Lowering the curing shrinkage of epoxy acrylate‐based photosensitive resins through nano‐TiO2 particle with surface grafted by thiol‐terminated hyperbranched polymer

Abstract UV curing three‐dimensional printing (3DP) technology has been developing rapidly due to its high molding accuracy and low cost. However, the curing shrinkage rate of the existing UV curing 3DP materials is still high. The use of inorganic particles to reduce the curing shrinkage of 3D printing materials has received more and more attention in recent years, but the poor dispersibility of inorganic particles in the photosensitive resins has not been effectively solved. In this paper, nano‐TiO 2 particles were treated by KH570 in advance and the surface of which were grafted by thiol‐terminated hyperbranched polymer (THBP), hereby THBP@TiO 2 was obtained. The results showed that by incorporating of 5 wt% THBP@TiO 2 , the volume shrinkage rate of epoxy acrylate (EA)‐based photosensitive resins decreased from 8.95% to 4.18%. The THBP@TiO 2 combined the anti‐shrinkage mechanism of thiol‐based hyperbranched polyester with that of and inorganic nanoparticles. Otherwise, surface grafting of THBP may effectively improve the dispersibility of nano‐TiO 2 particles in EA‐based photosensitive resin by reducing the nano‐TiO 2 particles surface energy, and increase the load transfer capacity. The impact strength of 5 wt% THBP@TiO 2 modified photosensitive resin increased from 11.2 to 18.1 kJ/m 2 .