Park Byung Kyu, Hwang David J, Kwon Dong Eui, Yoon Tae Jun, Lee Youn-Woo
Institute of Advanced Machine and Design, Seoul National University, Seoul 151-744, Korea.
Department of Mechanical Engineering, State University of New York, Stony Brook, NY 11794, USA.
Nanomaterials (Basel). 2018 Jul 27;8(8):575. doi: 10.3390/nano8080575.
Multiscale structured polymers have been considered as a promising category of functional materials with unique properties. We combined rapid prototyping and gas foaming technologies to fabricate multiscale functional materials of superior mechanical and thermal insulation properties. Through scanning electron microscope based morphological characterization, formation of multiscale porous structure with nanoscale cellular pores was confirmed. Improvement in mechanical strength is attributed to rearrangement of crystals within CO₂ saturated grid sample. It is also shown that a post-foaming temperature higher than the glass transition temperature deteriorates mechanical strength, providing process guidelines. Thermal decomposition of filament material sets the upper limit of temperature for 3D printed features, characterized by simultaneous differential scanning calorimetry and thermogravimetric analysis. Porosity of the fabricated 3D structured polylactic acid (PLA) foam is controllable by suitable tuning of foaming conditions. The fabricated multiscale 3D structures have potential for thermal insulation applications with lightweight and reasonable mechanical strength.
多尺度结构聚合物被认为是一类具有独特性能的很有前景的功能材料。我们结合快速成型和气体发泡技术来制造具有优异机械和隔热性能的多尺度功能材料。通过基于扫描电子显微镜的形态表征，证实了具有纳米级气孔的多尺度多孔结构的形成。机械强度的提高归因于CO₂饱和网格样品内晶体的重排。还表明，高于玻璃化转变温度的后发泡温度会降低机械强度，从而提供了工艺指导。通过同步差示扫描量热法和热重分析对长丝材料的热分解进行表征，确定了3D打印特征的温度上限。通过适当调整发泡条件，所制造的3D结构聚乳酸（PLA）泡沫的孔隙率是可控 的。所制造的多尺度3D结构具有用于隔热应用的潜力，具有轻质和合理的机械强度。
