Rapeseed oil gallate-amide-urethane coating material: Synthesis and evaluation of coating properties

Abstract

The present manuscript describes the synthesis of urethane (ROGAU) coating material from Rapeseed oil (RO), Gallic acid (GA) and Toluylene-2,4-diisocyanate [TDI], for the first time. The reaction was accomplished in the following steps: (i) amidation of RO, producing diol fatty amide, HERA, followed by (ii) gallation reaction of HERA with GA, resulting in RO-based gallate amide (ROGA). The structural elucidation by FTIR and NMR confirmed the insertion of amide and ester moieties in the ROGA backbone. To add applicational value to ROGA, it was then derivatized by urethanation reaction with TDI to develop ambient temperature-cured ROGAU, as a corrosion protective coating material. ROGAU coatings were scratch resistant, well-adherent, and flexible to a considerable extent and showed good corrosion resistance performance toward saline medium (3.5 wt% NaCl). ROGAU coatings can be safely used up to 200°C.

Keywords

• rapeseed oil
• gallic acid
• polyurethane
• coatings