3D printing of dual-cure benzoxazine networks

Abstract

A novel 3D printing formulation based on a multifunctional benzoxazine (BOX) monomer possessing both photo and thermally polymerizable functional groups is reported. Printing formulation viscosity is readily tuned using a monofunctional-acrylate reactive diluent to enable Stereolithography (SLA) 3D printing. In the primary curing step, the printing formulation is UV-cured by SLA 3D printing to prepare accurate parts on the millimeter size scale. The 3D printed parts are then heated in the secondary curing step to activate a thermally initiated BOX ring opening polymerization. Dynamic mechanical analysis demonstrated that the 3D printed parts exhibit a single Tan δ peak after both the primary UV-cure and secondary thermal cure steps, suggesting the two polymerizations behave as one crosslinked network. The unique dual-cure strategy demonstrated in this research utilizes both photo and thermally initiated polymerizations to expand the library of materials available for 3D printing applications.