Silicone Elastomer with High Elongation at Break Used in Digital Light Processing 3D Printing

3D printing silicone elastomer has demonstrated great potential in diverse areas such as medical devices, flexible electronics and soft robotics. It is of great value to investigate how to improve the mechanical properties, including tensile strength and elongation at break of printed parts. In this work, a light curing system that can be applied in silicone elastomer 3D printing is explored, which is composed of vinyl terminated polysiloxane as the macromer and thiol containing polysiloxane as the crosslinking agent, and a chain extension reaction is also introduced into this light curing system via the addition of the chain extender dithiol molecules, and a light curing system accompanied with chain extension is designed and realized based on the thiol-ene click reaction mechanism. After reinforced with silica fillers, the obtained light curing system can endow the light curing silicone elastomer with better mechanical properties under the condition of a lower viscosity of the precursor, the tensile strength and elongation at break can reach 525.5 kPa and 601%, respectively. This light curing system provides a feasible method to solve the contradiction between the viscosity of the precursor and the mechanical properties of the light curing elastomer in the digital light processing (DLP) 3D printing field.