Effect of carbon nanofillers on anticorrosive and physico-mechanical properties of hyperbranched urethane alkyd coatings

Abstract

Abstract Effects of three geometrically different carbon nanofillers (CNs) namely carbon black, multiwall carbon nanotubes and graphene on the anticorrosive and physico-mechanical properties of hyperbranched alkyd resin (HBA) based coatings were investigated. Hyperbranched urethane alkyd coatings (HBUA) were made by curing the synthesized resin with hexamethylene diisocyanate trimer. All the carbon fillers are treated with a surfactant (Nonidate-P40) to achieve a uniform dispersion. The addition of surfactant treated CNs to HBUA resulted in a significant improvement in the corrosion resistance and mechanical properties in comparison with the neat HBUA coating. Among the HBUA/CN composites, the improvement in corrosion resistance was found to be superior in the case of HBUA/graphene composite. Transmission electron microscope (TEM) clearly indicated the uniform dispersion of carbon nanofillers in the resin. The uniform dispersion of CNs is believed to originate from an interaction of π electron clouds of CNs with the delocalized π electrons of Nonidet-P40 and H-bonding interaction between Nonidet-P40 and the HBA. This type of interaction does not disturb the π electron clouds of MWCNTs as opposed to chemical functionalization strategy.