Design of enhanced mechanical properties by interpenetrating network of 3D printing dual-curing resins

Photopolymer resins with low viscosity are used in 3D printing for accuracy and process performance, although the major of their mechanical strength does not meet engineering requirements. In this work, we develop a photothermal dual-curing 3D printing resin with high mechanical strength and great toughness through the construction of interpenetrating network (IPN) structures composed of epoxy resin and bio-based methacrylate. The nonbonded energy and the number of hydrogen bonds per unit volume of the IPN structures are found to increase for a certain ratio of epoxy resin and bio-based methacrylate based on the molecular dynamic simulation, which are the key factors in the mechanism for improving the mechanical properties of dual-curing resins. The resulting dual-curing resin exhibits satisfactory mechanical properties at the viscosity of 803 mPa s: A tensile strength of 60 MPa and a flexural strength of 119 MPa are comparable to the epoxy resin, and an impact toughness of 12.9 kJ cm-2 and an elongation at break of 7.9% are founded to increase by 126% and 316%, respectively, as compared to the epoxy resin. The dual-curing resin also shows high 3D printing precision, relatively low water absorption and volume shrinkage, excellent thermostability, and great dielectric properties. The results presented in this paper provide a promising route to develop high-performance 3D printing materials.