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11 – 20 of 34Xianghong Lv, Guoxian Zhao, Fuxiang Zhang, Xiang Tong Yang, Dan Ba, Junfeng Xie and Yan Xue
The purpose of this investigation was to study the function mechanisms of a corrosion inhibitor package used for martensitic stainless steel tubulars in acid solution at high…
Abstract
Purpose
The purpose of this investigation was to study the function mechanisms of a corrosion inhibitor package used for martensitic stainless steel tubulars in acid solution at high temperatures.
Design/methodology/approach
The inhibition performance was evaluated by means of an acid corrosion test at high temperature and high pressure, and the functional mechanism of the inhibitor package at different temperatures was investigated using polarization curve and electrochemical impedance spectroscopy measurements.
Findings
The results showed that the corrosion inhibitor package chosen for high-temperature and high-pressure gas well applications was very suitable for use with 13Cr super martensitic stainless steel. At lower temperatures, the function mechanism of the corrosion inhibitor package was characterized as a type of negative catalytic effect. As the temperature was increased, the effect of the intensifier in the package became more significant and the function mechanism changed to be the geometric covering effect type.
Originality/value
This study has the important practical value for guiding the oil field to conduct reasonable screening and using the acidizing corrosion inhibitor for martensite stainless steel tubulars.
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The purpose of this study is to use polybenzoxazine (Pbz) functionalized ZrO2 nanoparticles to synthesize polyurethane (PU)-PbZ/ZrO2 nanocomposite. The results derived from the…
Abstract
Purpose
The purpose of this study is to use polybenzoxazine (Pbz) functionalized ZrO2 nanoparticles to synthesize polyurethane (PU)-PbZ/ZrO2 nanocomposite. The results derived from the electrochemical impedance spectroscopy (EIS) and polarization studies indicated the superior anticorrosive activity of PU-Pbz/ZrO2 nanocomposite coatings compared to those of plain PU coatings. The decreased corrosion current was detected on the scratch of the PU-Pbz/ZrO2 nanocomposite-coated mild steel surface by scanning electrochemical microscopy (SECM) compared to other studied coatings. The superior anticorrosive and mechanical properties of the proposed nanocomposite coatings provide a new horizon in the development of high-performance anticorrosive coatings for various industries.
Design/methodology/approach
The Pbz functionalized ZrO2 nanoparticles were characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX) and thermogravimetric analysis (TGA) in terms of the structural, morphological and thermal properties of these coatings. A different formulation of coatings such as PU, PU-Pbz, PU-ZrO2 and PU-Pbz/ZrO2 were prepared and investigated for their corrosion protection performance on mild steel in natural seawater by electrochemical techniques. The surface morphological studies were done by SEM/EDX and XRD analysis.
Findings
The superior anticorrosive property of the proposed nanocomposite coatings provides a new horizon in the development of high-performance anticorrosive coatings for various industries. Addition of Pbz wrapped ZrO2 nanoparticles into the PU coating resulted in the blockage of charge transfer at the metal/electrolyte interface, which reduced the dissolution of mild steel. It was revealed from the SEM/EDX analysis that the formation of the corrosion products at the metal/electrolyte interface behaved as the passive layer which reduced the dissolution of steel.
Originality/value
The inclusion of polybenzoxazine functionalized ZrO2 nanoparticles to the polyurethane coating reinforces the barrier and mechanical properties of PU-Pbz/ZrO2 nanocomposite, which is due to the synergistic effect of ZrO2 and Pbz.
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This study aims to the synthesis of some novel 4-arylazo-3-hydroxythiophene analogues containing sulphapyridine and sulphathiazole dyestuffs and studying their application in…
Abstract
Purpose
This study aims to the synthesis of some novel 4-arylazo-3-hydroxythiophene analogues containing sulphapyridine and sulphathiazole dyestuffs and studying their application in dyeing polyester fabrics and rendering their antibacterial efficacy.
Design/methodology/approach
Simultaneous dyeing and antibacterial finishing for polyester fabric using a new antibacterial disperse dye having a modified chemical structure to thiophene dyes were studied. Construction of the thiophene dyes was carried out by diazo-coupling of diazotized sulphonamide-containing heterocyclic rings sulphapyridine and sulphathiazole with ethyl α-phenylthiocarbamoyl-acetoacetate followed by cyclizing the produced 2-arylazo-thioacetanilide with various α-halogenated reagents. All newly synthesized compounds were characterized by elemental analysis and extensive study of their spectral data (IR and 1H-NMR). The dyeing characteristics of these thiophene dyestuffs were evaluated at optimum conditions. Antibacterial activities of the obtained thiophene dyes were studied against some Gram-positive and Gram-negative bacteria.
Findings
The synthesized thiophene-containing sulphonamides dyes were applied on polyester fabric. The modified dyes exhibited a good fastness properties and antibacterial efficacy against some Gram-positive and Gram-negative bacteria. Synthesized dyes showed higher antibacterial potency than the reference standard drug.
Research limitations/implications
Synthesis of these disperse azo dyes for textile dyeing had never been reported previously.
Practical implications
The dyestuffs derived from thiophene are reasonable azo disperse dyestuffs giving good all-round fastness properties on polyester fabrics.
Originality/value
Thiophene dyes are used for dyeing polyester fabrics with brilliant colour and good fastness properties. The presence of sulphonamides moieties increase their fastness properties and elevate their antibacterial properties. Moreover, they can be used as antimicrobial finish due to their bactericidal properties on dyed textiles. This work afforded a new thiophene colorant that can be used in many different uses like polyester packing, thread Surgery, blends and other uses in medical textile.
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Kunal Wazarkar and Anagha S. Sabnis
The purpose of this study is to synthesize structurally different phenalkamines based on cardanol, a renewable material obtained from cashew nut shell liquid, and to evaluate…
Abstract
Purpose
The purpose of this study is to synthesize structurally different phenalkamines based on cardanol, a renewable material obtained from cashew nut shell liquid, and to evaluate their effect on performance properties of the coatings.
Design/methodology/approach
For this purpose, the Mannich reaction between cardanol, formaldehyde and various diamines such as diaminodiphenyl methane (DDM), hexamethylene diamine, Jeffamine D400 and Jeffamine T403 were carried out to produce novel phenalkamines. Resultant phenalkamines were used as curing agents for commercial DGEBPA epoxy resin and were evaluated for performance properties.
Findings
The mechanical, optical, chemical, thermal and anticorrosive properties were evaluated and compared with those of commercial phenalkamine AG141. It was observed that anticorrosive properties evaluated using a salt spray test and electrochemical impedance spectroscopy revealed significant improvement in anticorrosive performance of coatings cured with synthesized phenalkamines based on DDM and T403 as compared to the coatings based on commercial phenalkamine AG141.
Research limitations/implications
To obtain optimum performance properties of the coatings, a combination of phenalkamines can be used.
Practical implications
Curing time and gel times of all the phenalkamines can be further studied under wet and humid conditions. In addition, the variation in coating properties under humid conditions can be investigated.
Originality/value
In this study, newer phenalkamines were synthesized and used as curing agents for epoxy coatings. So far, there have been no reports indicating the synthesis and application of phenalkamines based on polyetheramines, namely, Jeffamine D400 and Jeffamine T403, in coating applications.
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Gaiqing Zhao, Qin Zhao, Xiaobo Wang and Weimin Liu
The purpose of this paper is to study a novel Mannich adduct of benztriazole-containing diphenylamine (coded as BD) and its anti-oxidation properties as an additive in two typical…
Abstract
Purpose
The purpose of this paper is to study a novel Mannich adduct of benztriazole-containing diphenylamine (coded as BD) and its anti-oxidation properties as an additive in two typical synthetic ester-based oils.
Design/methodology/approach
The anti-oxidation properties in two typical synthetic ester-based oils were evaluated in detail, using rotating pressure vessel oxidation test. The tribological properties of BD in synthetic ester-based oil (A51) were also tested with Optimal SRV-I oscillating friction and wear tester at atmosphere.
Findings
The results of tests demonstrated that the novel BD compound is, indeed, a high-performance anti-oxidation additive that was able to remarkably improve the oxidation stability of synthetic ester-based oils, when it was added at only 0.5 per cent concentration and compared with the base oils containing 0.5 per cent of the commercial available antioxidant additives such as 2, 6-di-tert-butyl-4-methylphenol and octyl-butyl diphenylamine. A plausible mechanism of exceptional synergistic anti-oxidation was proposed.
Originality/value
This paper first investigated the anti-oxidation properties and mechanisms of the compound with the structure of BD, which can be very useful and would promote the application of BD antioxidant in the lubricant industry.
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Gang Chen, Jiao Lin, Qiaona Liu, Jie Zhang, Ya Wu, Hong Li, Chentun Qu and Wenqi Song
As an example of structure-efficiency relationship study, this paper aims to evaluate the corrosion inhibition effect of two cationic surfactants, cetyl-trimethyl ammonium…
Abstract
Purpose
As an example of structure-efficiency relationship study, this paper aims to evaluate the corrosion inhibition effect of two cationic surfactants, cetyl-trimethyl ammonium chloride (CTAC) and cetyl-dimethyl-hydroxyethyl ammonium chloride (CDHAC), and to discuss the effect of structure on the performance by thermodynamics methods.
Design/methodology/approach
The effect of the two cationic surfactants, CTAC and CDHAC, on the corrosion of the mild steel in HCl solution was investigated by using weight loss measurements, and the activation energies of CTAC and CDHAC involved in the corrosion inhibition were calculated and discussed.
Findings
The weight loss measurements showed that the corrosion inhibition efficiency of CDHAC was higher than that of CTAC in any case. The effects of the structure on performance were discussed, and the following data are available from the results, all of ΔS are positive, the values of ΔG are both close to −40 kJ·mol-1 and the values of ΔH are 10.960 and 36.996 kJ·mol-1, which indicate that the surfactant molecules are spontaneously adsorbed on the surface of the steel surface, and the adsorption on the steel plate is endothermic chemical adsorption.
Originality/value
The available data show that most organic inhibitors undergo physisorption on the metal surface, while in the presence of non-bonded and p-electrons, the inhibitor molecules may undergo chemisorption. This work showed that the two surfactant molecules are spontaneously adsorbed on the surface of the steel surface, and the adsorption on the steel plate is endothermic chemical adsorption.
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The purpose of this paper is to investigate some novel bis‐hetaryl dyes containing both azo and azo methine chromophores on their molecular structures: two series of different…
Abstract
Purpose
The purpose of this paper is to investigate some novel bis‐hetaryl dyes containing both azo and azo methine chromophores on their molecular structures: two series of different molecular structures of these dyes were synthesised. The spectral characteristics and the relationships between colour and constitution of these dyes in solvents with different polarities were systematically investigated and discussed.
Design/methodology/approach
A series of novel bichromophoric dyes containing azo and azomethine chromophores were synthesized using two kinds of reaction routes. 2‐amino‐4‐(p‐substituted) phenyl‐thiazole derivatives, which are coupling components, were subjected to diazotisation with aniline derivatives and then to condensation with benzaldehyde derivatives. By exchanging the synthesis route, two series of bichromophoric dyes could be obtained.
Findings
The maximum absorption wavelengths of the obtained dyes would be attributed to the higher bathochromic shift in basic organic solvent with high polarity, such as dimethylformamide, as compared with the solvent with low polarity, such as chloroform.
Research limitations/implications
In the present study, a series of novel bichromophoric dyes were synthesized by means of two‐step pathway. In addition, the effects of substituent on the primary aromatic amine and on benzaldehyde moieties will also be discussed.
Practical implications
This novel synthesis method of the thiazole ring would lead to the formation of 2‐amino‐4‐(p‐substituted)phenyl‐thiazole with heteroaromatic coupling component position at C‐5, and consequently would produce the heteroaromatic diazo component at C‐2 for the preparation of the heteroaryl diazo dyes.
Originality/value
In this paper, the bichromophoric dyes obtained by different synthesis routes would indicate that the effect of solvent polarity should be responsible for the bathochromic shifts of the dyes.
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Oleg L. Figovsky, Valeria M. Karchevsky and Dmitriy A. Beilin
Advanced crack‐resistant coatings based on water dispersion of chlorine‐sulpho‐polyethylene (CSPE, Hypalon®) vulcanized by Mannich alkalis (MA) water solution were obtained…
Abstract
Advanced crack‐resistant coatings based on water dispersion of chlorine‐sulpho‐polyethylene (CSPE, Hypalon®) vulcanized by Mannich alkalis (MA) water solution were obtained. Application of MA as a CSPE structure component makes it possible to produce a vulcanized net of saturated polymer, and thus to receive ecologically safe impenetrable crack resistant coatings of any substrata (concrete, metal, plastic, etc.). The coatings can be applied in aircraft, automotive, shipbuilding, paint and varnish industries, civil engineering, etc. as a corrosion‐resistant material. The optimal coating composition and its mechanical properties have been studied.
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S.A. Umoren, U.M. Eduok and M.M. Solomon
The purpose of this paper is to investigate the effect of polyethylene glycol (PEG), polyvinylpyrrolidone (PVP) and blended formulations on the corrosion inhibition of aluminium…
Abstract
Purpose
The purpose of this paper is to investigate the effect of polyethylene glycol (PEG), polyvinylpyrrolidone (PVP) and blended formulations on the corrosion inhibition of aluminium in HCl solutions at 30-60°C and to study the mechanism of action.
Design/methodology/approach
The inhibitive effect of the homopolymers and polymer blend was assessed using weight loss and hydrogen evolution methods at 30 and 60°C. The morphology of the corroding aluminium surface without and with the additives was visualized using atomic force microscopy. The trend of inhibition efficiency with temperature was used to propose the mechanism of inhibition and type of adsorption.
Findings
Results obtained show that inhibition efficiency (η%) increases with increase in concentration of the polymers but decreases with increase in temperature. The inhibition efficiency of the homopolymers and their blends decreased with rise in temperature. Inhibition efficiency was found to be synergistically enhanced on blending the two homopolymers with highest inhibition efficiency obtained for (PEG:PVP) blending ratio of 1:3. The phenomenon of physical adsorption is proposed from the trend of inhibition efficiency with temperature.
Research limitations/implications
The mechanistic aspect of the corrosion inhibition can be better understood using electrochemical studies such as potentiodynamic polarization and electrochemical impedance spectroscopy.
Originality/value
Studies involving the use of polymer blends/mixtures as corrosion inhibitor for metals in corrosive environments are scarce. The results suggest that the mixture could find practical application in corrosion control in aqueous acidic environment. The data obtained would form part of database on the use of polymer–polymer mixtures to control acid-induced corrosion of metal.
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Pingping Hou, HongYan Huang, Yong Wang, Jun Zhang and Dewen Sun
The purpose of this study is to prepare a robust superhydrophobic coating on concrete substrate with remarkable chemical and mechanical durability through “all-covalent” strategy.
Abstract
Purpose
The purpose of this study is to prepare a robust superhydrophobic coating on concrete substrate with remarkable chemical and mechanical durability through “all-covalent” strategy.
Design/methodology/approach
Amino-modified silica nano/micro-particles were prepared through two synthetic steps. “All-covalent” strategy was introduced to prepare a robust superhydrophobic coating on concrete surface via a “all-in-one” dispersion and a simple spraying method. The successful construction of the products was confirmed by Fourier transform infrared spectroscopy, water contact angles (WCA), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). The concrete protective properties were verified by solution immersion test, pull-off test and rapid chloride migration coefficient test. The mechanical durability was tested by falling sand impact.
Findings
Hierarchical structures combined with the low-surface-energy segments lead to typically superhydrophobic coating with a WCA of 156° and a sliding angle of 1.3°. The superhydrophobic coating prepared through “all-covalent” strategy not only improves chemical and mechanical durability but also achieves higher corrosion and wear resistance than the comparison sample prepared by physically blending strategy. More importantly, the robust superhydrophobic coating showed excellent adhesion and protective performance of concrete engineerings.
Practical implications
This new “all-covalent” superhydrophobic coating could be applied as a concrete protective layer with properties of self-cleaning, anti-graffiti, etc.
Originality/value
Introduction of both silica nanoparticles and silica microparticles to prepare a robust superhydrophobic coating on concrete surface through “all-covalent” strategy has not been systematically studied previously.
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