Development of tri-functional biobased reactive diluent from ricinoleic acid for UV curable coating application

Renewable based materials have come out as an environmentally friendly alternative to petrochemical based materials due to their sustainability, lower carbon footprints and often lesser price. A tri-functional acrylate monomer was synthesized from Ricinoleic acid (RA) and used as biobased reactive diluent along with an oligomer for a UV curable coating application. The ricinoleic acid was modified by using sodium methoxide catalyzed amidation with diethanolamine and converted into fatty amide based triol. This synthesized ricinamide triol (RTO) was further reacted with glycidyl methacrylate in presence of triphenylphosphine. The synthesized products were fully characterized by FTIR, GPC and end group analysis. The chemical structure of RTO and ricinamide triacrylate (RTA) was elucidated from 1H NMR, 13C NMR spectroscopy. In comparison, the commercial triacrylate was examined. The influence of addition of reactive diluents on the viscosity of oligomer with varying concentrations up to 10–30 wt% was studied using rheometer. The UV curing behavior of coatings was estimated by FTIR. The UV cured coatings was further characterized by DSC, XRD, and TGA analysis. The UV curing coatings were evaluated to determine the mechanical, physical and solvent resistance properties. The Biobased content, gel content and water absorption property of UV cured coatings was also examined.