| 초록 |
Porous ceramics are now expected to be used for a wide variety of industrial applications from filtration, absorption, catalysts and bone scaffolds to lightweight structural components. During the last decade, tremendous efforts have been devoted for the researches in bone tissue engineering, as it can resemble the anisotropic porous structure of natural cancellous bone and produce outstanding mechanical properties. This study intends to review these recent progresses of ceramic-based 3D printing techniques. In particular, a camphene/ceramic fiber was deposited at a room temperature using 3D plotting system, newly developed as a SFF technique, which can produce three-dimensional ceramic scaffolds with porous structure. In this novel technique, a continuous ceramic/camphene filament with a diameter of 1 mm, comprised of a pure camphene core and a frozen alumina/camphene shell, was produced by the co-extrusion process and then deposited in a layer-by-layer sequence using a computer-controlled 3-axis moving machine. Unidirectionally aligned macrochannels (~400um in diameter) and three-dimensionally interconnected pores (several tens of micrometers in size) in the ceramic walls were created by removing the camphene core and the camphene dendrites formed in the ceramic/camphene region, respectively. Additionally, last study demonstrates the versatility of 3-dimensional ceramic/camphene-based extrusion (3D-Ex) using a frozen ceramic/camphene body as a feedstock and 3-dimensional ceramic/camphene-based co-extrusion (3D-CoEx) using a pure camphene core and a frozen ceramic/camphene shell, which can produce porous ceramic scaffolds with a biomimetic macro/micro-porous structure and macroporous ceramic scaffolds consisting of highly elongated microporous hollow filaments, respectively. Three-dimensionally interconnected macro pores could be constructed through the deposition of frozen ceramic/camphene filaments in a layer-by-layer sequence at a stacking sequence of 0o/90o, while, at the same time, aligned micro pores could be created in ceramic frameworks as the replica of camphene dendrites that had been extensively elongated by the extrusion of a frozen ceramic/camphene body. The overall porosity of porous ceramic scaffolds and fraction of micro pores formed in ceramic frameworks could be controlled by adjusting initial ceramic content in ceramic/camphene slurries. Also, the compressive strength of porous ceramic scaffolds could be tailored by controlling their overall porosity |
