Exopolysaccharides (EPS) as anti-corrosive additives for coatings
article
Exopolysaccharides (EPS) are a class of renewable polymers that show interesting anti-corrosive properties and could potentially be used as an alternative for zinc phosphates. When combined with a waterborne styrene-acrylic polymer dispersion (SA-1), exopolysaccharides were shown to give an improvement in the anti-corrosive performance. Electrochemical studies show higher charge transfer resistance (Rct) values for the SA-1/EPS combinations as compared to the SA-1 itself suggesting that in the presence of EPS less corrosion took place. Outdoor exposure test shows that the presence of EPS188 gave good corrosion protection for up to a year when exposed under marine conditions. The distribution of EPS modification throughout the coating was made visible using Confocal Laser Scanning Microscopy
and indicated that EPS was distributed rather homogeneously. A working mechanism was proposed in which the carboxylic acid groups on the oxidised EPS form a complex with iron ions formed by the anodic reaction and this insoluble complex forms a protective layer between the coating and metal. The results in this paper show that by using renewable polysaccharide additives the anti-corrosive coating performance can be improved.
and indicated that EPS was distributed rather homogeneously. A working mechanism was proposed in which the carboxylic acid groups on the oxidised EPS form a complex with iron ions formed by the anodic reaction and this insoluble complex forms a protective layer between the coating and metal. The results in this paper show that by using renewable polysaccharide additives the anti-corrosive coating performance can be improved.
TNO Identifier
462000
ISSN
03009440
Source
Progress in Organic Coatings, 75, pp. 224-230.
Publisher
Elsevier
Collation
7 p.
Pages
224-230
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