Castor oil-based UV-curable polyurethane acrylate resins for digital light processing (DLP) 3D printing technology

In this work, a novel UV-curable polyurethane acrylate (PUA) oligomer was developed from castor oil (CO). Reaction monitoring and structures of the PUA oligomer were characterized by Fourier transform infrared (FTIR) and H-1 nuclear magnetic resonance (NMR). Subsequently, a series of UV-curable resins were prepared by combining PUA with different reactive diluents, and their effect on thermal and mechanical properties was investigated. From the overall characterization trend, it was observed that the formulation containing trimethylolpropane triacrylate (TMPTA) showed the highest mechanical strength and thermal stability. Whereas the formulation containing isobornyl acrylate (IBOA) showed the least performance, and dipropyleneglycol diacrylate (DPGDA) showed properties ranging between TMPTA and IBOA. Furthermore, incorporating 1% TiO2 into the formulation increases the resin's viscosity and mechanical properties without disturbing its thermal stability. This work offered a simple method to prepare vegetable oil-based high-performance PUA resins that could be used in the 3D printing industry for general-purpose prototyping applications to make architectural models, automotive components, and medical components.