Aqueous Biopolymeric Coatings for Corrosion Protection of Galvanized Steel* - poster

Arman Dastpak1, Philip Ansell2, Justin R Searle3, Mari Lundström1, and Benjamin P Wilson1

1Hydrometallurgy and Corrosion, Department of Chemical and Metallurgical Engineering (CMET), Aalto University, P.O. Box 16200, Aalto, Espoo FI-00076, Finland.
2Materials Research Centre, College of Engineering, Swansea University, Bay Campus, Crymlyn Burrow, Swansea SA1 8EN, Wales, U.K.
3SPECIFIC, College of Engineering, Swansea University, Bay Campus, Crymlyn Burrow, Swansea SA1 8EN, Wales, U.K.

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* The poster presentation is based on a recently published study, available at https://doi.org/10.1021/acsami.1c08274

This study investigated the utilisation of waste materials from the Biorefining industry for the preparation of colloidal lignin particles (CLPs) through solvent-exchange in water. A solution of kraft lignin in diethylene glycol monobutyl ether (150 g/L) was utilized for the synthesis of CLPs, which demonstrated a coalescing characteristic during drying. The prepared aqueous dispersion of CLPs was combined with a suspension of TEMPO-Oxidized cellulose nanofibrils at different concentrations (1 g/L or 2 g/L), and the aqueous mixture was used for potentiostatic electrophoretic deposition on galvanized steel at different potentials (0.5 V or 3 V). The resultant biopolymeric coatings were dried (21 °C for 12 hours and oven drying at 105 °C for 1 hour) and characterized by electrochemical impedance spectroscopy (EIS) during 15 days immersion in 3.5 wt.% NaCl. It was found that the coatings enhanced the charge transfer resistance of the steel substrate for the whole duration of the test. Such coalescing lignin particles could potentially form the basis for the preparation of sustainable lignin-based aqueous coatings for the corrosion protection of steel surfaces.