Novel camphene/photopolymer solution as pore-forming agent for photocuring-assisted additive manufacturing of porous ceramics

This study proposes camphene/photopolymer solutions as a novel pore-forming agent for the photocuring-assisted additive manufacturing of porous ceramics. Unlike conventional techniques using molten camphene, solid camphene can be directly dissolved in the photocurable monomer hexanediol diacrylate (HDDA) at room temperature, which can then crystallize with a dendrite-like morphology based on phase separation at lower temperatures. This unique approach allows alumina suspensions to solidify at ―2 °C and then effectively be photopolymerized using a digital light processing engine, resulting in camphene-rich crystals surrounded by photopolymerized alumina/HDDA walls. Sintered samples exhibited a highly porous structure, with the pores created after the removal of the camphene-rich crystals. Two different pore sizes were obtained in the lower and upper regions of a single layer, due to a decrease in the solidification rate along the building direction, although their porosities were similar (～ 52 vol%). The porous samples exhibited a compressive strength of ～ 265 MPa.