Search results
1 – 10 of 32Siddhesh Umesh Mestry, Vardhan B. Satalkar and S.T. Mhaske
This study aims to describe the design and synthesis of two novel azo and imine chromophores-based dyes derived from two different aldehydes with intramolecular colour matching…
Abstract
Purpose
This study aims to describe the design and synthesis of two novel azo and imine chromophores-based dyes derived from two different aldehydes with intramolecular colour matching that are pH sensitive.
Design/methodology/approach
The visible absorption wavelength (λmax) was extended when azo chromophore was included in imine-based systems. The dyed patterns created sophisticated colour-changing paper packaging sensors with pH-sensitive chromophores using alum as a mediator or mordant. Due to the tight adhesive bonding, the dyes on paper’s cellulose fibres could not be removed by ordinary water even at extremely high or low pH, which was confirmed by scanning electron microscopy analysis. The dyed patterns demonstrated an evident, sensitive and fast colour-changing mechanism with varying pH, from pale yellow to red for Dye-I and from pale yellow to brown-violet for Dye-II.
Findings
The λmax for colour changing was recorded from 400 to 490 nm for Dye-I, whereas from 400 to 520 for Dye-II. The freshness judgement of food was checked using actual experiments with cooked crab spoilage, where the cooked crab was incubated at 37 oC for 6 h to see the noticeable colour change from yellow to brown-violet with Dye-II. The colour-changing mechanism was studied with Fourier transform infrared (FTIR) spectra at different pH, and thin layer chromatography, nuclear magnetic resonance and FTIR spectroscopy studied the desired structure formation of the dyes. Potential uses for smart packaging sensors include quickly detecting food freshness during transportation or right before consumption.
Originality/value
1. Two novel azo-imine dyes have been synthesized with a pH-responsive effect. 2. The pH-responsive mechanism was studied. 3. The study was supported by computational chemistry using density functional theory. 4. The obtained dyes were used to make pH-responsive sensors for seafood packaging to judge the freshness.
Details
Keywords
Nivin M. Ahmed, Mostafa G. Mohamed and Walaa M. Abd El-Gawad
Long time ago, multistructured materials showed great interest being considered as the bridge between bulk and atomic materials. Core-shell particles are kind of composite…
Abstract
Purpose
Long time ago, multistructured materials showed great interest being considered as the bridge between bulk and atomic materials. Core-shell particles are kind of composite materials that refer to multilayered structures with a core totally surrounded by shell(s) (onion-like structure). These new structures can offer an advantage of applying new adjustable parameters like shape, stoichiometry and chemical ordering, in addition to the opportunity of tailoring more complexed structures for different applications. Recently it was found that these structures can be tuned and taken for more advanced path with novel structures formed of core surrounded by multishells. The purpose of this study is to study the effect of the new anticorrosive pigments with its mutual shells and how each shell affects the performance of the pigment in protecting the metal and which shell will be more relevant in its effect.
Design/methodology/approach
The prepared pigments were characterized using X-ray fluorescence, X-ray diffraction, TEM and SEM/EDX to prove their core-shell structure, and then they were integrated in coating formulations to evaluate their anticorrosive activity using immersion test and electrochemical impedance spectroscopy (EIS).
Findings
The results showed that the prepared core-shell pigments possess a lot of unique characteristics and can offer improved anticorrosive performance in the generated coatings.
Originality/value
Core-mutual shells structured pigments were prepared for improving the corrosion resistivity of the organic coatings as a new trend in anticorrosive pigments.
Details
Keywords
Walaa M. Abd El-Gawad and Wael Mohamed Abdelmaksoud
This study aims to investigate the possibility of synthesizing cobalt doped willemite ceramic blue pigment by using Egyptian white sand as environmental and economical raw…
Abstract
Purpose
This study aims to investigate the possibility of synthesizing cobalt doped willemite ceramic blue pigment by using Egyptian white sand as environmental and economical raw material for multi-applications in coatings and inks.
Design/methodology/approach
After the synthesis process, the prepared blue pigment was characterized via X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray analysis technique. Then the blue pigment was integrated into both coating and ink formulations. The effect of the prepared multifunctional coatings on corrosion resistance and thermal stability was evaluated using different standard tests. Also, the effect of inclusion of blue pigment in flexographic printing ink formulation was done.
Findings
The results showed that the coating containing the cobalt doped willemite blue pigment offered good anticorrosive performance and high thermal stability. Additionally, the presented results revealed that integration of the blue pigment in flexographic printing ink formulation enhanced fineness, gloss, viscosity and color more than the commercial one “FX 430–201.”
Originality/value
In conclusion, relied on the eco-friendly principle which can be regarded as an economic and green strategy, it can be obtained that this new pigment can provide good multifunctions such as corrosion resistance and thermal stability in coatings and good fineness, gloss, viscosity and color in inks which can enable them to be widely applied in different industries.
Details
Keywords
Yang Liu, Jialing Wang, Huayang Cai, Yawei Shao, Zhengyi Xu, Yanqiu Wang and Junyi Wang
Epoxy zinc-rich coatings are widely used in harsh environments because of the long-lasting cathodic protection of steel surfaces. The purpose of this paper is to use flake zinc…
Abstract
Purpose
Epoxy zinc-rich coatings are widely used in harsh environments because of the long-lasting cathodic protection of steel surfaces. The purpose of this paper is to use flake zinc powder instead of the commonly used spherical zinc powder to reduce the zinc powder content.
Design/methodology/approach
In this paper, the authors have prepared an anticorrosive zinc-rich coating using a flake zinc powder instead of the conventional spherical zinc powder. The optimal dispersion of scaly zinc powder in zinc-rich coatings has been explored by looking at the surface and cross-sectional morphology and studying the cathodic protection time of the coating.
Findings
The final epoxy zinc-rich coating with 35 Wt.% flake zinc powder content was prepared using sand-milling dispersions. It has a similar cathodic protection time and salt spray resistance as the 60 Wt.% spherical zinc-rich coating, with a higher low-frequency impedance modulus value.
Originality/value
This study uses flake zinc powder instead of the traditional spherical zinc powder. This reduces the amount of zinc powder in the coating and improves the corrosion resistance of the coating.
Details
Keywords
Yajun Chen, Zehuan Sui and Juan Du
This paper aims to focus on the research progress of intelligent self-healing anti-corrosion coatings in the aviation field in the past few years. The paper provides certain…
Abstract
Purpose
This paper aims to focus on the research progress of intelligent self-healing anti-corrosion coatings in the aviation field in the past few years. The paper provides certain literature review supports and development direction suggestions for future research on intelligent self-healing coatings in aviation.
Design/methodology/approach
This mini-review uses a systematic literature review process to provide a comprehensive and up-to-date review of intelligent self-healing anti-corrosion coatings that have been researched and applied in the field of aviation in recent years. In total, 64 articles published in journals in this field in the last few years were analysed in this paper.
Findings
The authors conclude that the incorporation of multiple external stimulus-response mechanisms makes the coatings smarter in addition to their original self-healing corrosion protection function. In the future, further research is still needed in the research and development of new coating materials, the synergistic release of multiple self-healing mechanisms, coating preparation technology and corrosion monitoring technology.
Originality/value
To the best of the authors’ knowledge, this is one of the few systematic literature reviews on intelligent self-healing anti-corrosion coatings in aviation. The authors provide a comprehensive overview of the topical issues of such coatings and present their views and opinions by discussing the opportunities and challenges that self-healing coatings will face in future development.
Details
Keywords
Thien Vuong Nguyen, Vy Do Truc, Tuan Anh Nguyen and Dai Lam Tran
This study aims to explore the synergistic effect of oxide nanoparticles (ZnO, Fe2O3, SiO2) and cerium nitrate inhibitor on anti-corrosion performance of epoxy coating. First…
Abstract
Purpose
This study aims to explore the synergistic effect of oxide nanoparticles (ZnO, Fe2O3, SiO2) and cerium nitrate inhibitor on anti-corrosion performance of epoxy coating. First, cerium nitrate inhibitors are absorbed on the surface of various oxide nanoparticles. Thereafter, epoxy nanocomposite coatings have been fabricated on carbon steel substrate using these oxide@Ce nanoparticles as both nano-fillers and nano-inhibitors.
Design/methodology/approach
To evaluate the impact of oxides@Ce nanoparticles on mechanical properties of epoxy coating, the abrasion resistance and impact resistance of epoxy coatings have been examined. To study the impact of oxides@Ce nanoparticles on anti-corrosion performance of epoxy coating for steel, the electrochemical impedance spectroscopy has been carried out in 3% NaCl solution.
Findings
ZnO@Ce3+ and SiO2@Ce3+ nanoparticles provide more enhancement in the epoxy pore network than modification of the epoxy/steel interface. Whereas, Fe2O3@Ce3+ nanoparticles have more to do with modification of the epoxy/steel interface than to change the epoxy pore network.
Originality/value
Incorporation of both oxide nanoparticles and inorganic inhibitor into the epoxy resin is a promising approach for enhancing the anti-corrosion performance of carbon steel.
H. Abd El-Wahab and Raafat A. El-Eisawy
This paper aims to prepare new modified alkyd resins and use it as an antimicrobial binder for surface coating applications.
Abstract
Purpose
This paper aims to prepare new modified alkyd resins and use it as an antimicrobial binder for surface coating applications.
Design/methodology/approach
Various modified alkyd resins were prepared by partial replacement of 3,6-dichloro benzo[b]thiophene-2-carbonyl bis-(2-hydroxy ethyl)-amide as a source of polyol with glycerol and confirmed by acid value, FT-IR, 1H-NMR. The modified alkyd resins were covering a wide range of oil lengths and hydroxyl content (0%, 10%, 20% and 30% excess-OH). The antimicrobial activity of the prepared alkyds was also investigated. The coatings of 60 ± 5 µm thickness were applied to the surface of glass panels and mild steel strips by means of a brush. Physico-mechanical tests, chemical resistance and antimicrobial activities were investigated.
Findings
The obtained results illustrate that the introduction of benzo[b]thiophene derivative as a modifier polyol within the resin structure improved the film performance and enhanced the physico-mechanical characteristics, chemical resistance and the antimicrobial activities.
Practical implications
The modified alkyd resins can be employed as antimicrobial binders in paint compositions for a variety of surfaces, particularly those that are susceptible to a high number of bacteria.
Originality/value
Modified alkyd resins based on antimicrobial heterocyclic compounds have the potential to be promising in the manufacturing of antimicrobial coatings and development of paints, allowing them to function to prevent the spread of microbial infection, which is exactly what the world requires at this time. Also, they can be applied in different substrates for industrial applications.
Details
Keywords
Roma G. Elfadel, Hala M. Refat, H. Abdelwahab, Salem S. Salem, Mohamed A. Awad and M.A.M. Abdel Reheim
This paper aims to investigate the prepared modified alkyd and poly(ester-amide) (PEA) resins as antimicrobial and insecticide binders for surface coating applications.
Abstract
Purpose
This paper aims to investigate the prepared modified alkyd and poly(ester-amide) (PEA) resins as antimicrobial and insecticide binders for surface coating applications.
Design/methodology/approach
Salicylic diethanolamine and 4-(N, N-dimethylamino) benzylidene glutamic acid were prepared and used as new sources of polyol and dibasic acid for PEA and alkyd resins, then confirmed by: acid value, FT-IR and 1H-NMR. The coating performance of the resins was determined using measurements of physico-mechanical properties. The biological and insecticide activities of the prepared resins were investigated.
Findings
The tests carried out revealed that the modified PEA and alkyd enhanced both phyisco-mechanical and chemical properties in addition to the biological and insecticide activities. The results of this paper illustrate that the introduction of salicylic diethanolamine and 4-(N, N-dimethylamino) benzylidene glutamic acid within the resin structure improved the film performance and enhanced the antimicrobial activity performance of PEA and alkyd resins.
Research limitations/implications
The modified alkyd and PEA organic resins can be used as biocidal binders when incorporated into paint formulations for multiple surface applications, especially those that are exposed to several organisms.
Originality/value
Modified alkyd and PEA resins based on newly synthesized modifiers have a significant potential to be promising in the production and development of antimicrobial and insecticide paints, allowing them to function to restrict the spread of insects and microbial infection.
Details
Keywords
Dongdong Song, Wenxiang Qin, Qian Zhou, Dong Xu and Bo Zhang
The anticorrosion coatings used in marine and atmospheric environment are subjected to many environmental factors. And the aging failure has been puzzling researchers. The purpose…
Abstract
Purpose
The anticorrosion coatings used in marine and atmospheric environment are subjected to many environmental factors. And the aging failure has been puzzling researchers. The purpose of this study is to find the correlation between the initial aging of epoxy coatings and the typical marine atmospheric environmental factors.
Design/methodology/approach
The epoxy coatings were subjected to a one-year exposure in three typical marine atmospheres. Meanwhile, principal component analysis, linear regression and Spearman and gray correlation analysis were applied to quantify the environmental characteristics and establish correlations with the coating aging.
Findings
The results indicate that the coating will undergo macroscopic fading and chalking upon exposure to the marine atmosphere, while microscopic examination reveals holes, cracks and partial peeling. The adhesion performance and electrochemical properties of the coating deteriorated with prolonged exposure, coating aging mainly occurs with the generation of O-H bonds and the breakage of molecular chains such as C-N and C-O-C. The coating was most deeply aged after exposure to the Xisha, followed by Zhoushan and finally Qingdao. Environmental factors affect the photooxidative aging and hydrolytic degradation processes of coatings and thus coating aging. To further demonstrate the correlation between environmental factors and coating aging, principal component analysis was used. The correlation model between environmental factors and coating aging was subsequently obtained. The correlation model between the rate of coating adhesion loss (E) and the comprehensive evaluation parameter of environmental factors (Z) is expressed as E = 0.142 + 0.028Z. Meanwhile, the Spearman correlation analysis and gray correlation method were used to investigate the impact of each environmental factor on coating aging. Solar irradiation, relative humidity and wetting time have the highest correlation with coating aging, which are all above 0.8 and have the greatest influence on coating aging; wind speed and temperature have the smallest correlation with coating aging, which are about 0.6 and have the least influence on coating aging.
Originality/value
This paper establishes a correlation between typical marine environmental factors and coating aging performance, which is crucial for predicting the service life of other coatings in diverse environments.
Details
Keywords
Shuliu Wang, Qianqian Liu, Jin Wang, Nana Chen, JunHang Chen, Jialiang Song, Xin Zhang and Kui Xiao
This study aims to investigate the role of aluminium (Al) in marine environment and the corrosion mechanism of galvalume coatings by conducting accelerated experiments and data…
Abstract
Purpose
This study aims to investigate the role of aluminium (Al) in marine environment and the corrosion mechanism of galvalume coatings by conducting accelerated experiments and data analysis.
Design/methodology/approach
Samples were subjected to accelerated corrosion for 136 days via salt spray tests to simulate the natural conditions of marine environment and consequently accelerate the experiments. Subsequently, the samples were examined using various test methods, such as EDS, scanning electron microscopy (SEM), X-ray diffraction (XRD) and electrochemical impedance spectroscopy (EIS), and the obtained data were analysed.
Findings
Galvalume coatings comprised interdigitated zinc (Zn)-rich and dendritic Al-rich phases. Corrosion was observed to begin with a Zn-rich phase. The primary components of the corrosion product film were Al2O3 and Zn5(OH)8Cl2·H2O. It was confirmed that the role of Al was to form a dense protective film, thereby successfully blocking the entry of corrosive media and protecting the iron substrate.
Originality/value
This study provides a clearer understanding of the corrosion mechanism and kinetics of galvalume coatings in a simulated marine environment. In addition, the role of Al, which is rarely mentioned in the literature, was investigated.
Details