Autonomous Healing of Smart Coating Materials for Corrosion Protection of Oil and Gas Assets

Abstract Most assets in the oil and gas sector that use metal substrates e.g., pipe supports, or structures are susceptible to corrosion problems primarily because of continual exposure of damaged areas to severe environmental conditions. The proliferation and merging of corrosion issues can cause catastrophic failure of materials, resulting in a reduction in the service life of the materials. To avoid these issues, it is crucial to protect the scratch or minor crack area as quickly as possible so that it does not spread too far. In this case, self-healing as a smart material can be applied to the coating system to repair coating damage instantaneously. Self-healing works in multiple functions where it can be used to protect against corrosion and at the same time heal the damaged area itself. In this research, the experimental work includes boronic ester (BE) and polyurethane (PU) synthesis, BE-PU coating specimen preparation, characterization and performance analysis. BE was introduced in the polyurethane (PU) and applied as an additional coating layer to the existing coating system according to PETRONAS technical standard (PTS) requirement with a thickness of approximately 300-400 μm. The healing performance of the scribed coating at room and 60°C with 80% humidity level was initially evaluated using 3D profilometer microscopy and electrical impedance spectroscopy (EIS). Corrosion resistance performance was evaluated by performing long term 3000 hours salt spray and 4200 hours cyclic UV. The mechanical performance or compatibility of the self-healing with current coating system was also assessed using a pull-off adhesion test and abrasion test. The assessment of the scratched BE-PU self-healing using 3D profilometer microscopy demonstrated remarkable healing efficiency of more than 85% and has excellent corrosion resistance performance through salt spray and cyclic UV test. In addition, BE-PU self-healing showed significant adhesion efficiency with more than 300 psi and abrasion performance.