Development of anticorrosive two pack polyurethane coatings based on modified fatty amide of Azadirachta indica Juss oil cured at room temperature – a sustainable resource

Abstract

We report the modification of Azadirachta indica Juss oil (renewable source) fatty amide by the piperazine molecule to develop a new polyol. Two pack polyurethane (PU) coatings on mild steel plates were prepared by reacting newly developed polyol with toluene diisocyanate (TDI) at room temperature. Spectral studies of Azadirachta indica Juss oil based fatty amide and piperazine modified fatty amide were carried out using spectroscopic techniques to confirm the modification. The prepared resins were also characterized by end group analysis such as amine and hydroxyl values. Anticorrosive properties of the prepared PU coatings were examined by immersion test in an aqueous salt solution. The thermal stability of coatings was studied by TGA. Other coating properties such as gloss, scratch hardness, adhesion, flexibility, impact resistance and chemical resistance were evaluated using standard methods. It was observed that the presence of nitrogen containing piperazine moiety in the back bone of the PU chain shows better anticorrosive properties compared with the Azadirachta indica Juss oil fatty amide based PU coatings.