JEFFAMINE M-600(R)改性六方氮化硼及其水性环氧复合涂层的腐蚀防护性能

Synthesis of JEFFAMINE M-600(R)Modified Hexagonal Boron Nitride Nanosheets and Anticorrosion Property of Its Waterborne Epoxy Composite Coatings

目的提高六方氮化硼的分散性和环氧涂层的腐蚀防护性能。方法利用O-(2-氨丙基)-O'-(2-甲氧基乙基)聚丙二醇(JEFFAMINE M-600(R))对六方氮化硼(h-BN)进行功能化,实现其在水性环氧树脂中的稳定分散和相容性,并将其添加至水性环氧树脂中制备了具有优异阻隔性能的水性环氧复合涂层。利用SEM、TEM、XPS等手段证实了h-BN@JEFFAMINE M-600(R)的成功制备;此外,采用电化学手段对涂层的腐蚀防护性能进行了评价。结果JEFFAMINE M-600(R)成功修饰在h-BN表面,有效提高了h-BN在水性环氧树脂中的分散稳定性和相容性;同时所制备的h-BN@JEFFAMINE M-600(R)/水性环氧复合涂层在浸泡38 d后仍表现出优异的抗腐蚀性能,其阻抗模值(1.05×10^(9)Ω·cm^(2))较水性环氧涂层(1.31×10^(7)Ω·cm^(2))提高了约2个数量级,这主要归因于h-BN@JEFFAMINE M-600(R)的添加可以有效提高水性环氧涂层的阻隔效应,从而延缓腐蚀介质向基底的扩散,进而表现出优异的腐蚀防护性能。结论JEFFAMINE M-600(R)功能化有效提高了h-BN的剥离效率和稳定分散,使得h-BN@JEFFAMINE M-600(R)纳米杂化材料的添加可以有效提高水性环氧基体的致密性和阻隔效应,进而增强复合涂层对金属基底的腐蚀防护。

Metal corrosion,as a significant challenge across various industries,has caused substantial economic losses and safety concerns to human society.Hence,it is imperative to develop new protective materials and techniques.To improve the corrosion protection to underlying steel substrates,organic coatings have been considered as an effective method owing to their superior chemical inertness and strong adhesion with steel substrates.Recently,nanomaterials are widely used to reinforce the corrosion protection performance of organic coatings,in which hexagonal boron nitride(h-BN)nanosheets with high aspect ratio,superior barrier properties and unique electrical insulation properties,hold immense potential for enhancing the anti-corrosion performance of organic coatings.Yet,their tendency to aggregate due to strong interlayer interactions within polymer matrix limits their applicability in anti-corrosion coatings.In this study,O-(2-aminopropyl)-O'-(2-methoxyethyl)polypro-pylene glycol(JEFFAMINE M-600(R))was utilized to functionalize h-BN nanosheets based on the Lewis acid-base interactions,and the prepared nanohybrids(h-BN@JEFFAMINE M-600(R))were incorporated into water-borne epoxy(WEP)coatings to improve their barrier and corrosion protection performance.To confirm the successful functionalization of JEFFAMINE M-600(R)molecules on the h-BN surface,the morphology and chemical composition of h-BN before and after functionalization of JEFFAMINE M-600(R)molecules were characterized by scanning electronic microscopy(SEM),transmission electron microscopy(TEM)and X-ray photoelectron spectroscopy(XPS).In addition,the corrosion protection performance of the h-BN@JEFFAMINE M-600(R)incorporated WEP coatings(h-BN@JEFFAMINE M-600(R)/WEP)in 3.5wt.%NaCl solution was evaluated by electrochemical impedance spectroscopy(EIS).Results showed that JEFFAMINE M-600(R)molecules were successfully modified on the h-BN surface based on the Lewis acid-base interactions between them,and the prepared h-BN@JEFFAMINE M-600(R)hybrids exhibited stable dispersion in anhydrous ethanol.Further SEM characterization showed that the h-BN@JEFFAMINE M-600(R)/WEP coating exhibited dense and rough fracture surface compared with the pure WEP coating,indicating that the addition of h-BN@JEFFAMINE M-600(R)hybrids were beneficial to the barrier property.EIS results revealed that the corrosion protection performance of all coatings decreased with the increase of immersion time in 3.5wt.%NaCl solution owing to the penetration of corrosive medium.However,impedance modulus(|Z|f=0.01 Hz)value of the h-BN@JEFFAMINE M-600(R)/WEP/steel system after 38 d of exposure was approximately 1.05×10^(9)Ω·cm^(2),which was nearly two orders of magnitude higher than that of the pure WEP coating(1.31×10^(7)Ω·cm^(2)).Eventually,the corrosion status of the steel beneath the coatings was characterized by SEM.SEM results showed that the steel beneath the pure WEP coating was severely corroded with high content of oxygen and chloride while the corrosion degree of the steel beneath the h-BN@JEFFAMINE M-600(R)/WEP coating was reduced with significant reduction in the oxygen and chloride contents.These findings suggest that the h-BN@JEFFAMINE M-600(R)/WEP coating exhibited exceptional corrosion protection performance with respect to the pure WEP coating,which can be primarily attributed to the fact that the addition of h-BN@JEFFAMINE M-600(R)hybrids effectively improve the barrier property of WEP matrix and prolong the diffusion path of the corrosive medium,thus inhibiting the corrosion of underlying steel substrates.This work could provide a novel method to facilitate the application of two-dimensional nanomaterials in anticorrosion field.