In this study, we evaluated the biodegradability of 3D-printed prototypes fabricated from 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 blend filaments (PLA/HDPE, PLA/PP, PHB/HDPE, PHB/PP, and PLA/PHB). FDM 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 test (86.4, 85.0% and 73.3, 32.3%, respectively) over 50 days, while PLA100 and other biodegradable/non-biodegradable blends 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 3D-printing resources, their diverse biodegradation performance requires adequate post-consumer management for sustainable 3D-printing.

Graphical abstract

Filaments extrusion and FDM printing process.

Do Hyun Lee

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