SiOC(N) Cellular Structures with Dense Struts by Integrating Fused Filament Fabrication 3D Printing with Polymer-Derived Ceramics

Great advances have been made in various 3D printing methods for ceramics. Fabrication of Si-based ceramics using polymer-derived ceramics (PDCs) is gaining popularity. Using this route, preceramic polymers can be shaped in the polymer state and then pyrolyzed to produce different types of ceramics. Cellular ceramics can be manufactured using this technique. Herein, the novel fabrication of cellular ceramics with a two-step process using PDCs is reported. First cellular structures are 3D printed with fused filament fabrication (FFF) using thermoplastic polyurethane and impregnated with preceramic polymer polysilazane. Second, pyrolysis of the impregnated structure produces a self-similar ceramic cellular structure. The impact of 1) catalysts, 2) curing environment, and 3) pyrolysis sequence optimization to form cellular ceramics with fully dense SiOC(N) struts are systemically evaluated. The resultant custom ceramic components can tolerate operating temperatures of 1500 degrees C and can be manufactured for less than 5% of the cost of competing methods. The ceramic material is shown to be biocompatible and promotes fast cell adhesion. Finally, early-stage cell activation on the SiOC(N) structure is shown to be tunable by adjusting the porosity with this 3D printing to mimic the bone tissue geometry for bone regeneration.