Preparation and characterisation of water-based aluminium pigments modified with SiO2 and polymer brushes

• To prevent corrosion, aluminium is coated with SiO2.
• Further, to improve dispersiveness, PAA brushes are grafted on it.
• Hydrogen generation is retarded, confirming improvement in corrosion resistance.
• The PAA brushes improve dispersiveness in aqueous media significantly.
• Thus-coated aluminium should find wide use in water-based paints and inks.

In order to improve the corrosion resistance and dispersiveness of aluminium pigments in aqueous media, SiO2-coated aluminium was prepared and polyacrylic acid brushes were grafted on its surface. A decrease in hydrogen generation indicated that the corrosion resistance was improved by the SiO2 coating, while the polyacrylic acid brushes improved dispersiveness. The d(0.5) (particle size of 50% volume fraction) values of the SiO2-coated aluminium sample and that of the sample with the polyacrylic acid brushes grafted on it were 41 μm and 29 μm, respectively. We believe that thus modified aluminium will find use in water-based paints and printing inks.

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