• Advances in nano research
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• v.4 no.4
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• pp.281-294
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• 2016

The advantages of nano-scale materials (size 1-99 nm in at least in one dimension) could be realized with their potential applications in diversified avenues. Herein, we report for the first time on the successful synthesis of homogeneous epoxy coatings containing phytogenic silver nanoparticles (Ag) on PVC and glass substrates by room-temperature curing of fully mixed epoxy slurry diluted by acetone. Alstonia scholaris bark extract was used to reduce and stabilize the silver ions. The surface morphology and mechanical properties of these coatings were characterized using the techniques like, UV-Vis (UV-Visible) spectrophotometry, X-ray diffraction (XRD), Fourier transform infrared spectrophotometry (FT-IR), Epifluorescence microscopy and scanning electron microscopy (SEM). The effect of incorporating Ag nanoparticles on the biofilm (scale) resistant epoxy-coated PVC was investigated by total viable counts ($CFU/cm^2$) from epoxy coating from (Initial) $1^{st}$ day to $25^{th}$ days. The phytogenic Ag nanoparticles were found to be significantly improving the microstructure of the coating matrix and thus enhanced the anti-biofilm performance of the epoxy coating. In addition, the antimicrobial mechanism of Ag nanoparticles played an important role in improving the anti-biofilm performance of these epoxy coatings.

• Corrosion Science and Technology
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• v.2 no.4
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• pp.202-206
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• 2003

Fusion Bonded Epoxy(FBE) systems have been widely used to protect pipelines for over 30 years. Numerous attempts have so far been made to improve the properties of FBE coatings such as chemical resistance, adhesion, water resistance, cathodic disbondment resistance, impact resistance, and flexibility to protect pipelines at a wet and a high temperature condition. But these attempts have not been successful in reducing some weakness, for instance, in pipeline operating at high temperature due to poor hot water resistance and cathodic protection. The purpose here is to build a basis for getting better corrosion resistance of FBE systems. Cresol-novolac epoxy coating systems were studied compared to bisphenol A type epoxy systems. After the immersion of the film in water at a high temperature for a long period, good adhesion to metal substrate and excellent cathodic disbond resistance were observed in the cresol-novolac epoxy resin systems. It is well known that the adhesion of organic coatings to metal substrate might be decreased due to the disruption of a chemical bond across the film and metal interface induced by water molecules. A high crosslinking density might decrease water permeability and improve cathodic disbonding protection in the coatings. Other factors are studied to understand anti-corrosion mechanism of Cresol-novolac epoxy coatings. In addition, the water absorption rate and the effect of cure temperature on the adhesion and cathodic disbonding resistance ofthe films were studied in different epoxy coatings and the effect of substrate was evaluated. The results of field application are proved that the Cresol-novolac epoxy coating system developed recently is one of the most suitable coatings for protection of pipelines.

• Corrosion Science and Technology
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• v.9 no.5
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• pp.201-208
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• 2010

Epoxy coatings cured by different amine based curing agents have been prepared. Atomic force microscopy (AFM) has been used to monitor the surface topology changes of epoxy coatings before and after hygrothermal cyclic test. The glass transition temperature ($T_g$) and coefficient of thermal expansion (CTE) of the epoxy coating were measured by Thermo-mechanical Analysis (TMA). The Electrochemical impedance spectroscopy (EIS) with hygrothermal cyclic test has been introduced to evaluate the corrosion protection of the epoxy coatings. In conclusion, thermal properties of epoxy coatings were in good agreement with the results of corrosion protection of epoxy coated carbon steel obtained result by EIS with hygrothermal cyclic test. The relationship between thermal properties, surface roughness changes and corrosion protection of epoxy coatings are discussed in this study.

• Journal of Ocean Engineering and Technology
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• v.18 no.1
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• pp.75-79
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• 2004

Organic coatings are widely used to control of the corrosion of a steel structure. The water in coatings may cause the coatings to swell, leading to the degradation of the coatings. In addition, water affects the permeation of oxygen and other corrosive agents, and consequently, the presence of such substances at coating-metal interface promotes corrosion of the metal substrate. In this study, the anticorrosive properties of 4 types of coating, such as epoxy-epoxy, epoxy-urethane, urethane-epoxy, urethane-urethane, were evaluated. The evaluation tests were conducted under cyclic water-absorption/desorption conditions, consisting of alternative exposure to diluted 0.001M-LiCl(a$H_2O$≒1) and concentrated 10M-LiCl(a$H_2O$≒0.15). The anticorrosive performance of coatings was found to decrease in the order of urethane-urethane > urethane-epoxy > epoxy-epoxy coating.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.262-268
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• 2003

Organic coatings are widely used to control the corrosion of steel structure. The water in coatings may cause swelling or solvation of coatings, leading to the degradation of coatings. In addition, water affects the permeation of oxygen and other corrosive agents, and consequently the presence of such substances at coating-metal interface promotes corrosion of metal substrate. In this study, the anticorrosive properties of 4 types of coating, such as epoxy-epoxy, epoxy-urethane, urethane-epoxy, urethane-urethane, were evaluated. The evaluation tests were carried out under cyclic water-absorption/desorption conditions, consisting of alternative exposure to diluted 0.001M-LiCl($a_{1120}{\fallingdotseq}1$) and concentrated l0M-LiCl($a_{1120}{\fallingdotseq}0.05$). The anticorrosive performances of coatings were found to decrease in the order of urethane-urethane> urethane-epoxy> epoxy-epoxy coating.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.2
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• pp.25-29
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• 2001

This study examined the effects of carbon surface modification by the epoxy resin coating on the electrochemical performance. The mesocarbon microbeads(MCMB) carbon was surface-modified by coating the epoxy resin and its electrochemical properties as an anode was examined. The surface coating of MCMB was carried out by refluxing the MCMB powders in a dilute H2SO4 solution, and mixing them with the epoxy resin-dissolved tetrahydrofuran(THF) solution. Under heat-treatment of the coated MCMB at the temperature over $1000^{\circ}C$, the epoxy-resin coating layer was converted into amorphous phase which was identified by a high resolution transmission electron microscope (HRTEM). The epoxy resin coated MCMB has higher Brunauer-Emmett-Teller (BET) surface area, higher charge/ discharge capacity and better cycleability than a raw MCMB without coating. The reason for the enhancement of cell performance by the epoxy resin coating were considered as the epoxy resin coating layer plays an important role to be a barrier for carbon reacting with electrolyte and to retard the formation of passivation layer.

• Computers and Concrete
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• v.19 no.3
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• pp.243-256
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• 2017

Epoxy-coated reinforcing bars are widely used to protect the corrosion of the reinforcing bars in the RC elements under their in-service environments and external loads. In most field surveys, it was reported that the corrosion resistance of the epoxy-coated reinforcing bars is typically better than the uncoated bars. However, from the experimental tests conducted in the labs, it was reported that, under the same loads, the RC elements with epoxy-coated reinforcing bars had wider cracks than the elements reinforced with the ordinary bars. Although this conclusion may be true considering the bond reduction of the reinforcing bar due to the epoxy coating, the maximum service loads used in the experimental research may be a main reason. To answer these two phenomena, service performance of 15 RC beam specimens with uncoated and epoxy-coated reinforcements under different fatigue loads was experimentally studied. Influences of different coating thicknesses of the reinforcing bars, the fatigue load range and load upper limit as well as fatigue load cycles on the mechanical performance of RC test specimens are discussed. It is concluded that, for the test specimens subjected to the comparatively lower load range and load upper limit, adverse effect on the service performance of test specimens with thicker epoxy-coated reinforcing bars is negligible. With the increments of the coating thickness and the in-service loading level, i.e., fatigue load range, load upper limit and fatigue cycles, the adverse factor resulting from the thicker coating becomes noticeable.

• Applied Chemistry for Engineering
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• v.25 no.4
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• pp.352-356
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• 2014

PDMS modified epoxy resin with epoxy group (EMPDMS) was prepared from the reaction of ${\alpha},{\omega}$-aminopropylpolydimethylsiloxane and diglycidyl ether of bisphenol-A (DGEBA) based epoxy resin, and PDMS modified epoxy hybrid compound (EMPDMSH) was prepared by introducing alkylesteraminopropyl alkoxy silane to EMPDMS. Their structures were characterized using FT-IR, $^1H$-NMR and $^{29}Si$-NMR. Coating materials were prepared by mixing EMPDMSH base and solvent. Physical properties of the coating materials coated on epoxy/glass fiber composite film were measured according to the content of PDMS in EMPDMSH. Contact angle of coating film was increased 30 to 71 degree. Adhesive property of coating film was 5B degree better then epoxy or acrylate coating materials, and surface roughness was decreased as increasing in EMPDMSH.

• Corrosion Science and Technology
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• v.5 no.2
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• pp.69-76
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• 2006

Premature cracking of the epoxy coatings applied on ship's ballast tanks(BT) can lead to damage of ship's hulls. To avoid this, it's important to have clear understanding of the underlying mechanism and primary factors of the coating crack. In this study, the efforts were made to clarify the integrated effects of main factors, i.e., initial coating shrinkage, thermally induced strain, steel-structural strain and the intrinsic coating flexibility at the initial and after aging, to the early cracking phenomena of epoxy coating in the ship's ballast tank. The coating crack is caused by combination of thermal stress, structural stress, and internal stresses which is closely related to chemical structures of the coatings. On the other hand, thermal stresses and dimensional stabilities would rarely play a major role in coating crack for ballast tank coatings with rather large flexibility. Crack resistance of the coatings at early stages can be estimated roughly by measuring internal stress, FT-IR and $T_g$ value of the coatings. A new screening test method was also proposed in this study, which can be possibly related to the long-term resistance of epoxy-based paints to cracking.

• Corrosion Science and Technology
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• v.11 no.5
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• pp.165-172
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• 2012

The corrosion resistance of epoxy-coated carbon steel was evaluated. The carbon steel surface was subjected to different treatment methods such as steel grit blasting with different size, steel shot ball blasting and power tool treatment. To study the effect of the treatments, the topology of the treated surface was observed by optical 3D microscopy and a pull-off adhesion test was conducted. The corrosion resistance of the epoxy-coated carbon steel was further examined by electrochemical impedance spectroscopy (EIS) combined with hygrothermal cyclic testing. The results of EIS indicated that the epoxy-coated carbon steel treated with steel grit blasting showed an improved corrosion resistance compared to untreated epoxy-coated surfaces or surfaces subjected to shot ball blasting and power tool treatments.