Preparation and properties of UV-curable di-functional sulfur-containing thioacrylate and thiourethane acrylate monomers with high refractive indices

We synthesized UV-curable di-functional sulfur-containing thioacrylate and thiourethane acrylate with high refractive indices. The structures of monomers were confirmed by nuclear magnetic resonance spectroscopy (NMR) and Fourier transform infrared spectroscopy (FT-IR). The formulation of UV-curable coating film was prepared by thioacrylate monomer, thiourethane acrylate monomer, α-hydroxy-α-methylpropiophenone as the photoinitiator, and bisphenol A epoxy acrylate as the oligomer. The cured coating films were investigated using thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), Taber abraser tests, transmittance, and refractive index. The value of refractive index for all coating films increased after UV-curing. Transparent, photocurable coating films with high abrasion resistance were prepared. The monomers showed high refractive index. The refractive indices of synthesized monomers (thioacrylate and thiourethane acrylate monomer) are 1.623 and 1.577, respectively.