Study of coating performance of bio-based hyperbranched polyester polyol/graphene oxide composites in PU-coating

The present work reports, two types of bio-based hyperbranched polyester polyols (HyBPs) were synthesized from castor oil-based polyols (monoglyceride and fatty amide) and 2,2-bis(hydroxymethyl) propionic acid. The structure of HyBPs was determined by FTIR and NMR. Graphene oxide was prepared from graphene powder by the Hummer's method and characterized by XRD and FESEM. Further, the composites of HyBPs and graphene oxide nanoparticles in various weight percentages (0, 0.1 and 0.5% of graphene oxide with respect to HyBPs weight) together with isophorone diisocyanate (maintaining an OH:NCO ratio of 1:1.2) were prepared. The coating properties like crosscut adhesion, impact, gloss and scratch resistance of HyBPs polyurethane graphene oxide nanocomposite coatings were studied. The chemical resistance of coatings was determined by immersion test in 0.5N NaOH, 0.5N HCl, 3.5% NaCl, water and xylene. Surface morphology, thermal stability and electrochemical properties of the coatings were recorded by FESEM, TGA and potentiostat, respectively. [GRAPHICS] .