Abstract:
In order to improve the corrosion resistance of epoxy resin (EP) coatings, both polyhedral oligomeric silsesquioxane (POSS) modified hexagonal boron nitride (h-BN) and aniline trimer (AT) were co-doped into the epoxy curing system using as functional fillers. The hydroxylated boron nitride OH-BN was obtained by peeling off the hexagonal boron nitride at high temperature. The surface of OH-BN was modified with the silane coupling agent KH-560, and then the aminopropyl heptaisobutyl POSS (APS) and octaaminophenyl POSS (OAPPS) were grafted to synthesize APS-BN and OAPPS-BN. The two modified h-BN and aniline trimer were dispersed into EP to prepare organic-inorganic hybrid coatings through π-π interactions. The coating's AC impedance spectroscopy, Tafel curve, salt spray test, and contact angle, thermal and mechanical properties were characterized by some techniques. The results show that, compared with the pure epoxy coating, the composited coating doped with 0.5wt% OAPPS-BN-AT has the largest improvement in performance with an impedance value of 1.27×10
11 Ω·cm
2. The corrosion potential is −0.052 V with an increasing of 0.35 V. The salt spray resistance test exhibites that no pitting or blistering occurred for 30 days. Based on the POSS surface migration effect and h-BN barrier effect, the pencil hardness of the composited coating is increased to 3H level. The surface contact angle is changed from 67.1° to 93.2°. In a word, the composited 0.5wt%OAPPS-BN-AT/EP coating has excellent adhesion, impact resistance, flexibility and heat resistance, which showed a promising potential in the field of anti-corrosion.