scholarly journals Preparation and Properties of Self-Healing and Self-Lubricating Epoxy Coatings with Polyurethane Microcapsules Containing Bifunctional Linseed Oil

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1578 ◽  
Author(s):  
Haijuan Yang ◽  
Qiufeng Mo ◽  
Weizhou Li ◽  
Fengmei Gu
Keyword(s):  
Interfacial Polymerization ◽  
Electrochemical Impedance ◽  
Linseed Oil ◽  
Salt Spray ◽  
Average Diameter ◽  
Organic Coating ◽  
Epoxy Coating ◽  
The Self ◽  
Self Healing ◽  
Pure Epoxy

An organic coating is commonly used to protect metal from corrosion, but it is prone to failure due to microcracks generated by internal stress and external mechanical action. The self-healing and self-lubricating achieved in the coating is novel, which allows an extension of life by providing resistance to damage and repair after damage. In this study, a new approach to microencapsulating bifunctional linseed oil with polyurethane shell by interfacial polymerization. Moreover, the self-healing and self-lubricating coatings with different concentrations of microcapsules were developed. The well-dispersed microcapsules showed a regular spherical morphology with an average diameter of ~64.9 μm and a core content of 74.0 wt.%. The results of the salt spray test demonstrated that coatings containing microcapsules still possess anticorrosion, which is improved with the increase of microcapsules content, after being scratched. The results of electrochemical impedance spectroscopy showed a |Z|f=0.01Hz value of 104 Ω·cm2 for pure epoxy coating after being immersed for 3 days, whereas the coating with 20 wt.% microcapsules was the highest, 1010 Ω·cm2. The results of friction wear showed that the tribological performance of the coating was enhanced greatly as microcapsule concentration reached 10 wt.% or more, which showed a 86.8% or more reduction in the friction coefficient compared to the pure epoxy coating. These results indicated that the coatings containing microcapsules exhibited excellent self-healing and self-lubricating properties, which are positively correlated with microcapsules content.

ANTICORROSION PERFORMANCE OF SELF-HEALING POLYMERIC COATINGS ON LOW CARBON STEEL SUBSTRATES

2017 ◽  
Vol 79 (7-4) ◽  
Author(s):  
Muhammad Ashraff Ahmad Seri ◽  
Esah Hamzah ◽  
Abdelsalam Ahdash ◽  
Mohd Fauzi Mamat
Keyword(s):  
Steel Substrate ◽  
Salt Spray ◽  
Immersion Test ◽  
Salt Spray Test ◽  
Test Method ◽  
The Self ◽  
Self Healing ◽  
Pure Epoxy ◽  
Steel Substrates ◽  
Epoxy Paint

Recently, self-healing coating is classified as one of the smart coatings which has the ability to heal or repair damage of the coating to prevent further corrosion. The aim of this study is to synthesize the self-healing coatings from polymeric material and evaluate the performance and their corrosion behavior when coated on steel substrates. The corrosion tests were performed using immersion test and salt spray test method at room temperature. The immersion test shows that self-healing coating gives lower corrosion rate compared to pure epoxy paint, with a value of 0.02 and 0.05 mm/year respectively. Also, salt spray test shows similar trend as the immersion test, which is 0.11 and 0.19 mm/year for self-healing coating and pure epoxy paint respectively. While uncoated samples without any protection corroded at 0.89 mm/year. It was also found that the damage on self-healing coating was covered with zeolite from the microcapsules indicating that the self-healing agent was successfully synthesized and could function well. In other words, self-healing coating shows better corrosion resistance compared to the pure epoxy coating on steel substrate.

The self-healing evaluation of microcapsule-based epoxy coatings applied on AA6061 Al alloy in 3.5% NaCl solution

2017 ◽  
Vol 64 (2) ◽  
pp. 225-232 ◽  
Author(s):  
Mehdi Shahidi Zandi ◽  
Majdeh Hasanzadeh
Keyword(s):  
Electrochemical Impedance ◽  
Linseed Oil ◽  
Theoretical Estimate ◽  
The Self ◽  
Al Alloy ◽  
Self Healing ◽  
Nacl Solution ◽  
Epoxy Coatings ◽  
Water Emulsion ◽  
Content Type

Purpose The aim of this work is to investigate the self-healing performance of epoxy coatings containing microcapsules. The microcapsule-based coatings were applied on AA6061 Al alloy and immersed in 3.5 per cent NaCl solution. Design/methodology/approach Microcapsules with urea–formaldehyde as the shell and linseed oil as the healing agent were prepared by in situ polymerization in an oil-in-water emulsion. For the sake of an optimum self-healing system, some coating samples were prepared by using different microcapsule concentrations: 0, 5, 10 and 20 Wt.%. The scratch-filling efficiency as the theoretical estimate of the self-healing performance was calculated for the coating samples with different microcapsule concentrations. The scratch-sealing efficiency (SSE) as a particularly crucial parameter in the self-healing evaluation of coatings was measured by both electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) techniques. Findings According to EIS and EN results, the coating samples containing 5 and 10 per cent microcapsules provided the insignificant self-healing performance, while the coating sample containing 20 per cent microcapsules exhibited the acceptable self-healing performance to AA6061 alloy in the NaCl solution. The measured SSE values confirmed the good agreement of EN data with electrochemical parameters obtained from the EIS technique. Originality/value This work is an attempt to evaluate the self-healing performance of microcapsule-based epoxy coatings applied on AA6061 Al alloy in sea water.

scholarly journals Self-healing and corrosion performance of polyurethane coating containing polyurethane microcapsules

2021 ◽  
Author(s):  
Hanieh Fathi Fathabadi ◽  
Mehdi Javidi
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Interfacial Polymerization ◽  
Electrochemical Impedance ◽  
Steel Substrate ◽  
The Self ◽  
Self Healing ◽  
Polyurethane Coating ◽  
Healing Efficiency ◽  
Scanning Electron

Abstract In this study, the self-healing behavior of the polyurethane coating containing polyurethane microcapsules was investigated. Microcapsules, with the average size of 99 µm and shell thickness of 11 µm, were successfully synthesized via the interfacial polymerization technique and were incorporated into the polyurethane coating matrix. The electrochemical impedance spectroscopy and scanning electron microscope were employed to investigate the healing performance and corrosion behavior of the coatings on the carbon steel substrate. The recorded results revealed that artificial scratches were successfully healed and the coating containing 20 wt% microcapsules exhibited the best healing performance (85% healing efficiency) among all the prepared coatings. The self-healing ability of the coatings were verified via scanning electron microscope. After 24 hours, the healing efficiency attained a reasonable value of 68% during exposure to test solution. It was found that corrosion resistance and coating adhesion were significantly improved by incorporating the microcapsules into the coating.

scholarly journals Self-Healing Epoxy Coating with Microencapsulation of Linseed Oil for the Corrosion Protection of Magnesium (Mg)

2021 ◽  
Vol 2129 (1) ◽  
pp. 012008
Author(s):  
J Alias ◽  
N A Johari ◽  
A Zanurin ◽  
N A Alang ◽  
M Z M Zain
Keyword(s):  
Corrosion Rate ◽  
Protective Coatings ◽  
Linseed Oil ◽  
Urea Formaldehyde ◽  
Epoxy Coating ◽  
The Self ◽  
Core Material ◽  
Resin Matrix ◽  
Self Healing ◽  
Magnesium Sheet

Abstract The ability to self-heal is an important feature for the long-term durability of protective coatings on metal alloys. Microcapsules in the self-healing coating allowed for automatic recovery of any damages or cracks, extending the life of the coating. In this study, self-healing microcapsules containing linseed oil as the core material and polyurea-formaldehyde (PUF) as the shell material were manufactured to epoxy resin matrix. Coatings were applied to a bare magnesium (Mg) substrate and scratched to test the self-healing ability. Optical and scanning electron microscopy (SEM) were used to characterize the microcapsules formed by varied stirring rates of 300 and 800 rpm. By using potentiodynamic polarization in a 3.5 wt.% NaCl solution, the corrosion rate of embedded microcapsules and coatings on Mg was evaluated, and the corrosion rate was studied using the Tafel plot. As a consequence, the epoxy coating containing linseed oil and urea formaldehyde, stirred at 800 rpm, significantly resists corrosion attack on the magnesium sheet, with decreased corrosion current density, icorr (1.552 μA/cm2) as compared to the bare magnesium sheet (109.8 μA/cm2). During the microcapsule preparation, increasing the stirring rate from 300 to 800 rpm reduces the icorr value by roughly half. As a result, the self-healing coatings demonstrated adequate self-healing and corrosion resistance recovery on magnesium alloys.

scholarly journals Cerium Dioxide Nanoparticles as Smart Carriers for Self-Healing Coatings

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 791 ◽  
Author(s):  
Sehrish Habib ◽  
Eman Fayyad ◽  
Muddasir Nawaz ◽  
Adnan Khan ◽  
Rana A. Shakoor ◽  
...  
Keyword(s):  
Corrosion Inhibition ◽  
Cerium Dioxide ◽  
Electrochemical Impedance ◽  
Protective Layer ◽  
Vital Role ◽  
Epoxy Coating ◽  
Gravimetric Analysis ◽  
Protective Film ◽  
Self Healing ◽  
Vis Spectroscopy

The utilization of self-healing cerium dioxide nanoparticles (CeO2), modified with organic corrosion inhibitors (dodecylamine (DDA) and n-methylthiourea (NMTU)), in epoxy coating is an efficient strategy for enhancing the protection of the epoxy coating and increasing its lifetime. Fourier transform infrared (FTIR) spectroscopy analysis was used to confirm the loading and presence of inhibitors in the nanoparticles. Thermal gravimetric analysis (TGA) measurement studies revealed the amount of 25% and 29.75% w/w for NMTU and DDA in the nanoparticles, respectively. The pH sensitive and self-release behavior of modified CeO2 nanoparticles is confirmed through UV-vis spectroscopy and Zeta potential. It was observed, through scanning electron microscopy (SEM), that a protective layer had been formed on the defect site separating the steel surface from the external environment and healed the artificially created scratch. This protective film played a vital role in the corrosion inhibition of steel by preventing the aggressiveness of Cl− in the solution. Electrochemical impedance spectroscopy (EIS) measurements exhibited the exceptional corrosion inhibition efficiency, reaching 99.8% and 95.7% for the modified coating with DDA and NMTU, respectively, after five days of immersion time.

Characterizations of UV Aging and Atmospheric Corrosion on Epoxy Coated 7A04 Aluminum Alloy

2011 ◽  
Vol 686 ◽  
pp. 784-791
Author(s):  
Chao Fang Dong ◽  
Kui Xiao ◽  
Hai Sheng ◽  
Y.H. An ◽  
Xiao Gang Li
Keyword(s):  
Aluminum Alloy ◽  
Uv Irradiation ◽  
Atmospheric Corrosion ◽  
Electrochemical Impedance ◽  
Salt Spray ◽  
Alloy System ◽  
Epoxy Coating ◽  
Test Time ◽  
Uv Aging ◽  
Resistance Decrease

The aim of this work is to investigate characterizations of corrosion on 7A04 aluminum alloy with epoxy coating under simulated marine atmosphere with/without ultraviolet irradiation. The environment containing Cl-and sunlight illumination was simulated by salt spray test and UV irradiation/condensation treatment. The corrosion behavior was studied by electrochemical impedance spectroscopy, and level of coating damage was evaluated through gloss measurement. Scanning electron microscope was chosen to observe surface properties of epoxy coating/7A04 aluminum alloy system. The results show that the electrochemical characters are closely related to the aging degree of epoxy coating, which could influence the penetrating process of oxygen and corrosive medium. The coating resistance decrease, while the coating capacitance and the pore rate increase as prolonging of the test time. Along with gloss loss of epoxy coating, pores appear on the surface and the blisters break, which may act as bulk defects of epoxy coating. The coating degradation and substrate corrosion were accelerated by the cooperation of UV irradiation and salt spray. UV aging significant accelerated the deterioration of coating with larger and deeper pores compared to that of non-UV irradiation coating.

Self-Healing Epoxy Coating Modified by Double-Walled Microcapsules Based Polyurea for Metallic Protection

2019 ◽  
Vol 821 ◽  
pp. 313-320
Author(s):  
Yan Xuan Ma ◽  
Ying Rui Zhang ◽  
Jia Tong Liu ◽  
Meng Yao Li ◽  
Ya Qian Xu
Keyword(s):  
Chemical Structure ◽  
Interfacial Polymerization ◽  
Electrochemical Impedance ◽  
Self Healing ◽  
High Corrosion Resistance ◽  
Hexamethylene Diamine ◽  
Thermogravimetric Analyzer ◽  
The Core ◽  
Core Content ◽  
Scanning Electronmicroscopy

The effectiveness of preploymer and 1,6-Hexamethylene diamine encapsulated by double-walled microcapsules based polyurea (PUA) was explored for healing the cracks generated in epoxy coatings. Double-walled microcapsules were systhesized by interfacial polymerization at the interface between the prepolymer droplets and the 1,6-Hexamethylene diamine droplets to form the polyurea shell. The effect of synthetic stirring speed on the morphology of the microcapsules was observed by scanning electronmicroscopy (SEM) and optical microscopy (OM). The chemical structure as well as the thermal properties and the core content were characterized by Fourier transform infrared spectroscopy (FTIR) and Thermogravimetric analyzer (TGA) respectively. Electrochemical impedance spectroscopy (EIS) studies of the artificial scratched area showed that the coating containing 2wt% and 5wt% microcapsules could effectively prevent further corrosion of the coating with high corrosion resistance efficiencies of 61.61% and 45.99% after immersing for 144h in seawater.

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