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1 – 10 of 355Wang Yu, Gang Chen, Haiyan Yang and Sisi Li
A series of sulfate-based Gemini anionic surfactants were synthesized via etherification, ring opening and sulfation reactions using epichlorohydrin, fatty alcohol, ethylene…
Abstract
Purpose
A series of sulfate-based Gemini anionic surfactants were synthesized via etherification, ring opening and sulfation reactions using epichlorohydrin, fatty alcohol, ethylene glycol and chlorosulfonic acid as the main raw materials. Orthogonal experiments for 1,8-bisalkoxymethylene-3,6-dioxin-1,8-octane disulfate were performed on the sulfation reaction to determine the optimal reaction conditions.
Design/methodology/approach
A series of sulfate-based Gemini anionic surfactants were synthesized via etherification, ring opening and sulfation reactions using epichlorohydrin, fatty alcohol, ethylene glycol and chlorosulfonic acid as the main raw materials. Orthogonal experiments for 1,8-bisalkoxymethylene-3,6-dioxin-1,8-octane disulfate were performed on the sulfation reaction to determine the optimal reaction conditions. The structures of the intermediate and final products were characterized by FT-IR (Fourier transform infrared spectroscopy analysis), 1H-NMR (proton nuclear magnetic resonance spectroscopy) methods. The thermal performance of surfactants was analyzed using thermogravimetric analysis (TGA). The thermogravimetric results showed that the sulfate-based Gemini surfactants had good heat resistance (the thermal decomposition temperature of which was in the range of 140∼170?). The Krafft point, surface tension, foaming, Hydrophile–Lipophile Balance Number (HLB), emulsifying, wetting, and lime-soap dispersing performance were measured by visual observation, hanging drop method, aqueous surfactant solution method and Borghetti–Bergman method, respectively. The results have shown that all the sulfate-based Gemini surfactants had good water solubility and lime-soap dispersing ability. When spacer group was -(CH2)2-, with the increase of the carbon chain length from C12 to C14, the micellar concentration critical micelle concentration and surface tension (CMC) gradually increased from 8.25 × 10–4 mol/L to 8.75 × 10–4 mol/L and 27.5 mN/m to 30.9 mN/m, respectively. Also, the sulfate-based Gemini surfactants with the different length of the spacer group had a different effect on their performance on foaming properties and foam properties, HLB and emulsifying ability and wetting ability.
Findings
In view of the important role of the spacer group and the general use of anionic surfactants in oil fields, this article considers the preparation of a series of sulfate-based Gemini surfactants by changing the spacer group and the chain length of the hydrophobic group and evaluating their surface activity, and finally its Kraffi, on the foam properties, HLB value, emulsifying performance, lime soap dispersing ability etc.
Originality/value
Sulfate-based Gemini surfactants have broad application prospects in the fields of oil and gas exploitation, environmental protection, chemistry and daily chemical industry and so on.
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Chupo Ho, Jintu Fan, Edward Newton and Raymond Au
Maintaining air circulation between the wearer and garment layer is crucial for activating heat and moisture transfer from the body. If an air gap is trapped, air circulation may…
Abstract
Purpose
Maintaining air circulation between the wearer and garment layer is crucial for activating heat and moisture transfer from the body. If an air gap is trapped, air circulation may become ineffective and the ventilation of the garment is, thus, hindered. To maintain and extend the air gap, this study aims to propose a design method that involves placing spacer blocks underneath the garment to prevent the fabric from clinging directly to the skin.
Design/methodology/approach
To study the application of this design method, a series of T-shirts were produced and tested using a thermal manikin in standing and walking postures. All the T-shirts were made of fabric ostensibly manufactured to have high air permeability. Porous mesh fabric was used to construct the vented panels on the T-shirts. The test was conducted in a chamber with controlled temperature, relative humidity and wind velocity. Total thermal insulation (Rt) and moisture vapour resistance (Ret) were measured.
Findings
The test results showed that extension of the air gap between wearer and fabric provided higher ventilation to the wearer if the vented panels were also present on the T-shirts. Different placements of the vented panels on the T-shirts also affected the heat and moisture transfer from the thermal manikin.
Research limitations/implications
Due to limited resources, the evaluation of total thermal insulation and moisture vapour resistance was based on the testing result from a thermal manikin instead of any subjective wearer trial.
Practical implications
This research can contribute to the clothing designer who is developing function wear for a better ventilation.
Social implications
This research can contribute to the clothing designer who is developing function wear for a better ventilation.
Originality/value
This study aimed to further develop a new design concept in T-shirt design by improving the construction of the spacer blocks. Fabric with higher air and water vapour permeability was used to determine to what extent this design method is applicable to higher performance on heat and moisture transfer.
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Rajesh Mishra, Arumugam Veerakumar and Jiri Militky
– The purpose of this paper is to investigate effect of material properties in 3D knitted fabrics on thermo-physiological comfort.
Abstract
Purpose
The purpose of this paper is to investigate effect of material properties in 3D knitted fabrics on thermo-physiological comfort.
Design/methodology/approach
In the present study six different spacer fabrics were developed. Among these six fabrics, it was classified into two groups for convenient analysis of results, the first group has been developed using polyester/polypropylene blend with three different proportion and second group with polyester/polypropylene/lycra blend having another three different composition. As a spacer yarn, three different types of 88 dtex polyester monofilament yarn and polyester multifilament yarns (167 dtex and 14.5 tex) were used and 14.5 tex polypropylene and 44 dtex lycra multifilament yarns were also used for the face and back side of the spacer fabrics (Table I). These fabrics were developed in Syntax Pvt Ltd Czech Republic.
Findings
The main influence on the water vapour permeability of warp knitted spacer fabrics is the kind of raw material, i.e. fibre wetting and wicking. Also there is no correlation between air permeability and water vapour permeability. It is found that both air permeability and thermal conductivity are closely related to the fabric density. It is also found that the fabric characteristics of spacer fabric show a very significant effect on the air permeability, thermal conductivity and mechanical properties of spacer fabric. Therefore, selection of spacer fabric for winter clothing according to its fabric characteristics.
Practical implications
The main objective of the present study is to produce spacer knitted 3D fabrics suitable for defined climatic conditions to be used as clothing or in sports goods.
Originality/value
New 3D knitted spacer fabrics can be produced with improved comfort properties.
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Fatima Bensajjay, Saliha Alehyen, Mohammed El Achouri, Najat Hajjaji, Abdelkbir Bellaouchou, Lourdes Perez and Maria Rosa Infante
The purpose of this investigation is the evaluation of the inhibitive performance of a new “gemini” surfactant in the series of bis‐quat: N, N, N′, N″, N″‐pentamethyl…
Abstract
Purpose
The purpose of this investigation is the evaluation of the inhibitive performance of a new “gemini” surfactant in the series of bis‐quat: N, N, N′, N″, N″‐pentamethyl diethyleneamine‐N, N″‐di‐[tetradecylammonium bromide] on the corrosion of iron in 1 M HCl by gravimetric, potentiodynamic and electrochemical impedance measurements. The effect of the temperature on the corrosion behavior of iron in 1 M HCl without and with inhibitor is studied in the temperature range (298‐333 K). This work also attempts to correlate thermodynamic and kinetic parameters with the inhibition effect.
Design/methodology/approach
The inhibition efficiency of gemini synthesized is investigated by weight loss, potentiodynamic polarization and impedance spectroscopy methods.
Findings
The synthesized gemini bis‐quat acted as a good inhibitor in 1 M HCl, and inhibition efficiency increased with inhibitor concentration and temperature. Polarization curves showed that the surfactant was a mixed‐type inhibitor in hydrochloric acid. Impedance spectroscopy measurements showed that the inhibitor acted through the formation of a multilayer film at the iron surface. The adsorption of inhibitor on the iron surface obeyed the Langmuir adsorption isotherm equation. The inhibition effect was satisfactorily explained by both thermodynamic and kinetic parameters.
Originality/value
The adsorption of surfactants in the metal surface can markedly change the corrosion resisting property of the metal. So the study of the relation between the adsorption and corrosion inhibition is of a great importance. This was the first attempt to study the inhibition properties of gemini surfactants at the host laboratory.
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J.S. Ullett, J.W. Schultz and R.P. Chartoff
The build characteristics of two liquid crystal (LC) reactive monomers were studied using a table‐top stereolithography apparatus (TTSLA). LC materials contain stiff, rod‐like…
Abstract
The build characteristics of two liquid crystal (LC) reactive monomers were studied using a table‐top stereolithography apparatus (TTSLA). LC materials contain stiff, rod‐like mesogenic segments in their molecules, which can be aligned causing an anisotropy in properties. When cured in the aligned state the anisotropic structure is “locked in” resulting in materials with anisotropic physical and mechanical properties. By varying the alignment of layers, properties such as thermal expansion coefficient can be optimized. High heat distortion (or glass transition) temperatures are possible depending on the monomer chemical structure. Working curves for the LC resins were developed under various conditions. A permanent magnet placed outside the TTSLA vat was used to uniformly align the monomer in the nematic state. Photo‐initiator type and content; alignment of the nematic phase; and operating conditions affected the working curve parameters. Glass transition temperatures of post‐cured parts ranged from 75 to 1488C depending on the resin and processing conditions. Mechanical analysis data revealed a factor of two difference between glassy moduli measured in the molecular alignment versus the transverse alignment directions. Based on these initial studies, more advanced resins with higher glass transitions are being developed at the University of Dayton.
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The purpose of this paper is to present the results of some corrosion inhibition studies of brass in 3N HNO3 by gemini surfactants.
Abstract
Purpose
The purpose of this paper is to present the results of some corrosion inhibition studies of brass in 3N HNO3 by gemini surfactants.
Design/methodology/approach
Gemini surfactants namely: N‐trimethyl butane‐diyl‐1,2‐ethane‐bis‐ammonium bromide (BEAB), N‐hexane‐diyl‐1,2‐ethane‐bis‐ammonium bromide (HEAB), N‐dodecane‐diyl‐1,2‐ethane‐bis‐ammonium bromide (DDEAB) and N‐hexadecane‐diyl‐1,2‐ethane‐bis‐ammonium bromide (HDEAB) were synthesized in the laboratory and their influence has been investigated for controlling the dissolution of brass in 3N HNO3. Weight loss, potentiodynamic polarization and electrochemical impedance have been employed for the study. Weight loss experiments were performed as per standard method (ASTM, 1987). Potentiodynamic polarization studies were carried out using EG&G PARC potentiostat/galvanostat (model 173), universal programmer (model 175) and X‐Y recorder (model RE 0089) and impedance measurements were carried out with an EG&G PAR (model 5301 A) lock‐in‐amplifier, using an IBM computer.
Findings
The inhibition efficiency for all the gemini surfactants increases with increase in concentrations. The maximum inhibition efficiency of each inhibitor was achieved at 250 ppm concentration. The inhibition efficiency of all the inhibitors decreases on increasing the temperature from 30 to 50°C. The results of potentiodynamic polarization studies revealed that all the compounds were mixed type inhibitors and inhibit the corrosion of brass by blocking the active sites of the metal. The adsorption of the compounds on brass surface in 3N HNO3 has been found to obey the Langmuir adsorption isotherm.
Originality/value
The paper provides information regarding corrosion inhibition of brass in 3N HNO3, the mechanism of the inhibition on the basis of molecular structures of the inhibitors, activation energy and free energy of adsorption.
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Wen Li, Zhongbin Bao, Lijun Chen and Dongshun Deng
At present, the conventional method of preparing cationic fluorinated acrylic latex is to emulsify copolymerised monomers with cationic surfactants. However, there has been a wide…
Abstract
Purpose
At present, the conventional method of preparing cationic fluorinated acrylic latex is to emulsify copolymerised monomers with cationic surfactants. However, there has been a wide concern about using Gemini surfactants to prepare cationic polymer latex to improve its properties. The purpose of this paper was to focus on the synthesis of novel self-crosslinked cationic fluorinated acrylic latex (SCFAL), during which the copolymerised monomers were initiated with a water soluble azo initiator and emulsified with mixed surfactants of Gemini emulsifier and alkyl polyglycoside (APG).
Design/methodology/approach
The novel SCFAL was prepared successfully by the semi-continuous seeded emulsion polymerisation of butyl acrylate, methyl methacrylate, hexafluorobutyl methacrylate (HFMA) and hydroxy propyl methacrylate (HPMA) in aqueous medium.
Findings
The conversion is the maximum and the coagulation percentage the minimum when the amounts of emulsifier and initiator are 8 and 0.6 per cent, respectively. The average particle size of the latex is significantly reduced with the increase of the amount of emulsifiers used. However, the average particle size of the latex is increased with the increase of the amount of HPMA. The particle size of the latex is of a unimodal distribution, which means that the particle size was reasonably uniform. Contact angle is increased with the increase of the amount of the HFMA.
Practical implications
The novel SCFAL can be widely used as significant components in the field of coatings, leather, textile, paper, adhesives and so on.
Originality/value
SCFAL, which was emulsified with novel mixed surfactants of Gemini surfactant and APG, has been prepared successfully. Influences of amount of initiator, emulsifier, HPMA and HFMA on emulsion polymerisation and/or properties of novel latex are investigated in detail.
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To study the use of “Quick Links”, a common navigational element, in the context of an academic library website.
Abstract
Purpose
To study the use of “Quick Links”, a common navigational element, in the context of an academic library website.
Design/methodology/approach
Transaction log files and web server logs are analyzed over a four‐year period to detect patterns in Quick Link usage.
Findings
Provides information about what Quick Links have been used over time, as well as the relationship of Quick Link usage to the rest of the library website. Finds generally that Quick Link usage is prevalent, tilted toward a few of the choices, and is drawn largely from the library homepage as referral source.
Research limitations/implications
Log analysis does not include IP referral data, which limits the ability to determine different patterns of use by specific locations including services desks, off‐campus, and in‐house library usage.
Practical implications
This paper is useful for website usability in terms of design decisions and log analysis.
Originality/value
This paper targets a specific website usability issue over time.
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Ryan Rudy and Wiah Wardiningsih
This study aimed to determine the peak impact force and force attenuation capacity of weft-knitted spacer fabrics intended for padding that can be used for human body protection…
Abstract
Purpose
This study aimed to determine the peak impact force and force attenuation capacity of weft-knitted spacer fabrics intended for padding that can be used for human body protection against impact.
Design/methodology/approach
A total of five weft-knitted spacer fabrics were fabricated with four different diameters of nylon monofilament yarns and one doubled monofilament yarns, respectively. The impact performances of the weft-knitted spacer fabrics were tested using a drop test method with a customized test rig to simulate falling. Impact tests were conducted on single- and multilayered experimental spacer fabrics to investigate the peak impact force and force attenuation capacity.
Findings
It was found that weft-knitted spacer fabric with a coarser or larger diameter of monofilament spacer yarn generated lower impact force and higher force attenuation capacity, thus resulting in better impact performance. Greater force attenuation can be achieved by utilizing a higher number of spacer fabric layers. However, the increase in thickness must be considered with the spacer fabric end use.
Originality/value
This study employed relatively coarse nylon monofilament yarn as spacer yarns to gain knowledge on the impact performance of weft-knitted spacer fabrics compared to warp-knitted spacer fabrics which are more common. The results showed that the diameter of spacer yarn significantly influenced the impact performance of the experimental weft-knitted spacer fabrics. These results could be useful for designing and engineering textile-based impact protectors.
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