Modification of SiO₂ Nanoparticle-Decorated TiO₂ Nanocomposites with Silane Coupling Agents for Enhanced Opacity in Blue Light-Curable Ink

To improve inkjet printing performance, surface single encapsulation of nano-TiO 2 particles has widely been reported. However, surface single encapsulation has a limited effect on improving the inkjet printing performance of nano-TiO 2 particles. In this study, SiO 2 nanoparticle-decorated TiO 2 (SiO 2 /TiO 2 ) nanocomposites modified with silane coupling agents were obtained by a two-step method to improve the inkjet printing performance. The effects of different Na 2 SiO 3 concentrations on the morphology, particle size, and opacity performance of SiO 2 /TiO 2 nanocomposites were studied. The results showed that when the molar ratio of Na 2 SiO 3 to TiO 2 was 0.06:1, SiO 2 /TiO 2 nanocomposites showed the best dispersibility and the best opacity performance. Then, the effect of different silane coupling agents on the properties of curing films was investigated. The results showed that the properties (opacity performance, tensile properties, thermal stability, and color fastness) of the KH570-SiO 2 /TiO 2 nanocomposite curing film were greatly improved. The characteristic peaks in the Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) confirmed that SiO 2 nanoparticles were anchored at the nano-TiO 2 particle surface via Si–O–Ti bonds, and silane coupling agents were successfully grafted onto the SiO 2 /TiO 2 nanocomposite surface via Si–O–Si/Si–O–Ti bonds. In addition, it was verified that the double bonds of KH570-SiO 2 /TiO 2 nanocomposites participated in the photopolymerization of oligomers/monomers by FTIR.