The influence of plasticizers on the process and properties of digital light processing 3D printed silica glass

Digital light processing (DLP) 3D printing technology fabricates silica glass parts with complex structures using a layer-by-layer curing approach. In this process, plasticizers directly influence the fluidity of the slurry, printing quality, debinding and sintering properties. However, the impact of plasticizers on DLP 3D printed silica glass remains underexplored. This study systematically investigates the influence of plasticizers on key fabrication processes in 3D printed silica glass. The results show that higher diethyl phthalate (DEP) content increases slurry viscosity while decreasing the crosslinking degree of monomers and the flexural strength of the green body. Despite these adverse effects, the green body achieves superior surface quality with elevated DEP content. Plasticizers reduce the extent of thermal decomposition in green bodies within a narrow temperature range. During debinding, DEP incorporation promotes the development of interconnected channels and pores, facilitating the evacuation of gaseous products and minimizing defect formation. Dense amorphous silica glass can be obtained at a temperature of 1300 °C. The 3D printed silica glass exhibits significant improvements in terms of density, surface quality and optical properties when the DEP content is between 10 wt% and 20 wt%. This research offers an important theoretical foundation for developing photopolymerization 3D printing technology applicable to silica glass.