Improved properties of coating binder from palm oil-based oleic acid by copolymerizing with acrylate monomers

Coating binders were synthesized from palm oil-based oleic acid and acrylate monomers. At the first stage, a macromer was prepared from condensation reactions of palm oil-based oleic acid, glycerol, and phthalic anhydride. At the next stage, the macromer was copolymerized with selected acrylic monomers, methyl methacrylate, and butyl acrylate. Changing the ratio of the palm oleic acid macromer with both the acrylate monomers in the synthesis gave a higher conversion rate and solid content. From 13C-NMR, the structure of the macromer retained the cis position of –C=C– as in the original oleic acid under the relatively high-temperature polycondensation reaction. The results showed that the thermal stability of the macromer improved after modification with the acrylate monomers. The coatings prepared with the highest ratio of the acrylate monomers exhibited better overall coating properties. The modified macromer coated on mild steel panels showed excellent adhesion, pencil hardness, and water and salt resistances. The Tafel polarization curves showed that the corrosion rate in NaCl solution decreased significantly when the acrylate monomer content was increased.