(637g) Epoxidized Technical Kraft Lignin As a Component for High-Performance Anticorrosive Coatings

Anticorrosive coatings production represents one for the largest markets, since they are applied in all scales to steel infrastructures in order to provide protection against corrosive agents. Nowadays, one of the major challenges in this field is the development of new sustainable resins. Indeed, fossil-based resins almost entirely constitute the base of anticorrosive coatings, threating the integrity of the environment when they are released over time. In this study, with the aim of obtaining a sustainable resin, softwood Kraft lignin was successfully epoxidized through a consistent and scalable procedure. The presence of epoxy groups was confirmed via spectroscopic analysis (NMR and FTIR). Then, a series of formulations were prepared by mixing fossil-based and lignin-based resins, and the films were cured under ambient conditions on steel panels. The structural properties of the cross-linked coatings were investigated by FTIR and scanning electron microscopy (SEM). Thermal and viscoelastic properties were analyzed by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Anticorrosive and adhesion properties were examined by salt spray exposure and pull-off adhesion test, respectively. The presence of lignin-based resin improved the performances as well as increased significantly the bio-based content of the coatings. The results achieved pave the way for a potential scalable process towards new lignin applications.

The authors would like to gratefully acknowledge the Knut and Alice Wallenberg Foundation through the Wallenberg Wood Science Center (WWSC) at KTH Royal Institute of Technology, and the Nordic Five Tech Alliance for funding supports.