High-performance bio-based UV-curable coatings with tunable mechanical and tribological properties

Three ultraviolet (UV)-curable coatings on AISI 1015 steel with a bio-based content of up to 82 % were formulated as sustainable alternatives to conventional coating resin systems. The compositions, based on acrylated epoxidized soybean oil (AESO) and isobornyl (meth)acrylates (IBOMA/IBOA), were characterized using FTIR, UV–VIS spectroscopy, tensile testing, dynamic mechanical analysis (DMA), thermal gravimetric analysis (TGA), adhesion testing, wettability, and tribological analysis through scratch and pin-on-disk tests. Mechanical evaluation revealed tunable behavior, varying from stiff to compliant, with Young's moduli ranging from 1.2 to 0.4 GPa and elongation at break from 3.7 % to 8.6 %, indicating a transition from hard to ductile. The glass transition temperature ranged from 22 to 71 °C, while the optical transmittance exceeded 92 % in the wavelength range of 420–700 nm. All coatings preserved their structural integrity under progressive loads of up to 20 N. The formulation with the highest AESO content, thanks to its softer and more flexible network, exhibited improved adhesion and enhanced resistance to abrasive wear, with no substrate exposure under dry sliding conditions. These results highlight that bio-based UV-curable systems can simultaneously deliver mechanical adaptability, optical clarity, and good tribological stability, offering a viable pathway toward sustainable high-performance coating materials. • Bio-based UV coatings were formulated from plant-derived acrylate monomers. • Tunable modulus of 0.4–1.2 GPa and elongation of 3.7–8.6 % were achieved. • Coatings endured progressive abrasive loading up to 20 N without failure. • Coating with the highest vegetable oil acrylate content reduced wear rate by 45 %.