交变压力环境下KH-550改性氧化石墨烯环氧涂层的失效机制

石墨烯因其优异的力学性能及热化学稳定性、较大的比表面积而在防腐涂层应用中备受关注。采用硅烷偶联剂KH550对氧化石墨烯(GO)进行表面改性，研究了改性GO对深海交变压力模拟环境下环氧涂层失效机制的影响。利用TEM和沉降实验观察了GO粉末的分散性及其与环氧树脂的相容性；利用重量法、附着力测试和拉伸测试研究了涂层的防护性能；利用OCP和EIS研究了涂层在交变压力下的失效历程。结果表明：KH550改性GO涂层在抗渗透性、强韧性、附着力等方面均有明显提高。添加改性GO减少了涂层的表面缺陷，更加致密的涂层结构有效阻碍了溶液的扩散。改性GO与环氧树脂结合良好的界面可延缓交变压力的破坏作用，从而延长了涂层在交变压力环境下的使役寿命。

Failure Mechanism of an Epoxy Coating with KH-550 Modified Graphene Oxide Under Alternating Hydrostatic Pressure

Graphene has attracted much attention in the application of anticorrosive coatings, due to its excellent mechanical properties, thermochemical stability and large specific surface area. The surface modification of graphene oxide (GO) was performed by silane coupling agent KH550, and the effect of modified GO on the failure mechanism of epoxy coating under simulated marine alternating hydrostatic pressure (AHP) was investigated. The dispersibility of GO powder and its compatibility with epoxy resin were observed by TEM and sedimentation experiments. The protective properties of the coating were studied by gravimetric method, adhesion test and tensile test. OCP and EIS were utilized to study the failure process of the coating under AHP. Results show that the anti-permeability, mechanical properties and adhesion of the coating are improved by modification of KH550-GO. The addition of modified GO reduces the surface defects of the coating, producing acompact coating structure, which effectively retards the diffusion of the solution. The well bonded interface between modified GO and epoxy resin can prevent the destruction of AHP and thus, extend the service life of the coating under AHP environment.