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Article

Sharul Hafiq Roslan, Sharifah Bee Abd Hamid and Nurin Wahidah Mohd Zulkifli

The purpose of this study is to synthesise and characterise surface-capped molybdenum sulphide (SCMS) nanoparticles using the solvothermal method and to investigate their…

Abstract

Purpose

The purpose of this study is to synthesise and characterise surface-capped molybdenum sulphide (SCMS) nanoparticles using the solvothermal method and to investigate their tribological behaviour towards friction improver and wear reduction for bio-based lubricant oil additives.

Design/methodology/approach

The design of the experiment was to use freshly prepared molybdenum (II) acetate, thioacetamide, fatty acid and hexane as the solvent inside an autoclave vessel which is heated at high temperature and pressure. Various types of fatty acids were used as the capping agent, such as caproic, lauric, stearic and oleic acid. The SCMS nanoparticles formed were characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffractometry, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy and thermal gravimetric analysis. These nanoadditives were then blended into pentaerythrityl tetracaprylate/caprate ester at 0.05 Wt.% concentration. The formulated bio-based lubricant oil samples were tested for viscosity, viscosity index (VI) and density based on standard method ASTM D445 and ASTM D2270. A four-ball test was carried out for determination of coefficient of friction and wear scar diameter. The wear scar formed on the surface of the ball bearing was analysed using scanning electron microscopy.

Findings

The characterisation results showed that SCMS nanoparticles were successfully formed with amorphous ball-like structure, and the presence of the capping layer surrounding the nanoparticles was confirmed. Then, the formulated bio-based lubricant oil with addition of nanoadditives displays improved tribological properties in term of VI, antifriction and wear reduction.

Originality/value

This research provides a synthesis method of producing SCMS nanoparticles using the organomolybdenum complex as the chemical precursor through the solvothermal reaction approach. Besides that, it also gives an alternative antifriction and antiwear nanoadditive for formulation of the bio-based lubricant oil.

Details

Industrial Lubrication and Tribology, vol. 69 no. 3
Type: Research Article
ISSN: 0036-8792

Keywords

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Article

Sofiya Bano and Sandhya Pillai

The purpose of this paper is to prepare calcium oxide (CaO) nanoparticles by green synthesis technique and study its structural, morphological and optical properties. The…

Abstract

Purpose

The purpose of this paper is to prepare calcium oxide (CaO) nanoparticles by green synthesis technique and study its structural, morphological and optical properties. The prepared samples were calcined at, 200°C, 300°C and 500°C, and the variation in the properties at different temperatures were investigated.

Design/methodology/approach

Green approach has been used in the present work to synthesise the CaO nanoparticles using Murraya Koenigii leaf (curry leaves) extract as a capping agent. This technique involves the use of nontoxic reagents and natural products derived from various parts of plants.

Findings

Studies reveal that CaO nanoparticles with good optical properties can be synthesized successfully by green approach. The optical absorbance spectra show a broad absorption peak around 400–500 nm. FTIR studies confirm the presence of different functional groups that help in the stabilization of CaO nanoparticles. PL emission spectra show a high intensity emission peak at around 231 nm in addition to peaks at 375 nm and 400 nm. XRD studies show planes of CaO cubic phase. SEM images show a nonuniform distribution of spherical particles along with some clusters. EDX spectra confirm the presence of calcium and oxygen.

Practical implications

CaO nanoparticles have wide applications in optical devices as well as in phototherapy. It is thus interesting to devise new and eco-friendly techniques to synthesise these nanoparticles to suit these applications.

Originality/value

This work would provide a new insight into the preparation of different metal oxide nanoparticles by a very simple and cost-effective green technique without the use of toxic reagents.

Details

World Journal of Science, Technology and Sustainable Development, vol. 17 no. 3
Type: Research Article
ISSN: 2042-5945

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Article

Yujuan Zhang, Yaohua Xu, Yuangbin Yang, Shengmao Zhang, Pingyu Zhang and Zhijun Zhang

The purpose of this paper is to synthesize oil-soluble copper (Cu) nanoparticles modified with free phosphorus and sulfur modifier and investigate its tribological…

Abstract

Purpose

The purpose of this paper is to synthesize oil-soluble copper (Cu) nanoparticles modified with free phosphorus and sulfur modifier and investigate its tribological properties as environment-friendly lubricating oil additives.

Design/methodology/approach

To improve the anti-oxidation properties of these nanoparticles, two kinds of surface modifiers, oleic acid and oleylamine were used simultaneously. The morphology, composition, structure and thermal properties of as-synthesized Cu nanoparticles were investigated by means of transmission electron microscopy, X-ray powder diffraction, Fourier transform infrared spectrometry and differential thermal and thermogravimetric analysis. The tribological properties of as-synthesized Cu nanoparticles as an additive in liquid paraffin were evaluated with a four-ball friction and wear tester.

Findings

It has been found that an as-synthesized Cu nanoparticle has a size of 2-5 nm and can be well dispersed in organic solvents. Tribological properties evaluation results show that as-synthesized Cu nanoparticles possess excellent anti-wear properties as an additive in liquid paraffin. The reason lies in that as-synthesized surface-capped Cu nanoparticles are able to deposit on sliding steel surface and form a low-shearing-strength protective layer thereon, showing promising application as an environmentally acceptable lubricating oil additive, owing to its free phosphorus and sulfur elements characteristics.

Originality/value

Oil-soluble surface-modified Cu nanoparticles without phosphorus and sulfur were synthesized and its tribological properties as lubricating oil additives were also investigated in this paper. These results could be very helpful for application of Cu nanoparticles as environment-friendly lubricating oil additives.

Details

Industrial Lubrication and Tribology, vol. 67 no. 3
Type: Research Article
ISSN: 0036-8792

Keywords

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Article

Margarita Ivanovna Skiba and Viktoria Vorobyova

This paper aims to propose a simple, eco-friendly method for obtaining colloidal solutions of silver nanoparticles (Ag NPs) by using of contact non-equilibrium…

Abstract

Purpose

This paper aims to propose a simple, eco-friendly method for obtaining colloidal solutions of silver nanoparticles (Ag NPs) by using of contact non-equilibrium low-temperature plasma in presents polysorbate-80 and to assess their antibacterial activity in composite materials (beads) for water treatment process.

Design/methodology/approach

Silver nanoparticles were prepared in aqueous AgNO3 solution by using of contact non-equilibrium low-temperature plasma in the present of nonionic surfactant polysorbate-80 (Tween 80) as capping agent. Ultraviolet–visible (UV) spectroscopy, X-ray diffraction and zeta potential analysis were used to study the formation and properties of silver nanoparticles.

Findings

The formation of silver colloidal solutions in the presence of capping agent under plasma discharge is characterized by the presence of peak λmax = 380 – 402 nm in the spectra. The addition of sodium alginate into the reaction mixture allows synthesizing stable colloidal silver solutions. The average size of formed silver particles is up to 50 nm. Ag NPs exhibited an excellent bactericidal activity against both gram-positive and gram- negative bacteria. Composite beads prepared using nonionic surfactant were found to be effective in disinfecting the Staphylococcus aureus to different extents.

Research limitations/implications

Further studies are necessary for confirmation of the practical application, especially of the toxicity of Ag NPs, as well as the sorption properties of the alginate beads with Ag NPs.

Practical implications

The method provides a simple and practical solution to improving the synthesis of colloidal solutions of Ag NPs for water treatment process.

Originality/value

Contact nonequilibrium low-temperature plasma can be used as an effective technique for synthesis of nanomaterials.

Details

Pigment & Resin Technology, vol. 48 no. 5
Type: Research Article
ISSN: 0369-9420

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Article

Hao Liu, Yujuan Zhang, Shengmao Zhang, Yanfen Chen, Pingyu Zhang and Zhijun Zhang

The purpose of this paper is synthesis of oil-soluble non-spherical nanoparticles modified with free phosphorus and sulphur modifier and investigation of their…

Abstract

Purpose

The purpose of this paper is synthesis of oil-soluble non-spherical nanoparticles modified with free phosphorus and sulphur modifier and investigation of their tribological properties as environment-friendly lubricating oil additives.

Design/methodology/approach

To study the effect of morphology of nanoparticles on their tribological properties, rice-like CuO nanoparticles were synthesized. To improve the solubility of CuO nanoparticles in organic media, the in-situ surface modification method was used to synthesize these products. The morphology, composition and structure of as-synthesized CuO nanoparticles were investigated by means of transmission electron microscopy, X-ray powder diffraction, thermogravimetric analysis and Fourier transform infrared spectrometry. The tribological properties of as-synthesized CuO nanoparticles as an additive in liquid paraffin (LP) were evaluated with a four-ball tribometer. The morphology and elemental composition of worn steel ball surfaces were analysed by X-ray photoelectron spectroscopy.

Findings

It has been found that as-synthesized CuO nanoparticles with rice-like morphology have an average size of 7 and 15 nm along the shorter axle and longer axle, respectively, and can be well-dispersed in LP. Tribological properties evaluation results show that as-synthesized CuO nanoparticles as additives in LP show good friction-reducing, anti-wear and load-carrying capacities, especially under a higher normal load.

Originality/value

Oil-soluble rice-like CuO nanoparticles without phosphorus and sulphur were synthesized and their tribological properties as lubricating oil additives were also investigated in this paper. These results could be very helpful for application of CuO nanoparticles as environment-friendly lubricating oil additives, owing to their free phosphorus and sulphur elements characteristics.

Details

Industrial Lubrication and Tribology, vol. 67 no. 3
Type: Research Article
ISSN: 0036-8792

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Article

Wei Li, Guilong Xu, Buqin Xu, Yi Wang, Jin Yang and Jian Hu

The flammability of epoxy resin is a major disadvantage in applications that require flame resistance. Epoxy monomers and hardeners containing flame-retardant elements are…

Abstract

Purpose

The flammability of epoxy resin is a major disadvantage in applications that require flame resistance. Epoxy monomers and hardeners containing flame-retardant elements are molecularly incorporated in the resin network are expected to exhibit better flame resistance than those borne on an additive approach. In recent years, because of health and environmental regulation, the use of waterborne coatings has received many attentions. However, waterborne epoxy resin curing agent with excellent flame retardancy has been seldom reported. The paper aims to study the preparation of waterborne P-N-containing epoxy resin curing agent and its performances (P-N – phosphorous and nitrogen).

Design/methodology/approach

Waterborne P-N-containing epoxy curing agent was prepared in this study using reactive flame retardant 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-xa-10-phosphaphenanthrene-10-oxide, liquid epoxy resin, triethylenetetramine and butyl glycidyl ether at the mole ratio of 1.0:2.0:2.0:2.0.

Findings

The results show that the epoxy thermoset from the prepared P-N-containing curing agent presents good flame retardancy and can pass the V-1 rating, and the cured epoxy thermoset film presents excellent performances such as water resistance, adhesion, impact resistance and pencil hardness. This study provides useful suggestions for the application of the water-borne flame retardancy epoxy resins in coating industry.

Research limitations/implications

Each step of products during the preparation of waterborne P-N-containing epoxy curing agent cannot be accurately tested.

Originality/value

This method for synthesis of waterborne P-N-containing epoxy curing agent is novel and could be used for various applications in epoxy coating industry.

Details

Pigment & Resin Technology, vol. 45 no. 5
Type: Research Article
ISSN: 0369-9420

Keywords

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Article

Ehsan Jafarnejad, Jafar Abolhasani and Arezoo Derakhshan

This study aims to develop a new simple and sensitive method for the microextraction of trace levels of lead in environmental samples. It is based on the use of ionic…

Abstract

Purpose

This study aims to develop a new simple and sensitive method for the microextraction of trace levels of lead in environmental samples. It is based on the use of ionic liquids based dispersive liquid–liquid microextraction (IL–DLLME) before spectrofluorometry.

Design/methodology/approach

Cadmium sulphide quantum dots have been synthesised using thioglycolic acid as capping agent through a one-step process with stability and excellent water-solubility, and have strong affinity for lead (Pb). This probe is based on the fluorescence quenching effect of functionalised cadmium sulphide quantum dots.

Findings

Factors affecting the extraction efficiency and fluorescence quenching of metals, such as the amount of ionic liquid, amount of metanol, microextraction and centrifugation time, volume of quantum dots and buffer pH, were investigated. Under optimum conditions, the calibration graph was linear in the range of 0.01-3 µg.L-1, with the detection limit of 0.004 µg.L-1 for Pb2+. The relative standard deviation (RSD%, n = 5) of 5.4 per cent at 1 µg.L-1 of Pb2+ was obtained.

Originality/value

This method for pre-concentration of the Pb ions by dispersive liquid–liquid microextraction is novel and could be used for various applications in the synthesis of a wide variety of determination of fluorescence quenching of cadmium sulphide quantum dots.

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Article

It must be difficult for many to contemplate the numerous changes in progress and projected without wondering why it all has to happen now. Of course, there have always…

Abstract

It must be difficult for many to contemplate the numerous changes in progress and projected without wondering why it all has to happen now. Of course, there have always been with us those who would change everything, even those who would spoil; all seemingly unable to leave anything alone; unwillingly to let us be for what we are. Then there are those who dislike change of any kind in their familiar environment and strangely, children are the most conservative of us all, and others who do not object to change when it is necessary, but only when it is change merely for the sake of change. The changeover to the metric system, or to use one of the grating terms of the new technological language, metrication, must be accepted as a natural sequence to decimal currency and advances in industry. A revolution in weights and measures, it will indeed present very great problems throughout the country and at all levels, which will dwarf those presented by the switch to decimal coinage, for at worst, these may be just confusing to the general public and a price‐raiser in small‐value commodities, despite assurances to the contrary.

Details

British Food Journal, vol. 71 no. 3
Type: Research Article
ISSN: 0007-070X

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Article

Zhang Yidong

The purpose of this paper is to prove the self‐repairing Cu film of Cu‐DDP additive in base lubricating oil.

Abstract

Purpose

The purpose of this paper is to prove the self‐repairing Cu film of Cu‐DDP additive in base lubricating oil.

Design/methodology/approach

Cu nanoparticles coated with dialkydithiophosphate (Coded as Cu‐DDP) were synthesized in situ by redox method. The size and structure of Cu‐DDP were characterized using transmission electronic microscopy (TEM) and electronic diffraction (ED) analysis. The self‐repairing performance of Cu‐DDP as additive in base lubricating oil was evaluated by MRH‐3 stock‐on‐ring testing machine. Scanning electronic microscopy (SEM), UMT‐2 tribometer, X‐ray photoelectron spectroscopy (XPS), and energy‐dispersive spectrum (EDS) were used to study the self‐repairing Cu film on the stock.

Findings

The test results showed that the modified Cu‐DDP additive in base lubricating oil exhibited excellent anti‐wear and friction‐reducing properties, as well as good self‐repairing performance.

Research limitations/implications

The thickness of the self‐repairing Cu film was unknown, and the relationship between thickness of the Cu film and load, time, rotation velocity was still necessary to investigate.

Practical implications

The Cu‐DDP additive was involved P and S elements, therefore, it is still promising to seek environment friendly additive without P and S elements.

Originality/value

For the first time, MRH‐3 stock‐on‐ring testing machine, Scanning electronic microscopy (SEM), UMT‐2 tribometer, X‐ray photoelectron spectroscopy (XPS), and energy‐dispersive spectrum (EDS) were widely used to study the self‐repairing Cu film on the stock.

Details

Industrial Lubrication and Tribology, vol. 64 no. 1
Type: Research Article
ISSN: 0036-8792

Keywords

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Article

Ozgur Ekmekci and Andrea Casey

Very little is known about how contingent workers' identification with an organization evolves over time. This study seeks to contribute to the literature by investigating…

Abstract

Purpose

Very little is known about how contingent workers' identification with an organization evolves over time. This study seeks to contribute to the literature by investigating how the emergence and strength of organizational identification is affected by four variables: duration of primacy; duration of recency; frequency of interaction with other members of the organization; and frequency of information received about the organization.

Design/methodology/approach

Using a cognitive model of organizational identification grounded in memory, agent‐based modeling and NetLogo language were employed to form a model in which two groups of 567 contingent workers joined 1,134 different organizations and worked for 365 days. Correlation and multiple linear regression were used to analyze the data.

Findings

Evolution of organizational identification for a contingent worker depends on how much the individual interacts with other members of the organization and how much information about the organization that particular individual receives over time.

Research limitations/implications

The generalizability of the simulation study's findings may be expanded if similar studies are carried out incorporating factors that mark differences in individuals, groups, organizations, sectors, industries, cultures, and geographies.

Originality/value

The existing literature on how contingent employees identify with an organization does not adequately provide a process‐based view of the phenomenon. This study extends and complements literature on contingent workers by emphasizing the social construction of time in and from memory throughout the process of organizational identification.

Details

Team Performance Management: An International Journal, vol. 17 no. 5/6
Type: Research Article
ISSN: 1352-7592

Keywords

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