High-performance UV-curable Polyurethane Acrylate Resins Derived from Low-iodine Woody Plant Oils

In this study, we report the preparation of high-performance UV-curable polyurethane acrylate (PUA) materials from two low-iodine woody plant oils, rubber seed oil (RSO) and wilsoniana seed oil (WSO). First, high-functionality oil-based PUA oligomers were synthesized via isocyanate polyurethane reaction between hydroxylated woody plant oils, isophorone diisocyanate, and pentaerythritol triacrylate, in which the hydroxylated oils were obtained by ring opening of epoxidized oils with ethylene glycol. Chemical structures of the obtained RSO-based and WSO-based PUA oligomers (RSO-PUA and WSO-PUA) were confirmed by FT-IR and H-1 NMR. The H-1 NMR results indicated that the RSO-PUA and WSO-PUA oligomers reached a C = C functionality up to 20.9 and 15.2 per triglyceride, respectively. The obtained oil-based PUA oligomers were then blended with hydroxyethyl methacrylate (HEMA) to form UV-curable resins and ultimate properties of the resultant materials were investigated. The oil-based PUA materials showed excellent performance after UV-curing. For example, the RSO-based PUA film containing 30% of HEMA demonstrated the tensile strength of 22.2 MPa, tensile modulus 1.78 GPa, glass transition temperature of 118.1 degrees C, adhesion of 2 grade, pencil hardness of 2H, and flexibility of 2 mm. In general, the developed woody plant oil-based PUA resins are very promising to be applied as green UV-curable coatings.