Research on the Durability Evaluation and Failure Mechanism of Modified Polyurethane Coating for the Roof of Crude Oil Storage Tanks

Abstract The top coating of an external floating roof crude oil storage tank is highly prone to failure due to the easy water accumulation on the tank top and strong ultraviolet radiation. In this paper, a modified polyurethane coating was subjected to cyclic aging experiments according to the methods specified in ISO12944 - 6. The anti - aging performance of the modified polyurethane coating was studied by using the changes in macroscopic and microscopic morphologies, glossiness, color difference, adhesion and other indicators before and after the experiment. In addition, the failure behavior and mechanism of the coating were investigated by means of Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy/energy - dispersive spectroscopy (SEM/EDS), and electrochemical impedance spectroscopy (EIS). The results show that the modified polyurethane coating exhibits excellent anti - aging performance compared with traditional anti - corrosion coatings. However, the corrosion spread width is large, and the coating needs to be further improved to enhance its resistance to mechanical damage.