Synthesis of Polyfunctional Castor Oil-Based Polyurethane Acrylate by the Auxiliary of Thiol-Ene Click Reaction

In this paper, we report a synthetic method to prepare vegetable oil-based polyurethane acrylate (PUA) resin, which can be used in photo polymerization coating, ink and other fields. First, the mercaptoethanol was introduced into castor oil via thiol-ene photo-click reaction with UV irradiation, forming polyhydroxy compounds, then we added the isocyanate acrylate, which was obtained by the reaction between hydroxypropyl acrylate (HPA) and isophorone diisocyanate (IPDI), into polyhydroxy compounds, the molar ratio of HPA and IPDI is 1:1. Finally, we get the castor oil-based polyurethane acrylate. Different functional acrylate can be obtained by adjusting the hydroxyl content. Furthermore, the structure and performance of Polyurethane acrylate was confirmed by FT-IR and TG. The water absorption and adhesion of synthetic polyurethane acrylate were tested. Meanwhile, the thermal stability was studied. The results indicated that the thiol-ene addition reaction was proceeded and compared to our previous studies, the properties of cured film are greatly improved, especially the hardness and thermal stability.