【摘 要】
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Epoxy coatings, as the most commonly used anticorrosion coatings, has been applied for ships and bridges. However, they are susceptible to damage under stress, particularly under cyclic stress, and le
【机 构】
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Institute of Materials, China Academy of Engineering Physics, Jiangyou, 621908, China
【出 处】
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第十一届全国表面工程大会暨第八届全国青年表面工程学术会议
论文部分内容阅读
Epoxy coatings, as the most commonly used anticorrosion coatings, has been applied for ships and bridges. However, they are susceptible to damage under stress, particularly under cyclic stress, and leading to produce small cracks in the epoxy coatings, which are often difficult to detect. Damage to the protective epoxy coatings on metal substrates initiates corrosion undercutting and other forms of environmental degradation. Therefore, early detection of damage in epoxy coatings and self-healing is an important requirement for the prevention of catastrophic losses. In this paper, a robust double-wall core-shell microcapsule system was prepared for the visual detection of mechanical damage and self-healing for epoxy coatings. The core material was 2, 7-dichlorofluorescein (DCF) dissolved in acrylate self-healing agents, encapsulated by a combination of polyurethane and poly (urea-formaldehyde). When the epoxy coatings suffer from mechanical damage, the DCF indicator is released and is able to react with the residual free amines in the coating matrix, creating a highly localized red color in the cracked region. Then, UV light was given to initiate the polymerization of acrylate mon mer and healed the cracks in the epoxy coatings. The diameter and morphology of microcapsules could be controlled by agitation speeds, the amount of PU prepolymer and urea-formaldehyde content. The results indicate that the inner shell thickness increases with the amount of PU prepolymer and the surface morphology of microcapsules is influenced by urea-formaldehyde content. Microcapsules with this damage indication and self-healing ability held promise for serving as an easy and effective damage indicator for amine-contained polymer coatings. The coating with this damage-reporting and self-healing ability is very usable for ships and bridges to detect the cracks at an early stage and to prevent corrosion, particularly in marine settings.
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