생분해성-난분해성 플라스틱 블렌드로 제작한 3D 프린터 시제품의 생분해

Biodegradation of 3D-Printed Biodegradable/non-biodegradable Plastic Blends

Thermoplastic blends are applied for three-dimensional (3D) printing to obtain improved functionality. While thermal, chemical, and mechanical properties of 3D-printed blends were typically examined, biodegradability of the 3D-printed plastics rarely has been the focus of research. In this study, we evaluated the biodegradation behavior of 3D-printed prototypes fabricated from various plastics and blends, including biodegradable polylactic acid (PLA), poly (3-hydroxybutyrate) (PHB) and non-biodegradable high-density polyethylene (HDPE), polypropylene (PP). Letter-shaped specimens were prototyped using a fused deposition modeling (FDM) printer with various filaments (PLA, PHB, HDPE, PP, PLA/HDPE, PLA/PP, PHB/HDPE, PHB/PP, and PLA/PHB), and their printing performance and optimal printing conditions were evaluated. FDM 3D printing of HDPE and PP has been problematic due to thermal shrinkage, warping deformation, and poor adhesion. We demonstrate that PLA/HDPE and PLA/PP blends are printable, and PLA/PHB blends exhibit outstanding printing performance. Biodegradation tests on 3D-printed prototypes were performed employing a systematically designed respirometry by simulating i) controlled composting and ii) the aerobic aqueous environment. PHB100 and PLA50/PHB50 showed significant biodegradation in controlled composting and an aerobic aqueous tests (86.4, 85.0% and 73.3, 32.3%, respectively) in 50 days, while PLA100 and other biodegradable/non-biodegradable blends (PLA/HDPE, PLA/PP, PHB/HDPE, PHB/PP) barely biodegraded. The immiscible biodegradable/non-biodegradable plastic blends revealed evidence of partial degradation and even antagonism to biodegradation, most likely due to phase separation and barrier effect. Taken together, although PLA/HDPE, PLA/PP, and PLA/PHB blends could be promising and sustainable 3D-printing resources with some notable improvements in mechanical properties and printing performance, their diverse biodegradation behavior indicate the need for adequate post-consumer management for sustainable 3D-printing.