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1 – 10 of 130Xin Wang, Xiaoling Xu, Zuowan Zhou and Jihua Gou
This paper aims to exploit shape memory polymer (SMP) composite as multifunctional coatings for protecting substrates from surface wear and bacterial. The efficiency of added nano…
Abstract
Purpose
This paper aims to exploit shape memory polymer (SMP) composite as multifunctional coatings for protecting substrates from surface wear and bacterial. The efficiency of added nano or micro-sized particles in enhancing the properties of SMP was investigated. This study also attempts to use a low-cost and effective spraying approach to fabricate the coatings. The coatings are expected to have good conformability with the substrate and deliver multi-functional performance, such as wrinkle free, wear resistance, thermal stability and antimicrobial property.
Design/methodology/approach
High-performance SMP composite coatings or thin films were fabricated by a home-made continuous spray-deposition system. The morphologies of the coatings were studied using the scanning electron microscope and the transmission electron microscope. The abrasion properties were evaluated by Taber Abraser test, and thermo-gravimetric analysis was carried out to investigate the thermal properties of prepared composites. The antimicrobial property was determined by the inhibition zone method using E. coli. The thermally responsive shape memory effect of the resulting composites was also characterized.
Findings
The morphology analysis indicated that the nanoclay was distributed on the surface of the coating which resulted in a significant improvement of the wear property. The wear resistance of the coatings with nanoclay was improved as much as 40 per cent compared with that of the control sample. The thermo-gravimetric analysis revealed that the weight loss rate of composites with nanoclay was dropped over 40 per cent. The SMP coating with zinc oxide (ZnO) showed excellent antimicrobial effect. The shape recovery effect of SMP/nanoclay and SMP/ZnO composites can be triggered by external heating and the composites can reach a full shape recovery within 60 s.
Research limitations/implications
This study proposed a continuous spray-deposition fabrication of SMP composite coatings, which provides a new avenue to prepare novel multi-functional coatings with low cost.
Originality/value
Most studies have emphasized on the sole property of SMP composites. Herein, a novel SMP composite coating which could deliver multi-functionality such as wrinkle free, wear resistance, thermal stability and antimicrobial property was proposed.
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M. Taheri, Reza Naderi and Mohamad Mahdavian
This paper aims to enhance the barrier properties and active protection of a water-based silane coating on mild steel through nanoclay and zinc acetylacetonate simultaneously…
Abstract
Purpose
This paper aims to enhance the barrier properties and active protection of a water-based silane coating on mild steel through nanoclay and zinc acetylacetonate simultaneously included into the formulation.
Design/methodology/approach
The corrosion protection performance of the silane sol-gel coatings with no additive, zinc acetylacetonate, nanoclay and nanoclay + zinc acetylacetonate was monitored using electrochemical impedance spectroscopy during 5 h of immersion in a sodium chloride solution. Moreover, the surface of coatings was analyzed using a field emission scanning electron microscopy equipped with an energy dispersive X-ray spectrometer (FESEM-EDX) and water contact angle measurements.
Findings
In electrochemical impedance spectroscopy analysis, the impedance at low frequencies, coating resistance and charge transfer resistance were the parameters considered which indicated the superiority of silane coating formulated with both nanoclay and zinc acetylacetonate. According to the results of FESEM/EDX and water contact angle measurements, the superiority was linked with the enhancement in the barrier properties in the presence of nanoclay, as well as function of the corrosion inhibitor at coating–substrate interface.
Originality/value
According to the literature, there is no research conducted to study the impact of the simultaneous use of nanoclay and zinc acetylacetonate on the barrier properties and active protection of an eco-friendly silane sol-gel coating including glycidyloxypropyltrimethoxysilane, tetraethoxysilane and methyltriethoxysilane on mild steel in a sodium chloride solution.
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Mazeyar Parvinzadeh Gashti, Rambod Rashidian, Arash Almasian and Ali Badakhshan Zohouri
In recent years, the textile industry has been required to develop new methods and technologies through introduction of some new materials in various processes rather than…
Abstract
Purpose
In recent years, the textile industry has been required to develop new methods and technologies through introduction of some new materials in various processes rather than employing the same conventional chemicals. The aim of this research was to investigate the changes induced on the cotton fibre by the nanoclay treatment using a pre‐treatment method.
Design/methodology/approach
The fibres were dyed with basic and direct dyes after the nanoclay pre‐treatment. Technical measurements were studied including Fourier‐transform infrared spectroscopy (FTIR), UV‐visible spectrophotometer, differential scanning calorimetry (DSC), thermal degradation analysis (TGA), scanning electron microscopy (SEM), moisture regain measurement (MRM), tensile strength test (TST), reflectance spectroscopy (RS) and fastnesses evaluation.
Findings
The intensity of the major peaks in FTIR spectra of the nanoclay treated sample is in favour of the chemical changes of the cellulose functional groups. Basic dyes showed a higher dyeability on the clay pre‐treated samples compared to raw materials. The results of the colour measurements showed that the more concentration of the clay mineral was used, the darker the colour of the dyed sample was. Some interesting results were obtained in the research.
Research limitations/implications
The nanoclay and a dispersing agent used in the present context were used as received. Besides, the type of the dispersing agent is important for preparation of a colloidal dispersion of nanoclay.
Practical implications
The method developed in this research provides a simple and practical solution for improving the dyeability of cotton with direct and basic dyes.
Originality/value
The method for enhancing the dyeability of cotton is novel and can be used in cotton processing with new properties.
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Harun Sepet and Necmettin Tarakçıoğlu
This paper presents the experimental study of mechanical and thermal properties of organically modified montmorillonite clay (Nanoclay) (0, 1, 2, 3, 4 and 5 wt.%) in the vinyl…
Abstract
This paper presents the experimental study of mechanical and thermal properties of organically modified montmorillonite clay (Nanoclay) (0, 1, 2, 3, 4 and 5 wt.%) in the vinyl ester matrix by ultrasonic stirrer. The changes in mechanical properties are investigated by using tensile and impact testing machine. It was found that the addition of nanoclay particles significantly improved tensile properties of pure vinyl ester, but impact properties of pure vinyl ester were affected negatively with the nanoclay content in the nanocomposite. It was found that the absorbed energy and impact resistance of the nanocomposites decreased with increasing the nanoclay content. DSC curves showed the glass transition temperature change in the nanoclay reinforced vinyl ester nanocomposites as compared to the pure vinyl ester. XRD analysis was performed to identify the structure of nanocomposites. SEM results showed the change in fracture surface morphology of nanoclay reinforced vinyl ester nanocomposite. Also, homogeneous distribution of nanoclays in the matrix was showed by SEM micrographs. This observation helped in identifying the morphology of the nanocaly in the vinyl ester matrix.
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Zaker Bahreini, Vahid Heydari and Zahra Namdari
Mechanical and chemical properties of acrylic-melamine automotive clear coat in the presence of different percentages of well dispersed nano-layered sodium montmorillonite…
Abstract
Purpose
Mechanical and chemical properties of acrylic-melamine automotive clear coat in the presence of different percentages of well dispersed nano-layered sodium montmorillonite (Na-MMT) silicate particles were investigated. For this purpose, prepared dry clear coat film samples were subjected to the entire standard test series, usually carried out in automotive coating industry.
Design/methodology/approach
Effects of adding different percentages of nano-layered silicate on mechanical and chemical properties of acrylic-melamine automotive clear coat were investigated. To increase the compatibility of nanoclays with polymer matrix of clear coat, the surface of nanoclays was modified by benzalkonium chloride as a cationic surfactant. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used for characterization and comparison between clays before and after modification, and also after dispersion in coating. Prepared dry clear coat film samples subjected to the test series are usually carried out in automotive coating industry.
Findings
The results indicated that incorporation of 1 and 2 Wt.% of nano-layered silicate caused desired improvement in chemical and physical properties of the acrylic-melamine clear coat. Increasing the percentage of nanoclay to over 2 Wt.% caused damage in some properties such as hardness, cupping and gloss.
Research limitations/implications
All materials and methods were used in this research are industrial grade. Therefore, the introduced modified clear coat sample has potential for commercial production as an automotive clear coat.
Originality/value
As far as it was searched in the literature, effects of adding nanoclay particles on mechanical and physical properties of different clear coats, such as epoxy clear coat, have been investigated in a few researches, but in this research, common and special tests which are necessary in automotive coating industry have been ignored. In the present study for the first time, acrylic-melamine clear coat was subjected to modification using nano-clay, and also, the most common industrial test methods were used for investigation of mechanical and chemical properties.
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Suzhu Yu, Aloysius Tan, Wei Ming Tan, Xinying Deng, Cher Lin Tan and Jun Wei
This paper aims to develop flame-retardant (FR) polyamide 12 (PA12) nanocomposite from regenerated powder via selective laser sintering (SLS), an additive manufacturing technique.
Abstract
Purpose
This paper aims to develop flame-retardant (FR) polyamide 12 (PA12) nanocomposite from regenerated powder via selective laser sintering (SLS), an additive manufacturing technique.
Design/methodology/approach
First, the morphology, processibility, thermal and mechanical properties of PA12 regenerated powder, consisting of 50 wt% new and 50 wt% recycled powder, as well as corresponding printed specimens, were evaluated to characterize the effects of previous SLS processing. Second, flame-retardant PA12 was developed by incorporating both single and binary halogen-free flame retardants into the regenerated powder.
Findings
It was found that the printed specimens from regenerated powder had much higher tensile and impact properties compared to specimens made from new powder, which is attributed to better particulate fusion and coalescence realized in higher temperature SLS printing. The effect of FRs on thermal, mechanical and flame retardant properties of the PA12 composites/nanocomposites was investigated systematically. It was found that the nanoclay, as a synergist, improved both flame-retardant and mechanical properties of PA12. UL94 standard rating of V-0 was achieved for the printed nanocomposite by incorporating 1 wt% nanoclay into 15 wt% phosphinates FR. Moreover, on average, the tensile and impact strength of the nanocomposite were increased by 26.13% and 17.09%, respectively, in XY, YZ and Z printing orientations as compared to the equivalent flame retardant composite with 20 wt% of the phosphinates FR.
Originality/value
This paper fulfills the need to develop flame retardant parts via SLS technology with waste feedstock. It also addresses the challenge of developing flame retardant materials without obviously compromising the mechanical properties by making use of the synergistic effect of nanoclay and organic phosphinates.
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Shanti Kiran Zade, Suresh Babu V. and Sai Srinadh K.V.
The purpose of this study is to manufacture test boards for re-enacting plant or field situations where vacuum chamber for expelling gas bubbles and autoclave equipment would not…
Abstract
Purpose
The purpose of this study is to manufacture test boards for re-enacting plant or field situations where vacuum chamber for expelling gas bubbles and autoclave equipment would not be accessible. This research focuses on the examination and enhancement of tensile strength for the nanocomposites consisting of uniaxial glass fiber mats, nanoclay (NC) and epoxy.
Design/methodology/approach
The parameters considered are the weight content of Cloisite 15A NC, the volume of glass fiber (Vgf) and the direction of glass fibers (θ). The composites are made by hand lay-up technique and tested according to ASTM D 638 standard. Taguchi L9 orthogonal array is used to design the experiments.
Findings
The results imply that the orientation of fibers exhibited high significance with a p-value of 0.001 for the upgrade of strength. NC percentage and the volume of fiber have a low effect as the p-values obtained were 0.375 and 0.294. Confirmation tests were performed at the optimal levels of parameters and the outcomes were in the permissible range of the anticipated values of S/N ratio and mean tensile strength. The negligible effect of nanoclay is due to the lack of infusion of resin into the d-spacing of clay layers due to the low configuration settings of mixing conditions which was confirmed by XRD studies. The negligible effect of glass fiber volume is due to the void content and lack of stress transfer between fibers uniformly due to the void content and improper mixing of nanoclay.
Research limitations/implications
The limitation of this study is that a low-speed mechanical stirrer was used to mix NC in the epoxy and the mixture was not subjected to vacuum and ultrasonication for degassing and deagglomeration.
Practical implications
These composites can be used as substitute materials in place of metallic parts in the aerospace and automobile sector. These composites can be used in civil structures instead of steel and concrete, which have low strength-to-weight ratio and where the requirement of strength is in the range of 60 to 390 MPa.
Social implications
The composites can be used in a variety of applications, for example, structural works, automotive panels and low-cost housing.
Originality/value
This research gives an idea about the combined contribution of NC, Vgf and “θ” to the improvement of tensile strength of the glass-epoxy composite.
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M. Abdullah, K. Zamhari, N. Nayan, M. Hainin and M. Hermadi
Nowadays, researchers are interested in using the material at nanoscales as one of asphalt binder modifier. In this paper, Malaysian asphalt binder was modified with nanoclay and…
Abstract
Nowadays, researchers are interested in using the material at nanoscales as one of asphalt binder modifier. In this paper, Malaysian asphalt binder was modified with nanoclay and warm asphalt additives (WAA) and tested to determine the physical properties and storage stability. The results of the investigation indicated that the modified asphalt binders were stable in term of storage and they also have potential to improve physical properties of asphalts such as increasing softening point and decreasing the penetration. In addition, there was a significant reduction of temperature for mixing and compaction of asphalt mixtures.
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V. Marchante Rodríguez, F.M. Martínez‐Verdú, M.I. Beltrán Rico and A. Marcilla Gomis
This research deals with a new kind of nanopigment, obtained from the combination of organic dyes and layered nanoclays, that the authors call nanoclay‐colorant pigment (NCP)…
Abstract
Purpose
This research deals with a new kind of nanopigment, obtained from the combination of organic dyes and layered nanoclays, that the authors call nanoclay‐colorant pigment (NCP). Whilst they have already been employed in inks and coatings, to date these nanopigments have not been used as pigments for polymers. The existing lack of knowledge surrounding them must be redressed in order to bridge the gap between current academic studies and commercial exploitation. Therefore, the main purpose of this paper is to examine the hitherto unknown aspects of the NCP, which relate specifically to their applicability as a new type of colorant for polymers.
Design/methodology/approach
A blue NCP has been prepared at the laboratory according to the patented method of synthesis (patent WO0104216), using methylene blue and montmorillonite nanoclay. It has then been applied to a thermoplastic polymer (linear low‐density polyethylene – LLDPE) to obtain a coloured sample. Furthermore, samples with the same polymer but using conventional blue colorants have been prepared under the same processing conditions. The mechanical, thermal and colorimetric properties of these materials have been compared.
Findings
The thermal stability of the sample coloured with NCP is reduced to some extent, while the mechanical strength is slightly increased. Moreover, this sample has better colour performance than the conventionally pigmented samples.
Originality/value
In this paper, a blue NCP has been synthesised and successfully employed with polyethylene and the obtained sample shows better colour performance than polyethylene with conventional pigments.
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Juan Esteban Aponte Gonzalez, William Jordan Wright, Raden Gustinvil and Emrah Celik
Direct ink writing (DIW) is a robust additive manufacturing technology for the fabrication of fiber-reinforced thermoset composites. However, this technique is currently limited…
Abstract
Purpose
Direct ink writing (DIW) is a robust additive manufacturing technology for the fabrication of fiber-reinforced thermoset composites. However, this technique is currently limited to low design complexity and minimal heights. This study aims to investigate the feasibility of UV-assisted DIW of composites to enhance the green-part strength of the printed inks and resolve the complexity and the height limitations of DIW technology.
Design/methodology/approach
The experimental approach involved the preparation of the thermoset inks that are composed of nanoclay, epoxy, photopolymer and glass fiber reinforcement. Composite specimens were fabricated in complex geometries from these ink feedstocks using UV-assisted, hybrid 3D-printing technology. Fabricated specimens were characterized using optical microscopy, three-point bending mechanical tests and numerical simulations.
Findings
The introduced hybrid, UV-assisted 3D-printing technology allowed the fabrication of tall and overhanging thermoset composite structures up to 30% glass fiber reinforcement without sagging during or after printing. Glass fiber reinforcement tremendously enhanced the mechanical performance of the composites. UV-curable resin addition led to a reduction in strength (approximately 15%) compared to composites fabricated without UV resin. However, this reduction can be eliminated by increasing the glass fiber content within the hybrid thermoset composite. Numerical simulations indicate that the fiber orientation significantly affects the mechanical performance of the printed composites.
Originality/value
This study showed that the fabrication of high-performing thermoset composites in complex geometries was possible via hybrid DIW technology. This new technology will tremendously expand the application envelope of the additively manufactured thermoset composites and the fabrication of large composite structures with high mechanical performance and dimensional freedom will benefit various engineering fields including the fields of aerospace, automotive and marine engineering.
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