Enhanced anti-corrosion and hydrogen resistance performance for epoxy resin composite coating with modified boron nitride

Traditional hydrogen barrier composite coatings possess weak corrosion resistance and are hard to apply in actual high-pressure hydrogen environments. As a two-dimensional (2D) material, boron nitride (BN) is expected to address this problem due to its high specific surface area, excellent physical barrier properties and electrical insulation properties, but the agglomeration events are easily occurred by the poor dispersibility of BN during the process of fabrication and application. To address above issues, in this work, firstly, hydroxyl groups are successfully grafted onto BN by the NaOH. Then, the corresponding silane alcohols hydrolyzed (AH) by the methoxy group of silane coupling agent are covalently bonded with hydroxyl BN, and eventually form the modified BN. BN-AH/polytetrafluoroethylene (PTFE)/epoxy resin (EP) composite (BN-AH/PTFE/EP) films were prepared using different amounts of modified BN, followed by scrape-coating the BN-AH/PTFE/EP composite material onto different substrates. The electrochemical impedance spectroscopy (EIS) test results showed that the optimal sample was immersed in a 3.5 wt% NaCl solution for 30 d, and the impedance value |Z |_0.01Hz remained at 1.5 × 10⁹ Ω cm². Notably, the impedance is about 2 orders of magnitude higher than that of pure EP coating. Moreover, compared with pure EP coating, its H₂ permeability coefficient decreased by 66.9 %. This is mainly attributed to the good physical barrier performance of BN and the better dispersion performance of composite fillers in EP.