Lignin-Reinforced Thermoset Coatings for Extreme Conditions of Temperature and Pressure

Corrosion of equipment and pipelines in the oil and gas industry, particularly under high pressure and high temperature (HPHT) conditions, necessitates high-performance anticorrosive coatings derived from fossil binder materials and energy-intensive pigments. With the aim of integrating sustainable biomaterials into industrial coating systems, this study investigates the stability of Kraft lignin-reinforced epoxy novolac (LEN) coatings under HPHT. These extreme conditions were simulated in a non-stirred batch reactor with gas (N2 and CO2 mixture), hydrocarbon (aromatic para-xylene), and seawater (SW) phases at 100 bar pressure. Incorporating lignin particles in epoxy novolac coatings inhibited the hydrocarbon softening of the binder network, preventing the reported underfilm corrosion at HPHT. The findings demonstrated that LEN coatings can withstand HPHT conditions up to 120 °C. Above this temperature, the presence or absence of CO2 affected the barrier properties of LEN coatings in the SW-exposed zone. A life-cycle assessment highlighted the environmental impact of LEN coatings for sustainable coating applications.