Polythiourethane composite film with high transparency, high refractive index and low dispersion containing ZnS nanoparticle via thiol-ene click chemistry

In recent years, high refractive index polythiourethane materials have attracted increasing attention. In this study, the soft segment part of conventional polyurethane was replaced by ethylenedithiol, and a series of nanocomposite films containing Mercaptoethanol (ME) capped ZnS NPs were prepared by UV curing after the synthesis of the bifunctional linear prepolymer with hydroxyethyl acrylate as capping agent and trifunctional prepolymer with trimethylolpropane triacrylate as sulfhydrylate capping. ZnS NPs were well dispersed in the resin system, and the transmittance of the film decreased with the increase of ZnS content, but it did not float much and still has 80% transmittance at 40%. The addition of ZnS had a significant improvement on the refractive index. The RI of the system without the addition of particles was less than 1.5, the system with 40% was greater than 1.6. It was worth noting that the Abbe number was almost greater than 30, which was in the category of low dispersion. Graphical abstract Preparation of highly refractive polythiourethane-ZnS composite film by “click” chemical reaction