.M.H. Abo‐Shosa and N.A. Ibrahim

Modifies short and medium alkyd resins using perfluori‐nated urethane toluene isocyanate (PFUTI), and incorporates the modified resins in a set of paint formulations…

Abstract

Modifies short and medium alkyd resins using perfluori‐nated urethane toluene isocyanate (PFUTI), and incorporates the modified resins in a set of paint formulations containing different ratios of zinc phosphate as an inhibitive pigment. Achieves promising results and illustrates corrosion‐protective properties in various paint formulations and also a paint formulation free of the inhibitive pigment. Shows enhancement of the corrosion protection efficiencies by the improvement in the hydrophobicity of alkyd resin modified with PFUTI. In view of these results, minimizes or neglects the most expensive inhibitive pigments from an economical standpoint.

Details

Pigment & Resin Technology, vol. 25 no. 6
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 23 April 2020

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…

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.

Details

Pigment & Resin Technology, vol. 49 no. 4
Type: Research Article
ISSN: 0369-9420

Keywords

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Article
Publication date: 1 June 1996

M.A. Abd El‐Ghaffar, E.A.M. Youssef, M.M.H. Abo‐Shosha and N.A. Ibrahim

Short and medium alkyd resins were modified using perfluorinated urethane toluene isocyanate (PFUTI). The modified resins were incorporated in a set of paint formulations…

Abstract

Short and medium alkyd resins were modified using perfluorinated urethane toluene isocyanate (PFUTI). The modified resins were incorporated in a set of paint formulations containing different ratios of zinc phosphate as an inhibitive pigment. Promising results were achieved and corrosion protective properties were illustrated in various paint formulations and also in a paint formulation free of the inhibitive pigment. The corrosion protection efficiencies were enhanced by the improvement in the hydrophobicity of alkyd resin modified with perfluorinated toluene isocyanate (PFUTI). These results encourage us to minimize or neglect the most expensive inhibitive pigments from the economic point of view.

Details

Anti-Corrosion Methods and Materials, vol. 43 no. 6
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 October 1988

M.A. Abd El‐Ghaffar, A.Z. Gomaa, M.M. Abd El‐Malek, E.A.M. Youssef and A.A. Abd El‐Hakim

The corrosion protective properties of the primer films prepared from Egyptian manganese ore (high and medium grades) and epoxy resin have been determined by immersing…

Abstract

The corrosion protective properties of the primer films prepared from Egyptian manganese ore (high and medium grades) and epoxy resin have been determined by immersing coated films in artificial sea water for 28 days. The good corrosion protective properties indicate that the Egyptian manganese ore can be satisfactorily used in anticorrosive primer formulations for steel surface protection.

Details

Anti-Corrosion Methods and Materials, vol. 35 no. 10
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 January 1990

A.A. Abd El‐Hakim, M.A. Abd El‐Ghaffar, M.M. Abd El‐Malek and E.A.M. Youssef

The adsorption of stearic acid molecules onto the surface of the Egyptian manganese ore (high and medium grades, H.G. & M.G.) was followed by adsorption isotherm…

Abstract

The adsorption of stearic acid molecules onto the surface of the Egyptian manganese ore (high and medium grades, H.G. & M.G.) was followed by adsorption isotherm determination and the sedimentation properties of the ore in apolar medium. It was found that the sedimentation properties depend on the adsorbed amount in the isotherm, the most stable dispersion for the ore in the organic medium was detected at monolayer surface coverage of stearic acid molecules on the surface of the ore.

Details

Anti-Corrosion Methods and Materials, vol. 37 no. 1
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 February 1993

This article has been withdrawn as it was published elsewhere and accidentally duplicated. The original article can be seen here: 10.1108/eb043004. When citing the…

Abstract

This article has been withdrawn as it was published elsewhere and accidentally duplicated. The original article can be seen here: 10.1108/eb043004. When citing the article, please cite: S.M. El-Sawy, F.A. Abdel Mohdy, M.A. Abd El-Ghaffar, (1993), “Highly efficient anticorrosive water-borne paints”, Pigment & Resin Technology, Vol. 22 Iss: 1, pp. 4 - 11.

Details

Anti-Corrosion Methods and Materials, vol. 40 no. 2
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 December 2004

R.A. El‐Adly, E.A.M. Youssef, S.M. El‐Sayed and M.A. Abd El‐Ghaffar

This paper reports on the preparation of six formulations (G1‐G6) containing mixed soap greases based on cotton soap stock, aromatic extract, heavy alkylate and lube base…

Abstract

This paper reports on the preparation of six formulations (G1‐G6) containing mixed soap greases based on cotton soap stock, aromatic extract, heavy alkylate and lube base oil. The physicochemical properties of these ingredients were characterised. The consistency, dropping point and mechanical stability of the formulated greases were assessed and tested in accordance with the National Laboratory for Grease Institute standards, and compared with the Egyptian Standards. The properties of the formulated grease G4 proved to be the best. The work reported also includes preparation of itaconyl‐o‐tolidine‐, itaconyl bisaniline‐ and itaconyl m‐phenylene‐ amide polymers. The structure of these polymers was investigated using infrared spectroscopy, micro analysis and gel permeation chromatography. The polymers prepared were evaluated as antioxidants for the optimum formulated grease G4. The study revealed that the itaconyl m‐phenylene amide polymer was a weak antioxidant, while itaconyl bisaniline‐ and itaconyl‐o‐tolidine amide polymers showed good anti‐oxidation property.

Details

Pigment & Resin Technology, vol. 33 no. 6
Type: Research Article
ISSN: 0369-9420

Keywords

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