Photocurable Elastomer Composites with SiO₂-Mediated Cross-Links for Mechanically Durable 3D Printing Materials

Abstract

To realize a wide range of applications using three-dimensional (3D) printing, it is urgent to develop 3D printing resins with exceptional features such as enhanced mechanical properties. Herein, we developed a series of photocurable elastomers incorporating a cross-linkable SiO2 nanofiller for digital light processing (DLP) 3D printing. Methacrylate-functionalized polyether polyol was synthesized for the photocurable elastomers. To enhance the mechanical properties, surface-modified SiO2 nanoparticles (NPs) were incorporated into photocurable elastomers; this led to the generation of interfacial cross-links between the polymer matrix and the NPs surface. The effect of SiO2 NPs on the photocuring behavior of the elastomers was monitored using a photocuring depth test. Due to the small size and exceptional dispersibility of surface-modified SiO2 NPs, suppressed severe light scattering, photocuring process, and 3D printing with a large amount of SiO2 NPs (up to 20 wt %) were evenly conducted. Furthermore, tensile testing and hardness measurements were performed to reveal the effect of SiO2 NPs on the mechanical properties of 3D-printed structures. The elastomer containing 20 wt % of cross-linkable SiO2 NPs was observed to enhance the tensile strength and hardness by 87 and 52%, respectively, overcoming the limitation of conventional composites. To evaluate the resilience of the various photocurable elastomers containing SiO2 NPs, continuous tensile loading–unloading tests were conducted. Furthermore, 3D printing of various structures was carried out using a DLP printer, and their compression and bending deformation was monitored in terms of the amount of SiO2 NPs. Under high pressure, 3D-printed structures containing cross-linkable SiO2 NPs were observed to exhibit mechanical durability without defects. Therefore, this study proposes a promising method for the development of photocurable elastomers, which can be utilized in practical 3D printing applications.