A novel, hyperbranched polysiloxane (HBPSi) is successfully synthesized via hydrolysis using γ-methacryloxypropyl trimethoxysilane (A174) and deionized water, under catalyst-free conditions. Then, for the first time, the HBPSis are used to modify a 3D printing light-curing epoxy resin. Thermogravimetry results showed that the addition of HBPSi improved the heat resistance of the epoxy resin. Experimental results also show that the addition of HBPSi simultaneously improves tensile strength, elongation at break, and impact strength. In particular, a great increase in the toughness of 3D printing light-curing epoxy resin is observed, with 5 wt % HBPSi loading. These results indicate that the HBPSi containg OH– and Si–O–Si can be potentially effective at improving the performance of the 3D printing light-curing epoxy resin. This investigation suggests that the method proposed herein is a new approach to develop the performance of 3D printing light-curing epoxy resin for cutting-edge industries, especially those that simultaneously have outstanding thermal resistance and toughness.

The surface of nano-TiO2 was modified by a silane coupling agent KH570, and the photosensitive resin was modified by blending the modified nano-TiO2 with three-dimensional (3D) printing light-curing resin. The modified nano-TiO2 powder was characterized by infrared spectrum, X-ray diffraction, contact angle test, and scanning electron microscope. The effects of different content of modified TiO2 on the viscosity, curing shrinkage, tensile strength, elongation at break, hardness, thermal stability, and cross-section morphology of 3D printing photosensitive resin were studied. The results showed that the mechanical properties of epoxy resin were improved obviously after surface modification with a silane coupling agent. When the mass fraction of TiO2 was 1.5%, the mechanical properties of the molded parts were the best. The tensile strength, impact strength, and elongation at break were increased by 51.1, 43.8, and 10.8%, respectively, and the hardness value was maintained at 81–83 HD. The addition of modified TiO2 can improve the heat resistance of the epoxy resin. When the amount of TiO2 is 1.5%, the T 50%, T max, and carbon residue rate of the epoxy resin are increased by 3.44°C, 6.34°C, and 25.3%, respectively.