Shabnam Ashhari - Academia.edu (original) (raw)

Papers by Shabnam Ashhari

Nanomaterial-Based Antibacterial and Antiviral Thin Film Coatings

Acs Symposium Series, Dec 12, 2023

Journal of Coatings Technology and Research, 2015

The MnAl 2 O 4 and CoAl 2 O 4 nanopigments were synthesized through solution combustion method. T... more The MnAl 2 O 4 and CoAl 2 O 4 nanopigments were synthesized through solution combustion method. The nanopigments extracts in the 3.5 wt% NaCl solution were prepared. Electrochemical impedance spectroscopy (EIS) and linear polarization (LP) techniques were utilized to investigate the corrosion inhibition properties of the pigments in the solutions containing pigments extracts. The epoxy nanocomposites were prepared and applied on the aluminum specimens. EIS and pull-off measurements were performed to characterize the corrosion protection properties of the epoxy nanocomposites. It was revealed that the MnAl 2 O 4 pigment showed higher corrosion inhibition properties than CoAl 2 O 4 in the solution phase. In addition, MnAl 2 O 4 enhanced the corrosion resistance and decreased the adhesion loss of the epoxy coating on the aluminum substrate significantly. The MnAl 2 O 4 nanopigment improved the corrosion resistance of the epoxy coating through increasing the barrier performance and releasing inhibitive species.

A r c h i v e o f S I D Study of Anticorrosive Behavior of a Gemini Cationic Surfactant and Its Monomeric Counterpart on Mild Steel in Hydrochloric Acid During Immersion Time

ABSTRACT

Polymer nanocomposite films and coatings in aerospace applications

Elsevier eBooks, 2024

Evaluation of Corrosion Inhibition of Mercapto Functional Compounds for Mild Steel in 1M Hydrochloric Acid Solution During Immersion Time

... Corros. Sci. 51(2009), 409-414. 15. R. Naderi, M. Mahdavian, MM Attar, Electrochemicalbehavio... more ... Corros. Sci. 51(2009), 409-414. 15. R. Naderi, M. Mahdavian, MM Attar, Electrochemicalbehavior of organic and inorganic complexes of Zn(II) as corrosion inhibitors for mild steel:Solution phase study. Electrochim. Acta. 54(2009), 6892-6895. 16. ...

Indole-3-carbaldehyde and 2-methylindole as corrosion inhibitors of mild steel during pickling

Pigment & Resin Technology, Sep 7, 2015

Corrosion Science, Jun 1, 2018

The effect of some phosphonic acid derivatives on the corrosion behaviour of carbon steel has bee... more The effect of some phosphonic acid derivatives on the corrosion behaviour of carbon steel has been investigated in hydrochloric acid solutions by gravimetric and electrochemical methods. Some phosphonic acids were found to have inhibitive effects. These effects depend on the molecular structure: on the number of nitrogen atoms and of phosphono groups, but mainly on their position in the molecules, as shown by the differences in corrosion rate in the presence of various phosphonic acids. The variation of polarisation resistance with time suggests that the inhibitive action of diethylenetriaminepentamethylenephosphonic acid depends mainly on the protective inhibitor film formed on the surface of the steel and is independent of changes in solution composition with time.

Polyurethane-clay nanocomposites were prepared by applying high-intensity ultrasound during the s... more Polyurethane-clay nanocomposites were prepared by applying high-intensity ultrasound during the synthesis of clay-urethane nanocomposites. In this article, rheological measurements along with turbidimetry, optical microscopy, X ray diffraction (XRD) and Transmission electron microscope (TEM) analyses were carried out. The results of XRD showed that the distances between silicate layers of clay reached to 41 A 0 in the polymeric matrix. Results showed that nanocomposites had higher dynamic moduli, and solid like behavior in comparison to that of neat polyurethane. The strong increase in modulus of nanocomposites was due to the intercalated and dispersed silicate platelets. The increase rate in storage modulus of these composites decreased at higher organoclay loadings and was not linear. Also, the sample that contained 5% organic clay showed a shear thinning behavior at low frequencies. By using the results of XRD, optical microscopy and rheometery analysis, the state of dispersion and optimum percent of clay that has the best dispersion state were obtained.

Anticorrosive property of a gemini cationic surfactant (12-4-12) and its monomeric counterpart, d... more Anticorrosive property of a gemini cationic surfactant (12-4-12) and its monomeric counterpart, dodecyl trimethyl ammonium bromide (DTAB), on mild steel in 1M hydrochloric acid solution was investigated by electrochemical impedance spectroscopy (EIS). The results revealed the corrosion inhibition effect of these two surfactants on mild steel in acidic solution. It was observed that by increasing the immersion time in test solutions, corrosion resistance of mild steel increased, reaching a constant value after 2 h and 4 h immersions for 12-4-12 and DTAB, respectively. The monomeric surfactant, DTAB, had better corrosion inhibition effect compared to 12-4-12. The lower performance of 12-4-12 could be related to steric hindrance of the free head group. J. Color Sci. Tech. 4

Surface and Interface Analysis, Dec 7, 2014

Corrosion inhibition of indole-3-acetic acid and N-acetyl tryptophan on carbon steel was investig... more Corrosion inhibition of indole-3-acetic acid and N-acetyl tryptophan on carbon steel was investigated using polarization and electrochemical impedance spectroscopy (EIS). Polarization results revealed that corrosion inhibitors could reduce the rate of cathodic and anodic reactions on metal surface. EIS analysis showed inhibition efficiency of indoles increases by increasing the inhibitor concentration. The maximum inhibition efficiency was 97% and 80% in solutions containing 10 mM indole-3-acetic acid and 10 mM N-acetyl tryptophan, respectively. The adsorption of inhibitors was found to follow Langmuir isotherm. Adsorption and film formation of inhibitors on the metal substrate were confirmed by calculating thermodynamic adsorption parameter (ΔG 0 ads) and characterization of exposed metals' surface through contact angle measurements.

Effects of organically modified nanoclay particles on the mechanical properties of aliphatic polyurethane/clay nanocomposite coatings

Polymer Composites, Jul 17, 2015

Nano clay particles were modified organically by indole‐3‐carbaldehyde and indole‐3‐acetic acid w... more Nano clay particles were modified organically by indole‐3‐carbaldehyde and indole‐3‐acetic acid with the purpose of preparing aliphatic polyurethane nanocomposite coatings. X‐ray diffraction (XRD), thermogravimetric analysis, and Fourier transform infrared spectroscopy (FTIR) analysis confirmed the ion exchange through the silicate layer of nano clay particles. XRD result showed about 5 A° increment in the distance of silicate layers. Transmission electron microscopic images showed good dispersion of modified nanoparticles in polymeric matrix. Mechanical properties of nanocomposites were evaluated using dynamic thermal analysis and tensile techniques. Results illustrated that nanocomposite coatings have higher toughness property and lower brittleness due to the proper nanoparticles dispersion. Morphology of the fractured surface of free films was examined by preparing scanning electron microscopic images; less ruptures and more roughness in the fractured surface of nano composites in comparison to the polyurethane‐free films have been proven. POLYM. COMPOS., 38:1167–1174, 2017. © 2015 Society of Plastics Engineers

Progress in Color, Colorants and Coatings, Jun 8, 2013

n this study, a series of epoxy/silica nanocomposites were prepared by using nano silica particle... more n this study, a series of epoxy/silica nanocomposites were prepared by using nano silica particles which had different surface modifications. The morphology of the nanocomposite coatings was characterized by scanning electron microscopy (SEM). The effects of the hydrophilic and hydrophobic feature of the nano particles on the T g and anticorrosive properties of nanocomposite coatings were evaluated by DSC and EIS instruments. It was observed that the presence of the hydrophobic nano silica particles affected the curing and cross linking density of the organic coatings and consequently reduction in corrosion resistance of nanocomposite coatings. On the other hand, hydrophilic nano composite coatings showed better corrosion resistance even after 60 days immersion in 3.5% NaCl solution in comparison to pure epoxy coating.

Polyurethane-clay nanocomposites were prepared by applying high-intensity ultrasound during the s... more Polyurethane-clay nanocomposites were prepared by applying high-intensity ultrasound during the synthesis of clay-urethane nanocomposites. In this article, rheological measurements along with turbidimetry, optical microscopy, X ray diffraction (XRD) and Transmission electron microscope (TEM) analyses were carried out. The results of XRD showed that the distances between silicate layers of clay reached to 41 A 0 in the polymeric matrix. Results showed that nanocomposites had higher dynamic moduli, and solid like behavior in comparison to that of neat polyurethane. The strong increase in modulus of nanocomposites was due to the intercalated and dispersed silicate platelets. The increase rate in storage modulus of these composites decreased at higher organoclay loadings and was not linear. Also, the sample that contained 5% organic clay showed a shear thinning behavior at low frequencies. By using the results of XRD, optical microscopy and rheometery analysis, the state of dispersion and optimum percent of clay that has the best dispersion state were obtained.

Progress in Organic Coatings, 2017

For preparing epoxy based thermal insulations three types of hollow glass microspheres with diffe... more For preparing epoxy based thermal insulations three types of hollow glass microspheres with different particle sizes 70, 115, and 170 μm were used. Thermal conductivity of coatings in the absence and presence of hollow spheres were evaluated. Thermal conductivity of microsphere containing insulations was found to be much less than epoxy coatings. Hollow spheres with 170 μm diameter showed better insulating properties. Epoxy thermal insulations were exposed to accelerated cyclic corrosion test conditions, and then corrosion resistance reduction of coatings was evaluated by electrochemical impedance spectroscopy. Results showed that microspheres can not only improve insulating properties but also raising corrosion protection features of epoxy coating during 37 days of exposure to cyclic corrosion conditions. Impedance modulus at low frequency (0.01 Hz) of 170 μm hollow sphere containing epoxy coatings were 1.10 and 530 ohm cm2 after 37 days, respectively.

Surface and Interface Analysis, 2014

Corrosion inhibition of indole-3-acetic acid and N-acetyl tryptophan on carbon steel was investig... more Corrosion inhibition of indole-3-acetic acid and N-acetyl tryptophan on carbon steel was investigated using polarization and electrochemical impedance spectroscopy (EIS). Polarization results revealed that corrosion inhibitors could reduce the rate of cathodic and anodic reactions on metal surface. EIS analysis showed inhibition efficiency of indoles increases by increasing the inhibitor concentration. The maximum inhibition efficiency was 97% and 80% in solutions containing 10 mM indole-3-acetic acid and 10 mM N-acetyl tryptophan, respectively. The adsorption of inhibitors was found to follow Langmuir isotherm. Adsorption and film formation of inhibitors on the metal substrate were confirmed by calculating thermodynamic adsorption parameter (ΔG 0 ads) and characterization of exposed metals' surface through contact angle measurements.

Effects of organically modified nanoclay particles on the mechanical properties of aliphatic polyurethane/clay nanocomposite coatings

Polymer Composites, 2015

Nano clay particles were modified organically by indole‐3‐carbaldehyde and indole‐3‐acetic acid w... more Nano clay particles were modified organically by indole‐3‐carbaldehyde and indole‐3‐acetic acid with the purpose of preparing aliphatic polyurethane nanocomposite coatings. X‐ray diffraction (XRD), thermogravimetric analysis, and Fourier transform infrared spectroscopy (FTIR) analysis confirmed the ion exchange through the silicate layer of nano clay particles. XRD result showed about 5 A° increment in the distance of silicate layers. Transmission electron microscopic images showed good dispersion of modified nanoparticles in polymeric matrix. Mechanical properties of nanocomposites were evaluated using dynamic thermal analysis and tensile techniques. Results illustrated that nanocomposite coatings have higher toughness property and lower brittleness due to the proper nanoparticles dispersion. Morphology of the fractured surface of free films was examined by preparing scanning electron microscopic images; less ruptures and more roughness in the fractured surface of nano composites i...

Indole-3-carbaldehyde and 2-methylindole as corrosion inhibitors of mild steel during pickling

Pigment & Resin Technology, 2015

Purpose– This paper aims to investigate the corrosion inhibition effects of indole-3-carbaldehyde... more 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 in...

Mercapto functional azole compounds as organic corrosion inhibitors in a polyester-melamine coating

Progress in Organic Coatings, 2010

... Two mercapto functional azole compounds including 2-mercaptobenzimidazole (MBI) and2-mercapto... more ... Two mercapto functional azole compounds including 2-mercaptobenzimidazole (MBI) and2-mercaptobenzoxazole (MBO) were ... in different frontier orbital energies, dipole moment, atomic charges [17] which consequently affects their corrosion inhibition performance. ...

Aliphatic polyurethane-montmorillonite nanocomposite coatings: Preparation, characterization, and anticorrosive properties

Journal of Applied Polymer Science, 2010

... Aliphatic polyurethane–montmorillonite nanocomposite coatings: Preparation, characterization,... more ... Aliphatic polyurethane–montmorillonite nanocomposite coatings: Preparation, characterization, and anticorrosive properties. Shabnam Ashhari,; Ali Asghar Sarabi,; Seyed Mahmoud Kasiriha,; Davood Zaarei. ... S.; Samui, AB; Chakraborty, BC; Banthia, AK Polymer 2006, 47, 4068. ...

Electrochimica Acta, 2010

The effect of some mercapto functional azole compounds on the corrosion of mild steel in 1 M hydr... more The effect of some mercapto functional azole compounds on the corrosion of mild steel in 1 M hydrochloric acid solution was studied by polarization and electrochemical impedance spectroscopy (EIS). Polarization studies showed depression of cathodic and anodic polarization curves in the presence of mercapto functional azole compounds, indicating mixed type corrosion inhibition of the compounds. Double layer capacitance and charge transfer resistance values were derived from EIS results. Changes in impedance parameters are indicative of adsorption of these compounds on the metal surface. Surface analysis SEM/EDX showing presence of sulfur on the surface confirmed the adsorption of the azole compounds on the mild steel surface as showed by electrochemical methods. Both compounds contain a pyridine-like nitrogen atom and a sulfur atom in their molecular structure, while they differ in only one heteroatom: oxygen in the oxazole ring and pyrrole-like nitrogen in the imidazole ring. The results of the electrochemical techniques revealed that changing the pyrrole like nitrogen atom to oxygen atom in the azole ring results in a decrease of corrosion inhibition performance in hydrochloric acid solution, which could be related to more negative charge on pyrrole-like nitrogen atom in comparison to oxygen atom as depicted by quantum chemical calculations.

Nanomaterial-Based Antibacterial and Antiviral Thin Film Coatings

Acs Symposium Series, Dec 12, 2023

Journal of Coatings Technology and Research, 2015

The MnAl 2 O 4 and CoAl 2 O 4 nanopigments were synthesized through solution combustion method. T... more The MnAl 2 O 4 and CoAl 2 O 4 nanopigments were synthesized through solution combustion method. The nanopigments extracts in the 3.5 wt% NaCl solution were prepared. Electrochemical impedance spectroscopy (EIS) and linear polarization (LP) techniques were utilized to investigate the corrosion inhibition properties of the pigments in the solutions containing pigments extracts. The epoxy nanocomposites were prepared and applied on the aluminum specimens. EIS and pull-off measurements were performed to characterize the corrosion protection properties of the epoxy nanocomposites. It was revealed that the MnAl 2 O 4 pigment showed higher corrosion inhibition properties than CoAl 2 O 4 in the solution phase. In addition, MnAl 2 O 4 enhanced the corrosion resistance and decreased the adhesion loss of the epoxy coating on the aluminum substrate significantly. The MnAl 2 O 4 nanopigment improved the corrosion resistance of the epoxy coating through increasing the barrier performance and releasing inhibitive species.

A r c h i v e o f S I D Study of Anticorrosive Behavior of a Gemini Cationic Surfactant and Its Monomeric Counterpart on Mild Steel in Hydrochloric Acid During Immersion Time

ABSTRACT

Polymer nanocomposite films and coatings in aerospace applications

Elsevier eBooks, 2024

Evaluation of Corrosion Inhibition of Mercapto Functional Compounds for Mild Steel in 1M Hydrochloric Acid Solution During Immersion Time

... Corros. Sci. 51(2009), 409-414. 15. R. Naderi, M. Mahdavian, MM Attar, Electrochemicalbehavio... more ... Corros. Sci. 51(2009), 409-414. 15. R. Naderi, M. Mahdavian, MM Attar, Electrochemicalbehavior of organic and inorganic complexes of Zn(II) as corrosion inhibitors for mild steel:Solution phase study. Electrochim. Acta. 54(2009), 6892-6895. 16. ...

Indole-3-carbaldehyde and 2-methylindole as corrosion inhibitors of mild steel during pickling

Pigment & Resin Technology, Sep 7, 2015

Corrosion Science, Jun 1, 2018

The effect of some phosphonic acid derivatives on the corrosion behaviour of carbon steel has bee... more The effect of some phosphonic acid derivatives on the corrosion behaviour of carbon steel has been investigated in hydrochloric acid solutions by gravimetric and electrochemical methods. Some phosphonic acids were found to have inhibitive effects. These effects depend on the molecular structure: on the number of nitrogen atoms and of phosphono groups, but mainly on their position in the molecules, as shown by the differences in corrosion rate in the presence of various phosphonic acids. The variation of polarisation resistance with time suggests that the inhibitive action of diethylenetriaminepentamethylenephosphonic acid depends mainly on the protective inhibitor film formed on the surface of the steel and is independent of changes in solution composition with time.

Polyurethane-clay nanocomposites were prepared by applying high-intensity ultrasound during the s... more Polyurethane-clay nanocomposites were prepared by applying high-intensity ultrasound during the synthesis of clay-urethane nanocomposites. In this article, rheological measurements along with turbidimetry, optical microscopy, X ray diffraction (XRD) and Transmission electron microscope (TEM) analyses were carried out. The results of XRD showed that the distances between silicate layers of clay reached to 41 A 0 in the polymeric matrix. Results showed that nanocomposites had higher dynamic moduli, and solid like behavior in comparison to that of neat polyurethane. The strong increase in modulus of nanocomposites was due to the intercalated and dispersed silicate platelets. The increase rate in storage modulus of these composites decreased at higher organoclay loadings and was not linear. Also, the sample that contained 5% organic clay showed a shear thinning behavior at low frequencies. By using the results of XRD, optical microscopy and rheometery analysis, the state of dispersion and optimum percent of clay that has the best dispersion state were obtained.

Anticorrosive property of a gemini cationic surfactant (12-4-12) and its monomeric counterpart, d... more Anticorrosive property of a gemini cationic surfactant (12-4-12) and its monomeric counterpart, dodecyl trimethyl ammonium bromide (DTAB), on mild steel in 1M hydrochloric acid solution was investigated by electrochemical impedance spectroscopy (EIS). The results revealed the corrosion inhibition effect of these two surfactants on mild steel in acidic solution. It was observed that by increasing the immersion time in test solutions, corrosion resistance of mild steel increased, reaching a constant value after 2 h and 4 h immersions for 12-4-12 and DTAB, respectively. The monomeric surfactant, DTAB, had better corrosion inhibition effect compared to 12-4-12. The lower performance of 12-4-12 could be related to steric hindrance of the free head group. J. Color Sci. Tech. 4

Surface and Interface Analysis, Dec 7, 2014

Corrosion inhibition of indole-3-acetic acid and N-acetyl tryptophan on carbon steel was investig... more Corrosion inhibition of indole-3-acetic acid and N-acetyl tryptophan on carbon steel was investigated using polarization and electrochemical impedance spectroscopy (EIS). Polarization results revealed that corrosion inhibitors could reduce the rate of cathodic and anodic reactions on metal surface. EIS analysis showed inhibition efficiency of indoles increases by increasing the inhibitor concentration. The maximum inhibition efficiency was 97% and 80% in solutions containing 10 mM indole-3-acetic acid and 10 mM N-acetyl tryptophan, respectively. The adsorption of inhibitors was found to follow Langmuir isotherm. Adsorption and film formation of inhibitors on the metal substrate were confirmed by calculating thermodynamic adsorption parameter (ΔG 0 ads) and characterization of exposed metals' surface through contact angle measurements.

Effects of organically modified nanoclay particles on the mechanical properties of aliphatic polyurethane/clay nanocomposite coatings

Polymer Composites, Jul 17, 2015

Nano clay particles were modified organically by indole‐3‐carbaldehyde and indole‐3‐acetic acid w... more Nano clay particles were modified organically by indole‐3‐carbaldehyde and indole‐3‐acetic acid with the purpose of preparing aliphatic polyurethane nanocomposite coatings. X‐ray diffraction (XRD), thermogravimetric analysis, and Fourier transform infrared spectroscopy (FTIR) analysis confirmed the ion exchange through the silicate layer of nano clay particles. XRD result showed about 5 A° increment in the distance of silicate layers. Transmission electron microscopic images showed good dispersion of modified nanoparticles in polymeric matrix. Mechanical properties of nanocomposites were evaluated using dynamic thermal analysis and tensile techniques. Results illustrated that nanocomposite coatings have higher toughness property and lower brittleness due to the proper nanoparticles dispersion. Morphology of the fractured surface of free films was examined by preparing scanning electron microscopic images; less ruptures and more roughness in the fractured surface of nano composites in comparison to the polyurethane‐free films have been proven. POLYM. COMPOS., 38:1167–1174, 2017. © 2015 Society of Plastics Engineers

Progress in Color, Colorants and Coatings, Jun 8, 2013

n this study, a series of epoxy/silica nanocomposites were prepared by using nano silica particle... more n this study, a series of epoxy/silica nanocomposites were prepared by using nano silica particles which had different surface modifications. The morphology of the nanocomposite coatings was characterized by scanning electron microscopy (SEM). The effects of the hydrophilic and hydrophobic feature of the nano particles on the T g and anticorrosive properties of nanocomposite coatings were evaluated by DSC and EIS instruments. It was observed that the presence of the hydrophobic nano silica particles affected the curing and cross linking density of the organic coatings and consequently reduction in corrosion resistance of nanocomposite coatings. On the other hand, hydrophilic nano composite coatings showed better corrosion resistance even after 60 days immersion in 3.5% NaCl solution in comparison to pure epoxy coating.

Polyurethane-clay nanocomposites were prepared by applying high-intensity ultrasound during the s... more Polyurethane-clay nanocomposites were prepared by applying high-intensity ultrasound during the synthesis of clay-urethane nanocomposites. In this article, rheological measurements along with turbidimetry, optical microscopy, X ray diffraction (XRD) and Transmission electron microscope (TEM) analyses were carried out. The results of XRD showed that the distances between silicate layers of clay reached to 41 A 0 in the polymeric matrix. Results showed that nanocomposites had higher dynamic moduli, and solid like behavior in comparison to that of neat polyurethane. The strong increase in modulus of nanocomposites was due to the intercalated and dispersed silicate platelets. The increase rate in storage modulus of these composites decreased at higher organoclay loadings and was not linear. Also, the sample that contained 5% organic clay showed a shear thinning behavior at low frequencies. By using the results of XRD, optical microscopy and rheometery analysis, the state of dispersion and optimum percent of clay that has the best dispersion state were obtained.

Progress in Organic Coatings, 2017

For preparing epoxy based thermal insulations three types of hollow glass microspheres with diffe... more For preparing epoxy based thermal insulations three types of hollow glass microspheres with different particle sizes 70, 115, and 170 μm were used. Thermal conductivity of coatings in the absence and presence of hollow spheres were evaluated. Thermal conductivity of microsphere containing insulations was found to be much less than epoxy coatings. Hollow spheres with 170 μm diameter showed better insulating properties. Epoxy thermal insulations were exposed to accelerated cyclic corrosion test conditions, and then corrosion resistance reduction of coatings was evaluated by electrochemical impedance spectroscopy. Results showed that microspheres can not only improve insulating properties but also raising corrosion protection features of epoxy coating during 37 days of exposure to cyclic corrosion conditions. Impedance modulus at low frequency (0.01 Hz) of 170 μm hollow sphere containing epoxy coatings were 1.10 and 530 ohm cm2 after 37 days, respectively.

Surface and Interface Analysis, 2014

Corrosion inhibition of indole-3-acetic acid and N-acetyl tryptophan on carbon steel was investig... more Corrosion inhibition of indole-3-acetic acid and N-acetyl tryptophan on carbon steel was investigated using polarization and electrochemical impedance spectroscopy (EIS). Polarization results revealed that corrosion inhibitors could reduce the rate of cathodic and anodic reactions on metal surface. EIS analysis showed inhibition efficiency of indoles increases by increasing the inhibitor concentration. The maximum inhibition efficiency was 97% and 80% in solutions containing 10 mM indole-3-acetic acid and 10 mM N-acetyl tryptophan, respectively. The adsorption of inhibitors was found to follow Langmuir isotherm. Adsorption and film formation of inhibitors on the metal substrate were confirmed by calculating thermodynamic adsorption parameter (ΔG 0 ads) and characterization of exposed metals' surface through contact angle measurements.

Effects of organically modified nanoclay particles on the mechanical properties of aliphatic polyurethane/clay nanocomposite coatings

Polymer Composites, 2015

Nano clay particles were modified organically by indole‐3‐carbaldehyde and indole‐3‐acetic acid w... more Nano clay particles were modified organically by indole‐3‐carbaldehyde and indole‐3‐acetic acid with the purpose of preparing aliphatic polyurethane nanocomposite coatings. X‐ray diffraction (XRD), thermogravimetric analysis, and Fourier transform infrared spectroscopy (FTIR) analysis confirmed the ion exchange through the silicate layer of nano clay particles. XRD result showed about 5 A° increment in the distance of silicate layers. Transmission electron microscopic images showed good dispersion of modified nanoparticles in polymeric matrix. Mechanical properties of nanocomposites were evaluated using dynamic thermal analysis and tensile techniques. Results illustrated that nanocomposite coatings have higher toughness property and lower brittleness due to the proper nanoparticles dispersion. Morphology of the fractured surface of free films was examined by preparing scanning electron microscopic images; less ruptures and more roughness in the fractured surface of nano composites i...

Indole-3-carbaldehyde and 2-methylindole as corrosion inhibitors of mild steel during pickling

Pigment & Resin Technology, 2015

Purpose– This paper aims to investigate the corrosion inhibition effects of indole-3-carbaldehyde... more 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 in...

Mercapto functional azole compounds as organic corrosion inhibitors in a polyester-melamine coating

Progress in Organic Coatings, 2010

... Two mercapto functional azole compounds including 2-mercaptobenzimidazole (MBI) and2-mercapto... more ... Two mercapto functional azole compounds including 2-mercaptobenzimidazole (MBI) and2-mercaptobenzoxazole (MBO) were ... in different frontier orbital energies, dipole moment, atomic charges [17] which consequently affects their corrosion inhibition performance. ...

Aliphatic polyurethane-montmorillonite nanocomposite coatings: Preparation, characterization, and anticorrosive properties

Journal of Applied Polymer Science, 2010

... Aliphatic polyurethane–montmorillonite nanocomposite coatings: Preparation, characterization,... more ... Aliphatic polyurethane–montmorillonite nanocomposite coatings: Preparation, characterization, and anticorrosive properties. Shabnam Ashhari,; Ali Asghar Sarabi,; Seyed Mahmoud Kasiriha,; Davood Zaarei. ... S.; Samui, AB; Chakraborty, BC; Banthia, AK Polymer 2006, 47, 4068. ...

Electrochimica Acta, 2010

The effect of some mercapto functional azole compounds on the corrosion of mild steel in 1 M hydr... more The effect of some mercapto functional azole compounds on the corrosion of mild steel in 1 M hydrochloric acid solution was studied by polarization and electrochemical impedance spectroscopy (EIS). Polarization studies showed depression of cathodic and anodic polarization curves in the presence of mercapto functional azole compounds, indicating mixed type corrosion inhibition of the compounds. Double layer capacitance and charge transfer resistance values were derived from EIS results. Changes in impedance parameters are indicative of adsorption of these compounds on the metal surface. Surface analysis SEM/EDX showing presence of sulfur on the surface confirmed the adsorption of the azole compounds on the mild steel surface as showed by electrochemical methods. Both compounds contain a pyridine-like nitrogen atom and a sulfur atom in their molecular structure, while they differ in only one heteroatom: oxygen in the oxazole ring and pyrrole-like nitrogen in the imidazole ring. The results of the electrochemical techniques revealed that changing the pyrrole like nitrogen atom to oxygen atom in the azole ring results in a decrease of corrosion inhibition performance in hydrochloric acid solution, which could be related to more negative charge on pyrrole-like nitrogen atom in comparison to oxygen atom as depicted by quantum chemical calculations.