Location: Plant Polymer ResearchTitle: Bacterial exopolysaccharides for corrosion resistance on low carbon steel Author
|Bucur, Claudiu - Toyota Central Research & Development Laboratory|
Submitted to: Journal of Applied Polymer Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/17/2017
Publication Date: 3/24/2017
Citation: Finkenstadt, V.L., Bucur, C., Cote, G.L., Evans, K.O. 2017. Bacterial exopolysaccharides for corrosion resistance on low carbon steel. Journal of Applied Polymer Science. doi: 10.1002/app.45032.
Interpretive Summary: Lactic acid bacteria produce dextran-like polymers that are usually considered a liability in the food and agriculture industries; however, ARS scientists in Peoria, Illinois, discovered that some of these polymers inhibit corrosion of low-carbon steel. We have identified and patented four different polymers that inhibit corrosion, can be applied with current spray technology in very thin films (nanoscale), and display limited self-healing when damaged and wet. Production of the bacterial polymer can be accomplished with current equipment as well. Corrosion causes economic and material losses at a staggering rate, and this discovery will decrease these losses and improve the durability of steel infrastructure.
Technical Abstract: Corrosion is a global issue that affects safety and economics. There is an increasing demand for bio-based polymers for industrial applications and production of polymers by micro-organisms is especially attractive. This work reports on the electrochemical and physical properties of exopolysaccharides produced from lactic acid bacteria and their suitability as anti-corrosive coatings. Bacterial exopolysaccharide coatings protected low carbon steel from corrosion by reducing ionic diffusion rates and maintaining a relatively passive metal-coating interface. The data suggest the kinetics of film deposition are fast (<5 min) and there is little excess (loosely bound) material when hydrated. Measurements show thin (50 nm) coatings that when exposed to water exhibit self-repairing phenomenon. The corrosion protection offered by the coatings is reported as the corrosion rate calculated from the corrosion current obtained by electrochemical impedance and polarization spectroscopy.