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Article
Publication date: 21 March 2008

A. Elidrissi, O. Krim and S. Ousslimane

To evaluate in the first stage, the efficiency of changing the nature and the length of diols on the properties of perfectly hard sequences polyurethanes (PU). In the…

Abstract

Purpose

To evaluate in the first stage, the efficiency of changing the nature and the length of diols on the properties of perfectly hard sequences polyurethanes (PU). In the second, the thermal properties of a new series of segmented PU with different concentrations of soft sequences were determined.

Design/methodology/approach

The synthesis of segmented PU has been realised in two stages known as the pre‐polymer method. Various compositions of PU were obtained by keeping the poly(tetramethylene glycol) – PTMG molecular weights constant, but varying its concentration. The products obtained were characterised by IR, NMR, gel permeation chromatography and studied by differential scanning calorimetry.

Findings

The level of phase segregation depends on several parameters, especially the nature of the soft segment and its average molecular weight, nature of the hard sequence and the number of hydrogen bonds established in the PU sequences.

Research limitations/implications

The segmented PU obtained were synthesised from PTMG of number molecular weight 2,000. They could also be synthesised from PTMG of molecular weight 600, 1,000, 2,000, 4,000, etc. The effect of change of PTMG molecular weight on PU properties could also be studied.

Practical implications

Better understanding of the morphology of segmented PU and its effect in the practical domains.

Originality/value

Novel perfectly hard sequences PU have been synthesised and characterised. The effect of soft sequence nature and concentration on the phase segregation in these new series of segmented PU is discussed.

Details

Pigment & Resin Technology, vol. 37 no. 2
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 1 December 2004

M. Elayyachy, M. El Kodadi, B. Hammouti, A. Ramdani and A. Elidrissi

The inhibition of corrosion of steel in 1 M HCl solution by newly synthesised pyrazole derivatives has been studied by weight loss and polarisation techniques at 308°K…

Abstract

The inhibition of corrosion of steel in 1 M HCl solution by newly synthesised pyrazole derivatives has been studied by weight loss and polarisation techniques at 308°K. Its inhibitory power is compared to N,N′‐bis(3,5‐dimethylpyrazol‐1‐yl‐methyl)‐pentanolamine (Bipyr). The results obtained reveal that tripyrazole exhibits a good protection. Inhibition is found to increase with increase in inhibitor concentration. The inhibition behaviour of the compound has been explained on the basis of molecule size and charge density of adsorption active centres. The adsorption phenomenon obeys the Langmuir adsorption isotherm model.

Details

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

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Article
Publication date: 4 September 2017

Asmae Bouoidina, Mehdi Chaouch, Abdelfattah Abdellaoui, Amal Lahkimi, Belkheir Hammouti, Fadoua El-Hajjaji, Mustapha Taleb and Ayssar Nahle

The inhibition effect of Foeniculum vulgare seeds’ (FVS) extract on the corrosion of mild steel in acidic medium was studied using weight loss, electrochemical impedance…

Abstract

Purpose

The inhibition effect of Foeniculum vulgare seeds’ (FVS) extract on the corrosion of mild steel in acidic medium was studied using weight loss, electrochemical impedance spectroscopy and Tafel polarization, as well as the surface morphology of the mild steel.

Design/methodology/approach

Weight loss measurements, potentiodynamic tests, electrochemical impedance spectroscopy studies and gas chromatography/mass spectrometry and scanning electron microscopy analysis of FVS extract were performed.

Findings

FVS extract acts as a good inhibitor for the corrosion of mild steel in 1.0 M HCl. The inhibition efficiency increases with the increase in inhibitor concentration but decreases with the increase of temperature.

Practical implications

FVS extract was observed to play an important role in the corrosion inhibition of mild steel in acidic solution.

Originality/value

This paper is intended to be added to the family of green inhibitors which are highly efficient inhibitors and can be used in the area of corrosion prevention and control.

Details

Anti-Corrosion Methods and Materials, vol. 64 no. 5
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 4 July 2016

Moses M. Solomon, Saviour A. Umoren, Aniekemeabasi U. Israel and Idongesit G. Etim

The purpose of this paper is to evaluate the performance of polypropylene glycol (PPG), as a corrosion inhibitor for aluminium corrosion in 0.5 M H2SO4 solution at 303-333…

Abstract

Purpose

The purpose of this paper is to evaluate the performance of polypropylene glycol (PPG), as a corrosion inhibitor for aluminium corrosion in 0.5 M H2SO4 solution at 303-333 K and the effect of addition of iodide ions on the corrosion inhibition efficacy of PPG.

Design/methodology/approach

The corrosion inhibition performance of PPG alone and on addition of iodide ions in the acid medium was evaluated using weight loss and electrochemical [electrochemical impedance spectroscopy (EIS), linear polarisation resistance (LPR) and potentiodynamic polarization (PDP)] methods as well as surface analysis approach at 303-333 K. The morphology of the corroding aluminium surface without and with the additives was visualised using scanning electron microscopy (SEM). The trend of inhibition efficiency with temperature was used to propose the mechanism of inhibition and type of adsorption.

Findings

Results obtained showed that PPG moderately retarded the corrosion of Al in 0.5 M H2SO4 solution. Addition of KI to PPG is found to synergistically improve the inhibitive ability of PPG. From the variation of inhibition efficiency, K_ads, and E_a, with rise in temperature, physisorption mechanism is proposed for the adsorption of PPG and PPG + KI onto the Al surface in 0.5 M H2SO4 solution. Polarisation results showed that PPG and PPG + KI acted as mixed type inhibitor. The adsorption of PPG and PPG + KI, respectively, onto the metal surface followed El-Awady et al. adsorption isotherm model. SEM and water contact angle analysis confirmed the adsorption of PPG and PPG + KI on Al surface.

Research limitations/implications

The research is limited to aqueous acid environment in aerated condition, and all tests were performed under static conditions.

Practical implications

The use of PPG as corrosion inhibitor for Al corrosion in acidic medium were reported for the first time. The results suggest that iodide ions could be used to enhance corrosion protection ability of PPG which could find practical application in corrosion control in aqueous acidic environment. The data obtained would form part of database on the synergistic effect of iodide ions addition to polymer to control acid-induced corrosion of metal.

Originality/value

The use of PPG as corrosion inhibitor for Al corrosion in acidic medium were reported for the first time. The results suggest that iodide ions could be used to enhance corrosion protection ability of PPG which could find practical application in corrosion control in aqueous acidic environment. The data obtained would form part of database on the synergistic effect of iodide ions addition to polymer to control acid-induced corrosion of metal.

Details

Pigment & Resin Technology, vol. 45 no. 4
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 7 September 2015

Shabnam Ashhari and Ali Asghar Sarabi

– This paper aims to investigate the corrosion inhibition effects of indole-3-carbaldehyde and 2-methylindole on mild steel in 1 M HCl solution.

Abstract

Purpose

This paper aims to investigate the corrosion inhibition effects of indole-3-carbaldehyde and 2-methylindole on mild steel in 1 M HCl solution.

Design/methodology/approach

Indole-3-carbaldehyde and 2-methylindole as corrosion inhibitors of mild steel in 1 M HCl solution were investigated by polarisation and electrochemical impedance spectroscopy (EIS). Adsorption isotherm and mechanism were calculated. Quantum chemical calculations were used to find out a correlation between electronic structure of inhibitors and inhibition efficiency. Changes in the properties of metal surface in HCl solution in the presence of inhibitors were studied by contact angle measurements.

Findings

Polarisation results revealed inhibitors could reduce cathodic and anodic reactions rates on metal surface. EIS analysis showed that inhibition efficiency of indoles increases by increasing the inhibitors’ concentration; maximum inhibition efficiency was 95 and 94 per cent in solutions containing 1 mM indole-3-carbaldehyde and 2-methylindole, respectively. Inhibitors’ adsorptions on metal surface were confirmed by analysing the exposed metals’ surface through contact angles measurements. The adsorption of inhibitors was found to follow Langmuir isotherm. Quantum chemical calculations showed that a more positively charged benzene ring in the structure of two indole-based inhibitors would lead to higher adsorption to metal.

Originality/value

This research was carried out to understand the effects of two different functional groups (-C=O, -CH3) with different induction effects on the indole structure and on inhibition efficiency of corrosion inhibitors with the purpose of using these components in industrial application as acid wash solutions to etch and remove rusts from metal surfaces.

Details

Pigment & Resin Technology, vol. 44 no. 5
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 1 June 2015

Asiful Hossain Seikh and Mohammad Rezaul Karim

The purpose of this paper is to evaluate the effect of thiourea (TU) on corrosion resistance property for rolled and recrystallized E-34 microalloyed steels by using…

Abstract

Purpose

The purpose of this paper is to evaluate the effect of thiourea (TU) on corrosion resistance property for rolled and recrystallized E-34 microalloyed steels by using electrochemical polarization techniques.

Design/methodology/approach

To perceive the effect of TU on the corrosion inhibition efficiency, various concentrations of TU (from 1 × 10 − 4 to 1 × 10 − 2M) and different temperatures (20, 30 and 400°C) in 1N sulfuric acid are used.

Findings

It is found that TU has significant inhibition effect on corrosion process. Moreover, it reveals that both the inhibitor concentrations and temperatures have a strong influence on the corrosion prevention efficiency of inhibitor. Thermodynamics studies confirm that the inhibitor adsorption follows the Langmuir adsorption isotherm model.

Originality/value

To the best of the authors’ knowledge, it is the first work that has been disclosed the corrosion inhibitory effect of TU for recrystallized E-34 microalloyed steels in acidic media.

Details

Anti-Corrosion Methods and Materials, vol. 62 no. 4
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 9 February 2015

Ala Qatatsheh, Reema Tayyem, Islam Al-Shami, Murad A. Al-Holy and Abdallah S. Al-rethaia

This paper aims to assess the prevalence of vitamin D deficiency among female university students and employees at the Hashemite University (HU) and, then, to identify…

Abstract

Purpose

This paper aims to assess the prevalence of vitamin D deficiency among female university students and employees at the Hashemite University (HU) and, then, to identify risk factors for developing vitamin D deficiency among this population. Vitamin D deficiency remains widespread in many countries, including Jordan, and has been linked to many diseases.

Design/methodology/approach

In this cross-sectional study, blood samples were taken from 320 healthy females – 160 students and 160 employees – aged between 18 and 65 years old who presented for routine checkup at the medical center of HU. Level of direct sun exposure and barriers to getting enough sunlight (dress style, skin color and sunscreen use) were questioned. Serum levels of 25-hydroxyvitamin D were measured, and the daily intakes of vitamin D, calcium and phosphorous were estimated through completing an adopted food frequency questionnaire. All required data were collected using a face-to-face interview by trained dietitians. The software package ESHA was used to determine the daily intake from the nutrients.

Findings

The prevalence of vitamin D deficiency (25-OHD < 25 nmol/L) was 31.2 per cent in female students compared to 20.5 per cent in female employees. Prolonged exposure to sun was independently related to vitamin D deficiency (odds ratio = 4.55); participants exposed for 30 minutes daily were at a higher risk for vitamin D deficiency. However, estimated vitamin D intake was not affected by age and working status.

Research limitations/implications

The present study has some important limitations. First, this study based on serum 25-OHD results, which alone, without biochemical parameters such as parathyroid hormone (either primary or secondary), might be linked to accelerated degradation of 25-OHD and shorter half-life. Second, the half-life of 25-OHD was not consistently available. Third, the smaller sample size of participants. Finally, the present study did not distinguish between intake of vitamin D2 and D3. This limitation caused the inability to precisely evaluate the prevalence of vitamin D deficiency in the studied population.

Practical implications

This study indicates that it is crucial to create awareness concerning the daily intake of vitamin D in the community to avoid long-term complications related to vitamin D deficiency, by using urgent measures including vitamin D supplementation and fortification of some highly consumed food, milk and other dairy products. Educational endeavors about sensible sun exposure should be implemented to improve vitamin D status among this population. The findings of the present study call for action at the national level to build strategies for health promotion about vitamin D supplementation in groups at risk for low supplementation (e.g. younger female students, with previous chronic diseases and poor sun exposure), and engage these populations in strategizing for successful and demographically relevant outreach and education in their own communities along with effort to prevent obesity and diabetes as well as raising awareness through simple programs to prevent and treat vitamin D deficiency among women living in Jordan.

Originality/value

The high prevalence of vitamin D deficiency among female university students in this study emphasizes the necessity of vitamin D supplementation and calls for action to build strategies for health promotion concerning vitamin D supplementation.

Details

Nutrition & Food Science, vol. 45 no. 1
Type: Research Article
ISSN: 0034-6659

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Article
Publication date: 28 November 2019

Serdar Ulubeyli and Dilek Yorulmaz

The purpose of this paper is to report the possible impact of intellectual capital (IC) on firm reputation (FR) and investigates if there is a relationship between FR and…

Abstract

Purpose

The purpose of this paper is to report the possible impact of intellectual capital (IC) on firm reputation (FR) and investigates if there is a relationship between FR and market internationalization (MI).

Design/methodology/approach

The data were collected from engineering consultancy firms (ECFs) in Turkey. The study employed structural equation modeling to examine the hypothesized relationships between IC, FR, and MI of ECFs.

Findings

ECFs with strong human and structural capital can have a good FR. However, healthy relational capital may not lead to the same effect on FR. On the contrary, FR can create high-quality relational capital for ECFs. Lastly, a good FR, based on robust human and structural capital, can provide the success of ECFs’ MI process.

Research limitations/implications

This model may be analyzed for other knowledge-intensive business services. Also, subsequent researches may investigate potential variations in results about other sectors and geographical areas. Moreover, various constructs may be included in the model. However, a greater number of samples could lead to distinctive outcomes.

Practical implications

The research may be a general guide for related professionals and their companies to build long-term strategies, given IC, FR and MI. In this respect, they should take into account human and structural capital for MI.

Social implications

ECFs that can be active in the international arena may maintain their services by financial sustainability. Thus, the advantage may result in a prosperous society.

Originality/value

The study is first to suggest a model joining IC and FR for the MI process of ECFs. This is suitable for competition of ECFs that are willing to be sustainable firms.

Details

Journal of Intellectual Capital, vol. 21 no. 1
Type: Research Article
ISSN: 1469-1930

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Article
Publication date: 2 September 2019

Aziz Boutouil, My Rachid Laamari, Ilham Elazhary, Hafid Anane, Abdeslem Ben Tama and Salah-Eddine Stiriba

This study aims to investigate the inhibition effect of a newly synthesized1,2,3-triazole containing a carbohydrate and imidazole substituents, namely…

Abstract

Purpose

This study aims to investigate the inhibition effect of a newly synthesized1,2,3-triazole containing a carbohydrate and imidazole substituents, namely, 1-((1-((2,2,7,7-tetramethyltetrahydro-5H-bis([1,3]dioxolo)[4,5-b:4′,5′-d]pyran-5-yl)methyl)-1H-1,2,3-triazol-4-yl)methyl)-1H-benzo[d]imidazole (TTB) on the corrosion of mild steel in aerated 1 M H2SO4.

Design/methodology/approach

The authors have used weight loss measurement, potentiodynamic polarization, electrochemical impedance spectroscopy, FT-IR studies, scanning electron microscopy analysis and energy dispersive X-ray (EDX) spectroscopy techniques.

Findings

It is found that, in the working range of 298-328 K, the inhibition efficiency of TTB increases with increasing concentration to attain the highest value (92 per cent) at 2.5 × 10−3 M. Both chemisorption and physisorption of TTB take place on the mild steel, resulting in the formation of an inhibiting film. Computational methods point to the imidazole and phenyl ring as the main structural parts responsible of adsorption by electron-donating to the steel surface, while the triazol ring is responsible for the electron accepting. Such strong donating–accepting interactions lead to higher inhibition efficiency of TTB in the aqueous working system.

Originality/value

This work is original with the aim of finding new acid corrosion inhibitors.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 6
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 9 August 2019

Ilham Elazhary, My Rachid Laamari, Aziz Boutouil, Lahoucine Bahsis, Mohammadine El Haddad, Hafid Anane and Salah-Eddine Stiriba

This paper aims to study the corrosion inhibition of Methyl 2-(benzamido)-2-(4-phenyl-1H-1,2,3-triazol-1-yl) acetate (MBPTA) and Methyl…

Abstract

Purpose

This paper aims to study the corrosion inhibition of Methyl 2-(benzamido)-2-(4-phenyl-1H-1,2,3-triazol-1-yl) acetate (MBPTA) and Methyl 2-(benzamido)-2-(4-p-tolyl-1H-1,2,3-triazol-1-yl) acetate (MBTTA) in 1 M H2SO4 solution at 25 °C.

Design/methodology/approach

The authors have used weight loss measurements, electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, FT-IR, quantum chemical calculations and scanning electron microscopy (SEM) techniques.

Findings

The polarization measurements indicate that both compounds are mixed type inhibitors, and that MBTTA is more effective than MBPTA. The effect of temperature on the corrosion behavior using optimal concentration of MBTTA and MBPTA was studied in the temperature range 298-328 K. SEM was used to examine the morphology of the metal surface. Thermodynamic parameters were calculated and discussed. Monte Carlo simulations were applied to lookup for the most stalls configuration and adsorption energy for the interaction of inhibitors on Fe (1 1 1) interface. The difference in inhibition efficiencies between the two organic inhibitors can be clearly explained in terms of frontier molecular orbital theory.

Originality/value

The authors report on the comparative inhibiting effect of two new 1,4-disubstituted 1,2,3-triazoles, namely Methyl 2-(benzamido)-2-(4-phenyl-1H-1,2,3-triazol-1-yl) acetate (MBPTA) and Methyl 2-(benzamido)-2-(4-p-tolyl-1H-1, 2, 3-triazol-1-yl) acetate (MBTTA) on mild steel corrosion in 1 M H2SO4 solution.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

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