Two-dimensional nanocontainers with sheet structure endow epoxy resin with triple effects of oxygen barrier, anti-corrosion and corrosion inhibition

Abstract

Previous coatings or barrier films have failed to focus on the combined application of oxygen barrier and long-term corrosion protection. In this paper, a two-dimensional sheet filler KCB with triple functions of anti-corrosion, oxygen barrier and corrosion inhibition was prepared by growing cerium dioxide (CeO2) on the surface of natural nanocontainer kieselguhr and adsorbing benzotriazole (BTA). Then applied KCB to epoxy resin (EP) to obtain EP/KCB composite coating. The hydroxyl group of CeO2 improves the compatibility of EP with KCB. The hydrogen bonding between BTA and KC, and the adsorption at the Ce3+ defect sites turn KCB into an impermeable physical barrier, which can form an inert protective film at the interface after the BTA later release. The experimental data show that the O2 GTR value of the EP/KCB5 composite coating is reduced by 35.88 % compared with that of the PET film. The |Z|0.01 Hz value both are as high as 1011 Ω·cm2 after immersed in 3.5 wt% NaCl solution for four months and with 3.0 MPa pure oxygen for 7 days, showing excellent potential for long-term oxygen resistance and corrosion protection. EP/KCB5 composite coating has an adhesion up to 11.63 MPa. Moreover, the BTA released in KCB chelates with the metal substrate to form an inert protective film, which further improves the anti-corrosion performance of the composite coating and has a certain self-healing ability. In summary, the EP/KCB5 composite coating shows excellent comprehensive properties, providing a new solution for long-term oxygen barrier and corrosion protection.