石墨烯增强的自修复性有机复合涂层的耐腐蚀机理

Graphene reinforced self-healing polymer composite coatings will be fabricated on steel surfaces. Graphene will function as the carrier of the self-healing agents, as well as the reinforcement of the composite coatings for barrier properties and mechanical properties. With the assistance of graphene, the self-healing agents will be dispersed and stored in the composite coatings and released on demand. The fabrication of the composite coatings will be focused on the selection of the healing-agents, the storage of the healing-agent on graphene surfaces and the dispersion of graphene. The permeability of chloride ions in the composite coatings will be studied under high humidity, high atmospheric temperature condition. The self-healing properties of the composite coatings will also be characterized. A systematic analysis of the composite coatings will be emphasized on the synergetic effects of the physical barrier properties and the chemical self-healing abilities, according to the different corrosion stages (diffusion, under-painting corrosion initiation, coating damage). The anticorrosion mechanism and the critical factors will be proposed for the graphene reinforced self-healing polymer composite coatings on steel surfaces under the condition of high humidity, high atmospheric temperature and high concentration of chloride ion.

在钢铁材料表面制备石墨烯增强的自修复性高分子基复合涂层。其中，石墨烯同时起到负载自修复剂以及增强涂层的阻隔性能和力学性能的作用。自修复剂在石墨烯表面的负载辅助实现自修复剂的分散、储存和缓释。通过优化自修复剂的选择、自修复剂在石墨烯表面的负载方法、石墨烯在涂层中的分散状态等制备复合涂层。在此基础上，研究湿热条件下氯离子在复合涂层中的渗透现象以及涂层发生破坏时的自修复性能。并根据涂层的不同腐蚀阶段（腐蚀介质扩散阶段、膜下腐蚀起始阶段、涂层破坏阶段），系统研究石墨烯的物理阻隔作用和自修复剂的化学修复作用对复合涂层耐蚀性的协同增强机理。提出钢铁材料表面石墨烯增强的自修复性复合涂层在高氯离子、高湿热条件下的防护机理以及起主导作用的因素。

钢铁材料的表面涂层已基本完成无铬化转变和水性化转变，替代了对环境影响较大的有铬涂层和溶剂型涂层。智能化涂层是钢铁表面涂层技术发展的趋势之一，即针对特定的环境变化，涂层自发地做出相应的调整和响应，如自修复和自检测等。本项目利用氧化石墨烯的两亲性，首次提出了氧化石墨烯在皮克林乳液的水/油界面自组装的方法，制备了氧化石墨烯微胶囊。其中，微胶囊外壳由氧化石墨烯片层组成，具有短程有序结构，厚度只有55纳米。亚麻籽油做为修复剂，包裹在氧化石墨烯外壳中，装载率高达97.2%。实现了氧化石墨烯辅助的自修复剂的分散、储存和有效释放。研究了制备氧化石墨烯稳定的皮克林乳液，以及完整的氧化石墨烯微胶囊的主要影响因素，包括氧化石墨烯水分散液的pH值，以及氧化石墨烯和亚麻籽油的质量比等。为了提高微胶囊的化学稳定性和机械稳定性，提出了聚醚胺分子化学缝合氧化石墨烯片层的方法。在钢板表面制备了氧化石墨烯微胶囊增强的水性聚氨酯自修复性复合涂层，在实现涂层自修复性能的同时，增强了涂层的耐蚀性能。含有10%微胶囊的水性聚氨酯复合涂层能自发性地修复20微米宽的划痕。修复后，复合涂层的阻抗模值比纯聚氨酯涂层高4个数量级。 为提高涂层在近海腐蚀环境下或高磨损条件下的耐蚀性，提供了氧化石墨烯微胶囊外壳的物理阻隔作用和修复剂的化学修复作用协同增强的新途径。