Epoxidized technical Kraft lignin as a particulate resin component for high-performance anticorrosive coatings

Deterioration of steel infrastructures is oftencaused by corrosive substances. In harsh conditions, theprotection against corrosion is provided by high-performancecoatings. The major challenge in this field is tofind replacements for the fossil-based resins constitutinganticorrosive coatings, due to increasing needs tosynthesize new environmentally friendly materials. Inthis study, softwood Kraft lignin was epoxidized with theaim of obtaining a renewable resin for anticorrosivecoatings. The reaction resulted in the formation ofheterogeneous, solid, coarse agglomerates. Therefore,the synthetized lignin particles were mechanicallyground and sieved to break up the agglomerates andobtain a fine powder. To reduce the use of fossil fuelbasedepoxy novolac resins in commercial anticorrosivecoatings, a series of formulations were prepared andcured on steel panels varying the content of epoxidizedlignin resin. Epoxidized lignin-based coatings used inconjunction with conventional epoxy novolac resindemonstrated improved performance in terms of corrosionprotection and adhesion properties, as measuredby salt spray exposure and pull-off adhesion test,respectively. In addition, the importance of size fractionationfor the homogeneity of the final coatingformulations was highlighted. The findings from thisstudy suggest a promising route to develop highperforminglignin-based anticorrosive coatings. ; QC 20240923