Performance of UV curable lignin based epoxy acrylate coatings

Curing schematic diagram of lignin based epoxy acrylate resin. [Display omitted] •Lignin based EA oligomers (LBEA) with various lignin content were in situ synthesized.•Epoxy value and acid value were measured to determine the reaction conditions.•The performance of LBEA coatings was much improved than that of EA coating. In this work, lignin based epoxy acrylate (LBEA) oligomer with various percentage of lignin was in situ synthesized with epoxy and acrylic acid. The first step was the etherification between lignin and epoxy to produce lignin based epoxy (LBE), and the second step was the esterification between LBE and acrylic acid to synthesize LBEA. Epoxy value and acid value were measured to determine the reaction conditions of the two steps, respectively. The structure of prepared LBEA was confirmed by Flourier infrared spectroscopy (FTIR) characterization. LBEA coatings were prepared through ultraviolet radiation curing method. The gel content, chemical resistance, mechanical properties and thermal properties of coatings were investigated. It was found that the mechanical properties and chemical resistance were much improved than those of epoxy acrylate (EA) resin with the addition of lignin. Thus, lignin was proved to be a new promising biomaterial which could be applied in biobased EA coatings.